Interesting??? NimH notes....

I use almost only Energizer NimHs. I try to treat them well, but do use a 15 minute as well as sloooow chargers and a C Crane QC as well.

I run my EDC, fun lights and my GPSr on NimH. I haven't had any problem that I notice in lights. But my GPSr has cut off WAY sooner than it should for the third time today. In each case one cell has +- 1.24V while the other has +- 1.06V.

It COULD be a connection thing in the GPSr but everything LOOKS okay.

Do I likely have cells dying this quick? Or have I just not found the problem yet?

dead cell

try a slow charge on it

if it still fails, toss it

If one cell is at 1.06V with no load, then it's definitely completely discharged, and much weaker than the others. The moment you draw power, that cell is probably instantly dropping to ~0.6V, then shortly after, probably being reversed.

When you fire up your GPS (assuming it's using 2 cells), it's only seeing 1.8V, which is probably near its low voltage cutoff.

The cell is near the end of its life - it sounds like it has significantly shorter life than the other, and probably should just be tossed.

I haven't kept PRECISE notes and have many NimHs from 1850 to 2500

Some I KNOW have been in flashlights too, and never saw early dimming.

I need to do some more precise testing I guess.

It's important to keep your NiMH cells grouped together so that they charge and discharge at similar rates. Not doing this can cause cell imbalance and under/overcharging. Try charging the cell by itself, do the same for it's mate or the rest of it's "group".

Hello Playboy,

I believe Turbodog hit the nail on the head.

The GPS units usually cut off when the voltage under load reaches 1.0 volts per cell. A weak cell will drag the other on down quickly.

Tom

If you could measure the current drain of the device in use and substitute a resistance load you could measure each cell to see how far they actually drop in voltage comparatively while in use.

I just flash-amped 4 batteries of which one was a problem. They haven't been on a charger in a few days and all flash 7.23 or so.

I'm thinking the 15 minute charger has an issue of contact or something.

Fancier measurements are WAY over my head!