WalMart Li-Ion guts?

[kskreider]

Anyone taken one of these apart yet?  I don't have one, but if someone has a dead one I'll take it off your hands for you.

kurious,

...Kk

[poorlyconditioned]

Anyone taken one of these apart yet?  I don't have one, but if someone has a dead one I'll take it off your hands for you.

kurious,

...Kk

Yes, I've done it.  Four cells, in series-parallel arrangement, that is, 3.6V x2= 7.2V output.  Then there is some kind of stepup circuit to get 9V out.

So, what do you want to do with this?  By the way, the usual disclaimer applies: don't mess with LiON batteries unless you know what you're doing.  I already got flamed for this in another thread .

  Richard

[Patrick]

FWIW, Li-Ion batteries are a lot more dangerous that folks know about.  You should see what they do when they get wet!  Lithium is EXTREMELY water reactive.  A hazardous waste facility that I used to work with in Clarence, NY had a hydrolysis pit where they used to neutralize haz-mat.  Somehow some lithium batteries got into the pit and the whole place went up in flames.  That wasn't your normal cookie-cutter fire.

[drewloo]

Yes, I've done it.  Four cells, in series-parallel arrangement, that is, 3.6V x2= 7.2V output.  Then there is some kind of stepup circuit to get 9V out.

I wonder if that could explain what happened to me Saturday night.  I was taping a show and was using the battery to power a jb3 via a hacked RS car 12V>4.5V adapter.  I had three lights left on the battery when I set everything up at the show.  Unplugged the adapter and waited for the band to come out.  Plugged the adapter back in and bupkus...nothing.  No lights at all.  I thought the battery might have gone bad.  (Thankfully I happened to have a D100 in the bag otherwised I'd have been totally screwed).  Got home and checked the battery again.  Still nothing at all.  Plugged it in to the recharger and finally got a red light to come on.  Charged it up overnight and tested it the next day w/ the same adapter/jb3 setup and it recorded for over 3 hours before I stopped it w/ 4 lights still on the meter.

So, I'm guessing that 1) maybe the meter isn't all that accurate, or 2) maybe there's a threshold that if the battery goes down past it'll stop working altogether, or 3) I just have a flakey battery.  I think from now on I'll judge the battery's charge not by the button and meter but by how fast the recharger makes the one red light blink green when recharging.

[Todd R]

I think it was none of the above.  I'm pretty sure these Li-ion batteries have a protection circuit built into them.  If for some reason you short circuit the battery even briefly, perhaps even just by plugging and unplugging the RS adapter somehow, the protection circuit shuts off the battery and the only way to reset it is to plug it back into its charger.  Maybe Richard can comment since he's actually opened up one of these batteries.  But I had the same thing happen at a SKB show, luckily someone had an AC wallwart for a V3 and I got access to AC power to make the tape.  But my battery was fully charged and then went dead, just like yours.  All was well again after plugging it into the charger, and I've used it for 7-8 months since without any problems.

[momule]

Double check your wiring . A friend of mine complained about this once on one of his lithium batt's . Come to find out he had a short in his cable. I fixed the cable for him and he's been good to go since.
he too thought one of his batt's was flaky 

Im guessing there is some kinda reverse polarity/short protection in it. And this is why it shuts down on ya . The battery can be full charge and still do this too ya. Then ya plug it into the charger for 2 seconds and all is well again..

Edit to say, I should have known i would not be nearly fast enough

[drewloo]

Cool, that's good to know!  thanks +t's

[capnhook]

FWIW, Li-Ion batteries are a lot more dangerous that folks know about.  You should see what they do when they get wet!  Lithium is EXTREMELY water reactive.  A hazardous waste facility that I used to work with in Clarence, NY had a hydrolysis pit where they used to neutralize haz-mat.  Somehow some lithium batteries got into the pit and the whole place went up in flames.  That wasn't your normal cookie-cutter fire.

Small world, Kk.....I worked a couple years final inspection there at WG and BDT in the eighties.  I remember the guy that snuck out of the super-dry room with a quarter-sized piece of Li......he dropped it into the toilet and flushed....fubarred the plumbing up something fierce!! 

[capnhook]

What we used to call "Mach 10" work because that is about how fast your haert rate was beating.

Mach 10 work......rotflmao

Yeah, man, that was a big fire....I never made the bankruptcy/takeover connection until now   

[Chuck]

I think it was none of the above.  I'm pretty sure these Li-ion batteries have a protection circuit built into them.  If for some reason you short circuit the battery even briefly, perhaps even just by plugging and unplugging the RS adapter somehow, the protection circuit shuts off the battery and the only way to reset it is to plug it back into its charger.  Maybe Richard can comment since he's actually opened up one of these batteries.  But I had the same thing happen at a SKB show, luckily someone had an AC wallwart for a V3 and I got access to AC power to make the tape.  But my battery was fully charged and then went dead, just like yours.  All was well again after plugging it into the charger, and I've used it for 7-8 months since without any problems.

I've had the same experience and believe there is a protection circuit. Because of this, I've been leaving everything all connected togther after I charge it, so it won't shut down when I need it most