What causes alkalines to leak?

I only use alkalines in devises that consume batteries quickly enough to change them out often. Thought that light would get used more. :~

I used to do that until I had a few leak and ruin my devices. Now those devices get Eneloops.

That is a really stark reminder that either extremes of the PH scale are always corrosive!

Most smoke detectors use 9v. They’re a true “battery” of 6 alkalines. Maybe higher standards? A leaky cell wouldn’t show any signs immediately because of the housing which also offers some protection to the device. Our TV remote always gets new cells before old ones start there destruction.

Same thing happened to my Stanley 3 in 1 tripod. Bad design.

Unscrew the head. If it won't shift unscrew the bezel ring, remove the lens and reflector. If the bezel won't shift you are probably stuffed.

I unscrewed the head and can see the plastic bulb holder thing. Does that unscrew?

No - to remove the switch assembly you need to prise off the switch cover and insert a 5/64" hex key into the hole in the middle of the switch assembly and unscrew the pointy screw that cuts through the internal anodising to make contact with the aluminium body. I believe more recent Mags use a Torx screw which would be around TX5 or thereabouts - I've never seen one so don't know. Then there's a C ring retaining clip in front of the switch assembly that needs circlip pliers to release. Then you can pull out the switch assembly. Then have at it with vinegar/lemon juice whatever mild acid you have knocking around. It's best not to use stronger acids as the reaction with the strongly alkaline crap could be violent.

If the sun comes out from behind the rain and fog we have here just now, I'll do pics today.

Thanks. I’ll need to get some circlip pliers then.

A couple of fine nails or screws can be substituted. Or some strong tweezers.

You just need to pull the ends of the ring in enough to release it from the groove cut into the body.

Here's how to take out the switch the easy way.

Unfortunately this won't work with the cells stuck inside which is why we have to go in from the front.

Oops, my memory was at fault. A fine flatheaded screwdriver is what you want to shift the retaining ring - I'm sure the older ones needed circlip pliers but my memory may be at fault here.

In this pic you can see the retaining ring - it is the lighter coloured ring at the base of the bulb tower. I used this old pic as my cameras have gone into hiding so the pic of the ends where you can remove it was taken with a nasty phone cam of stupidly high resolution and equally stupidly high over-sharpening and noise.

You can see the notches in the ends of the ring here. They're at about 2-3 o'clock. Just get a small flathead screwdriver in there and lever it out of the groove. If it won't shift try washing it out with well hot water, dry it and shoot some WD40 in there then shake it out after a minute or two.

Good luck

Thanks for the tips. Had to get a 2mm allen key, got one today. Been trying for the last 20 minutes to release the circlip. Really difficult.

I read on another forum that the guy gave up on alkylines for remotes and things like that and just uses plain ol carbon ones. They might not last as long but they don’t leak. I’m going to try that.

Back in the day, I needed one of those teenytiny 12V batteries (A23) for my car’s remote. Rat Shack sold the C-Zn ones for 89¢ each, and they lasted for years.

Then, those were discontinued, and they only sold the hateful little alkaleak versions for almost 3bux a pop… which only lasted a year at best.

If anyone even made C-Zn AA/AAA cells anymore, I’d buy ’em by the box for clocks, remotes, small instruments, etc.

Do you mean something like this ?

That’s a candidate…

They leak nasty stuff.

They still leak potassium hydroxide+ferric chloride, which tends to eat away at the steel springs used in most battery appliances.

TLDR: NiMH Eneloop is king.

I’m old enough to remember when everyone had carbon-zinc cells, before alkalines became the newly available improved thing.

The carbon-zinc cells did occasionally leak.

https://www.google.com/search?client=firefox-b-1-d&channel=tus&q=carbon-zinc+battery+leakage

As I mentioned above long ago, the chemistry (of both kinds) slowly dissolves away some zinc that makes up the outside cylindrical case for the battery, and eventually a pinhole opens.

The other trick with carbon-zinc cells was that if you dropped one on pavement, the internal carbon rod could fracture, killing the internal circuit.