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How do I build a solar chargeable NiMH power pack to run AC appliances? Answered

At a thrift shop I found a new 1.8 W (125mA) solar panel with all the parts that is used to trickle charge car batteries. It has three connectors, one a cigarette lighter, pos and neg cable clips and a regular connector for a power pack. Is it possible to use it to build a solar charger for a NiMH battery pack that will power a low end AC item like a cordless phone base or broadband modem during a power outage? If so, what else do I need and can it be done cheaply? Why I want to do this is because I don't want to have lead acid batteries in the house.

Answers to this would be much appreciated as I know there are issues with differences in voltage, etc.



Best Answer 5 years ago

NiMH batteries have a bad memory of the shortest discharge after a charge
which can occur in a sun charge barely used situation and thereafter fail to
deliver the full capacity of the battery.

Yes it can be recovered by many discharge recharge cycles.
Hatefully annoying bother when it happens to you.

Use lead acid or Lion batteries instead.

And listen to mpilchfamily's wise suggestion.


5 years ago

You would need a 12V dc pack, maybe something from a cordless drill and an inverter. The problem with your panel is that its a low amperage solar trickle panel and wont even be able to keep up with the drain of running the inverter alone without any accessories connected. In all probability it wont even charge the power pack. I had a similar idea to keep my internet adsl modem going in a power outage and got one of those small coke can sized 100 watt inverters, its no load current draw is 200mA so that gives you an idea of the size solar panel you'd need, probably a 5W or 10W panel.


5 years ago

Sure if the battery is a 12V battery and you get a 12V to mains power inverter. But the battery will not last very long and the panel will take days to charge the battery up. A better option would be to buy a cheap UPS. When the power cuts out the UPS will kick in and keep the items running for as long as the battery will last. When the power comes back on the batteries will be recharged.