I am trying to design a solar panel to maintian the electrical charge on 2 two 12 volts battery?
Question:
Answer:
It depends on what you want to power with the batteries. If the charge on the batteries will be drained off completely every night, then you will need some large panels.
I assume you are using deep-cycle marine batteries, and *reasonably* use 1/10th of the energy of the 2-battery set every night. So that's about 100 Amp-hours * 24 Volts = 2400 watt-hours of energy.
You can buy a 5' x 2.5' panel rated at 110 Watts, 32 Volts.
110 Watts * 10 hours in sunlight will only give you 1/2 of what you need to charge the batteries. It will even be worse than that, because you need to take cloudy days into account. 3 of these panels might be sufficient.
There is no need to build your own charging unit. Commercial products are available.
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you're trying to design something that's already desigend. They are readily available at rv supply stores and many auto parts stores.
That is an easy one.
Total amps of the batteries times .05 will give you the minium amps in solar power required to charge the batteries. Then amps times the battery voltage will give you the wattage in solar modules. Then just go shopping for that many watts in solar modules and a charge controller that can handle the amps.
What is the AH of the batteries? If they are deep cycle as should be for solar. There should be an AH ratting on the battery some where. Being you are hooking two 12 volt batteries in series you are really trying to charge a 24 volt battery.
If the batteries are in series and you only have two of them and both batteries are the same size. Then you add the volts so to have 24 volts but the amp hours stay the same as one battery.
A Trojan T-105 has a 225 AH rating and would take 2 of them to make 12 volts. So for this battery bank at 12 volts you would
225 * .05 = 11.25 amps needed in Solar power
11.25 * 12 volts = 135 watts in solar modules.
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