The Joshua Tree

I've got a Dewalt brushless cordless drill that i rarely use, what's the best way of keeping the battery packs in good shape, are you supposed to keep them fully charged when not in use ?, charge them every so often ? I did look online but i didn't get a definitive answer. Thanks

andy97

iTrader: (1)

Lithium cells, should be stored around half charge, not allowed to be kept too cold, eg freezing or too hot 25C plus. Once a month if not using for many months check charge ( volts) either with multi meter or charger display. Other than that not more you can do.


I have a lithium cell charger, it has a storage charge feature. This sets the voltage at 3.7V per cell. Full charge per cell is 4.2Volts, minimum charge 3.2V

edit
You can work out what voltage you are likely to see by dividing the voltage on the pack by 3.7.

eg 18.4V pack will have 5 cells.

fully charged rhe voltage will be near 21 volts.

Discharged around 16 Volts

ALi-B

iTrader: (1)

If they are Li-ion bung it on the charger once every few months or so. Some li-ion cells can self discharge a little, especially as they get older they get more out of balance. You can confirm this by getting a voltmeter on the two outer contacts ...as above fully charged should be about 20v for a 18v pack.

The chargers have cell monitoring and if one cell goes out of range (over discharged) it will refuse to charge the whole battery.


Makitas have a similar issue, made worse by a monitoring pcb that drains the middle cells when not in use....of course I found this out after I bricked a battery pack that had been left too long.