Latest revision as of 07:52, 5 October 2016

I have a few laptops that need new batteries. The fact that OEM is expensive and most of the time you cannot find any good after market I would like to rebuild them. I would also like to rebuild them because battery technology is better now and I think I can get better batteries.

Jump Starting Dead Batteries

One of the problems that I have read about is if the battery side of the battery circuit loses power then the circuit blocks/locks. Recommendations so far seem to be:

Jump start the circuit with voltage^[1] Independently charge the battery side^[2]

I have also read somewhere that you can never get the circuit to start again so during the repair process keep it powered.

It has been called a control circuit,

Really

• http://hackaday.com/2011/08/01/who-knew-thinkpad-batteries-require-a-jump-start/
• https://jaforeck.wordpress.com/2012/07/24/t40-recelling/

• http://hackaday.com/2011/08/01/who-knew-thinkpad-batteries-require-a-jump-start/

I work with single-cell lithium polymer batteries at work. I would imagine that they use the same type of protection mechanism that is used in the larger batteries. The quick trick we use to reset the under-voltage lockout is even easier:
1) Set a multimeter to check continuity (beep when a short is detected)
2) Touch the multimeter leads to the + and – terminals of the battery pack
3) Touch the multimeter leads to the – and + terminals of the battery pack (switch which probe touches which pin)
4) Use the multimeter to measure the voltage across the battery. It should now be >0V as the protection circuit has been reset.

• Constant Power needs to be applied T61:

i’ve tried your nice little trick for the battery of my Lenovo T61 but, unfortunately,
this didn’t work (neither for the positive nor for the negative ends of the cells).

i guess that the chips on the board of your battery are of different types.
in order to check this hypothesis, it would be very kind if you could post
your chip types here.

on the board of my battery there are 2 TI chips of types BQ8030DBT and
BQ29330.

the Lenovo power management software shows “SANYO” in the manufacture
field. do you see a different string there ?

• Then again:
• T61, worked like a charm. thanks alot.

Recalibration

• To correctly build a battery pack, you'd have to clear the EEPROM through the SMBUS interface using a software.^[3]
• https://media.blackhat.com/bh-us-11/Miller/BH_US_11_Miller_Battery_Firmware_Public_WP.pdf
• http://be2works.com/ ??
• http://www.thinkwiki.org/wiki/Maintenance#Battery_treatment
• http://forums.lenovo.com/t5/T61-and-prior-T-series-ThinkPad/Battery-gauge-reset-destroyed-my-battery/td-p/72628
• http://forum.notebookreview.com/threads/toughbook-batteries-replacements-usage-calibration-feedback-and-experiences.528542/

Rebuilding Tips

• http://www.linuxjournal.com/content/rebuilding-laptop-battery
• http://www.engadget.com/2005/06/28/how-to-rebuild-your-laptop-battery/
• http://www.buchmann.ca/article21-page1.asp
• http://www.summet.com/blog/2007/02/17/laptop-battery-refill/ (BMS System)
• http://www.notebookreview.com/news/diy-laptop-battery-rebuild/
• http://www.electronicspoint.com/threads/opened-laptop-battery-to-replace-lithium-ion-cells-lenovo-x61tablet-pc-where-do-i-get-replaceme.226081/

Build Your Own

• http://www.batteryspace.com/PCB-for-7.4V-Li-Ion-Battery-Pack-3.0A-Limit.aspx
• http://batteryuniversity.com/learn/article/building_a_lithium_ion_pack