Revive exhausted battery?

I (stupidly) allowed my Intermec 6651 batteries to run down completely and now I can't charge the main battery. I know the battery was 'good' before it ran flat as it held almost 100% charge and would last for hours. Now when I plug in the mains the battery refuses to charge, even with a fresh set of backup batteries and a full reset. I've had this happen before with another battery which I took apart thinking it was 'dead', in an attempt to rebuild it.

I'm not going to do the same with this one however because I know it's good. Does anybody know if there is a way to revive this battery? I assume the charging circuitry has gone a bit haywire because the battery was allowed to run flat. I have tried another good battery in the Intermec and it runs fine so I know it's not the devices circuitry so it must be the PCB within the battery itself that is at fault. Can these be reset in any way? Any help would be much appreciated!

it would be better if you knew how completely you ran it down, just below 3 V or even more? if you're lucky it can be revived by charging it with a higher voltage than the usual. if it is ran below 2 V, it can be dangerous trying to recharge it. i don't know more than that, no battery expert myself
btw, how did you manage to run it down so flat? you used it until the intermec shut down and then you didn't charge it for weeks, and left it in the device, or how..?

Hi cmonex, thanks for the reply. Basically I left the Intermec to do nothing for weeks when I purchased a Sharp Telios with HPC 2000 (the 6651 is CE 2.11 ) and when I next tried to turn fire up the Intermec the batteries were dead

I know I should have charged it up now and then to keep the battery in good shape but I forgot

This isn't the first time like I said in my previous post. I think the 6651/Telios batteries must have some kind of regulator that gets screwed up if left to discharge completely. As I said, the battery was good before it was allowed to run flat so there must be a way to revive it.

Incidentally, I've tried to charge it in the newer Telios too but it's not having any of it. No charging lights, nothing

every li-ion battery is like this, not only intermec/telios. they absolutely hate being discharged too deeply i can't say more than in my first post here, try to charge it with a higher voltage (search for it on the net for the exact details). of course the standard charger won't supply it, so you have to do it another way.
but i hope there's some battery expert on the forum..

mmmm, I have a 20v power supply that will fit the 6651's power socket but I'm afraid of frying the machine itself. I'll wait to see if anybody here on the forums can offer any other advice before trying that.

Unfortunately I don't think there's any other way to charge the battery other than in the device itself. Thanks for trying to help though cmonex

yes, that's the problem, of course you shouldn't charge it in the intermec, at least i'd be afraid of trying it. there're other ways to do it, charging the battery directly for example with a smart li-ion charger.. ok, that would cost money.

I had quite a few issues with running down batteries on my ppc, and then it also didnt want to charge right away. a few presses of the softreset button in my case works for me. It seems like the battery is just on a dead position, and by resetting the device, you drain a little bit more out of it, putting it beyond a dead point.
I dont have any technical explenation for it, but it works for me. Maybe worth a shot.

Or you can refurb the batteries! ... overkill? you don't refurb your batteries once they run down? You mean you actually use the ac adapter to recharge your batteries? ... hehe ... just kidding ...

lextre, I've read on other forums of similar situations as yours. Basically, the battery appears dead to the circuitry, so the charging circuit refuses to charge or fails to charge and bring it to full level(charge). Trying plugging in AC and leaving it running for awhile ... sometimes, it starts charging after awhile.

If after awhile (read a few days or weeks. Or for some, a few minutes!) of trying, it still does not work, you may want to open up the case and unsolder one of the battery wire. This would open the circuit and "reset" the charging circuit. Aftter say, 1 min or so, resolder back, and plung into the device. Plug in AC and try to recharge again. Some reported to have to repeat a few times to "reset" the charging circuit while others' batteries work on first try.

This trick works on some of the the Apple iBook batteries, iPod, M300 and also once for my MP790, when newly refurb batteries refused to charge.

If it still fails, then you already have the battery case opened, so you are half way through refurbing your batt! ... Get 18650 cells and replace the cells for your batts. You should need just two 18650 cells. The newer ones are 2400mah and should give you even more mileage or KMage () ...

Hopefully, plugging on ac forces the charging circuit to wake up!

Thanks Snappy but it's already been on mains power for 24hours with no lights to indicate charging

I also read about those apple batteries being apparently *dead* but resetting PRAM on the iBook enables them to be recharged - unfortunately the 6651 does not have a similar design. Again, I think the circuitry on the battery is at fault and not the charging circuitry of the 6651 itself.

I have attempted a rebuild of the previous battery but it failed. Why? because the 6651/Telios use THREE 18650 cells connected not by two fixed tabs but by four tabs, two of which are 'twisted' which makes rebuilding complicated. I did however managed to 'fudge' the batteries together and after the rebuild the battery lights came on OK and it appeared to be charging. However even leaving it on charge for hours on end it refused o power-on without the mains attached.

Oh well, looks like I'm gonna have to try rebuilding it again!!!

Yeah, I've tried soft resets. hard resets all to no avail - thanks for offering suggestions though

Hi lextre, looks like your only option is to REFURB! ... get the new 18650 cells and replace them in the batt case.

The charging circuits *are* in the batts. Li-ion batts are self contained in this sense to protect against 1) Over-charging 2) Over discharging 3) Short circuits etc ... as 1&3 can lead to explosions

Most circuits also have so-called smart circuits that return to the device 1) voltage level 2) # cycles and sometimes 3) shutdown itself if it is over-discharged.

As I said, if all fails, get new cells and refurb!

I've so far, refurbed MP790, J680e cells successfully, both 2cell type. I've also refurb a M300 notebook batt (4cell) and gotten more life than a new original batt.

If you need help, you can send the new cells and your batt over to me. I can help you with it, as a free service to the community. ... shipping on you.

Snappy, my soldering iron is on my dfesktop and hot!

Problem is the solder just runs off the battery tabs and I can't get a decent enough join. I'm now trying to solder a strip of wire between the batteries to see if I can get a better connection.

Luckily I already had some new cells from my previous rebuild attempt

Any suggestions on soldering the whole lot together???

Yes, those tabs are nasty to solder! ... I read somewhere about using acid-based or flux solder ... What I sometimes do is, I cut a little slit or hole in the tab (tough one!) and secure the wire to it physically. Then I solder. Works for me. Also, you can "clean" the wires' exposed ends by soldering them first. Apply heat to wire first, then apply lead to the wire, not the heating element. This coats the copper wire with lead and allows better contact with the tabs ...

Copper wire? Does it HAVE to be copper wire