Recharging Alkaline Batteries

DON'T

I did it for over 50 years. It works but:

-1/ For most but not all of them. You've got to try: there is no danger if you respect points 3 & 4.

-2/ They must be not fully discharded. Let say 1.3 or 1.2V min.

-3/ You need to use a current source never a voltage source

-4/ The choice of the intensity dépends on the battery shape. For exemple 10 to 20mA for R20, 5 to 10 mA for AA & AAA, down to .5 to 2 mA for button shaped. Let it connected long enough: let say 1 or 2 days. Disconnect before measuring the recovery voltage.

-5/ You can try this a couple times no more. There is no danger. But you never recover the number of Coulombs they had when they were new. The internal resistance might increase to a point that normal use becomes impossible. It still might help.

true, current not voltage for charging, I also monitor the temp as well. But I don't do this anymore, haven't used those types of batteries for yr's. As I remember some time back, there was a charger for these being sold.

Ray-O-Vac used to make rechargeable alkalines, but I think they have replaced them with something else. I liked those because they put out 1.5 V when charged, instead of the 1.2 V per cell for NiCd's or NiMH's.

Sometimes you can get a little extra juice out of an alkaline by placing it next to an incandescent light bulb for a few hours.
Also, you might be able to use them in a device that draws less current. I have a small handheld LCD TV, and when the batteries can no longer run it, they can still run my portable AM/FM/shortwave radio for a couple of weeks.

Otherwise, don't ever connect a non-rechargeable battery to any kind of charging device or circuit!

<Otherwise, don't ever connect a non-rechargeable battery to any kind of charging device or circuit!>

While respecting the above caution, one of the electronics magazines did produce a charger circuit for non-rechargeable batteries several years ago. The charging principle was based upon a lop-sided AC waveform, where the negative-going cycle was much smaller than the positive-going one. This was just sufficient to overcome a zinc-carbon battery's inherent reluctance to be recharged, and a trial circuit did actually work.

Recent investments in rechargeable cells have sent the circuit into disuse.

Let me emphasize your last statement:

"don't EVER connect a non-rechargable battery to any kind of charging device or circuit!"

To the originator of the thread:

Even with rechargable batteries, you have to know the charging parameters for the battery (or battery pack) you are using... whether NiCad, NiMH, Li-ion or whatever. Contact the manufacturer of the battery first.

I got the tip from a electronic expert and have used it a few times.

I was using a wireless alarm system using 9v (PM#) batteries.

The batteries would normally go flat at about bedtime.

Instead of having to put up with the annoying warning beeps I charged the batteries for 8 seconds on a normal 12v charger.

This charge usually extended the life of the battery for another night or 2.

If I remember correctly it worked on alkaline and not on sink-carbon.

Would this be aceptable or did I took my life into my hands?

Has anyone ever worked out why for example fire/smoke detector batteries always need changing in the middle of the night and almost never in the day?

I have found out I believe so if anyone is interested, I will post it for you later, just ask me.

If I am right, it is really really simple when you know why! Perhaps someone else has also worked it out, share your ideas my friends, I am open to learning more, but I think my answer is correct!!! Perhaps you have the same answer as I....!

Post it post it post it

Jim

Is it Murphy's law?

its all in how you hold your mouth!

Scooter

Anyone care to comment on this:

http://www.afrotechmods.com/reallycheap/batteries/batts.htm

Anyone care to comment on this:

http://www.afrotechmods.com/reallycheap/batteries/batts.htm

Absolute Pleasure - Thats how much I enjoyed this fellas site. Refreshing, I found myself exploring his other creations and those of his peers laughing the whole time as I rolled my eyes as I read. Thanks for making this engineers day - Talk about "Keep it Simple Stupid" - KISS . . .

Mmmm Disney fruit snacks. That Ariel is smokin'!

that guy's site was so refreshing in this world of plastic and pre-fabbed everything. I absolutely loved it!

My dad was an electrical engineer (I'm a mechanical one) I grew up with this funky contraption down on his workbench he made for charging zinc-carbon batteries. When I got old enough, someone told me that it couldn't be done, I asked him about it he asked me "who are you going to trust, the guy who say's it can't be done or the guy who's been letting you use all these recharged batteries for all these years?"

Practical application wins out over theory every time.

Scooter

As a lad...i used to drill two small holes in the top, through the pitch like substance that was there, and...simmer in a pan of water for an hour or two. Our physics teacher said it would work, and it did.

In those days getting a battery to work by putting 2 or 3 kilowatss into it was a real bargain.

More recently one night, the room was filled with a static-like crackling noise, and there was a strange warm feeling coming from in front of me, whichever way I turned...! The rechargeables in my head torch shorting out. Nearly a lobotomy.

Jim

look at this: How To Recharge Standard Duracell Batteries - Gizmodo

This is going to be a bit of a let down, it is so simple, my apologies in advance....but I am sure that it is true....

I have found that the smoke detector always starts its peeping for a new battery sometime in the night, the reason is that a battery is also a chemical reaction, chemical reactions are usually speeded up by warmth.

It is a know fact (mentioned on this Blog too) that warming a battery will squeeze some more life out of it.....

Well the opposite is also true, cooling a battery down will slow down its reaction, it produces less voltage and wowee, when is it at its coolest?

No matter what time of year it is, AT NIGHT of course.....nights are ALWAYS cooler than days....or sometimes around the same temperature, but very, very seldom is the night warmer and if it was AND the battery were on its last legs at the same time, it would peep during the day....About once in one million times.....so the other 999,999 times, it peeps at night! QED.

Better is to buy good batteries and replace them on one date, every year, even if not empty!!!

Tried three times yesterday to post that answer, but my connection kept dropping....

Nice one though.

Jim

Hi,

it took several years for me before the penny dropped!!! I thought at one point it was something to do with darkness.....

Good that you and I have the same take on this one!!

nope, its still how you hold your mouth

I guess this is supposed to be an attempt at humour and truly we at CR4 LOVE to have humour with everything, but sadly, your "sense" of humour is completely "senseless".....

...and just in case you think differently, this was NOT an attempt at humour either.....

So either start taking the pills, or leave the wacky baccy or the bottle untouched.......you are the only one who thinks you are funny......

I like it!

Yes I agree with the temp idea.

I suppose my charging for a few seconds (Post 5) only raises the temperature and allow the release of the last drop of power.

Put simply, yes it is possible and yes it can be done safely. Achieving the right charging parameters can be a little tricky so its best that you don't try and do it yourself unless you know what you are doing and take the proper safety precautions.

However, there are companies that make chargers that work (just don't expect the same cycle life as a rechargeable battery).

www.rezap.com.au/

There are others too.

Play safe.