Instructables

Step 3: Choose Some Batteries

Picture of Choose Some Batteries

What I really find annoying is that on all the commercial solar USB chargers I see their internal battery is only 1000 ma. That isn't a lot. A rechargeable AA battery has between 2000 - 3000 ma of current in it. Once again, we can do better.

We need to use rechargeable batteries for this project. I prefer NiMh AAs over everything else because they're easy to find, cheap, and reliable. You probably even have a few at home. Since we're using two AAs in this project our charger will have 2000 - 3000 ma of current. You could even have two sets of AAs in parallel and boost that capacity to 4000 - 6000 ma.

An added bonus from rechargeable AAs is that you can take them out of the Solar Charger, charge them up or replace them, and be on your way.

If you're making this project into a very small container you can use a smaller NiMh battery pack. You can find these at places like American Science and Surplus as well as many places on the web.

 
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valiantX1 year ago
In regards to batteries, I think people should try buying some of these new japanese 'water charging', that's right, batteries instead. Excuse my language here, but these batteries can be charged by any form of non-acidic water including urine, sewage water, creek water, your sweat, etc.

Check out the site info right here: http://waterbattery.com/

A cheaper site to buy from: http://shop.conics.net/nopopo-3pk.html
agqy28011 year ago
Can rechargeable batteries above 2000mAh - 3000 mAh be used? I managed to find one claiming to be 3500mAh. Plus, the battery claims to be AA Lithium Ion and not NiMh, will that affect anything?
budabob072 years ago
Don't you mean 2000-3000 mAh of capacity, not 2000-3000 ma of current?