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Warning! Exploding Maxell PRAM Batteries

MacGyver

Member
Hi there,

over the years, I've seen several cases of 68k Macs with leaking PRAM batteries. Many of them didn't really leak slowly - instead they seemed to have exploded in an impressive way. Spray of corrosive materials seemed to have landed everywhere inside the machine.

Then, I began to recognize a pattern: Every single leaked or exploded PRAM battery I found was exactly the same type and manufactured by the same company: Maxell.

Here some photos of a Macintosh LC to visualize the problem:

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I've placed the same type of battery, but still intact, in the last photo to show what these batterys look like when they're new.

You should really search for these batteries and remove them as soon as possible as they can suddenly explode, even when they're discharged?, without warning.

Some weeks ago, I had a IIci sitting on the shelf in my work room. It wasn't plugged in and hasn't been connected to the mains for at least as long as a year. One day, I was browsing the web in the same room, suddenly a strong acidic smell caught my attention. I searched for the source of the smell when I saw smoke coming from the case slots of the IIci - which wasn't even connected to anything!

I immediately opened the case and revealed the battery,which was spraying a mist of chemicals and smoke all over the place.

I took it outside and tried to remove the battery protected by a piece of cloth. The battery had turned darker because of heat generated by the reaction, it was incredibly hot. I was able to remove the battery and cleaned the IIci as good as possible by completely disassembling it, cleaning every part and washing the logic board.It works still fine, but the battery holder is a little warped and bent from the heat.

If you want to avoid such accidents, which I believe could lead to a fire any time (and kill your classic Macs), then you should really hunt for these batteries and remove them ASAP.

Hope this helps,

macgyver

 

Concorde1993

Well-known member
then you should really hunt for these batteries and remove them ASAP.
Weird. I've always used Maxell PRAM batteries in my Macs, and I've never had a problem with them.

Perhaps your replacement was defective? Also, are you sure you didn't install it backwards?

 

Dennis Nedry

Well-known member
YES I have noticed this too - nearly every blown battery I have encountered has been one of those blasted red Maxell ones! I've never seen one of the common purple/green ones blow up.

The risks of leaving PRAM batteries in Macs far outweigh the occasional visit to AppleTalk settings. Even my MDD G4 that I use daily has NO battery installed. Not worth it.

 

MacGyver

Member
Hi :)

Weird. I've always used Maxell PRAM batteries in my Macs, and I've never had a problem with them.
You're not going to have a problem as long as they don't blow up. It seems like they get a tendency to blow up when they're getting old and weak, so they're really time bombs. I haven't seen a single case of a different PRAM battery leaking or blowing up. I'd recommend you to remove them _before_ they blow up, instead of waiting for them to blow up.

Perhaps your replacement was defective? Also, are you sure you didn't install it backwards?
I don't replace PRAM batteries, I only remove them ;-) . To make it clear, I didn't change anything to the mentioned IIci. I haven't even opened it up before it started smoking (while it wasn't even connected to the mains).

A friend of mine had the same phenomenon, it was an LC 475. Stored in working condition (battery had still good voltage) for about 2-3 years. He was very surprised when he opened it up after the storage period to find that the (Maxell) PRAM battery had exploded while the mac was in storage and killed the logic board.

Macgyver

 

Mk.558

Well-known member
Perhaps one of our resident chemists can explain what could be going on inside the battery when it decides it has served long enough?

It is not really a big deal to put a new one in and replace it every 5 years or so.

 

Dennis Nedry

Well-known member
I'm thinking that acid eats through some layer inside the battery causing an internal short circuit, and the too-fast reaction thereafter causes the explosion. You can recreate this explosion by attempting to charge one of them. They go off reeeeal good. }:)

 

BGoins12

Well-known member
Out of all the Macs I just picked up yesterday, only one suffered a battery explosion.... one of the SE/30s with.........a Maxell battery. All the purple Tadiran batteries were 100% intact. The LCII I got yesterday as well had a Maxell battery in it that was starting to leak.

SE/30 murder -

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Tadiran batteries of the same vintage... 100% intact.

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Dennis Nedry

Well-known member
I would try scrubbing that board really well with a toothbrush and soapy water. If all of the pins and traces are still connected, it might work. Even if they aren't, it might only require a small amount of surgery. It's not too bad to run a few thin wires for rotted traces if necessary.

When all is said and done, if it still doesn't work, unsolder the battery holder and inspect for any corroded traces under it. I had a IIci that BARELY leaked, you couldn't even tell before you took out the battery, and it dripped and burned off a ROM-related trace under the battery holder.

edit

I see that the battery holder has already fallen off for you! :beige:

Seriously, though, it looks pretty bad but it might clean up okay. You never know.

 

CelGen

Well-known member
I think it has more to do with how Maxell makes their lithium cells compared to Tadiran. I know some batteries which when they die reverse polarity and others which simply chemically break down and leak like they are made of water.

 

Scott Baret

Well-known member
The only battery I've ever had fail on me personally in terms of leakage was a black battery. I don't recall the name of it offhand.

I have encountered a few of the red Maxells. There's only one I recall going bad, and that battery had been installed about 14 years when it decided to leak. The computer it was in, an original LC, was still operational for some time.

The purple and black batteries seem to be the most reliable. I have one from the 80s sitting around (pulled but never taken to the recycler) which still looks new. The blue batteries also seem to be good (the old ones, at least; I haven't had one of the lighter blue ones Mike sells long enough but am using several right now). The black batteries are usually OK although, as mentioned, I did have a problem with one a few years back. The battery had been installed about three years when it went and was about 11 years old in terms of manufacture date.

There's also a variant of this battery which is lime green and white. I got one from a medical supply company online (the price was good although I don't recall where exactly I bought it). Again, my data is too limited on this battery since it's only been installed for half a year in a Mac Classic.

I'm not sure if Maxell make these anymore. This may not relate much since we're comparing apples and oranges, but I have found Maxell diskettes to be less reliable than other brands, so I'm not sure if it's a company quality issue or not. (To be fair, the P/I Plus line of cassettes and VHS tapes was great; most of mine from the 1980s are still playing fine).

 

BGoins12

Well-known member
Sad to report... another SE/30 is dead.

A friend of mine asked me to come look at his SE/30 because when he powered it up after sitting for 2 years, it had lines across the screen. Went over there to open it up... only to find an exploded Maxell battery that ruined the logic board. nearly all of the chips around the battery were corroded off the board, rattling around inside of the computer. xx(

 

J English Smith

Well-known member
I just ordered two new Tadiran batteries (purples) on the bay, one for my CII, the other for my Centris. Took out the Interstate Battery I got a few months ago - better safe than sorry. The Tadiran batteries were far cheaper than going to Interstate...two for about $9.50 shipped. They have a nice spec sheet showing decay/life expectency etc.

 

LCGuy

LC Doctor/Hot Rodder
Just out of curiousity, I just did a Google search on, "Maxell battery explosion". As luck would have it, this thread comes up as the first hit. Can't really find anything else, apart from issues with counterfeit Maxell batteries exploding, though my guess is that Apple would have used the real ones.

For what its worth, I have no idea what Maxell disks are like, but back when I was a kid (in the 90's) I usually used Maxell cassettes to record stuff on and they still play perfectly today.

 

Concorde1993

Well-known member
(To be fair, the P/I Plus line of cassettes and VHS tapes was great; most of mine from the 1980s are still playing fine).
I picked up a whole bunch of new old-stock P/I Plus tapes dirt cheap from a liquidator last year, and the sound quality, and picture reproduction is absolutely fantastic when recording from my BR-7000, and AG-1980. The P/I Plus tapes that my father purchased new in the 80s are still holding up fairly well also. Same with his (and my) BASF HG tapes, JVC EHG tapes, and Scotch EG tapes. Some of our Memorex tapes aren't holding up as well, however.

I should also add that my Maxell C90, and C60 normal bias Communicator-series cassettes are holding up pretty well. Same with my XLII, and XLII-S tapes. :beige:

 

maceffects

Well-known member
ANOTHER CASE:

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Maxell PRAM Battery... Just noticed... Horrible.

This should be stickied if not already.

Should also point out that, every single other Mac that had the purple Tadiran battery sitting for over 10+ years on the self are still perfect (even if all but one no longer holds a charge), they didn't explode and wreck the computer. I remember seeing a few other cases of this years ago (didn't give it much thought) and now that I recall they were all Maxell batteries too. Just remove em' boys and get something else like Tadiran (or even no battery if your Mac is ok with that)

 

Mk.558

Well-known member
The sad thing is that the core of the system, the motherboard, is the usual victim.

If it was something inside a PSU, or blew up a floppy drive, KB!'d a hard drive, it wouldn't be so big of a deal. But once the motherboard is gone, it's just a parts machine or a write off.

I know the feeling. Picked up my SE/30 on craigslist, an amazing event in itself. Jailbar pattern upon powering on. Figured. Open up the computer and the battery detonated, eating up the ROM traces and attacking the chassis with vigor. Cleaned up the chassis, cleaned up the bottom of the FDD carrier, sprayed with grey primer, a new $40 motherboard from Canada eh? and after awhile, a proper floppy drive.

Unfortunately I highly believe that reports like these are only going to increase exponentially, same with electrolytic capacitors oozing out acidic liquids. We are getting close to the practical end of life of these machines, and only people who still have them are 1)hobbyists, 2)too busy or lazy to remove it from the attic, or 3)don't know what to do with it. (A fourth option, those soldiering on with old hardware like a Performa 630 server they got back in the day and can't see why they'd need anything else, is also an possibility, though likely extremely rare.)

 

maceffects

Well-known member
Yep between the capcitiors and the pram batteries these older units in working order are truely a rare sight. A pram battery explosion meant that the Ethernet card power supply main board and ram are toast. Only good this left is the case, hard drive and floppy drive. I have had too many good Macs end their life like this. Truely sad.

 
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