Discussion

kdklol: I was recently searching for NiMH charging ICs, turns out they basically don't exist. Most devices which charge their NiMH batteries implement low CC charging, which is slow. It's a shame, because NiMH batteries do have their advantages (safety, ease of finding replacements, etc.) and can be recharged fairly quickly if the charger is smart enough.

cmbuck: What do you mean by "they basically don't exist"? Solutions like the TI BQ25172 are designed exactly for this purpose.

Liftyee: I have done similar searches before. They do exist, but most dedicated ICs are targeted towards tightly-integrated cells or battery packs. The variety available is much smaller than for Li-ion batteries, and the ICs are more expensive.It seems like commercial multi-cell battery chargers mostly use custom microcontrollers to achieve this, instead of multiple charging ASICs.

joecool1029: If it doesn’t overshoot it’s fine. Modern low self discharge (lsd) nimh’s like eneloops do not like to be held on indefinite trickle charge or be overshot. Older nimh were less picky about overcharge so long as current was below its reabsorption rate.But really thinking about it, this method doesn’t match up with how I’ve experienced nimh behaving on a charge. Intuitively, I want to say this will cause some (reversible) loss of capacity due to not fully charging the cells. It probably works best on new-ish high quality cells, ones with a few full cycles on a good charger. negative delta charge detection won’t work here.

skvmb: I thought this was about charging batteries made from coins. I'll stick do salt water lmao