DeWalt 18V 2.6Ah NiMH battery issues

9 May 2009
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United Kingdom
I've got three DW 18V 2.6Ah NiMH batteries that are around 6/7 years old but have seen only very light use. They've been charged maybe 200x max in that time. One of them has recently stopped taking a charge (rapid flash) and one of the others seems to be going the same way (charger only flashes for 5-10 mins or so before claiming it's done, then I don't get much out of the battery before it's dead again).

Obviously the number of charges these batteries have been through is pretty low and nowhere near the expected # of lifetime cycles, but as I say they are a few years old now and have not been used frequently.

Can anyone with a bit of battery chemistry knowledge confirm whether their age and lack of use is likely to be the reason for them dying after so few charge cycles?

I found an old thread on another forum where a guy had the same problem ( but the responders immediately started talking about NiCad batteries and nobody seemed to notice or pick up on this.
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batteries prefer regular use
7 years is a fair life so the best you can do is try several reinserts making sure the battery and charger are cool [below around 25%]
if this doesn't help then consider useing the worst battery as a donner battery to replace any poor cells on the other battery
and the only real difference in this instance is nicads must be cycled [fully charged and discharged before charging] where as nmh can be charged at any time
Cheers All - I went through the reinsert thing for a while with the one that's now not taking charge at all, and it's what I'm currently doing with the second one but I think the writing's on the wall for it too.

Tbh this seems like the perfect opportunity for me to cut down to two batteries given the amount of use they get, which in turn makes me wonder: most of the jobs I use them for are quite short and don't require more than one charge/swapping packs, but occasionally I'll have an all-day job where being able to swap packs is handy. Would I be better using one pack as the day-to-day and keeping the other discharged unless/until I need it (maybe using it every couple of months to condition it) or is it better to keep them both in equal use?

I've read somewhere that batteries stored for more than a month or so really need a slow charge first time round to get them back in condition - maybe I've answered my own question here as I don't think there's a way to do that with the DE9116 charger I've got, is there?

Greetings from Auld Reekie :)
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i personally cycle my batteries at least once a month and i still have the then 7 year old batteries refered to in the origional article although they hold little charge :D

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