I believe, and cannot prove, that what you are doing will extend the life of your packs and cells.
I have an Inspiron with 2 packs, and I always left one in the bag, one in the PC on the wire. I’d swap them when onsite and one ran down. I considered one as a “favorite”, but tried to keep them both topped off. I didn’t think about it until it was too late, but one of them died a lot sooner than the other.
If you could stand to kill one, maybe you could pick one to stay on the wire and the other to get deeply discharged and recharged as needed… That might answer some of the “dead pack” questions…
Just sayin…
PS: the individual cells should be in the 2200mAh range, which means they’re not all that exciting, but they’d certainly make lots of light for you.
Was in town earlier and stopped in at a PC repair place, he is going to see if he has any dead laptop batteries - but they might have just been chucked out. Going back tomorrow.
Got lucky today, clients laptop was stolen and he had a habit if using his laptop without battery installed, I ended up with 6 Sanyo cells that are 4V pulled , busy charging now before I do capacity tests.
Believe it or not, I re-wrote that part something like seven or eight times, trying to come up with some unifying formula. I kept stumbling over second-order unknowns like the current draw and residual capacity at the low-voltage cutoff (and that nagging low-alcohol warning) … But that kept me from seeing all the other, more sensible posts.
Plus, it turns out, it’s hard to find a pack rated in “Wh”. The ads may say that, but the labels on the packs mostly seem to give V and mAh, which is much easier to compute. But why would any of that matter since I know I’ll get a different runtime out of my “xyz” cell than you will of yours, even from the same batch, just because we use them differently.
Then the magic mushrooms wore off and it dawned on me, the OP is probably just looking to buy a pack to rob, with the deepest cells in it, & needs a way to tell which is which. That’s the only thing that makes sense, with the “YMMV” rule in effect.
So, just to kick me and my dog :bigsmile: (just kidding), would you concur that, given the different rated pack voltages, wouldn’t the “plain” Wh ratings (or calculation) of packs serve to show which has the deepest cells?
I’m not sure it matters at all to me. As long as laptop packs die, I will continue to churn these freebies “with extreme prejudice”. But if a fellow had to buy the best pack available as a cell donor, it would be handy to have a way to pick the best.
Went back to the computer repair place today, didn’t exactly hit a gold mine but I did walk away with 1 6 cell Dell battery. A bit of butchery later, and I got 4 cells reading 4v, 1 reading 1v and 1 reading 0v.
They are grey LG cells.
I asked the owner to hold on to any laptop batteries he gets in, he didn’t seem to think they got many in but agreed all the same.
I was at the Lowes return desk today to return a lamp. That area is were the recycle bin is. I reached in and pulled out this. I only took the one, what am I a pig?
Anyway here are the pics, no words are necessary. I am charging them up as I post this.
No pain, no gain, dchomak?
Don't worry... with bleeding... the blood will always stop... one way or the other.
Hope you didn't get hurt to badly.
Anyways: For your cells: 4400mAh, 6 cell, 2 parallels.
[(4,400mAh x 6cells) ÷ 2 parallels] ÷ 6cells = 2200mAh min capacity per cell (Actual min capacity 2291mAh per US18650GT's thread)
I got a New Dell cell origin Korea (Only korea cell: LG) Extended battery coming. Thinking it will yield 3000mAh Pink LGs. Will post once it arrives.
Does anyone have any info on which brands will come from a cell origin? Like LGs from Korea.
I hope everybody knows to keep some superglue (old-style runny liquid if you can find it anymore, instead of gel) on hand for when that happens. Works great. It sets almost instantly when it contacts blood. Dribble some down inside the cut, squeeze it closed, then get back to work.
I’ve been very busy lately but today I decided to check the forum. I was going to post a similar thread. I have a couple of batteries that I pulled from around five laptop packs and to my surprise only one of the packs had all the batteries bad. I was able to charge the rest although I confess I have no idea of a method to check how “good” these batteries are. What I don’t understand is why the laptop pack as a whole won’t hold charge but the individual batteries do? Does it mean that there are one or more bad batteries in the laptop pack? But since they all charge individually how could I know which ones are good/bad? By the way, if anybody needs any batteries I could mail them to you if you are willing to pay the shipping; or maybe send them to any moderators for giveaways? Thanks.
Did you notice a circuit board in the casing with the 18650s? That’s probably what failed. Most of the new-model dead packs I’ve found have had 100% good 18650s.
The pcb failing could be the issue in a couple of packs but I doubt that is the cause in all of them. It has to be one or more of the batteries but I don’t know much about battery chemistry. I read the post in the other forum that is mentioned in this thread and I think that when the poster says to throw away any battery that has a variation of 0.1 volts is too extreme. Does anybody else has a better insight on this?
I took a course in laptop battery refurbishing for the company I used to work for. The main issue why a laptop pack “goes bad”… the end of life switch. The manufacturer can set this to activate at a certain age, or after a specific cycle count. Also, if the battery pack senses a temperature over 68c (for most of the ones I worked on) it can also flick the “end of life” switch. Sometimes they have a thermal “fuse” too.
They are difficult to refurbish because as soon as you remove power from the battery pack circuit it wipes all the programming in it (and won’t charge when you put it in a laptop)
