Can a solar powered battery maintainer (1.44 W, or 120 mA at 12V DC) overcharge a car battery?
Wednesday, September 30th, 2009 at
11:10 pm
I have not been able to directly find the answer if a solar powered battery maintainer that charges very slowly can overcharge a car battery? It is for a car that isn’t driven very much, and we are in MN and need to have a good charge on the battery to start the car.
Thanks for any help! The product I purchased make no claims that it won’t overcharge – it’s one of those made in China things from Fleet Farm store.
Filed under: Solar Products
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I keep one in my car (also in MN) and have never had a problem with overcharging.
In this case, the question is more likely will it have enough output to keep the battery up?
Most of these devices barely pass any test to do what you buy them for. But the direct answer is no………they don’t have the capacity to do that.
I would say no they are not large enough to maintain a large car battery and in no way could charge one. Chances are the most you could expect is to hold a charge in a new battery. A battery with any problems at all would discharge faster then you could put the power back into it with that small of a solar module.
If you had a mid sized car battery (about 100 amp hours deep cycle rating) you would need 3 amps just to barly be able charge it on a good day. 120 mA is about 1/8 of an amp. No chance of charging a battery of that size in any way.