Any device to drain and store residual power from partially spent batteries

[gll99]

A thought crossed my mind:
Every year we throw away many AA, AAA or 9v batteries with sometimes up to 1/8, 1/4 or even 1/2 of their power remaining. It's not enough to run the device they were in so we pitch them (hopefully recycle). Any pent up residual energy is lost. What a waste!

I've often moved batteries from peak demand devices like cameras and flashlights to lower demand devices like remotes and got many weeks and even months out of them until there was barely anything left in the batteries. I know about alkaline chargers (I have a really old one that even charges so called regular non-rechargeable alkaline) and other types of rechargeable batteries (NI-MH, NI-CA etc., but that's not the question.

I was wondering if there was any device that would allow someone to take say 2-4 low batteries in series and use the left over energy to recharge another. Or possibly a device that would drain and store the energy from many low batteries that could then be used to recharge others.

[yoda313]

Maybe that's how doc brown made the flux capicator????



Sorry all kidding aside that is a good idea. Don't know if its possible but I'm sure duracell won't come up with it. They want you to buy more batteries! But also you can buy rechargeable batteries - but they never seem to be quite as good as the first time or as good as brand new one-time use ones.

[redwudz]

You would likely have to limit the current flow or you might have two dead, hot batteries if you used two to charge one.

One other risk is that quite a few batteries swell up and leak when they reach the end of their life cycle. I've damaged several remotes and flashlights over the years by leaving old batteries in them. Best to closely monitor them when they get low. Or just recycle.