cordless 18v drill,charging issues

[m3vuv]

Hi all,i have an 18v cordless drill,it has a charger with a red + green led,normaly the red indicates its charging and green = when i insert the battery into the charger,a relay clicks but the green led is on,the battery is at about 14v and not charging,the red charging led never lights up,its a nicad pack not lion,the charger contacts have 21v on them,is there a thermal fuse of some sort in these batterys?,any ideas where to look?,TIA.

[m3vuv]

Sorted it,it was a wire broke away from the 3rd small contact on the side of the batterys nose where it inserts into the charger.

[madires]

NiCd/NiMH battery packs with three contacs have a thermistor to monitor the temperature.

[m3vuv]

Tbh,it looked more like a thermal cutout to me,i have the same on my ebike battery packs.open when hot then close when they cool.

[madires]

There's also cheap stuff. I've seen some battery packs for cheap power tools with three contacts but neither thermistor nor thermal cutout. Professional chargers use the battery pack's thermistor for optimal fast charging. For example, Panasonic's pro chargers do NiCd/NiMH packs in just 15 minutes. I've rebuilt several packs over years because the original replacement packs are insanely expensive. It's also possible to replace NiCd/NiMH with 18650 Li-Ion cells and a proper BMS.