ORIGINAL: gaRCfield
My chargers (iCharger1010) have a storage (discharge) feature - it's incredibly slow, maybe 5-8hrs, to discharge a full pack to storage.
However, they do have 'regenerative discharge' - if hooked up to a battery instead of a power supply, they will discharge faster. Haven't tried it yet though, but plan on buying a small 12V tractor battery for discharging purposes to see.
Storage is about 3.8v/cell.
it will be great if the energy can be re-used instead of wasted. The regenerative discharge sounds interesting.
What else the energy can be dumped? Maybe hook up to an inverter to power a lamp or charge computer/phone batteries? An inverter capable of taking 21v DC should work.