Rechargeable batteries (AAs)

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rayonline

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# 212788 12-Apr-2017 14:54

We hear about they have cycles up to or over 1,000. Many users including myself don't go thru that many cycles, do they after some years suddenly go bad?

I picked up 4 Eneloops and a bundled discounted charger, I went for the one that charges the cells individually and have colour lights. I found 8 AAs are all bad, 4 were bought in 2005 and the other 4 in 2009. They still charge up with my other charger though but it was good to know that they were in error. Maybe they are ok for low drain devices like remotes.

Cheers.

ubergeeknz

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Vocus

# 1762265 12-Apr-2017 15:03

The voltage will have dropped if they've been sitting around for a while, maybe below some threshold set in the charger.

IMO charge them a while in your other charger and then try them again on the eneloop charger.

Most battery chemistries have a "Shelf-life" anyway regardless of cycles, NiMH is no exception, as you say it's unlikely you will use 1000 cycles unless you run them in a high-drain device you use every day (camera etc) but that's when they make the most sense

rayonline

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# 1762323 12-Apr-2017 17:04

Thanks just tried that. Still error. Will just use them with remotes. Well .. the newer batteries have a 10yr shelf life. Eneloops say they hold a 70% charge after 10yrs.

raytaylor

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# 1763352 12-Apr-2017 19:08

Realistically a rechargable battery would last about 2-3 years. I also dont believe the 1000 cycle hype.

If you discharge it by no more than a 90% state of charge you might be able to get 1000 cycles, but if you discharge them by 50% you will get less than 200 cycles. Lithium might be better though.

Also remember that rechargable batteries only supply 1.2 volts instead of 1.5 volts. This means if an appliance uses 3 volts from alkalines, its only getting 2.4v from rechargables.

Ray Taylor
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rayonline

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# 1763358 12-Apr-2017 19:12

raytaylor:

Realistically a rechargable battery would last about 2-3 years. I also dont believe the 1000 cycle hype.

If you discharge it by no more than a 90% state of charge you might be able to get 1000 cycles, but if you discharge them by 50% you will get less than 200 cycles. Lithium might be better though.

Also remember that rechargable batteries only supply 1.2 volts instead of 1.5 volts. This means if an appliance uses 3 volts from alkalines, its only getting 2.4v from rechargables.

They now saying 2,100 cycles and 10yr store and use :D ;)

timmmay

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# 1763376 12-Apr-2017 19:42

I had some Powerex (very good quality), probably put them through 150 cycles over 5+ years before they wore out. That's with a great quality charger. So yes I think they do fail. It could be that more use makes them last longer, not sure.

Battery university is a good resource.

JimmyH

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# 1763404 12-Apr-2017 20:35

I have some Powerhaus NiMh AAs purchased in 1999.

They have probably had circa 250-300 charge cycles (mostly in a camera flash).

They still work fine.

rayonline

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# 1763408 12-Apr-2017 20:45

JimmyH:

I have some Powerhaus NiMh AAs purchased in 1999.

They have probably had circa 250-300 charge cycles (mostly in a camera flash).

They still work fine.

With you camera flash are you still getting the recycle times as specified in the users manual?

Both the 2 sets of 4 AAs of mine works in my speedlight but they take 16-20sec to recycle a full power flash instead of the 4sec. These batteries continue to charge fine but with my Panasonic charger they blink red signalling error.

k1w1k1d

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# 1763414 12-Apr-2017 20:57

I have stopped using rechargeable AA's and AAA's except for the cordless phone. Much easier to buy packs of alkaline batteries. As Ray advised the rechargeables are only 1.2v.

rayonline

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# 1763415 12-Apr-2017 21:00

k1w1k1d:

I have stopped using rechargeable AA's and AAA's except for the cordless phone. Much easier to buy packs of alkaline batteries. As Ray advised the rechargeables are only 1.2v.

Can certainly see your point. Most items now are specialised lithium rechargeables. The only item I use it for is a film SLR and a speedlight which may go thru them a bit quicker. For clocks, remotes etc ... seems easier with alkalines.

JimmyH

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# 1763422 12-Apr-2017 21:07

rayonline:

With you camera flash are you still getting the recycle times as specified in the users manual?

Both the 2 sets of 4 AAs of mine works in my speedlight but they take 16-20sec to recycle a full power flash instead of the 4sec. These batteries continue to charge fine but with my Panasonic charger they blink red signalling error.

I'm using them in a Canon external flash (420ex). The cycle times are just fine. No perceptible difference with the old batteries and a new set I acquired at the end of last year.