Revival/ charging of rechargeable batteries (AA/AAA)

[palinurus]

Ni-metal hydride types.

Left my Dinotte on over the weekend so have drained my batteries (4 x AA) nicely. The (Engergizer) charger I have at work is sniffy about very discharged batteries and throws up a row of crap battery symbols and refuses to charge them. My previous Vapex charger didn't do this. Can anyone recommend a more tolerant charger/ give me some tips on battery revival?

I have my spares in the charger and they are cooking nicely, normally they only get partially discharged and I top them up daily.

 

[palinurus]

[QUOTE 4031917, member: 45"]I'll be watching this with interest. I have similar problems with my smart charger. I used to bang the dead batteries into a cheap standard charger get get some energy into them, then put them in the smart charger, but I've lost the old standard one.[/QUOTE]

That is exactly what I used to do! I dropped and broke the transformer on my Vapex charger.

 

[Milkfloat]

If you don't have a cheap standard charger around to boost them to something recognisable by the smart charger, you could try boosting from another AA/AAA.

 

[Hardrock93]

Don't know of this will help, but I had a similar problem with my charger for an Olympus camera battery. It wouldn't start charging if the battery was completely flat. I found that if I connected a new Duracell AA across the discharged battery for a couple of minutes, it gave it just enough of a charge such that the charger would then start doing its stuff.

 

[palinurus]

Will try as soon as my spare ones are done.

 

[Mile195]

Sounds like you have an "intelligent charger" that monitors the output of each battery as it charges and modifies the current accordingly. I have one too, but if the battery is too discharged it throws up "null" and doesn't do anything.

In that situation, I put the batteries in a "dumb charger" - that is, a cheap charger that just charges at a given rate for a given amount of time. That's the kind you often find provided with a set of rechargeable batteries (and costs about £15 in the supermarket). A couple of hours in that will get enough charge in for the intelligent charger to work properly.

 

[albion]

Just go on ebay. The cheapest USB AA charger will near always be a dumb charger and so will raise the voltage fine for charging.

 

[deptfordmarmoset]

I've had a couple of batteries that have thrown up ''null'' and refused to recharge. What I'm now wondering is why there isn't a ''rescue'' setting on smart chargers, something that makes it act dumb for a little while. Or perhaps there is but I don't know of one.

 

[the snail]

had exaxtly the same problem with my energiser charger, this one did the trick - quite a handy one fir travelling too:
http://www.hotukdeals.com/deals/uniross-globe-trotter-pocket-travel-601586

 

[Lonestar]

Ha.came off AA/AAA years ago and now am a firm believer in 18650 batteries and their torches.Juts ordered five focus 590 torched from china to go with the others I have already got.

 

[palinurus]

Gave them a boost with a new Duracell and a paperclip and I'm up and running.

I've got some really old AAAs in my desk drawer at work, tomorrow I'll try giving them a few volts from a variable power supply in the lab and see if I can get them to charge after.

 

[jefmcg]

I've had one of these for 5 years. The refresh button fixes reluctant batteries.

 

[migrantwing]

I got my charger from an online retailer named 7dayshop. They sell all sorts of stuff. I got my charger and 4xAAA and 4xAA which are higher capacity than the standard batteries you buy, giving longer run times. Got them all for around £10.

 

[mjr]

Can anyone recommend a more tolerant charger/ give me some tips on battery revival?

I recently bought a new smart charger because it had a better display and I wanted to see what capacity was left in some of my batteries, but it is very sniffy about ones that have been discharged heavily in a low-drain device like a clock. My older tri-mode NiCd/NiMH/Alkaline charger manages to recharge them and doesn't seem to cause leaks or anything, but it does mean I still don't know what capacity is left. A review is http://www.geekalerts.com/battery-wizard-alkaline-recharger/ but I don't know if it or a later model is on sale anywhere.

 

[fossyant]

I still have a dumb charger to sort our overly discharged batteries. I don't think rechargeable batteries are overly keen on low drain devices like clocks though.