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Cheap AA and AAA battery charger

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audioguru

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For years I have used an Energizer AA and AAA Ni-MH battery charger. It is simple and does not detect a full charge, instead it simply has a timer. It shuts off after charging for about 6 hours. If it is charging and the power fails then comes back the timer starts again and the batteries are over-charged. It refuses to charge more cells for a while after it has timed out.

I recently found a Rayovac charger and it looks similar to the Energizer one. Except it does not stop charging because it does not detect anything and does not have a timer. It keeps on charging forever. I think the battery manufacturer wants it to over-charge and destroy batteries then you buy new ones.
 
Ah, there you have it! You bought "cheap Chinese junk" (your favorite term) chargers with an American name on it. I got rid of all my Ni-MH batteries because of unpredictable charging and switched to Li-ion wherever possible. For those I can't switch over I go and by batteries at the "$-Store". E
 
Yes, the Energizer battery charger I bought and the Rayovac one I found are made in China. But their labels are written in perfect English, French and Spanish.
I never buy anything Chinese with spelling errors like the new Chinese grocery store selling Lamp Chops. I guess a "b" looks the same as "p" to a Chinese person.

Energizer Ni-MH cells:
1) AAA are made in China but they work fine.
2) AA cells are made in Japan.
3) 9V were made in Germany, mine is about 4 years old.
Energizer alkaline AA cells are made in USA but you know what? They are not made by Energizer, instead they are made for Energizer.

The Li-Po batteries for my rc model airplanes do not say where they are made, probably China. I use only an American brand name ones and they work fine.
 
My Rayovac charger is better behaved than yours. I got it shortly after they came out, when R was practically giving them away because of poor market acceptance. With dead batteries it takes a reasonable amount of time. If I put the now fully charged batteries back into the charger the next day, it is on for fewer than 10 minutes. So it appears to evaluate the state of charge and then act accordingly. My toothbrushes and camera flashes are happy.

ak
 
I looked inside my Rayovac AA and AAA charger. It has a little transformer, an LED, 3 diodes, two capacitors and 5 resistors. No transistors and no ICs.

My Energizer charger has many parts inside.
 
I have a Good "HP" Smart Charger for AA, NiMH Batteries.
(It will charge One set or Two sets of two AA Batteries.)
It will charge up the batteries to full, than trickle charge them to maintain a full level as needed.
Or it can be set to Discharge the batteries down to their Low Level, than Re-Charge them to Full, at which time it switches to a Trickle charge.

Been using it for about 5 years now and It works Great.
 
I recently bought some eneloop NiMH batteries (which retain most of their charge for many years) along with the charger.
The charger manual states that the time it takes to charge the battery depends upon its state-of-charge so I would assume that it has some type of smart chip that monitors the voltage change with time to determine when full-charge is reached.
And since those type of batteries have such a low self-discharge rate they don't need to be trickle-charged after reaching a full charge.
 
Energizer Ni-MH cells made since 3 years ago also hold their charge for a long time like Eneloops. They are also made in Japan. Coincidence or same Sanyo/Panasonic manufacturer?
A battery charger IC follows common advice for charging Ni-MH cells by detecting the voltage leveling or voltage drop that occurs when the cell is fully charged, not simply the actual voltage it has risen to.
 
Yes, My charger detects that Knee point, as the voltage drops slightly.
 
This is a pretty good charger and comes in various forms and under various lables:

https://www.batterylogic.co.uk/technoline/technoline-BL700.asp

It takes AAA & AA NiCad & NMH and does -dV/I sensing. It also does cycling and recovered a load of batteries that I had abused with basic constant current chargers.

It's not cheap but not that expensive either, especially if you shop around. I have had mine for a few years now and it's been a good investment, in retrospect that is.

If a battery is discharged to far it just wont touch it it because it decides that the battery should not be used. If that happens just stick some current into the battery and the charger will then accept it.

Charging NMH batteries is difficult because of the small V drop when nearly charged and all chargers make mistakes for that reason- it's just a fact of life. NiCad are easier.

Batteries are one of the biggest rip-off areas, so best to stick with proper brands from a reliable source: Panasonic (Sanyo), Varta etc

Does anybody use LiIion batteries, like the CR123A?
 
Energizer Ni-MH cells made since 3 years ago also hold their charge for a long time like Eneloops. They are also made in Japan. Coincidence or same Sanyo/Panasonic manufacturer?
A battery charger IC follows common advice for charging Ni-MH cells by detecting the voltage leveling or voltage drop that occurs when the cell is fully charged, not simply the actual voltage it has risen to.

You just never know, and it can change from batch to batch. Anybody can stick labels on. Rechargeable batteries are awkward to make and the proper manufacturers do a load of test to ensure that the baterries will be ok in the field. But even so, some still fail. The second line and rip-of types either arn't made and tested so well or are possible rejects.

Have you seen some of the tests of batteries on the net. In one case they did a shoot-out between a famous Ebay brand (FEB) 18650 and Sanyo. The FEB was labeld 4 A/H and Sanyo 2.2 A/H (not exact figures but that order). Bet you can guess which had the higher capacity. Not only that, but less V droop. If that was taken into acount, in terms of useability, the Sanyo was effectively 4x better. Also, the FEB had a much higher ESR which meant that if you had a load which requirs bursts of high current the terminal voltage dropped like a brick. Of couse, you can always get around that by slapping a big c across the battery, but that is more complication and cost, not to mention the size increase.

I stick to Eneeloop now, although you can't get them in PP3 (very troublesome things) so I use 7 day-shop versions which seem to be better than the branded types.

While on holiday in Teneriffe, a fast talking salesman pesuaded me to buy a 4,700ma/h battery for the camera on my belt. At the time the Canon batteries for the camera were 900 mA/h. I knew the spec was outlandish, but I was in a holiday mood and needed a second battery. It was a good price too.

The battery worked OK after two or three charge/discharge cycles but it was no where near 5.2 times better than the original Canon, more like 1.1x. It carried on for a year, but one day, when I was depending on it for a shoot, it died. Back at home, I opened it up. Guess what was inside- two standard sized batteries labled 1000 maH. One was dead and wouldn't recover. The other was OK, so out of curiosity, I gave it a couple of charge discharge cycles and checked the capacity- around 500 mAHr at 20mA and at capacity/10= 100ma it dropped below useable voltage straight away. Overall the camera battery was beautifully made though- much better than the Canon.

It's been 12 years now and the Canon battery is the same as it ever was.
 
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Hi Spec,
Energizer sells a C size Ni-MH cell at a high price. Its specs show that it has the same capacity as a little AA Ni-MH cell that they sold a few years ago so I betcha there is a little AA cell inside.
You mentioned battery rip-off. What about ebay Chinese fakes? Maybe you have not seen this test of one:
 
Hello AG,

:joyful::joyful: That made me laugh- no I hadn't seen it. Great music too. Thks
 
Great music too.
Did you notice that the heavy compression pumped the volume of the background music down during each loud bass beat? I would like to hear in without the compressor then I could feel it more.

I wonder if the little battery and little capacitor were connected with the correct polarity.
 
Did you notice that the heavy compression pumped the volume of the background music down during each loud bass beat? I would like to hear in without the compressor then I could feel it more.

No, didn't notice that- only listened on cheap ear buds

I wonder if the little battery and little capacitor were connected with the correct polarity.

:p

(I missed your post- no notification)
 
previously i had ''dumb'' charger for AA/AAA, it just charged all the time and was ridiculously hot after a while. Now i have ansmann powerline 5 LCD (NiMh/NICd), been working for at least more than year now all the time when i have computer on. It has trickle charge so it shouldn't damage shells.....at least if there is damaged cell, it tells so. I'll probadly buy some changer for Li-ion/LiPo and similar cells too
 
Modern Ni-MH cells do not need a trickle charge because they hold a charge for one year. Sanyo/Panasonic Eneloop and Energizer have them.
 
Modern Ni-MH cells do not need a trickle charge because they hold a charge for one year. Sanyo/Panasonic Eneloop and Energizer have them.
Hehe, forgot to tell i have some chinese, haven't bought any better ones, these work for now. I've heard good things about eneloops ecpecially in cameras
in fact thought, i just checked while writing this and i do have energizers at that trickle charge....
 
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