[ltp] Almost dead battery

[Stefan Monnier]

Hi,

I have here a battery that was in a poor state and got one step closer
to death, but I'd like to keep it alive and I'm wondering if there's
something I could do about it.

The battery doesn't charge any more.  When I connect it to my T61 the
battery light blinks orange.  Yet it still has about 50% of charge
(well, 50% of the "current" capacity which is only about 25% of the
original design capacity) and if I unplug the machine it does keep
it running.
But since it doesn't charge any more, this is "the last charge".

I don't mind the small capacity of this battery; I only need it for
limited purposes:
- To keep the machine up while I move from one plug to another.
- To let it keep its (suspended) state during power outages.
- Most importantly so the CPU can run at full speed even when I'm using
  a 65W power adapter (otherwise it's limited to a frustrating 1.2GHz).

I attached the /sys/devices/platform/smapi/BAT0/ info: AFAICT it all
looks normal, so I don't understand why my machine refuses to charge it.
[ I checked that it's not a problem with the machine by trying it out
  in another machine which has no problem charging its own battery.  ]

How can I bring this battery back to life?


        Stefan


% (cd /sys/devices/platform/smapi/BAT0/; grep . *)
barcoding:1ZKTJ44WTTL
charging_max_current:0
charging_max_voltage:0
chemistry:LION
current_avg:0
current_now:0
cycle_count:253
design_capacity:84240
design_voltage:10800
dump:c0 80 01 02 e0 41 00 00 00 00 00 00 00 00 00 00 
dump:c0 c2 00 80 98 0b 19 2e 00 00 00 00 32 00 7c 04 
dump:c0 c2 1b 09 ff ff ff ff ff ff c0 00 fd 00 -- 00 
dump:c0 c2 e8 20 30 2a 31 00 9c 44 f9 96 -- -- -- 00 
dump:c0 c2 53 41 4e 59 4f 00 00 00 00 00 00 00 00 00 
dump:c0 c2 34 32 54 34 36 31 39 00 00 00 00 00 00 00 
dump:c0 c2 4c 49 4f 4e 00 85 93 02 00 00 00 00 00 00 
dump:c0 c2 31 5a 4b 54 4a 34 34 57 54 54 4c 00 00 00 
dump:c0 c2 7a 46 -- -- -- -- -- -- -- -- -- -- -- 00 
dump:c0 c2 11 0a 12 00 00 00 00 00 -- -- -- -- -- 00 
dump:c0 c2 42 85 93 02 00 00 5b 0f 60 0f 5e 0f 04 05 
first_use_date:2015-03-26
force_discharge:0
group0_voltage:3934
group1_voltage:3936
group2_voltage:3931
group3_voltage:0
inhibit_charge_minutes:0
installed:1
last_full_capacity:23310
manufacture_date:2014-04-28
manufacturer:SANYO
model:42T4619
power_avg:0
power_now:0
remaining_capacity:11480
remaining_charging_time:not_charging
remaining_percent:50
remaining_percent_error:18
remaining_running_time:not_discharging
remaining_running_time_now:not_discharging
serial:38649
start_charge_thresh:80
state:idle
stop_charge_thresh:90
temperature:23700
voltage:11801
%