Originally Posted by
Burton
The charger isn't usually the problem - its the battery. Different battery builds and qualities will have different maximum charging rates, even though the chemistry is similar. Since most electronics have batteries that aren't designed to be changed by the user - the only easy solution is an external backup battery that will accept a fast charge and has outputs to charge your other goodies when convenient.
RC Lipo batteries are available with incredible charge/discharge rates and a 11.1V battery pack or similar would interface with most 12V / 5V USB converters.
Thanks. Good points. I'm leaning toward 11.1 but still wondering about 14.8 too.
Max charging rate for standard rechargeable AAs and 18650s is usually said to be about 1C. Most people favor charging at .5C or lower to extend battery life. Some NiMH AAs seem to do okay at 1C, but many 'fry' quickly and stop holding a charge for long.
A trick that seems to solve this is to charge a set of them together in parallel so they can accept a much higher current. And to charge them to maybe 70-80% so they can accept more current. You can store the juice (the mAh's) quickly this way, which is the main objective.
Or just use those battery packs that are designed to handle the faster charge rates.
I believe ten-minute fastcharging is not unreasonable, with these batteries. Apparently the cycle life declines as charging rates get faster. I don't know the numbers though. It would be very interesting to see a graph.
My sense of it at this point is that some of these packs will last pretty well at ten- or fifteen-minute charging rates. Would like to find out more about this.
Apparently there are cheap Chinese packs that don't last long at all, and others that are much better. Need to learn more about this aspect.
All I know for sure is that some of these batteries work fine for some of the RC guys, and that they often use fast charge rates. That seems like good evidence that this can be made to work. It's just a matter of getting the details right.