Mixing NiMh brands

[fishx65]

Any problems mixing NiMh brands with different capacities? Say using an Energizer 2450 and a Duracell 2000 in a 2 cell light.

 

[Marduke]

Any problems mixing NiMh brands with different capacities? Say using an Energizer 2450 and a Duracell 2000 in a 2 cell light.

Yes, do NOT do it.

 

[jt4703]

I asked a similar question: here is the thread.

http://www.candlepowerforums.com/vb/showthread.php?t=228046

 

[Turbo Guy]

Here is the thing. Unless you have a charger / discharger that shows you the actual capacities then in fact you can have cells from the same package that are not the same at all.

Example four cells from a recent purchase. All from the same package.First refresh cycle on LaCross BC900 charge at 1000 discharge at 500.

1359 / 1405 / 127 / 1531.
second cycle
1311 / 1317 / 1168 / 1720


20 cycles latter
1443 / 1590 / 1357 / 2000

FYI The above are a reconized name brand listed as 2100 mAh LSD AA NiMh.

No way I am stating this is normal but it does show that if you use a charger which has no display you really have no idea if the cells are matched unless you charge them,use them and then check their voltage under load.

As a matter of record I have mixed different brands / capacity AA NiMH cells a lot during the past 14 years. I would rather have two cells of close to the same real capacity that two cells with the same stated capacity.

If you are using a charger that charges each cell sperately and you do not use more capacity than the weakest cell can deliver it really make no different at all,IMO.

 

[Marduke]

Here is the thing. Unless you have a charger / discharger that shows you the actual capacities then in fact you can have cells from the same package that are not the same at all.

But there is a HUGE difference between mixing cells of unknown condition of the same package, and PURPOSELY mixing cells of different brands AND capacities.


The likelihood of the same package of cells is much greater of operating relatively similarly vs a random assortment of brands and capacities.

 

[Turbo Guy]

Not to argue but OP

Say using an Energizer 2450 and a Duracell 2000 in a 2 cell light.

I theory that is a 20% difference however as I pointed out new 4 cells from same package had greater difference 1357/2000=33% after forming.Thing about general statements is that the only cover general conditions what ever that may be.

Once again I have used mixed brands of mixed stated capacities for many years. I try to start with matched(graded) cells and keep them in sets of 2,4,8 etc. but over the years some have to be replaced. I would rather have two cells which end up at the same voltage after X amount of useage as a pair no matter what the ststed capacity ,brand name or age than two which have a large different in voltage under the same condition.

KISS If possible use a good charger,match / grade cells to be used in sets. If you know very little about matching cells or use a charger which shows only fully charged them purchase and use in sets and hope for the best.

Once again if you do not deeply discharge the cells then a 20% capacity difference make little difference.

 

[Turbo Guy]

A real world test using diffrent brands,different age,different rated and different real capacities.

http://www.candlepowerforums.com/vb/showpost.php?p=2915008&postcount=15

 

[Wattnot]

If you mix the nimhs you will probably ruin (or at least shorten the life of) the cells but I doubt very much you will hurt the device or yourself. Lithiums are a WHOLE 'NUTHER STORY though.

EDIT: I'm not at all talking about CHARGING mixed cell capacities in a single charger, I'm only talking about USING the batteries in a flashlight or other device.