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Old celphone batteries

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NathanAllan

Veteran Member
Joined
Jun 1, 2003
Messages
2,437
Location
Bellevue, Colorado
Got these for $2, a banana box of old brick style cel batteries. Lots of differnt ones, can't list all the models or part numbers, but if you need one ask and I'll go looking. Great for personal projects, too, since some of these show little or no wear and some are new in packaging.

Nathan
 
One of the moderators is very annoyed

One of the moderators is very annoyed

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If you blatantly violate this rule and you have been around long enough to know better, I am just going to delete your reply. One of you will find out this happened the next time you sign on.
 
Has anyone ever used the odd battery to power some project? I use taped up packs of dustbuster batts for lots of things. These would need a holder to snap in to, but they would work.

This is not a plain ol for-sale post, also a discussion. I think I have one enough voltage to power a small handheld. Heck, maybe even the Fujitsu tablet (old 486) if I figure out a neat way to make it happen.

mbb, I know that you are kinda peeved, but I figger it's from another thread that there are posts in since we're the only posters. It's all good. It's a discussion. :)

Nathan
 
NathanAllen,

Nothing wrong with your initial post. The post to which I'm referring was deleted, and thus isn't visible anymore.
 
Funny you should mention battery packs and their uses.

My employer recently replaced all the battery packs for our hand-held inventory control computers.

I'm now the proud owner of 64 Li-Ion battery packs. All are 7.4v, 43 of them are 2200mAh and 21 are 1500mAh. Oh yeah, and two chargers.

Was going to use a few of them to rebuild a friend's laptop battery pack, but the cells I have are permanently attached in series. The laptop needs parallel cells. Not being completely stupid, I'm not going to solder or otherwise mess around with Li-Ion cells.

If you come up with a good use for your batts, let me (and the rest of the VC gang) know.

Kent
 
I believe all types of batteries possess that trait to some degree or another. Only one I ever had blow up was a tiny lil' mercury button-type cell, a long time ago. (Unless ya count the 12v. car battery, but that's a whole 'nother story).

--T
 
chuckcmagee said:
What's the deal? Li-Ion tend to explode in your face when being soldered?
Click to expand...

From what I've read on the net, elevated temperatures of Li-Ion cells cause a chemical change internally that leads to a runaway thermal event.

To help prevent this, there are safeguards built right into each cell. If you ever run across one that has 0v (or reads infinite resistance with an ohmmeter), chances are that the internal "fuse" is blown. That cell can't be revived.

With that said, I think that I can cut the spot welded straps on the cells and then use those as solder tabs. Soldering directly to the can may ruin your whole day.

Kent
 
Apologies, Nathan, I'm not trying to hijack your thread. I'll start a new thread when I'm ready to post the results of my Li-Ion pack build.

Kent
 
One of the tricks I use is to keep a grip onto the surface being soldered with my fingers. If the temperature becomes uncomfortably warm to my touch, then it's a pretty good bet that it's too hot for the battery, and shoud be backed off for awhile to allow the cell to cool. The key is to work as fast as possible, so as to transfer the minimum of heat to the cells being soldered. Also, if I run across any zero-voltage/infinite resistance cells, I just don't bother trying to save them, they're just trashed automatically. As always, YMMV.

--T
 
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The majority of my cell soldering skills comes from racing radio controlled cars. You can buy matched cells and assemble your own battery pack. Of course, those were NiCads and they can take a tremendous amount of abuse. I had a charger malfunction once and got the pack so hot that it melted the plastic wrap off the cells. It didn't seem to hurt the cells at all, the pack still worked great after replacing the wrap.

Anyway, when soldering the negative end of a sub-C cell, it takes a big soldering gun with a lot of heat reserve so that you can heat just that one spot very quickly. Spend too much time on it and the whole cell heats up.

Kent
 
Hijack away! Batteries are one of my favorite subjects.

When I rebuilt my cells for the Epson I didn't solderthem, I used what was there (had thick foil leads going from cell to cell) so I just crimped them and they work great. The box came with a few phones too, so I might be able to cut the latches and make frames from them to mount them onto other things.
 
Another trick I use is to take a small file and lightly scuff-up the area to be soldered. Seems most batteries have some kinda coating or plating that repels solder, but if you remove that, the solder grabs almost instantly, with very little heat being transferred to the cell.

--T
 
Step one is done, I was able to match two of the phones, motorolas, that take the same battery so I'll be able to mount the now-cut mounting brackets onto the back of my Fujitsu tablet. I figure this is better than pay $70 for a battery, and it takes two of them :p I'll get pics up when I get a chance to take the stuf out in the daytime.
 
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