What voltage to charge 14.4v power pack ?

[hw_user]

I have an old cordless drill which uses 14.4v NiCad battery. The charger that comes with it is AC/DC adapter with 18v 200ma output. The charger is broken and a replacement charger is expensive. I have 2 old laptop adapters, one is 16V 4.5A and one is 20V 3.5A. I tried the 16V because it is lower than the original 18V and I think it is safer. That seems to charge the battery but took very long time. I like to ask if I can use the 20V without risk and if that will be faster ?

 

[Eximo]

14.4v NiCAD should only be charged with a charger designed for NiCAD, at 14.4 volts. Unless you have some REALLY old laptop chargers, they will be Lithium Ion. Regardless, using the wrong voltage isn't ideal. Battery chemistry is important and you risk a fire by using anything other than what is intended for the job.

Essentially the fully charged voltage of a NiCAD cell vs a Lithium Ion cell is very different, not to mention that circuitry designed to charge battery packs is looking for specific signatures in the charging curve to know when to stop (for modern stuff at least, apparently older NiCAD charging systems used temperature to know when to stop.

Depending on where that circuit is, could be quite dangerous using the wrong charger.

 

[hw_user]

Totally agreed "Depending on where that circuit is, could be quite dangerous using the wrong charger "

Since I do not want to invest anymore with this old drill, I will stay with the 16V which seem to have worked. Of course, I will watch for abnormal battery temperature while charging and will not leave it on overnight or while I am not home.