SOS - Batteries exploded in machine


Hi everyone,

I read the responses to the 'Battery leakage and cleaning...' posting, and the last comment about toxicity prompted me to let you know about the following incident that happened to me a couple days ago.

I recently bid and won an HP-34C on eBay which was in good condition. [The HP-34C holds a dear place in my heart and there is a lot of history that goes with it.] The seller included a set of rechargeable alkaline batteries with the machine, and claimed that they worked with it. He had recently bought the machine from someone else who also claimed as well that those worked with the machine. The machine came with a charger that didn't work and the seller sent me a 'good' charger. He e-mailed me some instructions in which he mentioned that the rechargeable batteries needed to be charged about 10hrs in the machine. That seemed a little odd but I thought I would give it a shot!

I installed the rechargeable batteries in the machine, using the indicated polarity [and plugged the charger into the machine].
After about half an hour I heard some loud noise coming from my office (while I was in the living room), checked in there but nothing out of the ordinary had happened. Or so I thought. After about five minutes I heard another noise, which was similar to opening a beer can. I checked again and noticed that the batteries of the HP-34C had leaked all over my desk and some paperwork. The batteries were eminating a 'fuming' sound and they smelled. I immediately grabbed the machine - mistake - and unplugged it from the AC. I tried to take the batteries out with bare hands as quickly as possible but that was hard. (Apparently they were a tad longer than regular AA batteries.) I then used a pen for that, but I had acid all over my hands. I cleaned the machine in and out from the acid (or whatever that liquid was) and plugged a set of new batteries in after a while. I got an 'Fr Error' message, pressed CLX and the calculator seemed to function correctly.

My concern at this point is about the acid that came off on my hands and possible fumes (as well the marks on my desk from the acid, I guess.) The batteries that exploded were Alkaline Rechargeable, made in Korea. The name on them is 'charge.ables' and the brand is LENMAR. The company is based out of Westlake Village, CA.

It looks like either [the charger was bad again, or] the battery contacts were rebuilt incorrectly, or the batteries were bad. Who knows?

Next time, I should either buy from reputable people through the HPMo, or at least ask a lot of questions on the board before I buy. [No HP-34C now. I guess dreams are expensive.] Your thoughts would be greatly appreciated.



First and foremost, rinse your hands with water... for more than five minutes, in case of any toxic materials. DO NOT use any soap, as it might chemically complicate matters.

Now, if I recall (and I still own a partly working 34C), the batteries were Ni-Cd rechargeable cells. There should be no acid! This battery does not require an electrolyte. It's actually drier than the conventional "dry cell".

I suspect you might have been inadvertently or in ignorance given nonrechargeable cells of some kind.

*EDIT*- You said "alkaline rechargeables"; I am not aware of the existence of such a thing!-*EDIT*

But one necessary ingredient in common disposable batteries is potassium hydroxide, in the "alkaline" batteries. It is an alkali, or base, though it is corrosive as an acid would be, too. But the leakage from either type can be corrosive. I can't speak for the property damage, but if it got on your hands and you washed it off quickly, assuming it's this kind of (nonrechargeable) cell, you *should* be okay (I'm NOT a M.D. and am NOT giving advice; only commenting), but perhaps you should see a doctor just in case.

Now if one tries to recharge nonrechargeable batteries, including these "alkaline" ones, you will cause rather complex electrochemical reactions that do produce gases and if you're lucky, will just leak with a little of the sounds you might have heard. If you are unfortunate, it can explode like a grenade and never mind the mess, you can be severely injured. (If it is one of these types, again, if you rinse off the materials from your skin with a lot of water, there should be no real problem, unless you waited or it got in your eye. In either of these last two cases, GO TO A DOCTOR.)

The conditions you described sounded suspiciously like a nonrechargeable conventional C-Zn or "alkaline" battery attempting to get recharged... and leaking then exploding.

But at least your 34C is working. Get simple rechargeable AA sized Ni-Cd (nickel-cadmium) batteries. Just be sure to short the (-) ends together (but DO check this Museum site's pages for the correct procedure, as my memory is kind of foggy on this).

Edited: 20 Feb 2006, 10:01 p.m.


Hi Andreas,

Alkaline Rechargable batteries have been around for about 10 years or so. Rayovac makes them in the U.S. I had tried a couple a few years ago and was not overly impressed with them. I fould the following which describes the leaking or exploding that can occur if the batteries are charged when they are completely drained:


I don't remember ever getting any warnings in the literature I had rerceived with the Rayovac.

Glad to hear that the 34C is still working. It's a great calculator.



Hi Andreas,
pretty clear why this happens. The charger in the calculator is made for NiCad cells. These are a totally different technology than the alkaline rechargebles. I think the exploded cells were recharged in an external recharger and not inside the HP34C when the seller used them.


Hi there,
Thanks everyone. Those comments are very insightful. This is what happened: what Chris said. Unfortunately the eBay seller gave me the wrong directions... And when I mentioned to him what had happened, he wrote that I didn't realize those were not rechargeable batteries but plain alkaline. The batteries said 'Rechargeable Alkaline' on them. Well, I'll take it up with him, be careful next time and ask my HP'ers (sounds like H-peers) first.
This community rocks!!!


I, too, remember that rechargeable alkalines have been around for quite a while. But, I definitely recall cautions about using the wrong charger when the rechargeable alkalines first came out. I went to Wal-Mart and checked out their current display. They carry rechargeable alkalines (NIMH) from Rayovac, Duracell and Energizer. Somewhere in the literature accompanying each of the brands are cautions against using the wrong charger with the possibility of rupture or explosion if you do use the wrong charger. The manufacturers all claim a life with recharging of 3 to 4 times that for ordinary alkalines. I never saw much need for that as opposed to the use of NiCad rechargeables. Obviously someone does as the display of the rechargeable alkalines is quite large.


They carry rechargeable alkalines (NIMH) from...

It's either NiMH (Nickel Metal Hydrite) OR (rechargeable) alkaline. Two different beasts.


I'm not sure about the spelling of "hydrite".



It's either NiMH (Nickel Metal Hydrite) OR (rechargeable) alkaline. Two different beasts.


I'm not sure about the spelling of "hydrite".

It's hydride.

I believe they all use a potassium hydroxide electrolyte, so in a sense, they are all alkaline batteries.

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