Jornada 820 unable to charge battery

Hello there.

This is a horrible first post, but here it goes. I recently aquired a Jornada 820, in good condition, working perfectly. When it reached 8% of it's original charge (it came with 32%), I used the included official HP charger. As expected, the battery LED went red. Eventually, maybe after a soft reset, but without me noticing so I can't be sure, the LED went down, and the machine now claims it's running only from the AC line.

With the battery plugged in, it still reports 8% charge, with AC power the battery LED doesn't light up, and I can't boot the machine anymore using just battery (and disconnecting the AC imediately shuts down the machine). I've tried all the obvious things, cleaning, checking the plugs, hard resetting, and everything seems to be in top order. I did a long charging session as well, around 3 hours, to no avail.

This seems to be an uncommon situation. Did my battery just decided to die mid-way? Am I forgetting something?

Edited by Takashi 2006-03-21 10:41 PM

Did you notice at all when trying to charge the batteries if the pack was getting quite warm, or even what you would consider to be hot?

Or does the pack stay cold even after extended charging?

If the pack is getting quite hot, it means one or more of the rechargeable cells inside the pack has gone faulty/leaky, possibly even reached breakdown.

If the pack is cold it suggests the internal charging controller has failed. I suspect the thermal fuse may still be ok, since the 820 still registers some kind of battery charge.

Either way I suspect you will require getting either getting a new pack, or doing a battery refurbish, assuming you can find another charging circuit in working order.

The fact that the charger can run the unit fine with the battery pack still attached suggests the charger is still in good condition.

Thank you for your reply. The battery is cold and i didn't noticed it warming much. It's still cold, even after over 7 hours of "charging". So, I'm almost sure something is wrong other than the cells.

The Power control panel gives me this nonsense:

With 8% going (correctly) to Not Available when i remove the pack. It's easilly the most frustrating situation I've ever encountered myself.

If the charging controller is dead, then refurbishing will not do me any good. How much will another battery pack set me off for?

Edited by Takashi 2006-03-22 8:52 AM

no i do not agree. if the battery stays cold that doesn't mean anything...

yes a battery can die this suddenly. recently my t39's original battery died very very unexpectedly. i was using the t39 as a gprs modem in one afternoon then after ending the gprs session, switched the phone off (battery was at around 40-50% then), went home, wanted to turn it on again in the evening and it wouldn't. it wouldn1t even charge. i put another battery on it and it worked OK, charged OK. just the dead one won't. not even the charging LED comes on. oh and battery remained cold.

so i'd suggest it's worth rebuilding the pack especially as the 820 won't even run with the battery without AC even though it should still have a little power (8%) to drive the 820. (btw it wasn't a good idea to let it run down to 8%... that's almost full discharge. may have been the last straw for the battery )

before that, you could try charging the battery directly - this may not be too safe, i never tried it but it is possible. just watch its voltage and when it reaches 8.3-8.4V (the 820 battery has 7.2 V nominal voltage, doesn't it?), stop charging it. just to be safer

Well, the 8% was because I didn't knew in what state was the battery(it also was the first time ever I charged it after i got it), so it was hard to manage the amount of charge - and I also don't recall the Estimated Time actually working, what was annoying me. Just to be on the safe side, what are the chances all this being a Jornada problem, not a battery pack problem?

Directly charging is a possibility, albeit it doesn't sound very wise to charge something I don't really know how it works inside.

well if the charger is smart enough you just need to know how to connect it... if it is not a smart li-ion charger you need to be even more careful but certainly worth a try