by ericmark »
Mon May 06, 2019 2:02 pm
I looked at new drill from Lidi and cheaper than new cells for old drill, using some thing like the AA cell often the electronics needed to charge the cell is built in, so a NiMh cell can replace a NiCad, but it does depend on the charger.
There are three common methods to charge NiCad cells, one is a temperature switch in the cells idea is electrical energy into chemical energy no heat, but once finished the it gets hot so once it switches off it latches off.
There is also the very low charge rate and warning charge for 12 hours only.
And there is the Delta V which uses the way the voltage slowly raises but once fully charged with constant current it drops again, and it uses this to switch off, advantage is the charger can work with different voltage batteries. However the drop in voltage with the new breed of battery is less than with NiCad so some old chargers will not switch off.
We have seen even when charger is correct how phone, plane, and electric car batteries have gone on fire, when Richard Hammond crashed an electric car it took three days to put the fire out.
It seems although we call the cell a Ni-Mh the way they work changes and some will give high power and others last a long time, and lithium-ion batteries are not same as Ni-Mh or NiCad but all sold as rechargeable batteries, and it is easy to get it wrong.
