# Help with Solar Power Emergency communications



## survival (Sep 26, 2011)

Hopefully Nadja or some other expert on solar can help me out with this question. I am needing to setup a HAM radio to a rechargeable (by solar) Lead acid battery (inside my home), which is connected to a charge controller, then to the outdoor solar panel for emergency communications.

The radio I'm going to hook the solar to is a Kenwood TM-281A Transceiver. Specs on it are "high power 65W output". Power supply: 13.8 V DC +/-15% (11.7 ~ 15.8 V). Current: Transmit 14 A or less. Receive (at 2 W output) 1.0 A or less. Power output High: 65 W. Low: Approx 25 W.

My questions are as follows.

1. Battery: I know the lead acid batteries are bigger, cost less than the lithium batteries as well as the fire safety is better with the lead acid batteries, thus I plan on using the Lead acid. I will be using the radio about 3-4 hours per day (every day), mainly listening. What size of a battery should I get? I am assuming a 12 volt, not 24volt as well. I've read somewhere that a lead acid battery needs to be properly ventilated, if this is the case, are there alternatives since I'll be using the radio right next to the battery inside my home.

2. Charge controller: I'm getting confused with mppt and pwm's and the different verisons, sizes and prices. I only want to use this for the above usage, so which version/brand would you recommend?

3. Solar panel: Again, only using this for the above stated hours (3-4 hours per day) and need something that works with the size of the battery (12 volt). I'm in Kentucky and yes that this will be placed on my rooftop true south. I'm looking at the monocrystille from what I'm reading its better. What would you recommend wattage/brand and cheapest place to purchase.

Again, not needing this for anything else, this will be solely for this setup of this radio. Just trying to figure out what I would need and not do an overkill on the items that I purchase for this project. I guess I would need some sort of little meter that goes between everything to watch how much power I have left.

Here is a photo of my plans.


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## nadja (May 1, 2012)

Good morning Survival. Well, that will make a nice little set up. You could just buy a power converter or otherwise known as a 12v. power supply. However , if you do want to go with batteries and what not, the lead acid batteries do need to be vented out of your house. Could you put a nice strong 12v battery in a boat battery box ? You know, they are generally red or black and sold at marine places. Then, you could put the box outside of your wall, and just run the wiring into your house. A lot of things depend on your solar panel as well. Are you planing on the future to add to it to make other things work as well ? Also, charge controllers are the same way. I can give you the name of the cheaper types, which are ok, until you try adding panels, and then they are not so ok. 

Listening on your radio won't use much power, however talking or transmitting on it will use more power. Are you planing on using it more in the day or night ? These also make a difference, as during the day, you won't really need much power from the battery as the solar should equalize or trump what you actually need. Send me a pm and we can talk further about this if you like. Nadja


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## WoadWarrior (Oct 10, 2012)

Lead Acid needs to be vented as it recharges. You can smell em any time you enter a maintenance bay.  Without proper venting... you get a buildup on the contacts (as you might have seen under car hoods with little space in the engine compartment.) 

I'm no where near a solar expert ... but here's some small bits i can share:
- Since you are running 12 volts... keep in mind that you can use 6 volt batteries as well... when wired together as 12 volts. So... keep that in mind if you find them on sale. 
- It's my understanding that most 12 Volt batteries are designed with CCA (cold cranking amps) in mind. i.e., lots of power to power a starter to turn over a motor. Marine batteries (usually where you find the 6 volt kind) and designed for slow release of power over time and are most likely your best bet.
- Never buy the number of batteries you think you need. Always buy more than you think you need... since that is usually what happens. Then... buy some spares in case a battery goes out.


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## nadja (May 1, 2012)

Batteries. Lets take a brand most of us on solar use. They have been the standard of the industry for at least the last 16 or so years I have been living on solar. The brand of choice for my batteries is Trojan. Now, you can buy them in either 6v or 12v configuration, but 6 volt have much more storage capicity. However, for what you are planing, the 12v deep cycle batteries would due fine. Two batteries of 6v each, require a larger battery box , more heavy inter connect cables and twice as much money. If you are not planning to run more then what you estimate, then a good 12 marine battery would do fine. What you would want there would be a 12 deep cycle battery designed for "trolling" motors. They last for hours and hours and would recharge with a 100 watt panel fairly quickly. 2 - 6v batteries would do even better, but would cost twice as much.


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## WoadWarrior (Oct 10, 2012)

Nadja.. you say it so much better than me. I know just enough to not sound like a complete idiot... and usually keep myself out of trouble.


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## PrepperThyAngus (Sep 30, 2012)

Most of the solar panels either come with the charge controller or the manufacturer have recommendations to which controller to use. Since your setup uses 65W max, I would find one that can meet or exceed that charge capacity, however this is not required.

The solar panel/charger rating can be thought of as not being related to equipment power dissipation. Meaning the battery capacity supplies power to the equipment until depleted. The solar charging kit will charge the battery at any rate depending on the panel's wattage generation. There is no requirement for solar panel/controller wattage. The more wattage it can generate, the faster your batteries will charge. 65W and up solar setups can power the ham radio directly with a battery when the sun is out. Keep in mind there will also be "loss" with solar panels so they must put out 65W minimum after loss. However since you are using a battery, that is your energy backup buffer. The panels will just charge or "top off" the batteries after several hours use.

I recommend a standard automotive sealed lead acid deep cycle battery. Such batteries such as Optima are great batteries, do not leak, and are designed to be charged regularly. With an automotive battery, I'm sure you can get 8+ hours or more before it is dead. 

Cliffs:

Solar chargers refill battery charge at whatever rate they are designed to put out (power output in wattage)
Batteries will supply a certain current, at rated voltage, for a certain duration (amp hours)
The more amp hours or charge capacity a battery has, the longer your equipment will run.
The more wattage your solar setup outputs, the quicker your batteries will charge.

I hope that helps.


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## nadja (May 1, 2012)

PrepperThyAngus said:


> Most of the solar panels either come with the charge controller or the manufacturer have recommendations to which controller to use. Since your setup uses 65W max, I would find one that can meet or exceed that charge capacity, however this is not required.
> 
> The solar panel/charger rating can be thought of as not being related to equipment power dissipation. Meaning the battery capacity supplies power to the equipment until depleted. The solar charging kit will charge the battery at any rate depending on the panel's wattage generation. There is no requirement for solar panel/controller wattage. The more wattage it can generate, the faster your batteries will charge. 65W and up solar setups can power the ham radio directly with a battery when the sun is out. Keep in mind there will also be "loss" with solar panels so they must put out 65W minimum after loss. However since you are using a battery, that is your energy backup buffer. The panels will just charge or "top off" the batteries after several hours use.
> 
> ...


Survival did not say he would be using a 65 watt solar panel, so that is a -neg
Most solar panels do NOT come with a "built in charge controller"
And car lead acid batteries are not the correct way to go for solar. There fast discharge rate is actually no good for solar at all. They are fine for starting your automobile as a high amp short run cycle. Also, as soon as your car starts they are brought back up to your max via a altenator. 
Deep cycle slow discharge batteries do cost more , but are much more effective at running long periods of time as for ac units
Charge controllers, (I have and use 5) run your charge rate (providing you have enough solar) to a bulk charge of aprox 14.4 volts, then drop down to 13.4 volts and maintain that unless more is needed. 
They are variable as batteries dictate

And you never want to run your batteries down until they are "dead" Batteries are rated by the amount of recharges. That number decreases quickly if you run them below 11.9 volts


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## nadja (May 1, 2012)

Survival, as far as charge controllers go, the prostar 35 amp controller would be all you really needed for this small system. It also has the led meters in it to provide you with up to the second info on the state of charge, charge coming in and other as needed info. About $65.00 last time I looked. My Trace C-60's - cost about $200.00 each and the led panel for it another $100.00 or so. But better quality and 60 amp capacity rather then 35 amp. My Outback mppt controller cost about $450.00 and is even more state of the art. But there more things you can do with it. But you don't need that for your start up project.


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## survival (Sep 26, 2011)

_"You could just buy a power converter or otherwise known as a 12v. power supply"_

I agree, but if my power went out, my communications will go down.

_"Could you put a nice strong 12v battery in a boat battery box ? You know, they are generally red or black and sold at marine places. Then, you could put the box outside of your wall, and just run the wiring into your house."

_Yes, I will have my radio on the 2nd floor, solar panel on roof and I'll have to put the box on the bottom level of the home, so I'm assuming from the solar to the battery box will be at least a good 40 feet distance.

_"Are you planing on the future to add to it to make other things work as well ?"_

Not at this time, if so, then I'll buy a new setup. Mainly looking for emergency power to the radio.

_"Are you planing on using it more in the day or night ?"_

90% of use will be during the night time.

_"Lead Acid needs to be vented as it recharges."

_Thanks for the mind jogger, this was one of the first things I've learned as a HAM operator, just wanted to keep it in the thread.

_"Batteries will supply a certain current, at rated voltage, for a certain duration (amp hours) The more amp hours or charge capacity a battery has, the longer your equipment will run."

_Ok, so I'm seeing all these little to huge batteries that all have 12V, but have different amp hours. This now makes sense why... thanks for clearing that up.

This is what I'm looking at:
RV Solar Kit 100W Watts Solar Panel with Charge Controller Mount Rack Drill Free | eBay


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## PrepperThyAngus (Sep 30, 2012)

Please see red annotation.


nadja said:


> Survival did not say he would be using a 65 watt solar panel, so that is a -neg
> His Ham radio specified wattage use of 65 watts. So that is the criteria for "electrical load."
> Most solar panels do NOT come with a "built in charge controller"
> Yes, most do not come with a controller but almost all of them have a recommended controller per the manufacturer documentation. You want to follow your manufacturers recommended configuration.
> ...


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## PrepperThyAngus (Sep 30, 2012)

Per Wikipedia via "deep cycle batteries"

A deep-cycle battery is a lead-acid battery designed to be regularly deeply discharged using most of its capacity. In contrast, starter batteries (e.g. most automotive batteries) are designed to deliver short, high-current bursts for cranking the engine, thus frequently discharged of only a very small part of their capacity. While a deep-cycle battery can be used as a starting battery, the lower "cranking amps" imply that an oversized battery may be required.
A deep-cycle battery is designed to discharge between 50% and 80% depending on the manufacturer and construction of the battery. Although these batteries can be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge,as there is a direct correlation between depth of discharge on the battery and the number of charge and discharge cycles it can perform.


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## nadja (May 1, 2012)

Survival, I have looked at the solar panel you linked to and it seems to be ok with the price. The mounting rack however will most likely not work for your application as it is designed I believe to "clamp" to the gutter system of a vehicle. You could build a quick mounting system out of a couple of bed rails. They are stronger then reg. angle iron, lighter and are really cheap at thrift stores. 

Also, remember that D.C. current running 40' can be a problem for you. You need much larger wire to go that distance, which is why ac won over dc in the long battles back when.


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## inceptor (Nov 19, 2012)

I'm not an expert by any stretch of the imagination. Here is what I am using. I have 4 deep cycle marine batteries. I had a power supply die on me so I ran a dual band icom 2720 on 15watts (medium power setting) using it normally in the local repeater system. I ran off of 1 battery for 2 weeks before I had to change batteries. DO NOT LET THE BATTERY GO BELOW 10.5V it could damage your radio. I have also run my kenwood 450s off of this system. I have my equipment run through a rigrunner so if I loose ac power it automatically kicks it over to battery power. This has served me well. I have not been able to set up a solar panel yet. 

My best friend has his radio's running off of 12v gel batteries and has them hooked up to a solar panel. His solar panel is not a high output. This produces a little more than a trickle charge but they stay hooked up. He started with 4 batteries a couple of years ago but one of the gels died so he is down to 3. He runs off of 1 battery at a time. You should moniter your voltage and watt usage. You can get relatively cheap meters, like the one in many cars at a local eletronics shop. He also has a rigrunner hooked up to his system. He runs mainly off of battery power just because. 

What ever you do, keep it simple. The more you add to the equation, the more that can go wrong. 

JMHO


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## nadja (May 1, 2012)

inceptor said:


> I'm not an expert by any stretch of the imagination. Here is what I am using. I have 4 deep cycle marine batteries. I had a power supply die on me so I ran a dual band icom 2720 on 15watts (medium power setting) using it normally in the local repeater system. I ran off of 1 battery for 2 weeks before I had to change batteries. DO NOT LET THE BATTERY GO BELOW 10.5V it could damage your radio. I have also run my kenwood 450s off of this system. I have my equipment run through a rigrunner so if I loose ac power it automatically kicks it over to battery power. This has served me well. I have not been able to set up a solar panel yet.
> 
> My best friend has his radio's running off of 12v gel batteries and has them hooked up to a solar panel. His solar panel is not a high output. This produces a little more than a trickle charge but they stay hooked up. He started with 4 batteries a couple of years ago but one of the gels died so he is down to 3. He runs off of 1 battery at a time. You should moniter your voltage and watt usage. You can get relatively cheap meters, like the one in many cars at a local eletronics shop. He also has a rigrunner hooked up to his system. He runs mainly off of battery power just because.
> 
> ...


If your friend were to wire his remaining 3 batteries in parraral, that is to say, pos - pos-pos and neg to neg neg, then pull his power from oppisite corners neg and pos. then his voltage would remain the same, but his AMPS would go up and he would charge them and use them all at the same time. No dis or re connects all the time.


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## nadja (May 1, 2012)

When it comes to solar, any type of application, the batteries are the weakest link. That is why I advocate Trojan Golf Cart type batteries . I just lost 4 last week, that were over 10 years old. Since most of us living on solar know that the batteries are the most likely fail, we all choose the best we can buy.


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## OptimaJim (Dec 6, 2012)

Hello, I noticed your conversation regarding our batteries and wanted to offer some assistance. As others have indicated, all lead-acid batteries, even "sealed" batteries like Optimas, can vent gas that is both flammable and toxic in extreme situations. To be safe, any battery located in an enclosed area should be vented to the outside air. That doesn't necessarily mean the batteries have to be located outside, but a sealed battery box with a tube vented outside would work fine.

Our RedTops are SLI (starting/lighting/ignition) batteries and are not designed or warrantied for deep-cycle use, which would include an application such as this one. Our YellowTops are designed and warrantied for both starting and deep-cycle use and would be a more appropriate choice. Our BlueTops are identical internally to their YellowTops counterparts, but do come with additional threaded top posts for marine accessories and their warranty is one year shorter than the YellowTops.

This is true of many marine batteries- additional threaded top posts, identical internally and shorter warranties. Why are the warranties shorter? Because boaters tend to abuse their batteries, leaving them in various states of discharge for long periods of time. Fully-charged, our YellowTops and BlueTops will measure about 13.0-13.2 volts. Whenever any battery is discharged below 12.4 volts and left sitting in that state, sulfation begins to form within the battery, which diminishes both capacity and lifespan. That makes a quality battery maintenance device an excellent investment for any battery that doesn't see regular use. As for the solar panels, I strongly suggest that any charging system for batteries have proper regulation for both voltage and amperage, to prevent overcharging.

Physically larger batteries will have more reserve capacity, which is the specification that should be noted in comparisons for this specific application, versus cranking amps for car engines. Multiple batteries can be wired in parallel, which will increase reserve capacity. However, whenever any batteries are wired in series or parallel, they should be identical in age, size and type, which means replacing them at the same time as well. Our engineers have also recommended that batteries in banks of three or more be rotated periodically within their banks, as batteries that stay in the same order in relation to the charger and each other may not see the same lifespan. If anyone has any questions about our batteries, I'll do my best to answer them.

Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
OPTIMA® Batteries (optimabatteries) on Pinterest


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## whoppo (Nov 9, 2012)

The "shack" here is divided into two parts... the vintage radio part (lotsa tubes, 120/240VAC only) and the solid state part (all 12 volts).
The 12 volts side runs from a UPG UB-4D AGM battery (12v / 200AH). It's sealed and requires not venting. An Astron RM60M power supply provides primary power from the house and keeps the AGM battery charged through a PowerGate 40S switching/charging system. This AGM battery will easily run a Kenwood TS-2000X for several hours a day for a month.


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