Battery Charger - Alkaline


DISCLAIMER:Individual results may vary.

Thought of a novel application for a smart outlet.
Use a smart outlet to cycle a battery Charger on/off in order to recharge alkaline batteries.

Was reading online and alkaline batteries CAN be theoretically recharged at least a few times BUT they carry the risk of “exploding” as the process creates heat and internal pressure and a small amount of hydrogen gas.
Usually this just means that the AA batteries will pop their tops and acid paste will be exposed.

The trick to avoiding explosion or “popping their top” is to not get them too hot by only charging them for a short period of time. Like 15mins and then giving them 10-15mins to cool down.

This is where the smart outlet comes in. It can make a dumb (always on) charger into a slightly smarter one.
I created a schedule that cycles the outlet and thus the charger on and off for 15mins at a time for 2.5hrs. That’s enough to revive a 1.3v AA back to 1.55v.

Like I said this is controversial because it isn’t recommended by the manufacturer of batteries or anyone really.
I use a cheaper $9.99 slow charger in my garage and only 2 AAs at a time.
So far I’ve revived 4 Alkaline batteries this way.
I’ve only tested AAs because my cheap charger doesn’t have connectors for AAAs.

Please don’t do this. It’s a fire hazard and there’s no reason to do it at all.

Just get rechargeable batteries if you want rechargeables.

As Robert Heinlein once said:

Stupidity is always fatal. Unfortunately it doesn’t always get the right person. :scream:


Also, the problem is not because the non-rechargeable batteries overheat.

It’s because they are engineered differently.

Normally electrons flow from the negative pole to the positive pole in a battery. And they are flowing through a solution.

When you recharge a rechargeable battery (called a “secondary cell“), you are forcing the electrons to flow into reverse and the whole battery is designed to allow for this process. In particular, the liquid inside is able to store excess electrons, which is important during the recharging process.

Primary cells (the nonrechargeable kind) are not designed in the same way and don’t have the same chemical nature. The reverse charge is not efficient the way it is in a secondary cell and weird chemical reactions can happen, which then can cause a very real explosion. (No quotation marks.) And that can cause acid to blow out or a fire.

Your idea of powercycling the charger isn’t reducing the risk of this danger. Because, again, it’s not about overheating.

There is a separate issue which is related to heat and that has to do with the seals on the end of the battery. That’s when you will see leaks. But leaks are not the worst problem that can happen.


:man_facepalming:t4: Rechargeable batteries are too cheap to risk this.


Low Self Discharge (LSD) Nickel Metal Hydride (NiMH) rechargeable batteries are inexpensive, have significantly higher energy capacities vs alkaline, and are very safe. I have been using NiMH batteries for many, many years without problems.

Please don’t burn your house down, or encourage others to do so.