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cab

Recharging non-rechargeable batteries

Was flicking through a catalogue at Bagpuss's place yesterday, came across a battery charger that'll re-charge non-rechargeable batteries, apparently up to 10 times.

I can't immediately see that working... Any ideas what that gadget is all about?
Jonnyboy

My mate had one years ago. I'm sure it worked.
vegplot

I used to work for a famous battery manufacturer in their R&D dept. While I wasn't a research chemist I did test cells and batteries.

I would not advise doing it, you are much better served using batteries that are designed to be re-charged.

Technically, it is possible to partially reverse the chemical processes of discharge. BUT this may generate internal gases inside the battery causing a pressure rise and possible electrolyte (seriously caustic) leakage, or it could explode.

I used to reverse charge alkaline batteries deliberately in a special fume cupboard). You do not want to be in the vicinity of high velocity metal parts and gelled caustic. Need I say more?

I'm not saying the chargers advertised are unsafe, far from it, all I'm saying is that you should consider the implications of charging alkaline batteries NOT DESIGNED to be recharged.

You will never recharge to the original capacity of the battery and, more than likely, service life would be seriously reduced per charge.
sean

vegplot wrote:
I used to work for a famous battery manufacturer in their R&D dept. While I wasn't a research chemist I did test cells and batteries.


Do I know you?
vegplot

DETC?
sean

No then. I worked briefly for Berec Advanced Projects Group.
vegplot

I regret to say I don't you personally. Sad
sean

Never mind.
tahir

sean wrote:
No then. I worked briefly for Berec Advanced Projects Group.


dOING WHAT?
sean

I was working out the best way of removing contaminants (mainly iron) from very high surface area graphite for use in a putative electro-chemical oxygen generator which never came to anything. I was only there for about four months. Lab technician basically.
cab

vegplot wrote:

I'm not saying the chargers advertised are unsafe, far from it, all I'm saying is that you should consider the implications of charging alkaline batteries NOT DESIGNED to be recharged.


Presumably by having a specially adapted charger you might have a safer gadget, it might presumably charge the batteries more slowly to allow any excess heat to dissipate?
Jonnyboy

Wiki article
http://en.wikipedia.org/wiki/Recharging_alkaline_batteries
kevin.vinke

cab wrote:
vegplot wrote:

I'm not saying the chargers advertised are unsafe, far from it, all I'm saying is that you should consider the implications of charging alkaline batteries NOT DESIGNED to be recharged.


Presumably by having a specially adapted charger you might have a safer gadget, it might presumably charge the batteries more slowly to allow any excess heat to dissipate?


Not sure about this but they´ve been around for a while, the eaarly ones weren´t very good. I believe they used a pulse charge system similar to the cetec chargers, but don´t quote me Rolling Eyes
dougal

Its quite simple.
Buy proper rechargeables.
They are cheap. NiMH in Aldi & Lidl are actually cheaper than alkaline disposables.
The chargers are dead cheap too.

Don't buy disposables and then try to recharge them with a fancy charger.
They are designed to be disposable.

Straightforward enough?
vegplot

cab wrote:
vegplot wrote:

I'm not saying the chargers advertised are unsafe, far from it, all I'm saying is that you should consider the implications of charging alkaline batteries NOT DESIGNED to be recharged.


Presumably by having a specially adapted charger you might have a safer gadget, it might presumably charge the batteries more slowly to allow any excess heat to dissipate?


Battery charging is a form of electrolysis, a by product of which is hydrogen gas. That gas has to escape somehow. Alkaline batteries are sealed to prevent leakage but can vent a little generated gas under normal use. However, raise the gas levels and leakage will occur, raise it too quickly and the bu**er will explode.

In some designs the anode is a brass nail - sometimes with a pointy sharp bit at the end.

I'm describing worst case, but it's easy to get there.
thos

dougal wrote:

Buy proper rechargeables.
They are cheap.

Not here they're not. Lidl advertised AAs at €1 each on one of their specials, but they sold well before Terry got there. The normal price is about €8 each.
dougal

thos wrote:
dougal wrote:

Buy proper rechargeables.
They are cheap.

Not here they're not. Lidl advertised AAs at €1 each on one of their specials, but they sold well before Terry got there. The normal price is about €8 each.


In the UK, Lidl have sold AA (and AAA) NiMH rechargeables at £1.99 for a pack of 4. (The AAs are/were 2700mAh capacity.) Thats less than €3/pack. In the past they sold out very very quickly - now us locals are a bit more blasé! Very Happy
Just after this New Year I got a couple of packs in their 'odds and sods' clearance at just 99p per pack. They had more, but I'm not greedy, really! Had I but known, Thos, had I known.... Wink
Since then (but not this week) I happened to see them in Aldi at £2.99 for a pack of 4 ... these are all cheaper than alkaline disposables!


http://www.watchbattery.co.uk offer 4-packs of 2500mAh NiMH for £6.99
BUT note that you would pay a large premium for a marginal capacity increase to 2700 mAh...
The Watchbattery people though are best as a source of *unusual* things... like their "Hybrio" 2100 mAh AA very low self-discharge rechargeables. 4 for £8.49
cab

vegplot wrote:

Battery charging is a form of electrolysis, a by product of which is hydrogen gas. That gas has to escape somehow. Alkaline batteries are sealed to prevent leakage but can vent a little generated gas under normal use. However, raise the gas levels and leakage will occur, raise it too quickly and the bu**er will explode.

In some designs the anode is a brass nail - sometimes with a pointy sharp bit at the end.

I'm describing worst case, but it's easy to get there.


Enough said, that now makes perfect sense. Thanks!
cab

dougal wrote:
Its quite simple.
Buy proper rechargeables.
They are cheap. NiMH in Aldi & Lidl are actually cheaper than alkaline disposables.
The chargers are dead cheap too.

Don't buy disposables and then try to recharge them with a fancy charger.
They are designed to be disposable.

Straightforward enough?


Absolutely, and for the most part I use rechargeable batteries, with some 'proper' batteries in reserve because even the best rechargeables can let me down by apparently losing power too fast (cycle lights that get too dim all of a sudden). I'm really only asking about this here out of curiosity.
cab

Here it is, if you're interested:

http://tinyurl.com/2kqkey
dougal

cab wrote:
Here it is, if you're interested:

http://tinyurl.com/2kqkey


But that is £20....
... and claims *less* than 10 charge cycles.

4 proper rechargeable batteries + charger £9 total.
http://www.pixmania.co.uk/uk/uk/34331/art/eforce/v900-pc22-charger-lr6-aa.html

Downsizers shouldn't be buying *disposables*. Should they?
vegplot

cab wrote:
Here it is, if you're interested:

http://tinyurl.com/2kqkey


Nope! No interest, wouldn't wasted my money Smile
James

I've recharged alkakine batteries twice. Once, the battery exploded on me and that was quite nasty- there was hot caustic gunk all over the place. The other time, I succesfully kept the battery in one piece long enough to put it back into a torch, only to find that shortly afterwards it lost its charge.

Having said this, I was using jump leads off a 12v car battery . And that sits somewhere between the stupid and damn-right dangerous.

I've now got a nice little plug-in re-charger and subscribe to the dougal philosophy of battery use.
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