Power manager is reporting that my T420s (6-cell in-body battery) is reduced to a full charge capacity of ~35W/hr after only 30 cycles (!!!!!)... can this possibly be correct? The design capacity is >43 W/hr, which implies that in 30 cycles the battery has lost 18% of it's capacity.

This seems awfully fast for a battery to deteriorate. Do any other T420s owners have data they could share on battery cycles and current full charge capacity?

Read the Private Message (PM) that I sent you.

What battery do you have? Sanyo? Panasonic?
Lenovo Parts Lookup

Panasonic, evidently:

Mfg P/N FRU P/N Description Serviceable
42T4846 42T4847 Pana 6cell Yes

Here's what power manager thinks...

You should be fine.

1) Recalibrate it by doing a couple of full discharge-charge cycles
2) It won't continue losing capacity at the same rate.

Hi I noticed an issue like that too on my T510 there is no way right to make the wear level go back back to 0? My wear level right now is 12% on my extended battery. I noticed a big drop how long my battery lasts I got the laptop new last year.

With these batteries, once the capacity is "gone" it's "gone forever"... you can recalibrate the GAUGE, but over time these devices lose the ability to store charge.

The main question is whether they're losing charge "too quickly" which is what I was asking about... open power manager and see how many cycles your battery has been through. Every other one i've had would take a couple hundred cycles before it lost even 15% of the charge...