AA NiMh batteries

Jun 05, 2007 22 Replies

Looking for a battery re-charger for 2700mAh Ni MH AA batteries on a well known online auction site and can't seem to find one suitable. What output from the charger is sufficient to recharge 4x2700mAh AA batteries. A reply from on LCD charger supplier said the output was



1000mA per channel, so how that recharge a 2700 mAh battery ? I am looking to charge 1-4 2700mAh AA batteries and 1-4 1800mAh AAA batteries.

In just under 3 hours is the answer.

The charge rate dictates only how long it takes to charge the cells, not whether it can or not.

This is the sort of thing you need:

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can recommend the cells from this seller as well, they perform very well)

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> (I can recommend the cells from this seller as well, they perform very well)

I've just used this seller too - AA & AAA cells, and charger, highly recommended.

Martin

Within reason, the output current doesn't matter. Just that the lower it is the longer it will take. And I still reckon an overnight charge at

1/10th of the capacity is the kindest on the batteries.

At 1000mA (i.e. 1A) it would take nominally 2.7 hours to recharge a

2700mAh battery. (Do the sums!)

Actually it would take almost half as long again because batteries are far from perfect, but a good charger will keep applying current to a cell until it detects that it is full - whether that's 5 minutes to top up an almost charged one or 5 hours on a completely discharged mega-capacity cell.

7dayshop do an own-branded changer identical to the Vanson "1-hour" 4 x AA/AAA chargers.which I'm very happy with (the Vanson version that is).

In message , snipped-for-privacy@netscape.net wrote

You appear to be mixing up the current that is available to charge the battery with its capacity.

Consider that you have a 2700 mAh (milli Amp Hour) battery. This means that it can supply 1mA for 2700 hours or 10mA for 270 hours or 100mA for

27 hours or 1000mA for 2.7 hours. These are 'perfect world' figures and not what you would actually achieve.

Conversely, you have the same type of result when charging.

If a charger could only supply 1mA then it would take 2700 hours to charge.

In your stated case, if a charger could continuously supply 1000mA to a

2700mAh battery it would take 2.7 hours to charge. The battery may get rather hot.

|!in 642258 20070605 230841 snipped-for-privacy@netscape.net wrote: |!>Looking for a battery re-charger for 2700mAh Ni MH AA batteries on a |!>well known online auction site and can't seem to find one suitable. |!>What output from the charger is sufficient to recharge 4x2700mAh AA |!>batteries. A reply from on LCD charger supplier said the output was |!>1000mA per channel, so how that recharge a 2700 mAh battery ? I am |!>looking to charge 1-4 2700mAh AA batteries and 1-4 1800mAh AAA |!>batteries. |! |!

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redirects you to a log on page, does not give the product itself.

No connection with this seller, just a satisfied customer. I bought one of these;

Ebay Item No. 290035703991 , or

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batteries do, understandbly get quite warm, but the charger has a fan under the batteries which blows air across them to cool them (slightly). I am more than happy with my purchase.

Glenn

battery re-charger for 2700mAh Ni MH AA batteries on a

How long have you had it? How many times have you used in on any particular cell?

MBQ

Had it 6-9 months or so. I have not charged any individual cell more than about 10 times. I do only use branded cells though. I have not noticed any ill effects on the batteries in this fairly limited test.

Glenn

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>>> (I can recommend the cells from this seller as well, they perform >> very well)

Why doe he say 2700mAh when the batteries clearly show 2600mAh?

I have a Vanson V-6000. It works fine. It fast charges AA NiMH cells at about 2000 mA before dropping back to trickle (on delta-V, on over-temperature sense, or on a safety timeout).

However I recently had to discard three out of a set of eight "unknown brand" AA NiMH cells after about six cycles. They started to emit the odd sharp "crack" when on fast charge. The "cracks" even continued for a short while after removing the cells from the charger.

I have cells of two other brands that continue to charge uneventfully.

I have the same suspicion as above that fast chargers might best be partnered with "trusted brand" cells.

I wonder why everyone seems to want the complication of fast charging? I can understand a tradesman needing it for a much used drill, etc, but why with AA cells? What piece of equipment that uses these would benefit from a 1 hour charge? All the things I use these for last for more than a day - so a spare set of batteries and an overnight charge does just fine.

Wron photo perhaps:

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I was under the impression that a 2700 maH cell needed 1.4 times its capacity put in to fully recharge from flat i.e. approx 4000 mah, so at 1000 maH charging current that would be 4 hours.... or are NiMH cells 100% efficient now in converting charge current ?

Nick

1.4 times is certainly a 'benchmark' for recharging - you use 14 hours at a 1/10th rate with Ni-Cads. Whether it applies at other charge rates and battery types I dunno.

Because Sod's law decrees that just when you're about to take out your digicam, r/c toy or whatever you realise you haven't recharged the batteries for ages and you'd better do it now. That's when being able to slap them in the Vanson and get green LEDs within 10 or 20 minutes is _much_ more convenient than waiting 14 hours!

As for the "complication", why does everyone want the complication of a mobile phone? It's only complicated to the designer: for the user it makes life simpler.

I can see that with something like a camcorder. But the question was about AA cells which must be being used in something which doesn't have its own charger etc. So will require the discipline of changing batteries and also having spares?

But don't the design of these allow for easy recharging - you just plug them in at the end of the day? Of course I don't use my mobile as much as most.

Because once you start out with rechargeables you tend to make a /point/ of buying things that will re-use AA batteries, OK so most remote controls use them anyway, but I've been picky when choosing wireless mice, cameras, central heating programmers, torches, radios. Psion lost that and other battles for PDAs though.

Same applies for memory cards, I try to avoid anything other than CF or SD/MMC.

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