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WHAT KIND OF BATTERIES TO USE FOR A SOLAR PANEL?
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What kind of batteries to use for a solar panel?
I am planning to purchase some solar panels for my cabin and i want to be able to store the electricity. what kind of batteries should i get? i will be running easy things like a tv and radio. where can i purchase these batteries? where should i look for the ideal batteries?
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Answer by garylee
Deep cycle, Golf Cart Batteries. You can get them at a battery store.
Answer by billrussell42
If you will be storing them outdoors, you can use auto batteries. Indoors, use sealed marine batteries.
Number and size depends on your needs. You will need a charge controller between the solar panels and the batteries to get the maximum power out of the array and to avoid damage to the batteries.
And you will need an inverter to convert the 12 or 24 volts to 120 or 240 VAC.
One massive lead acid battery will supply about 1000 watt-hours of energy, enough for 200 watts for 5 hours. You have to look at your loads and decide on how many batteries you need.
Frequently it is cheaper to purchase new appliances that use less power, as that power difference can save a lot of money in batteries, inverter, charge controller and solar panels. But it sounds like a few thousand watt-hours will be enough, 1 or 2 massive batteries. The real limiting factor is how much money you want to spend for the solar panels themselves.
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Answer by Rudydoo
Hey Mark, you are on to a great project there. My first recommendation is to do some real research, beyond asking people on the net for advice. Home Power Magazine is the only periodical that is into the nuts and bolts of solar power. It is not expensive, and if you subscribe, then go online, you can look up old archived articles. We have a cabin that is solar and wind powered now, it was featured in that magazine some years ago. Like Gary Lee, we used golf cart batteries. For the dollar, you will not find a superior battery to store solar power. Each one holds about 1.2 kwh of electrictiy when fully charged. You do not want to discharge these batteries more than half way on a regular basis, it shortens their life considerably. Our system had 4 golf cart batteries and 3 50 watt panels.
In some applications, a solar charge controller is not necessary. A good rule of thumb is if your array puts out no more amperage than 2% of the battery banks amp hour capacity, a charge controller is not necessary, the panels will never overcharge the batteries. You just have to make sure you water the batteries at least once a month, more often in warm weather. A charge controller might be a good investment though, depending on what size your array is, and what voltage you operate it at. I know this is a lot to digest, and this is why I recommend reading Home Power, they get into all the specifics of this stuff. I would also look for a book called, “The Complete Battery Book, ” by Richard Perez, and read the chapters on lead acid batteries, it explains all about charge rates and controllers.
Something else to look for is telecommunications batteries. They are suddenly cheap and available, because the phone companies all over bought, and are now consolidating. They do not hold up quite as well as the T-105 (golf cart battery) but for the money, might work for you. You can use non gel cell type batteries inside, but they have to be in an enclosed cabinet and vented to the outside. Lead acid batteries vent hydrogen gas when charging, and it only takes a 4% concentration to cause an explosive environment to form. We have ours in a cabinet in the garage, and it is vented outside from the top of the cabinet, which is where the hydrogen collects. You might also invest in a Kill-A-Watt meter, about $ 30 USD. You can plug it into any outlet, and plug in some household items you want to power with your solar array, like the TV. Let it run for a week during normal use, and the meter will tell you exactly how many KWH’s that appliance uses, no more guessing.
If you do get on Home Power’s list and go to their website, use their search engine to look for Small Systems, lots of people have done what you are trying to do. You can read what mistakes they made and what they learned, so you do not make the same ones yourself. In the end, you might decide not to get involved, and that is fine, but at least you will be well informed. I will include some other sources below, again, do plenty of research. Good luck, and take care, Rudydoo
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