yes it'll work just fine...I've used adapters on a 10 port 510 multicharger to charge several KR808d-1
batteries as well...
just check the mA output rating of the charger... the mA output should be lower than the mAh of the battery...
the reason the eGo fast charger is a risk as far as stock
batteries go is because it outputs 420mA and a stock battery is 180mAh... max charging and discharging rates should be the same... and an eGo fast charger is about 3 times what the charge rate of a 510 stock battery should be...
a stock 510 charger is 150mA output... and the shortie KR8 batteries are 180mAh (same as a stock 510 battery) so those are good...