# Input Needed For Solar Setup



## rebeltaz (Sep 29, 2019)

I have wanted to go solar for two decades, but with this virus crap, I decided this was the time to at least dip my toe in the water. I bought a 400watt, 4 panel kit from Lowes that included the four solar panels, wiring and the charge controller. I then bought two 100aHr marine batteries from BatteriesPlus. I already have a couple of 700watt (continuous) inverters. 

Just for testing purposes, I am right now running a stereo, my TV and an LED lamp on the inverter/batteries just to see how long that will hold. 

I would like to install the panels on the roof of my shop, that is about 75 feet away from my home. It faces south and gets full sunlight through out the day.

Here's how I am thinking about running everything: The panels will be connected to the controller about 10-20 feet away. The batteries will be right there at the controller - within 5 feet or so. Here is where I am unsure the best route to go. I had planned on mounting the inverter at the batteries and connecting it to the underground cable and then tapping off that at the house. Or... would it be better to run the 12v from the battery over the underground cable and installing the inverter at the house. 

Running 12v over the cable would give me 12vdc at the house I could use if necessary, but I understand that the voltage drop will be higher than if I run 120vac over that line instead. 

I am not going to be running high current devices - stereo, tv, light or three, battery chargers... basic survival type needs. We're already a simple family, so... 

I've been an electronic technician for 30-ish years, and I know basic electrical wiring/formulas/etc, but installations like this are not my forte... Any help will be greatly appreciated.


----------



## Back Pack Hack (Sep 15, 2016)

Make sure your batteries don't produce flammable gas when charging if you're keeping them inside. Otherwise you may hear a big boom sometime.

Are your inverters modified or pure sine wave? The former isn't too compatible with many electronics.


----------



## rebeltaz (Sep 29, 2019)

Back Pack Hack said:


> Make sure your batteries don't produce flammable gas when charging if you're keeping them inside. Otherwise you may hear a big boom sometime.
> 
> Are your inverters modified or pure sine wave? The former isn't too compatible with many electronics.


Yeah... I'm not going to be charging them in the house. I've been charging them outside in an open air, fenced in shed. The current set is just for quick testing purposes. And yeah, they are modified. I haven't noticed any issues with the tv and the stereo is as old as I am (well, maybe not quite)... I should look for a pure sine wave inverter, I know...

Oh... just remembered... I have a power line conditioner I picked up at a yard sale years ago. Never knew what I was going to do with it... Now I think it might help with the modified sine wave inverters.


----------



## Kauboy (May 12, 2014)

With your limited expected usage, have you looked into switching your equipment to 12VDC? That would remove the worry about where the inverter goes.
There are lots of options if you look for "RV compatible" electronics. You won't suffer the efficiency loss of inverting the voltage either, saving more charge in your batteries and getting a longer drain time. That equates to shorter charge times as well, if you're using less.
It removes the need for the conditioner too.

Just a thought.
I like keeping things simple.
:tango_face_wink:

EDIT: This little 32" number will work with AC or DC: https://www.amazon.com/Supersonic-S...t+tv&qid=1585258345&s=electronics&sr=1-3&th=1


----------



## Chiefster23 (Feb 5, 2016)

If you stick to your original plan, run 120 volts to you house. It requires smaller, less expensive wire than running wire for 12 volts.


----------



## dwight55 (Nov 9, 2012)

Chiefster23 said:


> If you stick to your original plan, run 120 volts to you house. It requires smaller, less expensive wire than running wire for 12 volts.


What he ^^^^ said is gospel. Anything 50 volts and below requires much larger wires and involves a significant power drop over any distances.

Consider putting in a small second panel, . . . send your 120 volt electricity to that second panel, . . . and let that second panel provide power to your lighting, TV, and computer, . . . as well as sockets for your phones, and cell phone chargers.

I did that here in my house, . . . then installed all LED bulbs, . . . so my family can use the regular lights and light switches whenever the power goes down, . . . plus TV, computer, etc.

It's not a perfect system, . . . but it sure beats the devil out of chasing down a flashlight and candles every time the power goes down.

I go into my pantry, . . . flip the bottom switch to the left, . . . plug in the pigtail you see, . . . I'm in business.

I've also got my solar panel for charging the batteries, . . . just have not installed the rascal yet. Its a 2020 project.

May God bless,
Dwight


----------



## Maine-Marine (Mar 7, 2014)

make sure you have batteries that are able to take/ all the panels are giving... IE - if your batteries recharge in a short period of time.. you need more batteries

if it take them too long to charge you need more solar panels

also charge both batteries as if they were one cell IE connect +PLUS to one battery and -NEG of the other (treat all batteries as one large cell) 

pull charge from all batteries connect the opposite + and - as the charge


----------



## Back Pack Hack (Sep 15, 2016)

Maine-Marine said:


> ............also charge both batteries as if they were one cell IE connect +PLUS to one battery and -NEG of the other (treat all batteries as one large cell)
> 
> pull charge from all batteries connect the opposite + and - as the charge


The downside to this is you have much more power losses when converting from 12v to 120v. Converting from 24v, all else being equal, has less losses. And 48v even less. 24 and 48v inverters are not as common, but they can be had.


----------



## rebeltaz (Sep 29, 2019)

Kauboy said:


> With your limited expected usage, have you looked into switching your equipment to 12VDC? That would remove the worry about where the inverter goes.There are lots of options if you look for "RV compatible" electronics. You won't suffer the efficiency loss of inverting the voltage either, saving more charge in your batteries and getting a longer drain time. That equates to shorter charge times as well, if you're using less.
> It removes the need for the conditioner too.


I would like to get some 12v equipment later on, but right now, I'm just working with what I've got. I'm on a limited budget, so I will have to do this a little bit at a time.



Chiefster23 said:


> If you stick to your original plan, run 120 volts to you house. It requires smaller, less expensive wire than running wire for 12 volts.





dwight55 said:


> What he ^^^^ said is gospel. Anything 50 volts and below requires much larger wires and involves a significant power drop over any distances.


That was what I had thought... I just wanted a second (and third  ) opinion. Thanks.



dwight55 said:


> Consider putting in a small second panel, . . . send your 120 volt electricity to that second panel, . . . and let that second panel provide power to your lighting, TV, and computer, . . . as well as sockets for your phones, and cell phone chargers. I did that here in my house, . . . then installed all LED bulbs, . . . so my family can use the regular lights and light switches whenever the power goes down, . . . plus TV, computer, etc. It's not a perfect system, . . . but it sure beats the devil out of chasing down a flashlight and candles every time the power goes down. I go into my pantry, . . . flip the bottom switch to the left, . . . plug in the pigtail you see, . . . I'm in business. I've also got my solar panel for charging the batteries, . . . just have not installed the rascal yet. Its a 2020 project. May God bless, Dwight


I like that... I'll have to do something like that as I go along. Thanks for the idea. No better time than a national shutdown to get around to those "round tuit" projects 



Maine-Marine said:


> ...charge both batteries as if they were one cell IE connect +PLUS to one battery and -NEG of the other (treat all batteries as one large cell) pull charge from all batteries connect the opposite + and - as the charge


I didn't think about that, but that is good advice.



Back Pack Hack said:


> The downside to this is you have much more power losses when converting from 12v to 120v. Converting from 24v, all else being equal, has less losses. And 48v even less. 24 and 48v inverters are not as common, but they can be had.


While that is true, in my case, though, the system is already setup up for 12v, so that is what I have to work with.


----------



## Chiefster23 (Feb 5, 2016)

If you are on a limited budget, consider the following. Run your 120 volt line into a central location inside your house and terminate it at one duplex receptacle. Then use extension cords from there to power the various things you want to run. This method is cheap but inconvenient. With your small battery capacity you will only be running maybe one or two items at a time. (You are gonna find that 200 amp hrs of batteries doesn’t last very long). Extension cords present a tripping hazard but this system is cheap and quick to get up and running. And it works just fine for emergency back up situations. 

I use this method with my 2000 watt Honda generator.


----------



## dwight55 (Nov 9, 2012)

Maine-Marine said:


> ............also charge both batteries as if they were one cell IE connect +PLUS to one battery and -NEG of the other (treat all batteries as one large cell)
> 
> pull charge from all batteries connect the opposite + and - as the charge


This is not necessarily gospel advice.

Batteries can be connected in parallel (+ to + and - to -) and the solar cell connected the same + to + and - to -). It will take longer to charge that way, . . . but you will also get longer output if you do that.

AND the upside is you do not need a 24 volt inverter. A 12 volt inverter works on that system, . . . regardless of how many batteries you have in the system.

Another upside to that system, . . . if your car battery or truck battery dies, . . . you can pull one of the 12 volt batteries from this system, . . . and use it in an emergency for the vehicle. You cripple and disable your other system if you have say 4 each 12 volt batteries, . . . and you pull one for your wife's station wagon.

May God bless,
Dwight


----------



## Maine-Marine (Mar 7, 2014)

Back Pack Hack said:


> The downside to this is you have much more power losses when converting from 12v to 120v. Converting from 24v, all else being equal, has less losses. And 48v even less. 24 and 48v inverters are not as common, but they can be had.


??? this has nothing to do with 12vdc versus 24 or 48... or converting to 120

A will charge ALL Batteries
B will charge one end (the battery that is connected) and will trickle charge the next in line, etc, etc


----------



## rebeltaz (Sep 29, 2019)

Chiefster23 said:


> If you are on a limited budget, consider the following. Run your 120 volt line into a central location inside your house and terminate it at one duplex receptacle. Then use extension cords from there to power the various things you want to run. This method is cheap but inconvenient. With your small battery capacity you will only be running maybe one or two items at a time. (You are gonna find that 200 amp hrs of batteries doesn't last very long). Extension cords present a tripping hazard but this system is cheap and quick to get up and running. And it works just fine for emergency back up situations.
> 
> I use this method with my 2000 watt Honda generator.


That's what I am planning to do. I've got some underground power cable coming. I will probably run power lines inside to the devices I need to power so I don't, like you said, the tripping hazard and inconvenience of extension cords.

Like I said, we don't need much electricity. My experiment with the TV, stereo and an LED light bulb lasted 7 hours before I shut it down for the night with power left to go. It should be good for me for a start. I can always add more later if I need it, maybe even another 400w setup.


----------



## Back Pack Hack (Sep 15, 2016)

Maine-Marine said:


> ??? this has nothing to do with 12vdc versus 24 or 48... or converting to 120
> 
> A will charge ALL Batteries
> B will charge one end (the battery that is connected) and will trickle charge the next in line, etc, etc
> ...


Sorry. Your post sounded more like comparing parallel v. series.


----------



## Maine-Marine (Mar 7, 2014)

dwight55 said:


> This is not necessarily gospel advice.


Yes it is.


----------



## dwight55 (Nov 9, 2012)

Maine-Marine said:


> ??? this has nothing to do with 12vdc versus 24 or 48... or converting to 120
> 
> A will charge ALL Batteries
> B will charge one end (the battery that is connected) and will trickle charge the next in line, etc, etc
> ...


Maine Marine, . . . straight up, . . . that is a crock.

Solar panels that most of us buy are 12 v DC output, . . . your diagram for one solar panel will only drop 2 VDC over each battery, . . . which will in essence do nothing.

NOW IF, . . . in the first diagram, . . . you also have 6 solar panels hooked up in series, . . . then it will work, . . . as you will drop 12 VDC across each battery.

The second diagram applies IF YOU ONLY HAVE ONE SOLAR PANEL, . . . OR THEY ARE ALL HOOKED IN PARALLEL, . . . and the charging voltage (generally about 13.5 VDC) goes to the total bank of batteries, . . . the battery that is lowest in voltage will take the most current at first, . . . until they are all leveled off at an equal voltage.

And yes, . . . I've only been doing electrical work, . . . successfully, . . . since 1963.

May God bless,
Dwight


----------



## Back Pack Hack (Sep 15, 2016)

dwight55 said:


> Maine Marine, . . . straight up, . . . that is a crock.
> 
> Solar panels that most of us buy are 12 v DC output, . . . your diagram for one solar panel will only drop 2 VDC over each battery, . . . which will in essence do nothing.
> 
> ...


The controller will be outputting the proper charge voltage for 12v batteries (assuming the input voltage is enough for the controller to do this). Even if there's 6 panels in series, they're rated for (typical) 18 volts, the solar panels will pump 108 volts into the controller. The controller will then convert it to a 12v charge. If the sun goes behind a cloud and the panels drop to, say, 8 volts yeach, they're still sending 48volts to the controller, which will still maintain a 12v output to the batteries.


----------



## Elvis (Jun 22, 2018)

Back Pack Hack said:


> The controller will be outputting the proper charge voltage for 12v batteries (assuming the input voltage is enough for the controller to do this). Even if there's 6 panels in series, they're rated for (typical) 18 volts, the solar panels will pump 108 volts into the controller. The controller will then convert it to a 12v charge. If the sun goes behind a cloud and the panels drop to, say, 8 volts yeach, they're still sending 48volts to the controller, which will still maintain a 12v output to the batteries.


Yes but,,,, If you're using a PMW type of controller (costs less than $80 with most costing around $25) and you run voltage that is more than about 150% of the battery bank voltage (say 40v total panel voltage to a 12v battery) you'll be losing over half of the panel's output.

To run high voltage panels into a lower voltage battery bank you'll need a much more expensive MPPT type controller. 
Bottom line is if your battery bank is 12v and you're using a PMW type controller like most of the inexpensive solar kits use you want to keep the panel voltage feeding into the controller to be less than about 20v to get the most power from those panels. Instead you'll need to wire the panels in parallel to keep the input voltage around 18-20v.

Big and overly simplified example.... Lets say you have 10 panels, each rated for 200 watts at 10 amps, that's potentially 2000 watts. But these are 20v panels and you hook them in series so they are putting out 200v into an inexpensive PMW charge controller. Instead of the potential 2000 watts you'll only be putting out the panel rated 10 amps or 120 watts at 12v into your battery. If instead you want to keep the input voltage to your controller high you'll need a MPPT type controller which will convert that high input voltage to the required 12v and increase the amperage from 10 amps to 100 amps giving you all the watts your panels are producing.


----------



## Back Pack Hack (Sep 15, 2016)

Elvis said:


> Yes but,,,, If you're using a PMW type of controller (costs less than $80 with most costing around $25) and you run voltage that is more than about 150% of the battery bank voltage (say 40v total panel voltage to a 12v battery) you'll be losing over half of the panel's output.
> 
> To run high voltage panels into a lower voltage battery bank you'll need a much more expensive MPPT type controller.
> Bottom line is if your battery bank is 12v and you're using a PMW type controller like most of the inexpensive solar kits use you want to keep the panel voltage feeding into the controller to be less than about 20v to get the most power from those panels. Instead you'll need to wire the panels in parallel to keep the input voltage around 18-20v.
> ...


Which has nothing to do with dwight55's statement I was responding to that each battery would see 2 volts. That would be true if the batteries in the diagram were in series, but they're in parallel.


----------



## dwight55 (Nov 9, 2012)

Here are a couple videos from others showing successful . . . small . . . installations:

Battery Bank Design Tool for wiring battery banks






May God bless,
Dwight


----------



## Maine-Marine (Mar 7, 2014)

dwight55 said:


> Maine Marine, . . . straight up, . . . that is a crock.
> 
> Solar panels that most of us buy are 12 v DC output, . . . your diagram for one solar panel will only drop 2 VDC over each battery, . . . which will in essence do nothing.
> 
> ...


you can have 50 solar panels.. I have to assume they are all hooked to ONE charge controller... !!!!! which then connects to the batteries + - right????


----------



## dwight55 (Nov 9, 2012)

Maine-Marine said:


> you can have 50 solar panels.. I have to assume they are all hooked to ONE charge controller... !!!!! which then connects to the batteries + - right????


Only if the charge controller is adequate to handle the power produced by 50 panels. Personally, . . . I want a charge controller for each panel, . . . can be more expensive that way, . . . but if you lose one panel, . . . or one charger, . . . you don't cripple the whole system. A 24 volt charger down, cripples two panels, . . . a 48 volt charger down, . . . cripples 4 panels. One panel down can cripple a 24 volt or 48 volt controller . . . and either way, . . . the whole array suffers.

Panels, . . . controllers, . . . and batteries all need to be "sized" in relation to each other. The only floater in the equation is the batteries. AND that is only within certain guidelines.

You should not have such a battery load that only a bright sunny 12 hour day will charge them all, . . . and you don't want so small a battery load that you run out of juice before 9PM.

Each system needs to take into consideration what is needed at the installation. My wife and I are alone in the house, . . . so something that will power a TV for her, my computer, . . . and give us and outlet or two for charging our cell phones is plenty. I have it sized big enough for everything but the freezer, fridge, and stove. We have a generator for those, . . . and will only be used on a necessary basis.

Lights are powered from the inverter as well, . . . so we look normal to outsiders who drive by when everyone else has no electricity.

May God bless,
Dwight


----------



## rebeltaz (Sep 29, 2019)

dwight55 said:


> Lights are powered from the inverter as well, . . . so we look normal to outsiders who drive by when everyone else has no electricity.


Wouldn't that look the opposite of normal? If everyone else has *no* electricity, but you have lights, you'll stand out like a sore thumb...


----------



## Maine-Marine (Mar 7, 2014)

dwight55 said:


> Only if the charge controller is adequate to handle the power produced by 50 panels. Personally, . . . I want a charge controller for each panel, . . . can be more expensive that way, . . . but if you lose one panel, . . . or one charger, . . . you don't cripple the whole system. A 24 volt charger down, cripples two panels, . . . a 48 volt charger down, . . . cripples 4 panels. One panel down can cripple a 24 volt or 48 volt controller . . . and either way, . . . the whole array suffers.
> 
> Panels, . . . controllers, . . . and batteries all need to be "sized" in relation to each other. The only floater in the equation is the batteries. AND that is only within certain guidelines.
> 
> ...


I was using hyperbole when i mentioned 50 panels.

as to 1 panel down crippling the system... yes it you are putting the panels in series.. no if they are all connected to one controller

if you are using 12 volt panels and a 12 volt controller how are you connecting to the batteries if they are set up for 24 or 48 volt???? I am confused!

frankly it is better (IMHO) to have a spare controller and have the panels in parallel


----------



## rebeltaz (Sep 29, 2019)

dwight55 said:


> Here are a couple videos from others showing successful . . . small . . . installations:
> 
> Battery Bank Design Tool for wiring battery banks
> 
> ...


Holy crap... did you watch that video!? So many wrongs... my head hurts just thinking about it!

For starters, that interconnect between the panels and the feed line in! He took a half dozen ring connectors and just twisted a stranded wire trough the rings and then back around itself. :vs_no_no_no: No worries though, because he's going to wrap it with electrical tape to protect it from rain... 

Then he has the two flooded, lead-acid batteries being charged indoors and sitting directly on carpet no less. So when those things vent, which they will, everything within a foot radius will be eaten by acid, including the carpet!

Could he have found a larger, more inefficient voltmeter to run on that setup? Hell, that thing'll probably use half the juice he's creating just to measure the batteries.

Wow... just wow... Some people should not be allowed to teach others anything, ever...


----------



## dwight55 (Nov 9, 2012)

Maine-Marine said:


> I was using hyperbole when i mentioned 50 panels.
> 
> as to 1 panel down crippling the system... yes it you are putting the panels in series.. no if they are all connected to one controller
> 
> ...


The simple answer is you set your panels up for 12 volts, . . . hook the batteries up as well for 12 volts. That is the way my system works, . . .

The really important thing IMHO about the different ways one can array the system, . . . 12 volts can be handled with bare hands, . . . don't have to worry about being shocked or worse.

Of course that is true going up somewhat higher, . . . but it is a comfort zone for me, . . . and I don't have to wonder where I am voltage and current wise.

I have not gotten around to doing it, . . . but when I do, . . . my system will also have a 12 volt light in the room which can be automatically turned on when the power drops, . . . so entering the room, . . . I'm not "in the dark" so to speak. Just one of those upgrades I have not had time to accomplish.

Mine is set up so I have to manually disconnect the main power, . . . manually engage the battery backup. It is simple and effective.

May God bless,
Dwight


----------



## Chiefster23 (Feb 5, 2016)

I built a 12 volt system. If I could get a do-over, I would go with 24 volts.


----------



## dwight55 (Nov 9, 2012)

Chiefster23 said:


> I built a 12 volt system. If I could get a do-over, I would go with 24 volts.


Well, . . . other than money, . . . what's stopping you??

That is the question I keep asking myself these days when I'm so bored.

Lots of projects I can think of, . . . but with not knowing where what is going, . . . just not ready to spend the bucks.

Best wishes on whatever you decide to do.

How big is your array (how many panels, . . . how many batteries, . . . etc.??)

May God bless,
Dwight


----------



## Chiefster23 (Feb 5, 2016)

My charge controller will do either 12 or 24 so no problem. But my OUTBACK 12 volt inverter is the big expense that is stopping me. I’ve already invested in all the larger cable sizes required for 12 volts. So I guess I stick with 12 until it’s time for a new inverter.

Right now I have 1000 watts of panels and a 2000 watt inverter. 615 amp-hrs of batteries but soon that will change to 700 amp-hrs. I’m also planing to install a couple of additional panels to use in the winter when there is less available sunlight.


----------



## Inor (Mar 22, 2013)

Robert said:


> That's a great idea. There's a future for solar energy.







Here's to you Mrs Robinson!


----------



## Redneck (Oct 6, 2016)

rebeltaz said:


> I have wanted to go solar for two decades, but with this virus crap, I decided this was the time to at least dip my toe in the water.


I dipped my toes in the water by purchasing two Humless solar generators. By no means, will they power everything I have, but they are simple and state of the art. My solution is to provide necessary power when needed and for utmost flexibility. I have a nice supply of 280w solar panels in storage, enough that I can recharge these solar generators, power my Grundfos flex well pump, and power my dc water heater. The flexibility allows me to add extra panels to the well pump when needed, say when the solar generators are fully charged. So with my system, I move the panels to where most needed at that moment.


----------

