MobileRead Forums - View Single Post - Kubrick: Live CD to debrick Kindle 3, 4, and Touch

greenalien · 11-09-2017, 09:21 AM

Having had exactly the same problems with my Kindle 3 as Kindleheadache documented in post #966, I thought I'd investigate the battery.

After opening the case and removing the battery, I measured its voltage as 0.2V - definitely discharged!

I thought I would try to recharge it via my bench power supply.

I am well aware of the dangers of overcharging lithium batteries, having seen an old camcorder battery explode under charge, scattering blazing debris over a wide area, so I proceeded with caution.

Most importantly, my bench supply has variable current as well as variable voltage, so I turned the current to a minimum before switching the power on and setting the voltage to 5V.

I had previously connected the battery pack via a pair of small crocodile clips, taking care to avoid the SDA and SCL data pads.

As soon as the power was applied, the power supply showed 250mA of charge current, and I carefully brought this up to 0.5A. It would easily have gone higher, but that would have been too risky.
After 30 minutes, the battery wasn't heating up. I measured the voltage, and it was up to 3.7V so the charging was working.
Charging continues as I write this, I'll give it a total of 3 carefully monitored hours and then try it back in my Kindle, I'll post the results later!

11-09-2017, 09:21 AM	#1108
greenalien Junior Member Posts: 4 Karma: 10 Join Date: Nov 2017 Device: Kindle 3	Recharging battery outside the Kindle Having had exactly the same problems with my Kindle 3 as Kindleheadache documented in post #966, I thought I'd investigate the battery. After opening the case and removing the battery, I measured its voltage as 0.2V - definitely discharged! I thought I would try to recharge it via my bench power supply. I am well aware of the dangers of overcharging lithium batteries, having seen an old camcorder battery explode under charge, scattering blazing debris over a wide area, so I proceeded with caution. Most importantly, my bench supply has variable current as well as variable voltage, so I turned the current to a minimum before switching the power on and setting the voltage to 5V. I had previously connected the battery pack via a pair of small crocodile clips, taking care to avoid the SDA and SCL data pads. As soon as the power was applied, the power supply showed 250mA of charge current, and I carefully brought this up to 0.5A. It would easily have gone higher, but that would have been too risky. After 30 minutes, the battery wasn't heating up. I measured the voltage, and it was up to 3.7V so the charging was working. Charging continues as I write this, I'll give it a total of 3 carefully monitored hours and then try it back in my Kindle, I'll post the results later!