Alkaline battery chargers (2023 Update)

[Art Todesco]

I just saw this ad:

Anyone know it they work and how much energy you get after a charge, compared to a new cell?

[philoÂÂ]

X

No, they do not work.

Dry cells are a non-reversable chemical process

[Ray]

[Stormin Mormon]

When i was a kid, my Dad had a charger for dry cells. It put some power back in, but not much.

BTW, alkaline cells are not dry.

[Stormin Mormon]

I've got a Battery Manager Ultra (no longer made) and a Re-Nu (will made) for AA and AAA cells. They both put power back into alkaline cells. Some will leak (maybe 25 to 40% of the cells leak). If a battery is slightly discharged, it freshes up better, and less likely to leak. Cells deeply dis charged more likely to fail and leak.

I charge the cells, and put into the plastic holders with paper towels or toilet paper below the cells, wait a week or two. Pitch out the leakers, and check the cells for charge before using. Lot of work for not much benefit.

I've not compared first use to recharge. Less, but not sure how much less.

[clare]

Theoretically, and practically, yes. However the rechargers DO get a little bit of extra power out of the batteries because the reaction is not TOTALLY non-reversible. About 25% charge in "real world" - making it really not worth the expense and effort. This is assuming regular alkalines. There ARE rechargeable alkalines that work VERY well. - like "pure energy" and "envirocell". They are only good for about a dozen recharges - but unlike NiCads et al, they hold their charge for years. Their charge efficiency is also better than NiCad and NimH

[Stormin Mormon]

For AA cells, some folks have had good results with Powergenix. They are higher voltage than alkalines. Special charger needed. Not very forgiving of deep discharge. But, they do work. I've used them on occasion, with success. Great for digital cameras, or computer speakers.

[philoÂÂ]

The ad for that charger said "any" battery and showed photos of non-rechargeable batteries...that is why I said it's a scam.

A battery designed to be recharged is of course OK though

[philoÂÂ]

Though alkaline batteries may be moist inside they are considered dry cells.

"Wet" cells have actual liquid inside.

[JAS]

I don't know how good it is or if it is a scam but last year I had 20 outdoor rechargeable yard lights, some to battery and some four battery all with rechargeable batteries and most were over a year old and dying . I replaced all of the batteries with non rechargeable energizers and they are still going and have been running every night for a year. I do not know if they are getting a charge like the ones that were in the lights when they were purchased.

[philoÂÂ]

I've found that standard alkaline batteries have more capacity than many rechargeable batteries ...especially nicads which are only 1.2 volts. I have never tested a rechargeable alkaline battery though.

[nestork]

I know there are rechargeable alkaline batteries (developed in Canada). 'Rechargeable alkaline battery - Wikipedia, the free encyclopedia'

However, this ad says that it can discharge ANY battery and even shows a pile of Duracell non-rechargeable batteries if you click on "Specifications" and that's gotta be false. If anyone developed a recharger that would recharge disposable alkaline batteries, it would be big news, and so far I ain't heard nuthin.

[micky]

Are rechargeable AA cells wet or dry?

[clare]

"damp" - technically dry cells.

[H oM eG uy]

How many times can an ordinary alkaline battery be recharged?

Would you believe hundreds of times? The trick is to stop using the battery well before it has given up all of its available stored energy. Note that this is directly opposite to the instructions that were packed with your battery-operated drill or screwdriver with its NiCad batteries. When the drill stops turning, charge the battery, but not before. Good rule for NiCads, but not for alkaline batteries.

Assuming you now have a charger to safely charge alkalines, don't wait for the battery to stop working. In order to achieve ten times extension of the normal life of an everyday alkaline battery, you will have to recharge it frequently, many more times than ten. It makes sense to use a second set of batteries for a high drain device. Take out one set of batteries when the device is not being used, and put in the second set that has been recharged. Charge the first set and carry it with you as a backup if necessary.

You will be surprised how easily children will be attracted to charging their own batteries in their toys and possessions. Managing their own batteries is fun, and they know it helps the environment by not having to throw batteries away when they can recycle them.

Why did it take so long for a good alkaline charger to be developed?

There have been many more failures than successes along the road to developing a good charger. Products were announced, and then you didn't see any more of them. The reason is simple -- they didn't work. One came close to working, the Buddy-L SuperCharger, announced in 1993. Popular Science magazine named it as one of the 100 top scientific achievements of the year. But it did not live up to expectations. Apparently, the product was launched into production too quickly, and sub-standard operation resulted. Fortunately, the problems did not hurt the batteries. The batteries simply switched off prematurely before charging was complete, and the users had to restart the charging process several times. Also, it was not designed for easy battery insertion, always requiring two hands and a struggle. Eleven years later, many people are still using their SuperChargers and are reluctant to part with them.

All the background information was absorbed and a totally re-engineered product emerged, the Battery Xtender ? Tests have shown that it does live up to expectations, and that the claims of ten times life extension for ordinary alkaline batteries are not exaggerated. The case has been redesigned to allow easy one-handed access to the batteries, and it occupies much less space on a desk, table top or counter.

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See also:

[larrymoencurly]

BS, and don't trust Tested.com.

Even NiMHs and NiCads sometimes can't be recharged hundreds of times, and the manufacturers of rechargeable alkalines have claimed only about 10-30 recharges. In the 1970s Mallory (now known as Duracell) made rechargeable alkalines, and either Duracell or Energizer tried to sell them in the 1990s, but both times those alkalines just didn't work well, even when users did as you said and recharged them when they were still near full capacity.

Wireless World once featured a charger for regular alkalines. It would repeatedly charge for a few milliseconds and then load down the cell for a few milliseconds to check its state of charge, and a full charge for a D cell took something like 30 hours. This was an old design, not based on any microcontroller. The article mentioned the importance of not overcharging and showed a chart relating state of charge to internal pressure. Cells could reach 70 PSI when overcharged.

Tested.com once tried the Wet Circuits power strip, claimed to be safe even for use in very wet conditions:

Why didn't those people get shocked? Because the 120VAC came from a grounded circuit, and even if had been connected to only a 2-wire circuit, it's likely any electrical leakage would have been conducted by the neutral wire, instead of through any humans. But there's always the possibility of loss of neutral, which creates a very dangerous condition for ungrounded circuits. Also the Wet Circuits power strip was falsely claimed to be UL approved for safety, but UL said otherwise:

So why should you trust Tested.com about an alkaline recharger when it couldn't even catch something as simple as an obviously dangerous power strip?

[micky]

Philo said that dry cells are/use a non-reversable chemical process.

Doesn't that make someone wrong?

[Stormin Mormon]

I've had one of these for years. Works nicely if the cells aren't badly discharged. Many will leak, some hold.

[Moe DeLoughan]

That's just a sales pitch from a company peddling its charger.

Then there's this:

""The alkaline batteries (which are generally based on the conversion of MnO2 and Zn to Mn3O4 and ZnO) offer an excellent example of this last point. Although the chemical changes at the electrodes can be reversed, until recently alkaline batteries were manufactured only to function as primary cells. Recharging one of these primary cells could allow the battery to be reused, but the possible number of recharging cycles for such a cell is very limited--it performs more poorly with each recharge. More important, recharging an old-fashioned alkaline battery is not safe. During or after a recharge, the battery might generate enough hydrogen gas to cause an explosion. In their rechargeable form, alkaline cells have undergone several changes. They have been redesigned to allow for a more efficient reverse reaction, they contain a catalyst to minimize hydrogen formation and they have safety vents that prevent the buildup of excess pressure during recharging."

So - recharging standard alkalkine batteries isn't safe, nor is it very efficient, given that the potential number of recharges is very low, and the amount of available power decreases with each cycle.

Considering how cheap even the high-quality rechargeable batteries are getting, I can't see why anyone would bother messing around with trying to recharge disposable batteries.

[philoÂÂ]

This will save me a lot of typing