Author Topic: Ni HM AA surprising death  (Read 1045 times)

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Offline jdmcgraw

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Ni HM AA surprising death
« on: October 02, 2020, 01:30:22 AM »

Hi all, Thank you for giving me the opportunity to post here, although I'm not sure if this is the right place to make this post. If not, could you please direct me to a better source?
I'm used to flashlight batteries gradually getting dimmer & to flicker when running down, before total failure. Recently I had 2 fairly new AA  Powerex 2700 AA MIHM cells in a Fenex LD22 flashlight, just quit. They may have gotten dimmer, but it was not obvious, & they certainly didn't flicker. I've also had 2 of the same described cells in a Nikon SB-400 flash come out totally dead. Other Nikon SB flashes will go to sleep & remain in that condition for months w/ out exhausting the batteries. This may be a characteristic of just the SB-400, or I may have an anomalous unit. I tried to charge the 4 cells in a MAHA MC-C9000. After one charging & discharge & charge cycle, they read as “HIGH”.  I also tried, hopefully, “REFRESH / ANALYZE” & “BRAKE-IN” They still read as “HIGH”. At ~3 bucks a pop, I would like to find a way to prevent this from continuing.
Any suggestions to as to how to do this or to a source on-line would be greatly appreciated,
JD McGraw

Offline JohnnyMac

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Re: Ni HM AA surprising death
« Reply #1 on: October 16, 2020, 04:22:12 AM »
It really depends on the flashlight circuitry (low voltage protection) and the cells used. Alkaline cells will generally keep draining until they run out of juice. Quality NiMH cells will provide a fairly constant out put until they quit.  If a light doesn’t have LVP they can drain a cell too low to the point where they will not take or hold a charge well. It is best to charge or swap them when you see the output start dropping.

As for cell recommendations, I use and recommend Amazon Basic NiMH cells.  They are very inexpensive and hold 2700mAh. As good as Eneloop brand for half the cost.