Proper handling of laptop batteries in vintage machines

[wottle]

So my vintage collection probably has 15-20 laptops at this point, ranging from a Powerbook 165 up to a relatively modern Intel MacBook Air. Many of the older models have removable batteries, some of which even still hold a charge.

However, I recently broke out my Powerbook 540c (with a nice PowerPC upgrade in it) and I removed the battery module and discovered it had been leaking and the battery leakage had disintegrated the plastic between some of the contacts. So I removed it, cleaned the battery and the contacts inside the laptop, and have the two separated for now. I may try to rebuild the battery pack, but I do not have a tack welder, and I believe the heat from soldering the battery tabs together is bad for the batteries, so that may have to wait.

Anyway, the real purpose I'm hoping to get out of this thread is to hear best practices for storing old laptops and what to do with their batteries.

For the ones with removable batteries, should they be removed. If so, and they still hold a charge, should they be fully charged before removal, discharged completely, some in between SoC?

For ones without removable batteries, I think it's probably best not to keep them plugged in 24/7. I have a 5 year old work MacBook Pro that is already bulging because that was how I used it at work (they must be locked up at work, so leaving them in the locked dock was how I left it each night).

Any thoughts and practices would be appreciated!

 

[Androda]

My policy is that for any and all laptops where the battery can be removed, it is removed. Store batteries which are nicad, nimh, and lead acid in plastic bags (or containers) individually, double or triple bagged to attempt to prevent any leakage from escaping. These old batteries probably don't store any amount of charge any more.

Lithium ion batteries are a lot pickier. They are ideally stored long term at 60% of full charge capability, checked every few months. Pouch batteries will inevitably turn into balloons over time, where the cylinder cells are much less likely to do that.

Internal batteries for cmos/pram/etc are trickier. Usually these require disassembly to remove, but you really should do it. The older battery technologies (nicad, nimh, lead acid) will almost certainly start to leak over time, and the worst possible place for leakage is on the inside where you can't see it. Internal lithium ion backup batteries should similarly be removed, especially if pouch cell type. A pouch cell balloon which has a single puncture can turn into a fireball due to how much lithium loves to react with, you know, everything.

 

[3lectr1c]

Anything Ni-Cad or NiMH should be removed if storing for any longer than a week I'd say (if dead). Check the PRAM/CMOS batteries as well as @Androda said. The PowerBook 150, 2400 and 3400 series all use Varta NiMH PRAM batteries that leak and wreck whatever they're attached to (usually the logic board). These same batteries also ended up in many mid-late 90s laptops from Dell, Toshiba, IBM and others I'm sure, so make sure to check them as well! They're not all harmless lithium coin cells.

If you have any actively working Ni-Cad or NiMH main batteries in your laptops, than you can be more lenient, but still remove them if you plan to store them for months at a time (assuming they're older than about 10-15 years old).