I have a couple old Toshiba laptops that I use for programming. These laptops are over 20 year old and have the original lithium batteries. The batteries don’t last long, They do last longer then I ever imagined which is about 20 minutes.
Is there any issue using them? I know laptop packs use a BMS but is the BMS even working after 20 years?
While the laptops are plugged in they work better then any new laptop so no issues there.
Ive taken a bunch >10 year old 18650s out of various battery packs. If theyve never been used or weren’t put away >80% charged they’ll be be deeply discharged, probably <1v by that point. You shouldn’t really use those, even if they still have their original capacity. The ones that aren’t deeply discharged still all have fairly high internal resistance and get pretty hot pretty quick. Or sometimes won’t discharge fast enough to get hot, but will get hot on the recharge. They didn’t make them very high drain back in the day.
The ones that have been used the whole time don’t have enough capacity left to be worthwhile for me. I took some >3000mah Panasonic’s out of a laptop once that capacity tested to 200mah. What’s the point.
Some of the good ones I’ll hold on to for low drain stuff, things that use like ~500mah or below. They can’t handle much. I’ve been slowly getting rid of my stash lately. I definitely don’t use any of them in any flashlights.
What you would like to use them for? These laptops contain 4, 6 or 8 cells. And they don’t last long no more. But every chain is as strong as its weakest link so there is maybe just one bad cell that spoils the barrel. From my old Win-XP laptop I pulled 2 cells that were rather bad, 2 cells that were a bit better, and 2 cells that can be used in low power single cell flashlights. The laptop itself is now assigned to perform tedious chores, running from the power supply.
I’ve got plenty of laptop pulls, might find pairs completely dead (0V) out of maybe 10 cells total, but those that still show some oomf get pulled, detabbed, cycled a few times, resistance- and capacity-measured before and after, etc. As long as they don’t get too hot while charging, they’re still perfectly fine for lights that aren’t too high-strung.
I still got some ancient panny-As (yeah, A, not B) that I’m using in some old '501s pulling about 1A.
I have 9 18650’s I scavanged from a 20yo Thinkpad. I’ve been using them for a couple of years now with no ill effects. Sure they don’t last as long as a new cell, but they last longer than I would have thought.
Maybe I am wrong but I think most answers were referring to individual cells. I removed the battery pack from my laptop because the runtime had dropped from hours to minutes. After I pulled the cells I knew why. Most cells were performing quite well, considering their age, but there were two sub-par cells in the battery pack who acted as the proverbial spoke in the wheel. Bringing down the performance of the whole pack. I don’t think replacing the bad cells in the pack will improve the situation substantially.
That’s also why I assumed he was referring to pulling individual cells, because it’s almost a given that one pair in the series-string will be the weak link in the chain, rendering the whole pack as useless as that weak link.
When the pack loses capacity, just pull the cells and use the good ones.
Like academic exams, advice is always to read and answer the question .
If you wanted to be on the safe side, is there any issue running the laptop without the battery packs? I suppose you lose the ‘uninterrupted power supply’ nature of a laptop battery, and some laptops have feet on the pack, so without the pack, the laptop won’t rest on the desk nicely.
Many many years ago I had a laptop that would not run unless the battery pack was inserted into it. Didn’t matter if the pack was shot, and it was, but without it the laptop wouldn’t even fire up.