I bought both machines refurbished with working and apparently original lenovo 6-cell batteries. One of the batteries is a 30+ (X220 battery) which works fine in both machines.
I remember reading that the X230 has a battery whitelist and doesn't accept the 30+ battery, so I assume the refurbisher reflashed it.
Edit: the 30+ is not a X220 battery.
Both batteries work well considering their reported age, but the one I'm using regularly is losing capacity (not surprising after 700+ cycles), and I was thinking it would be cool to pop in some new, high-capacity cells and build a 6-cell, ~75Wh pack. I somewhat naively assumed this would be relatively easy to do.
I did some research and found very little information on re-celling thinkpad batteries, and almost none specific to the 44+ battery.
- non-destructively opening Thinkpad batteries is hard, the battery may not look too pretty afterwards
- the actual re-celling is tricky on modern Thinkpad batteries because the BMS will blow a fuse if it senses meddling, but it can be done
- re-celling will mess with the charge indicator function
- some (?) 44+ batteries use 4.3 V cells
Today I was trying (without success) to open my 44+. After removing the big label, I saw that there are openings through which the cells are visible.
(top: 44+ battery with label removed, bottom: 30+ battery with label removed)
- I can measure the voltage of the rightmost cell pair using these openings
- the cell wrappers match LG ICR18650 C2 cells (printed code on the cells LGABC21865). these are 4.3V cells
I quit trying to open the battery and charged it up instead, hoping that maybe the charge controller stops at 4.2V anyway. No such luck, though. The exposed cell contacts measure 4.26V to "ground" on my crappy DMM and the Lenovo Vantage app reports 12.72V (= 3 * 4.24) for the pack.
This means that using modern cells, typically rated for 4.2V+-1% would probably kind of work, with increased capacity even (80Wh pack, yay) but also with decreased safety and very poor cycle life.
After that discovery, I decided to rip the label off the 30+ too.
- instead of the small openings, there are big slots here
- the pack internals are different
- I can't easily measure cell voltage
- the plastic under the label is quite thin and flexible, the cells are visible very well, this may be a good entry point into the battery
I'm now considering recelling the 30+ pack because it seems a lot easier to do, even though it has more capacity left.
- Has anybody on here tried to recell or successfully recelled a 30+ or 44+ battery?
- Does anybody have pictures of opened batteries or pack internals?
- Do all 44+ batteries use the same cell type?
- How does the connector interface work? If I measure voltage across the slots that say + and -, both batteries measure 12.1V at 100%. This matches neither the reported voltages nor the cell pair voltage that I measured.
- Is it correct that the X230 won't run on unmodified 30+ batteries?