# Removing and charging battery with lipo charger



## paddyp (Sep 7, 2011)

Well I was unfortunate enough to have my touchpad battery die completely when I was away its too flat to charge now. I've dismantled it and I'm just wondering has anyone charged it externally and do I need to dismantle the battery pack and charge the cells individually or can I charge the pack directly with via the connector.


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## nevertells (Oct 29, 2011)

paddyp said:


> Well I was unfortunate enough to have my touchpad battery die completely when I was away its too flat to charge now. I've dismantled it and I'm just wondering has anyone charged it externally and do I need to dismantle the battery pack and charge the cells individually or can I charge the pack directly with via the connector.


I saw somewhere a guy used his model plane charger and some paperclips to get his recharged. You realize that until August 28 or possibly later, depending on when and where you purchased your TP, you could have sent it back to HP for repair. Now that you have taken it apart, you can probably forget that avenue.

Now, let's talk reality. Why do you think your's was too flat to recharge? Are you saying that you left it in a sleep state and never turned it off? What did you try to revive it? What date rom did you have on it? By any chance did you have the charger fix installed? I hear there are 6000mA replacement batteries available on the internet.


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## deboy69 (Oct 31, 2011)

http://forums.webosnation.com/hp-touchpad-tips-information-resources/311491-how-i-revived-my-dead-touchpad.html

hope this helps


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## paddyp (Sep 7, 2011)

Thanks deboy69 thats exactly what I was looking for.

@nevertells tried everything the battery voltage is too low for the touchpad to charge it, its a common enough problem wife couldn't find the touchpad charger so used another usb charger the touchpad is dumb enough to consume more power telling you to use the correct charger than the usb port supplies and you end up with a totally dead battery. I'm aware of the warranty but other people have gotten back different touchpad and it not worth it to me to start from scratch. I worked in rework and repair in electronics factories for years and have only ever sent one thing in for repair ever.


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## nevertells (Oct 29, 2011)

paddyp said:


> Thanks deboy69 thats exactly what I was looking for.
> 
> @nevertells tried everything the battery voltage is too low for the touchpad to charge it, its a common enough problem wife couldn't find the touchpad charger so used another usb charger the touchpad is dumb enough to consume more power telling you to use the correct charger than the usb port supplies and you end up with a totally dead battery. I'm aware of the warranty but other people have gotten back different touchpad and it not worth it to me to start from scratch. I worked in rework and repair in electronics factories for years and have only ever sent one thing in for repair ever.


You just identified why your TP would not charge up. Using any other charger will only apply 500mA and that is not enough to get a charge going. You have to use the original Hp wall charger that came with the TP. They are available on the HP Webstore right now for $4.99.

As far as starting from scratch, if you are making nandroid backups and copying them to your PC for safe keeping, once you got the TP back from Hp, it would be an easy process to get back to right where you were before sending it in.

BTW, the article deboy69 linked is exactly the one I was referring to.









And, here is what happens if you over charge:


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## paddyp (Sep 7, 2011)

It was on the original charger for 3 days also on 500ma charger as recommended by others for 48 hours no dice also tried all the resetting tricks during that time. And yes the charger, cable are operating perfectly as we have another touchpad in the house. The connector is perfect too.

When I dismantled it the battery voltage was 2.5V which is 100% dead very bad. Its a crap design this should never happen and there is no way the touchpad can charge it when its that low. By the time the lipo charger gets here in the post it will probably be non recoverable at that voltage so I've ordered a replacement battery.


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## nevertells (Oct 29, 2011)

paddyp said:


> It was on the original charger for 3 days also on 500ma charger as recommended by others for 48 hours no dice also tried all the resetting tricks during that time. And yes the charger, cable are operating perfectly as we have another touchpad in the house. The connector is perfect too.
> 
> When I dismantled it the battery voltage was 2.5V which is 100% dead very bad. Its a crap design this should never happen and there is no way the touchpad can charge it when its that low. By the time the lipo charger gets here in the post it will probably be non recoverable at that voltage so I've ordered a replacement battery.


Well, since you have it apart, what does the label on the battery say it is rated at in milliamps? Thanks


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## Colchiro (Aug 26, 2011)

I've seen posts of HP denying a warranty battery repair request like this due to Android installed on it. I believe they wanted more than what a replacement TP would cost.


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## mikestefoy (Oct 4, 2011)

the battery says 3.7volts
6000mAH
22.2WH

mine is dead, so I took it apart.

the LiPo is reading 2.83 volts, so I will give i a constant current of 1amp, check the voltage, and hope it springs back to life.

To take the thing apart is a major operation, only to be undertaken by skilled electronics people.

If it all works, I am going to drill a hole, and have a small connector so i can externally charge without this surgery again !!!


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## paddyp (Sep 7, 2011)

mikestefoy said:


> the battery says 3.7volts
> 6000mAH
> 22.2WH
> 
> ...


Did you get 2.83 volts on the red and black wires or directly on the cells, did yours revive?


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## Ultravore (Jun 30, 2012)

You should be able to revive your dead battery with a power supply. Give it some bursts of high voltage (maybe 10-15V) for a few seconds and you should be able to charge it again. Buying a new battery is the better way anyway. Even a revived battery will be damaged and probably lost capacity.


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## mikestefoy (Oct 4, 2011)

@paddyp.

2.83 on the red and black wires.

there are several different topics which basically have the same issue of a flat battery, which wont come back to life.

heres what I did, find my post a little way down

http://rootzwiki.com/topic/24844-touchpad-wont-charge-or-boot/page__st__20


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## paddyp (Sep 7, 2011)

Hi Mike, Thanks for that, replacement battery arrived looks 100% identical, new battery also reads zero. In answer to your question there is circuitry inside the battery pack and a ptc in case of overheating.

Remembered I had an olimex lipo charger bought for an accessibility project for a disabled kid. The original battery is on charge now kept tripping out initally at the same rate as the touchpad was but voltage is coming up nicely now. They are dirt cheap if anyone needs a charger.

http://www.olimex.com/dev/usb-ulipo.html


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## mcc05 (May 1, 2012)

Hi all, need some help, Touchpad is dead happened in the middle of webosdoctor....

Now I've opened it up after forgetting about it for a week or two, removed the battery sand it reads 0v, and won't charge, in or out of the tab.

Now I don't want to go and buy a new battery if the tablet is bricked and not recoverable.

I notice there are four wire on the battery can some tell me what the middle two wire do? If connected to part of the battery that is a voltage level what is it?

I was thinking of trying to use 3 2000mAh 1.2v rechargeable batteries to see if the unit comes to life and is recoverable before getting a new battery, anyone tried this think it may work for a short period?


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## Mpgrimm2 (Dec 6, 2012)

mcc05 said:


> I notice there are four wire on the battery can some tell me what the middle two wire do? If connected to part of the battery that is a voltage level what is it?
> 
> I was thinking of trying to use 3 2000mAh 1.2v rechargeable batteries to see if the unit comes to life and is recoverable before getting a new battery, anyone tried this think it may work for a short period?


Not sure what you are asking exactly, but you can read the battery voltage across the Red and Black wires (2 each). There are 3 wires in between the main battery leads, and from reading the thread, at least 2 of them are a PTC (positive temperature coefficient); kind of like a thermal fuse (self resetting) that will send a shut off signal to the TP if the battery gets too hot. My guess is that there is a PTC in each battery and they share a "common" wire of the 3 in the middle with 1 lead each for monitoring by the main board. Likely all you can do is check the resistance (ohm) through the PTC's and they will probably show a Short (0 ohms) when cool. If they get hot they will show a very high resistance/open circuit.








The TP battery is really 2 3000mah batteries sealed together with the individual leads brought out to the connector. Hence the 2 Reds and 2 Blacks.
If you tie the Positive leads/terminals (red) from all 3 2000mah batteries together, then all the Negative leads/terminals (blk) together and connect it to the TP battery connector's Red and Black leads respectively it should work if the TP is functional.


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## lburtell (Dec 31, 2012)

So I just had the issue of touchpad would not charge at all. Tried 3 days on stock charger, couple on pc and then low wall charge. I finally took the touchpad apart and removed the battery. I did not have a special charger, so I decided to give the usb charger a try. I cut the end off an old usb cord and plugged the black and red wire into the battery for about a 1/2 hr. I watched the battery slowly charge with a multimeter. It was at about 3.7v when I stopped. Put the unit back together and booted right up. When I first tested the green and yellow wires u was getting about 2.1 v. After it charged a bit it was 3.1.


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