# Installing your first off grid solar system 101



## budgetprepp-n

Hi 
Come with me and learn a little about installing your first free standing off grid solar system.
One month ago I knew nothing about solar system and now I know what I have read but I still know 
nothing about actually doing it. Within two weeks I hope to have my system up and running. I will be 
posting pictures and explaining what parts are called and what they do in a easy to understand hillbilly language.

In another post I referred to an inverter as a converter. I was quickly corrected by a forum member.
And he went on to explain what each of them did in a plane and simple manner. 
That's productive criticism and it is priceless and appreciated that's how we learn.

I will show every part used and tell what it does and what it is called. 
this will be a somewhat smaller set up mostly for basic needs Lights and water. --maybe a radio, 
tv or computer. for news (shortwave radio?)

I'm hoping that there are a few experts in here that can chime in and point out mistakes 
and help all of us learn with helpful suggestions. 
Don't hesitate to ask questions. Your survival may depend on what you learn here.
I will start posting here on Monday and continuing to post until it's working.

Please keep in mind when you make suggestion keep the language and explanations simple 
This is first grade for me -- Not my fourth year at Yale 
I hope you guys like this idea [/I]

SCROLL DOWN AND CHECK PAGE TWO FOR UPDATES


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## Denver

I too will be waiting to see the replies. I want to go solar, but get really lost on the solar websites. Look forward to seeing what you build.


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## Go2ndAmend

I will also be following this thread. Solar is something I don't know anything about, but I want to change that! I have been thinking of building a semi-portable BOL shelter out of a shipping container and would like to use solar to charge 12V batteries for the lights. Thanks for the thread.


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## Wallimiyama

Lookin' forward to the posts!


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## hayden

One thing to keep in mind is solar is real power. Yes it might only be a 12 volt system but they put out up to about 20 volts. The first half of the system I put up was 2x125 watt panels. I ran the wire inside an interior wall and put in a retro fit wall box and installed a double pole double throw switch. In the up position the power was sent to a grid tie inverter. The middle position was off. The down position sent the power to the charge controller for the battery bank. After awhile I noticed the switch had gone bad. When I removed the wall cover and looked at the switch it was fried. Probably a loose connection had caused it to over heat and burned it badly. Could have started a fire. I have replaced that switch with a 120 volt 3 way light switch. I feel much better about that now. I have left it hanging out of the wall and checked it on a sunny day and it doesn't get warm at all. One other thing I would suggest is to get a kill-a-watt meter. The grid tie system plugs into it and then into the wall outlet. You can see how many watts your system is making and how many kilowatt hours are made. I used to unplug it at the end of the month to reset it to zero but I found that we never have a month were the power doesn't go out at least for a split second. Now I do it everyday at sundown and record the readings on a piece of paper. The meter cost 20-23 bucks on ebay and it will help you set the angle of your panels for the most power. I just added 2x100 watt panels and I'm now making about 2 kilowatt hours a day. So about 60 kwh a month and my average usage is 300 kwh a month. So making about 20 percent of my monthly usage and keeping my batteries topped off. I bought 2 6volt gulf cart batteries that will be wired in series for 12 volts but haven't hooked them up yet. Good luck building your system.


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## paraquack

*Not all switches are rated to handle D*C. Make sure the switch is rated for the maximum possible amperage the system is capable of putting out. Make sure the wire is capable of carrying the maximum possible amperage for the length of the wire. The longer the wire, the "thicker" the wire should be. As an example, in my motorhome, the wire feeding my 400 watt inverter is # 1 welding cable. It is less than 22 feet long. This prevents voltage drop, which can cause heating etc. At least once a year, check the tightness of all connections, especially if you used solid rather that stranded wire. Even in your house(120/220 VAC), you should check the tightness of the wires on your breakers or fuses.


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## HuntingHawk




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## paraquack

What's the mast for, Ham???


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## HuntingHawk

TV antenna so I can watch local radar come a storm. There is also an external radio antenna & cell phone antenna.


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## budgetprepp-n

Hi Guys
Sorry about not posting but I had to go out of state. Ok back to the solar project.
The panels are mounted so tomorrow I'm going to get started on the wiring. So far I have learned that the correct wire to use is called AWG cable I'm going to use a 12 gauge stranded wire. Oh, Also I learned the smaller the number the thicker the wire. The connections used on solar panels are called "MC4" you can cut the cable to the length you need and install your own ends they're easy to find on eBay and so is the cable. 
Tip- When you're installing the ends don't stick the connection end into the MC4 assembly to see if it fits until your ready to install it. It seems as though the wire ends have Barbs on them that insures that the ends won't come loose it also makes them unforgiving. They won't come back out--Trust me on this one. The MC4 adapters connectors are like a two into one wire setup. And you can use two of them if you need a three into one or use three for a four into one and so on. In the picture you can see the white wire hold downs I'm going to use (maybe) they are for house wiring but I think they will work out nicely. I found them while roaming around aimlessly at Home Depot. This is learning experience so if you see something that is incorrect please correct me. 
If there is something that you would like to see a close up of let me know.


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## budgetprepp-n

Ok today I wired up the panels and the controller. 
When you use the adapters to join together the panels it looks a little scary but it's not hard to do at all.
The white wire holders that are for home wiring worked great on the solar wiring it held them down tight the height was just right. The one looks loose but I left them that way until I was all done then I went back
and pulled the wire tight and finished hammering them down.


I got thinking about what hayden said about needing a meter to see what was going on so I
left some slack in a place where I am going to wire in a watt meter to show what the panels
are putting out. The meter is ordered but might take a while to get here.


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## budgetprepp-n

From what I have read there are basically two types of controllers 
1-- pulse width modulator or PWM
2-- maximum power point tracking or MPPT
Everything I have read says that the MPPT will give you about 30% more charging power from the panels so
I went with the MPPT and I got a 30 amp. I guess if you get an amp that is too big it will work fine and you can add
more panels on later. But if it is too small (too low of amp rating) you might fry something. -bigger is better



As for batteries I have read that the golf cart batteries are the way to go and I was going to do
that until I priced them,,Ouch I did some checking around and I went with a Walmart dual purpose 
battery It even has the amp hour rating right on the battery it's 114 hr @1a I did some checking and for
$99 each it was about as good as your going to get and comes with a 2 year full replacement warranty
they are very heavy.



Here are some hold downs that worked great I not sure but I think they are for some sort of cable
but I'm not sure. They're easy to find at a home improvement store they work great on the smaller
12 volt wire for lights and stuff. After reading haydens suggestion on switches I went with a 20 amp switch.
I will be using the switches later.



This is what the cable hold downs will do. They worked out nice.



Well I hooked up the panels to the controller and batteries and the lights on the controller
came on and says it's working. But with no gauge it's hard to tell how well.
I also ordered a remote gauge that will go on the inside the house that will give me 
lots of information. It plugs directly into the controller.



This is the remote meter I will be installing when it comes in
I'm not sure how long it will take to get it.


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## bayoubowhunter

How do I follow a thread so I can keep up with this ??


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## paraquack

What does the switch disconnect? seems small if it's on the DC side.


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## budgetprepp-n

Before it's over I would like to have two battery packs with two batteries in each pack I was going to use two of these switches to switch from one pack to the other 20 amp was the heaviest I could find.



paraquack said:


> What does the switch disconnect? seems small if it's on the DC side.


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## paraquack

You need to have a switch that will handle the amp for the load or even higher. Remember that if you're switching the DC to an inverter pulling 3 amps AC, that going to be over 30 amps DC. DC switches handling 100 amp can be found at marine supply and frequently can handle to battery banks individually or can put them together in a combined bank. Check these for $30 to $40, if you need a switch to handle high load DC. I'd make sure the inverter is shut off before turning off the DC switch.
BLUE SEA SYSTEMS m-Series Mini Battery Switches at West Marine


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## Inor

budgetprepp-n said:


> Before it's over I would like to have two battery packs with two batteries in each pack I was going to use two of these switches to switch from one pack to the other 20 amp was the heaviest I could find.


I have a question, and I ask this out of pure ignorance: why is it advantageous to have two banks of batteries with a switch between them? Why not wire the banks in parallel (without a switch) so you are charging them at the same time and drawing from them at the same time? I would think that would double your watts without having to pay attention to when one bank is full (or empty) to switch over to the other bank.


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## budgetprepp-n

So far everything I have is 12 volt but I have been thinking about a inverter for TV, computer and maybe some 
other small items. What size inverter do you think I should get? How many watts? 

It's going to be a while before I have the parts to go any further and finish this project. (about 2 weeks)
For now it's up and running I have lights running off my solar setup and I'm happy with that for now. 
The basic setup is done I will be back to this thread when I get parts. Just a few add ons to tweak the system.
And I will check back to see if there is any questions

I was thinking about starting on another project until parts come in. I am going to put in a complete water system
with hot/cold running water. I think if I have independent lights and running water I'll be ahead of the curve when SHTF.
I hope to use a 6 gallon propane water heater and 12 volt water pump out of a travel camper.


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## budgetprepp-n

Inor said:


> I have a question, and I ask this out of pure ignorance: why is it advantageous to have two banks of batteries with a switch between them? Why not wire the banks in parallel (without a switch) so you are charging them at the same time and drawing from them at the same time? I would think that would double your watts without having to pay attention to when one bank is full (or empty) to switch over to the other bank.


Well just sort of a reserve set up I just like the idea of having a fully charged set of batteries in reserve just in case. 
These batteries are good for holding a charge while in reserve. -Just a preference- If a battery gives me a problem
I can switch over to the other set until I have time to figure out what's wrong (without being in the dark)

If you take a look at the wiring on the solar panels you can see that they are wired in so I can unhook one at a time if
I have a problem and need to replace or check one (I have two spares) hope for the best and plan for when TSHTF 
everything is wired 12 volt just to keep it simple


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## Inor

budgetprepp-n said:


> If you take a look at the wiring on the solar panels you can see that they are wired in so I can unhook one at a time if
> I have a problem and need to replace or check one (I have two spares) hope for the best and plan for when TSHTF
> everything is wired 12 volt just to keep it simple


I did not notice that until you pointed it out. Good thinkin'! Great thread - thanks!


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## paraquack

From my own experience, I prefer the golf cart battery. It is designed to do exactly what is used for. It has very thick plates and gives you a relatively constant supply of power at low amperage (like in an RV or camping trailer) for a long time (in hours). The "Max Start" battery in the photo is designed somewhere between a golf cart battery and car battery. It has thinner plates and is capable of a burst of high amperage for a short time to start an engine. because it has thinner plates, they don't usually last as long as a golf cart battery which is designed for "DEEP CYCLE" operation. The 2 golf cart batteries in my RV are 11 or 12 years old. Last year I was getting well over 50% of their capacity. It may cost more for golf cart batteries, but I believe it is a matter of pay me now, or pay me later. At my local Sam's club they have the size it use: Duracell® Golf Car Battery - Group Size GC2 for $83 each.


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## budgetprepp-n

paraquack said:


> From my own experience, I prefer the gold cart battery. It is designed to do exactly what is used for. It has very thick plates and gives you a relatively constant supply of power at low amperage (like in an RV or camping trailer) for a long time (in hours). The "Max Start" battery in the photo is designed somewhere between a golf cart battery and car battery. It has thinner plates and is capable of a burst of high amperage for a short time to start an engine. because it has thinner plates, they don't usually last as long as a golf cart battery which is designed for "DEEP CYCLE" operation. The 2 golf cart batteries in my RV are 11 or 12 years old. Last year I was getting well over 50% of their capacity. It may cost more for golf cart batteries, but I believe it is a matter of pay me now, or pay me later. At my local Sam's club they have the size it use: Duracell® Golf Car Battery - Group Size GC2 for $83 each.


Do you know what the amp hours rating is on this battery? It might be worth a drive to a Sam's club for me.
I could use them for my second battery pack. Are they 12 volt?


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## paraquack

Most golf cart batteries are 6 volt, but there are some 8 volt one around. 
Specifications
 *20 amp hour rate:215*
 5 amp hour rate:157
 6 amp hour rate:156
 BCI Group Size:GC2
 Contents:ONE EACH
 Minutes at 25 amps:395
 Minutes at 75 amps:105
 Volts:6
To use these, you need to connect the negative post of one battery to the positive post of the second battery. This hook up is called "series" and you add the voltage of the first battery to the second battery, hence 12 volts. This is the standard type of hook up for most large RVs. The diagram below shows the 2 most common hook ups with golf cart batteries
View attachment 1919


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## PaulS

Remember that there is a minimum and maximum charge voltage for lead acid batteries. The minimum is 12.8v to 13.2 volts and the maximum charge voltage is 14.2 to 15.5 volts. You also need at least .5 amps per cell so size your PV grid to charge your batteries or buy your batteries to fit your grid.


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## paraquack

Although it doesn't look like it, are you going to tie into the grid to sell you unused power back to the power companies to make a few bucks? If so, be warned that your system could be damaged by an EMP or geomagnetic storm when transient surges get into the grid.


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## budgetprepp-n

paraquack said:


> Although it doesn't like it, are you going to tie into the grid to sell you unused power back to the power companies to make a few bucks? If so, be warned that your system could be damaged by an EMP or geomagnetic storm when transient surges get into the grid.


 No I'm going to keep my system off grid,,,It's for when shtf and no one needs to know I have it


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## paraquack

Are you going to try and protect the installation from possible EMP?


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## budgetprepp-n

PaulS said:


> Remember that there is a minimum and maximum charge voltage for lead acid batteries. The minimum is 12.8v to 13.2 volts and the maximum charge voltage is 14.2 to 15.5 volts. You also need at least .5 amps per cell so size your PV grid to charge your batteries or buy your batteries to fit your grid.


I tried the system out last night I ran all the lights (11 of them ) for about 11-12 hours and they did fine. The controller has a light
that blinks when the batteries are fully charged. The light was blinking by noon today Maybe 3 100watt panels are a lot for the two 
batteries but the controller shuts the charging off when they are fully charged so I guess that doesn't hurt anything. 
These lights are really bright but they don't seem to use much electricity they are 12 volt.
I must admit I am curious to see what will happen when I hook up an inverter to run the TV and computer.
It would seem that the PV system should be able to charge two more batteries without any problem.
I'm trying to figure out what size inverter to get any suggestions? I am just going to run a tv and few small items

The sunshine was bright today good day for charging, I was told that the output was 7 amps per panel on a good day 
21 amps total. I'm really looking forward to installing a gauge to see what the system is doing.


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## paraquack

If the 120 volt AC appliance shows amp load, multiply by 120 for watts needed from the inverter. Add up the total watts you need at any one time. The inverter should be a little larger than that (10-15%). Let's say the TV is 75 watts, the DVD player is 50 watts and fan to keep cool takes 75 watts, add a 50 watt light bulb, totals 250 watts. Now that's only a tad over 2 amps at 120 VAC. But it will take over 20 amps from the battery (250 watts divide by 12 volts = 20.83 amps) if the inverter were 100% efficient. In reality it'll probably suck 23 -24 amps from the battery each hour.

I need to warn you about another problem that faces RV owners. Batteries also have a problem with sulphation. Check this site for explanation. Lead-acid batteries maintenance & restoration: Lead acid batteries sulphation....

Another problem is overheating and evaporation of water from the acid. Check water leve every week and only use distilled water. My golf cart batteries have lasted a long, long time thru proper maintenance.


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## budgetprepp-n

paraquack said:


> Are you going to try and protect the installation from possible EMP?


That's a good question, I would like to but I'm not sure how. From what I understand the panels, Batteries and controller could
fry from an EMP. One good thing is I am a long ways off from any target area. any suggestions?
I picked up some spare parts but still,,,,,,,,,,


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## PaulS

Your computer has a power supply that is rated in watts - to get it to work on an inverter you need a sine-wave inverter (more expensive than a modified sine wave inverter) rated at twice that listed watts. The TV is the same story you need at least twice the wattage that is listed for it. If it is listed as amps then multiply that by 120 and then double it for the size of your inverter. Most inverters will not run flourescent lighting and medium to large motors need up to ten times their rated amps during startup. (for that 12 amp drill (1440 watts) you need up to a 14000 watt inverter to operate it.


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## StarPD45

Definitely get a bigger inverter than you think you will need.
You know you will be adding things to it, even if now you think you won't


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## budgetprepp-n

Hey guys a quick update,, The remote meter that I ordered seems to have gotten stuck in customs (china stuff) Nuts,,,
But I have been using the system and so far it is working out great. I can run all the lights at night and the next day by
11 or noon the batteries are back up to full charge. (love it) I'm thinking that I will add the two batteries but not have 
them on a switch I'll just make it one big pack. So I'm pretty much done other than a control panel that will assessable
from inside the house. And I will post it when I install it. Oh and I want to install a 12 volt to 110 volt inverter.

PaulS ,, I checked out what you said about the pure sine wave and you're right, That's what I need I almost bought the
wrong kind of inverter. So thanks Now I'm just laying low and waiting on a good deal on a pure sine wave inverter.

StarPD45,, I got thinking about what you said about getting a bigger inverter than I need and I think I will take that advice.
if I get a good deal on used stuff I may get two (spare) and I guess it's like an extension cord if you buy a 25ft cord
you will surely need at least a 30ft. I just got a new gadget called a "kill A Watt" it shows how many watts it takes to 
power 110 volt items I'm going to add them up and go 50 or 100% bigger than what they use on startup.


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## HuntingHawk

My guess would be with two 100watt panels best case scenario would be 10amps to the controller. Alot less if your panels aren't adjustable for latitude. I have to adjust my panels + or - 5 degrees every month to get the most put of them.


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## Montana Rancher

Keep in mind they do make 12 volt florescent fixtures and 12v ballasts to convert your 110 watt units.


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## john10001

Following this thread with great interest and I'm learning a lot.

I'm curious as to why wont they run fluorescent lights? Aren't they low wattage?

The power tools I understand. It seems that you either have to make sacrifices and adjust your energy needs to be self sufficient or you have to shelf out a lot of money and wont see payback for 10, 15, 20 years.


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## PaulS

Fluorescent lights run on very high voltage. There is a transfomer (ballast) required to make them work. The transformer has a very high load at startup. It's a lot like an electric motor but it remains high draw for longer. If you want low wattage bulbs that run on solar or inverter power go with LED bulbs. Just remember that they are the most sensitive devices to EMP that exist - just like your solar cells they are diodes and even a moderate EMP will fry them in an instant.


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## john10001

HuntingHawk said:


> My guess would be with two 100watt panels best case scenario would be 10amps to the controller. Alot less if your panels aren't adjustable for latitude. I have to adjust my panels + or - 5 degrees every month to get the most put of them.


How much do you notice drop in power if your panels are not directly at the sun or a few degrees off? And for example quite a large amount off e.g. facing 90° from solar noon (either direction) and 180° from solar noon? I'd also be very interested to know what kind of difference in power you get in Spring, Autumn and Winter compared to the middle of Summer.


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## budgetprepp-n

john10001 said:


> How much do you notice drop in power if your panels are not directly at the sun or a few degrees off? And for example quite a large amount off e.g. facing 90° from solar noon (either direction) and 180° from solar noon? I'd also be very interested to know what kind of difference in power you get in Spring, Autumn and Winter compared to the middle of Summer.


 That's a really good question but I have no answer I just don't know. What I do know is that when I run lots of lights at night
and even keep some on in the day the panels will fully charge the batteries by 11 or 12 even while running a few lights. 
Today is an exception there is heavy cloud cover and no direct sunlight and I'm running 3 bright SMD lights 24-7 and the batteries are
not quite fully charged yet and it's 1:30. I have a gauge that shows how much charge the batteries have using a bar graph
and I am down but only 1 bar (almost full it's gaining) Keep in mind I have three 100 watt panels charging up my batteries.
And all I'm using them for is lights. I'm going to install an inverter to run the tv and computer. we will see how it does then.
Oh,, Also I am going to install an independent water system and it is going to have a 12 volt pump to run 
When the grid goes down I will have lights, shortwave radio, and running water hot and cold. 
That should put me ahead of the curve a little. 
I just went out and checked the remote gauge I just got it doesn't have amps but shows volts it says the panels are putting out 17.9 volts
and the battery has 13.0 volts this morning the battery was at 12.8 
I have a guy that knows a lot about solar panels coming over soon to check out my set up and see if it is working right or where I can
get the most bang for my buck by improving it.


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## haydukeprepper

A good corelation for panel angle is to use your lattitude. 43 degree lattitude = 43 degree angle on the panels.


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## HuntingHawk

But you also need to be able to adjust atleast +15 & -15 degrees for latitude for the sun's angle threw the year.


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## budgetprepp-n

I used this picture earlier in this thread I know it may sound low tec but my panels are adjustable just the pitch not side to side.
I'm planning on using the shadows on the post to set the panels for different seasons through the year.
You can see in this picture that they are set too high. This picture was taken while I was building the
solar setup.

I'm not sure how to say it,, But I would like to make a chart on one of the post with a pointer on the post and go by where the shadow 
of the pointer falls on a chart (numbers on chart) and then have some sort of matching chart and pointer on the panel to set it with.
I thought at different times of the year I would set it for the center of the daylight hours. 
Sort of like a sundial < theres an old idea with a new twist. Come to think of it I might make a post to get
some ideas and suggestions on how to do this. 
The mind of the collective is a powerful tool.

Resistance is futile


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## HuntingHawk

This $5 gauge is my friend. It has a magnetic strip on the back. It will give you the true angle you need to set your panels to. Whatver your latitude, you will need to be able to adjust the panels +15 & -15 degrees threw the year. This only needs done once a month though.

Angle Finder w/ Dial Gauge


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## budgetprepp-n

HuntingHawk said:


> This $5 gauge is my friend. It has a magnetic strip on the back. It will give you the true angle you need to set your panels to. Whatever your latitude, you will need to be able to adjust the panels +15 & -15 degrees threw the year. This only needs done once a month though.
> 
> Angle Finder w/ Dial Gauge


Thanks thats just what I need. The posts on the deck are level so using this tool I should be able to measure the angel 
of the shadow on the post then sit this on the panel and match the exact angel. The length of the mounting post are 
adjustable so setting the correct angle should be easy to adjust. I could drill new holes for adjustment if necessary. The project is almost done.
I guess this is just sort of tweaking it. HuntingHAWK my hat is off to you Thanks.

I could mark witch hole to use for the different seasons right on the post next to the hole.


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## HuntingHawk

Big advantage of that gauge is it adjusts to the horizon. So it doesn't care if anything is level as it will self level.


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## HuntingHawk

You have a single axis solar system being able to adjust for the latitude of the sun for the year. According to a gov't website, for me it makes a difference of 19.3% efficiency of the panels. Yours should be about the same. For 5-10 minutes once a month to adjust the panel angles I'll take that increase in a heartbeak.

I don't believe marking the deck will work. Different months the sun will come from different angles so marking the deck at one time you will be alittle off. For that reason, I use the gauge everytime I adjust panels. But, you would only have to use the gauge on one panel then match the position of the others.


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## HuntingHawk

The controllers I choose to use I can select to monitor the amperage from the panels. So I can see an immediate increase in the amperage from the panels when I adjust the panel angles.

A friend in La has a grid tie system of 10KW of panels. Has had it 1.5 years. Its fixed angle. After some convincing, he is looking to reconfigure his mounting to use ram jacks to adjust the panel angles. That is an additional about 20% he will get paid from the electric company per month for the next 20-30 years. I've no idea how much he gets from the electric company per month, but he's decided being able to adjust that huge solar rack would be well worth his time & investment.


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## HuntingHawk

Order one of these from amazon:
2 Wire Blue DC 4.5-30V LED Panel digital display Voltage Meter Voltmeter By BuyinCoins 

This eliminates your thought of two battery banks. Just by the voltage of the batteries you will know how much power you have. 12.8VDC from the batteries & you are at full charge. 12.3VDC & you better get to conservation mode. 12.1VDC & best turn off any non essentials.

With my controller I can select to monitor battery voltage so have no need of one. Controller actually gives percent of battery charge based on the sampled voltage.


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## PaulS

Within 10 degrees the panels lose a minimum efficiency but for every 10 degrees beyond that the inefficiency doubles.
ie: 20 degrees off the sun -10%; 30 degrees off the sun -30% (-10+ -20); 40 degrees off the sun -70%

The efficiency loss increases to 45 degrees and the the decrease reduces to near zero at 90 degrees off the sun. (the curve charted looks like a 1/4 sine wave with the efficiency starting at 100% and ending at 0%(nearly) There is always some reflected ambient light that hits the panels. Even a partial shaddow can render the panels completely ineffective depending on how they are wired.


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## john10001

paraquack said:


> Are you going to try and protect the installation from possible EMP?


Out of interest, how would you protect this system from an EMP?


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## PaulS

It is nearly impossible to protect a working solar array from EMP. At night you could fold the panels into a metal box that was insulated on the inside and close a cover over it but you would need to have the power cables run in an insulated sheath to keep them from transmitting the power from anEMP to the panels. If they are in use or not sheltered even a moderate EMP will make them totally useless. Diodes are the softest target for EMP and solar panels are just an assembly of diodes.


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## paraquack

An excerpt from 
_Getting Prepared for an Electromagnetic Pulse Attack or Severe Solar Storm_
by Jerry Emanuelson of Colorado Springs, Colorado. He was a part-time electronics consultant and a part-time science writer with an engineering degree from the University of Colorado. Most of his career has involved working at mountaintop radio and television transmitter sites protecting them from lightening damage, etc.
The entire document quoted here is at Electromagnetic Pulse Protection - EMP - Futurescience.com

"If you have something like a 50 watt solar panel, you can store it in a nested faraday cage. Only very rare individuals are going to be able to have full electric power after an EMP attack, no matter what advance preparations they might like to make. In a post-pulse world, though, any amount of reasonably reliable electricity is going to be a real personal luxury.
If you have solar panels that are now in use, you can obtain some EMP protection by proper shielding and transient protection on the wires going to the panels, and by surrounding the panels with aluminum wire cloth (also known as hardware cloth). Aluminum wire cloth is somewhat difficult to find, but it is available. Aluminum wire cloth with openings of 0.4 to 0.5 inches will not only supply a certain amount of EMP protection, but can provide some protection against larger hailstones that can cause damage in severe weather. The wire cloth will block some of the sunlight, but the right size of wire cloth will block less than 15 to 25 percent of the sunlight. If you are making a new solar panel system, some consideration should be given to putting the solar panels inside of a cage made of aluminum wire cloth. This is much easier to do during the original installation. The cage of aluminum wire cloth should completely surround the panels. If your solar panels are mounted just above the ground (as opposed to a rooftop system), don't make the mistake of assuming that the soil below is a mystical perfect ground into which EMP magically vanishes. In a ground-mounted solar panel system, the wire cloth enclosure needs to go underneath the system, preferably underground.
If you plan to use solar cells or battery power, you will probably want to keep a small inverter under shielding. Inverters that can step up ordinary 12 volt DC power to a few hundred watts of household AC are not terribly expensive. For people who own protected photovoltaic solar cells, a number of DC-powered appliances have recently become available. Transient protection (capable of reacting to the fast E1 pulse) must be supplied on the electronic components of any solar cell system, such as the inputs and outputs of charge controllers and inverters. Any wire runs of any length should be shielded.
If you're trying to protect an existing solar panel system, protecting the wiring (even if it is shielded) from transients will require the services of someone knowledgeable in EMP transient protection. In most cases, the most economical solution is to keep spare components, especially inverters and charge controllers, stored under electromagnetic shielding. For information about the EMP sensitivity of solar panels, and more details on the shielding of solar panel systems, see Donald J. R. White's new book, _ EMP - Protect Family, Homes & Community_. That book has chapters with information about EMP protection for even fairly large solar panel systems."


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## budgetprepp-n

Hey a quick update,, everything seems to be working fine I have installed 12volt lights in every room and a few outside
they are all I use now. I leave the regular lights off. I'm curious to see what happens to my electric bill.
It's been sort of high ever since the electric company installed a "smart meter" (smart for them) Also I have decided to 
just have all four batteries tied together without a switch. And I'm not going to put any gauges in the house this system
seems to be pretty much trouble free. I run all the lights a lot at night and if there is any sunlight by 11:00 or 12:00 the 
batteries are fully charged. It seems like the solar panels have really more power than I need for charging just the two batteries.
I been buying one battery a month. I just picked up a 3rd to install I hope to have four batteries buy the end of next month.
I want to install a small inverter to run the TV and computer (pure sine wave) it looks like I'm going to need about a max of
200 watts so I'm going to take the advice someone gave me earlier and go with an inverter that will handle 500 watts1000 surg
I'm going to mount the remote gauges in the room where the controller and batteries are are. I thought the batteries would 
go dead quickly if I ran all the light but the SMD bulbs pull such a small amount of power that they barely faze the batteries. 
I also hope to use this solar setup to run a 12 volt water pump when I need it. In another thread I want to build an independent 
water system with hot and cold running water using stuff out of campers. I will take some pictures of what the battery and controller
setup looks like. Oh, we had a bad storm and the panels set up to be retractable worked out great. (gets them out of harms way) 
I hope to just need to do maintenance on the batteries and not have to mess with the system I'm fine with the way it is working.
We'll see. 
I want to thank everyone that pitched in with ideas and tips on this project it really helped a lot this project is split into two threads 
if you want to see it from the start you need to see the other thread. it's called got some stuff done on the solar system today

DrPepper came up with this design and I used it



adjustable angle and fully retractable they will swing back under the roof for bad storms or deep snow

]


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## budgetprepp-n

Ok,, Well I decided to keep everything in one room and not have switches or remote information boards in the house. 
I plan on adding one more battery but other than that I think I'm done. The system seems to work great it's running all the lights
and according to the information being displayed by the information board I have plenty of juice left over.
Later I'm going to add a inverter and run the TV and computer from the batteries. And soon this will be running a water pump

I never said I was an expert at solar installation but I think I did ok. Thanks everyone for your help
Next Project: I'm going to do a post on building an independent water system with hot and cold water under 
Urban and Rural Survival


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## PaulS

The only thing I can see that needs improvement is to add a plastic tray between the batteries and the wood. The fumes from the batteries and any spilled water will rot that wood away and your batteries will fall. That may short your system and be very expensive.

Good job!


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## HuntingHawk

Keep some distilled water, basting ball, & screwdriver handy for checking the battery fluid levels atleast once a month. A large syringe will work as well as a basting ball for putting the water in the batteries.


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## HuntingHawk

You will not see much at all of a decrease in your electric bill as lights are not a big power draw. But when commercial power is lost & you still have your 12VDC lights is when you really get the payback. Hate scrambling for flashlights just to find the batteries are dead.


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## john10001

PaulS said:


> Even a partial shaddow can render the panels completely ineffective depending on how they are wired.


This is one of the things I am very interested in. I have heard this before and it got me thinking quite a bit.

I am guessing that a partial shadow would affect the output because the cells within the majority of solar panels are all connected in series right? So most Solar Panels will have a set number of cells within them to get them up to the right voltage to be able to charge 12v batteries.

If shade could be a problem for you at certain times of the day on any part of your panels, it may be better to get smaller panels and more of them, than one or two really big panels. The only alternative I can think of would be to have the cells within a panel connected in parallel to avoid this?


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## john10001

PaulS said:


> It is nearly impossible to protect a working solar array from EMP. At night you could fold the panels into a metal box that was insulated on the inside and close a cover over it but you would need to have the power cables run in an insulated sheath to keep them from transmitting the power from anEMP to the panels. If they are in use or not sheltered even a moderate EMP will make them totally useless. Diodes are the softest target for EMP and solar panels are just an assembly of diodes.


How about just take the EMP hit but have a load of spare diodes that are protected in a faraday cage? This way after the event you can just crack open the panels and replace the diodes?


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## budgetprepp-n

HuntingHawk said:


> You will not see much at all of a decrease in your electric bill as lights are not a big power draw. But when commercial power is lost & you still have your 12VDC lights is when you really get the payback. Hate scrambling for flashlights just to find the batteries are dead.


 I don't know,,,,, It dosen't take a lot to run a light bulb but they are a good part of the bill because they get used so much.


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## HuntingHawk

About 54KWH to run a 75watt light bulb for 30 days at 24 hours per day.

On the other hand, a 15watt 12VDC bulb would take 720AH to run 24 hours per day for 30 days. Figuring 5 good hours of sunlight per day, a 100 watt panel would provide enough power to the batteries to power that light.


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## PaulS

HuntingHawk said:


> About 54KWH to run a 75watt light bulb for 30 days at 24 hours per day.
> 
> On the other hand, a 15watt 12VDC bulb would take 720AH to run 24 hours per day for 30 days. Figuring 5 good hours of sunlight per day, a 100 watt panel would provide enough power to the batteries to power that light.


HuntingHawk,
A 15 watt bulb will use 360 watt/Hr per day - x 30 days = 10800 watt/hrs or 10.8 KWH.
A 75 watt bulb uses 1800 watt/Hr per day and x 30 days = 54 KWH
Now this assumes that the watt rating of the bulb is the input value at the bulb. 
The 75 watt bulb uses .625 Amps at 120 VAC while the 15 watt bulb uses 1.24 Amps at 12 VDC (nominally)


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## budgetprepp-n

OK,, I'm using 12 volt SMD bulbs that pull .3 amp So am I better off with the 12 volt bulbs and no inverter to 120 VOLT?
Is this correct? AMPS X VOLTS= WATTS ? SO,,, .3 AMPS X 12 VOLTS=3.6 WATTS? 


My panel shows AMPS but not watts Sorry but I don't speak techinezz but I'm going to take a shot at this,,
WATT X 24 = Watt Hrs per day? so,,,,, 3.6 WATTS X 24 = 86.4? and 86.4 x 30 = 2592 watt/hrs or 2.6 KWH ?
Am I even close?

I have three 100 watt panels and will have a total of four batteries that are rated 114hr @ 1 amp 
starting with a full charge how long can I run one light @ .3 amps? 126.6 hrs or 5days 4 hours?
I do appreciate the math lesson ,, I don't know the formulas ,,,,,,,, help?


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## PaulS

Yes, your math seems to be accurate. Watts
The formula for watts, volts and amps is ------------
......................................................... Volts | Amps

watts / amps = volts; watts / volts = amps; volts x amps = watts

hours x average watts = watt hours

Batteries can only be discharged to 20% of full charge and survive a "normal life". It takes 25% more power to charge a battery at the same amp rate as it takes to discharge it; If you run 3 amps off the battery for eight hours you need to charge it at 3 amps for 10 hours to bring it back to full charge. Batteries are less efficient at higher amp draws than they are at lower amp draws; A 100 amp hour battery is rated at a timed discharge - 6 hrs, 8 hrs, or whatever - there is no real standard. If I discharge a 100 amp/hour battery at 33 amps it will last for a lot less than three hours. If I discharge it at 10 amps it may last almost 10 hours. If I discharge it at 1 amp it will likely last more than 100 hours. The battery is an electro-chemical generator - not a storage device and the reaction that makes power can only work so fast. It works slower in the cold and better when warm. High amp draws will destroy a battery long before it is discharged. The plates in the battery can warp from the internal heat and short out - sometimes this results in a dead battery and sometimes it results in an explosion that throws acid and plastic all over.

Alternators are, at best, 90% efficient. Motors (electric) are at best 90% efficient (most are less). There are losses in every system and those losses are what you need to be aware of when using alternative energy sources.

First lesson, your 100 watt panels will only produce 100 watts in direct sunlight aimed perfectly at the sun. If they are fixed (non tracking) panels then you will get 100 watts for two hours of sunlight when they are facing the sun perfectly. For a 100% solar day lasting 12 hours you will only get about 33 watt average over that time span. so 1200 x .33 = 400 watt hours. That is almost enough to charge your batteries (from 80% discharge) IF you are not using power from them throughout the day.
If you had the panels mounted on a tracker frame then you could get up to about 90% of the 100 watt rating. For the same day 1200 x .90 = 1080 watt hours. 

Inverters, when used at 80% of their rated power conversion, are about 90% efficient so you lose 10% of your available power. You will always be better off with the fewest connections between the panels and the load but it is hard to find efficient motorized devices that run on the 12 volts that you are producing. Lighting would be better using high efficiency LED bulbs. They require .5 volts at .5 amps per LED. LED lights are made up of several LEDs so no one light bulb will use as little power as the single LED. 

If you have questions that are not mentioned and you can't find answers on your own feel free to ask. The only stupid question is the one that wasn't asked and leads to an injury.


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## budgetprepp-n

I tested the amp draw on the LEDs and on the SMDs 
I'm using all 12 volt stuff and it looks for about the same amount of light I can cut my watt draw in 1/2 by using the
SMD bulbs. have you tried them out?


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## PaulS

The SMD bulbs are the high efficiency LED bulbs. I havent tried them yet because of the cost but as I replace the compact flourescent buls I use now I will probably replace them with the SMD LED bulbs. They have a life of twenty years or so and can put out the same as 150 watt high intensity bulbs using as little as 5 watts.


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## HuntingHawk

I've not tried the SMDs yet either. But just the fact of using any 12VdC lights versus 120VAC threw an inverter is a big power saver. Really critical with a small system.


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## PaulS

HuntingHawk said:


> I've not tried the SMDs yet either. But just the fact of using any 12VdC lights versus 120VAC threw an inverter is a big power saver. Really critical with a small system.


Be sure to add the inefficiency of the inverter into your efficiency calculations. At best the inverter is only 90% efficient and it is usually down near 80%.
Some types of devices are more efficient with higher voltages - like motors - but not so much with lights.

The LED lights are using less than 80% of the power of an incandescent lamp at 110vac and you can get LEDS lights that will operate on 12, 24-28 vdc that are very efficient compared to the 12 volt incanescent lights using as little as 10% of the power for the same amount of light.


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## Prepadoodle

Interesting thread. A few notes...

Solar panels are only good for the rated output at their tested temperature, usually 72 F. The hotter they get, the less they produce. I'm (mentally) playing with the idea of cooling the backs of panels, then using the recovered heat in a domestic hot water preheat tank. If my numbers are right, the gain in panel power would offset the electricity used by the small pump, and the heat would be free.

Batteries like that gas off hydrogen when being charged. If your batteries are stored in a small space, be very careful. 4.1% hydrogen is the explosive threshold, after that, any relay, switch, source of flame, spark, or whatever can make the air in the room go BOOM. Make sure you have good ventilation when you're charging.

Since you aren't connected to the grid, what are you doing with the power generated after the batteries are recharged? Many systems just shunt it to a dummy resistance load, basically pissing it away as heat. It would be nice to find some good use for it. Pumping water would be good, and I'm sure you can think of other uses. I will be in the same boat soon, which is why I'm asking.

Overall, nice set up, and good info. Thanks for the thread.


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## HuntingHawk

If you produce more power from the panels then the batteries can handle, you simply add more batteries.


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## Prepadoodle

No offense intended, but why would you do that?

The OP said his batteries were fully charged by 1 PM, and buying more batteries wouldn't change that. Yes, he would end up with a larger reserve, but the excess power would still be wasted.

I'm planning to install a small 'semi solar' system once we move. This system won't be tied to the grid, and will be used to power our refrigeration and emergency lighting. It will have enough batteries to run for 2 or 3 days, but will generate excess power most of the time. 

I've about settled on 2 solutions to this problem. In the short term, I plan on installing an insulated 'tempering' tank before my domestic hot water heater, and dumping the excess power to an electric heating element. This will reduce the load on my normal hot water heater, and save energy and money.

My long term plan is to build a 2,000 gallon insulated hot water tank and dump all excess power there. Direct solar panels (not photovoltaic) will be the main heat source for this tank. A simple water/water heat exchanger will take heat out of this tank for domestic hot water, and another coil will provide some emergency heating through a water/air exchanger. If all else fails, I'll still have plenty of water stored.


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## budgetprepp-n

Prepadoodle said:


> No offense intended, but why would you do that?
> 
> The OP said his batteries were fully charged by 1 PM, and buying more batteries wouldn't change that. Yes, he would end up with a larger reserve, but the excess power would still be wasted.
> 
> I'm planning to install a small 'semi solar' system once we move. This system won't be tied to the grid, and will be used to power our refrigeration and emergency lighting. It will have enough batteries to run for 2 or 3 days, but will generate excess power most of the time.
> 
> I've about settled on 2 solutions to this problem. In the short term, I plan on installing an insulated 'tempering' tank before my domestic hot water heater, and dumping the excess power to an electric heating element. This will reduce the load on my normal hot water heater, and save energy and money.
> 
> My long term plan is to build a 2,000 gallon insulated hot water tank and dump all excess power there. Direct solar panels (not photovoltaic) will be the main heat source for this tank. A simple water/water heat exchanger will take heat out of this tank for domestic hot water, and another coil will provide some emergency heating through a water/air exchanger. If all else fails, I'll still have plenty of water stored.


No offense taken. I have moved in to my bol and I am peaking it as I live here.I'm still on the grid but sort of winging my place off of it a little at a time. Right now all lights, radios, TV, computers or any small stuff are are solar. And most is 12 volt. And yes I run the lights all night and by 10 to 1 the next day I'm back up to full power and I do plan on adding another battery this week. I'm trying to see where the panels will peak out far as power output goes. One thing I don't have is any refrigeration. Even just a small unit like 3.2 cube would be nice to keep some milk or a little something cold. I plan on having another way of heating the water soon so that electric water heater can get shut down. And there is nothing wrong with having some left over power in storage. P.S. Found a refrigerator and was going to to a post on it tonight looking for input.
If you look at my post you can see everything is home made and ass kicking and getting buy for $1600 in everything I think is excellent for a red neck like me.
And brother if you plan on heating water with electric from a solar panel system you may want to give that a second thought it takes a lot of power to do that. I'm no expert you may want to do a post and and ask some opinions. There's a lot of people in here with good ideas and input that can help you out.


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## Montana Rancher

I'm coming in again late to the conversation but here is what I know

Electric Vehicle or Golf Cart Batteries are easier to lift at 65 pounds each, size 10" x 7" x 11". These are a popular and economical battery for home power systems. This mass produced consumer battery has the best price per amp-hour of any quality battery. Each series string is rated 225 ampere hours.

Trojan L-16RE-B is a 370 amp hour industrial size 6 volt battery weighing 118 pounds. The L16 2 volt is a 1110 amp hour industrial size 2 volt battery weighing 118 pounds as well. Lifting handles are included. They are 30% taller than auto or golf cart batteries, 12" x 7" x 18 inches tall, so they take less floor space for a given battery capacity. Typical life is 8 - 11 years. L16 RE-B and 2 volt are High Capacity models in a red ribbed case with two handles, Trojan's best: Not the industry "standard" L-16 model which has less capacity and less longevity. Both Trojans have a reputation of reliability in home power systems.  2 year full warranty plus 5 more years prorated warranty on the L16 RE-B and 2 volt.

My understanding is the "golf cart batteries" are 2-3 year life expectancy and the L16 batteries are at least 10 years. I was able to purchase locally with a coupon the 16L8 Deka batteries for $215 each including the core charge.

My solar panels are due in Monday, all the other electronics are already here. I will try to remember to take some pictures and show the competed unit. I will be putting 3kw worth of panels up with a 48v system and 8 of the 16L8 batteries I mentioned. Total cost will be $10,500 but I need to buy the metal and weld it up into a frame to mount on my roof, I expect that to be about $400.


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## budgetprepp-n

Montana Rancher said:


> I'm coming in again late to the conversation but here is what I know
> 
> Electric Vehicle or Golf Cart Batteries are easier to lift at 65 pounds each, size 10" x 7" x 11". These are a popular and economical battery for home power systems. This mass produced consumer battery has the best price per amp-hour of any quality battery. Each series string is rated 225 ampere hours.
> 
> Trojan L-16RE-B is a 370 amp hour industrial size 6 volt battery weighing 118 pounds. The L16 2 volt is a 1110 amp hour industrial size 2 volt battery weighing 118 pounds as well. Lifting handles are included. They are 30% taller than auto or golf cart batteries, 12" x 7" x 18 inches tall, so they take less floor space for a given battery capacity. Typical life is 8 - 11 years. L16 RE-B and 2 volt are High Capacity models in a red ribbed case with two handles, Trojan's best: Not the industry "standard" L-16 model which has less capacity and less longevity. Both Trojans have a reputation of reliability in home power systems. 2 year full warranty plus 5 more years prorated warranty on the L16 RE-B and 2 volt.
> 
> My understanding is the "golf cart batteries" are 2-3 year life expectancy and the L16 batteries are at least 10 years. I was able to purchase locally with a coupon the 16L8 Deka batteries for $215 each including the core charge.
> 
> My solar panels are due in Monday, all the other electronics are already here. I will try to remember to take some pictures and show the competed unit. I will be putting 3kw worth of panels up with a 48v system and 8 of the 16L8 batteries I mentioned. Total cost will be $10,500 but I need to buy the metal and weld it up into a frame to mount on my roof, I expect that to be about $400.


Whoa,, Yes please do a string on this set up. I for one would love to see it as it happens. 
My set up is more of a budget survival set up --But it was fun


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## budgetprepp-n

HuntingHawk said:


> If you produce more power from the panels then the batteries can handle, you simply add more batteries.


yea and ad more comfort items to use power from the batteries ,, Sounds right to me .


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## Prepadoodle

budgetprepp-n, as you say, planning to heat your domestic hot water with solar is an expensive proposition. But that's not what I was suggesting.

When your batteries are fully charged and your panels are still generating, I was suggesting you dump the extra power into your hot water heater rather than just waste it. Your system should be sized to match your needs in the winter, when days are short, so you will always have excess power in the summer. Solar panels work better in cold weather, but not enough better to offset the short days of winter.

The National Renewable Energy Lab has their average solar radiation maps online. These maps, developed using data collected over the last 30 years, will show you the amounts of solar radiation (insolation) you can expect in each month across the US. U.S. Solar Radiation Resource Maps

Anyway, as I said, I'll soon be in the same boat as you. It would bug the hell out of me to be generating excess power and have no way to use it, so I will be looking at various ways to make use of it.


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## budgetprepp-n

Prepadoodle said:


> budgetprepp-n, as you say, planning to heat your domestic hot water with solar is an expensive proposition. But that's not what I was suggesting.
> 
> When your batteries are fully charged and your panels are still generating, I was suggesting you dump the extra power into your hot water heater rather than just waste it. Your system should be sized to match your needs in the winter, when days are short, so you will always have excess power in the summer. Solar panels work better in cold weather, but not enough better to offset the short days of winter.
> 
> The National Renewable Energy Lab has their average solar radiation maps online. These maps, developed using data collected over the last 30 years, will show you the amounts of solar radiation (insolation) you can expect in each month across the US. U.S. Solar Radiation Resource Maps
> 
> Anyway, as I said, I'll soon be in the same boat as you. It would bug the hell out of me to be generating excess power and have no way to use it, so I will be looking at various ways to make use of it.


 I hear you but where I live it gets cold (I mean cold in the winter) And that's going to free up some of my solar power.
I plan on mounting a refrigerator against the wall with a stove pipe size hole and screen with ambient temp spring to
control the "inside the frig" temp --but that's another string -- Also I was considering building a used oil heater that would double as a water heater. So at this point if I can just get some refrigeration going for for summer months I'll be set


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