Battery recovery issues

Emiliano Pastorino epastorino at
Wed May 6 13:17:44 EDT 2009

Here's the logfile.

Just one observation: it tooked me 3:30 h to discharge the battery (I did a
bat-recover for 16 hours previously),
so the battery seems to be in good shape, and also the XO, since with other
batteries the led and output from
all these commands behave as expected.

Also, I want you to know that the first 20 batteries I tested weren't
faulty, they just needed to be charged
(trickle charged at the begining, then normal charged). I think that kids
and our technicians don't know what
does the 4-times-blinking-orange-led mean, so I'm giving them immediate
instructions on how to proceed.

On Tue, May 5, 2009 at 6:44 PM, Richard A. Smith <richard at> wrote:

> Emiliano Pastorino wrote:
>  bat-charge reports this: 320.83 mAh (7d53) 1428.12 mA (2ddc) 6.492 V
>> (195c) Chg: 0.41mAh (  29) then every column raises line to line (I
>> copied that by hand because
>  bat-charge-log always says "Can't open file", even when usb stick is
>> plugged in.
> Turns out the way I did the disk devices won't work unless you either:
> 1) boot with a usb drive plugged in
> 2) run 'p2' before bat-debug-log
> 'p2' will re-probe usb devices.
>  If the first column is battery's charge, then it's almost dry. Should
>> I try bat-recover or charge it the usual way?
> The first column is the ACR reading and you can't tell anything by just
> 1 reading.  You have to know what it was when you started discharging or
> charging.  I don't report SOC in that listing cause generally I don't care.
>  I want to know what it does after I turn on charge rather than what level
> it was at previously.
> bat-charge simply enables charging and then starts reading the battery
> directly.  Thus it does not care about any of the settings in the EEPROM.
>  Its a good diag tool to see if the battery just physically won't take
> charge or if you just can't communicate to it at all.  If bat-charge works
> but normal charging does not then its EC or EEPROM badness.  The LFP
> batteries have an overvoltage cutoff that will protect them so its ok to
> just turn one on and leave it.  For NiMH you would end up reducing its life.
>  But since you don't have any NiMH you don't care.
> 'bat-recover' works by PWMing the charge pin to keep the charge current
> very low and allow the cells to equalize yet not trip the over voltage like
> they would if you just turned on the charge and left it.  The settings I've
> picked by default seem to work in most cases but I've had many batteries
> where I needed to reduce the current even further from the default settings.
> To speed up the process you can use normal charging methods to get the
> battery close to full (or wherever it cuts out at)  That way the recover
> process will be much shorter.
>  I'll try bat-recover with a bunch of batteries today, so maybe
>> tomorrow or on Wednesday I'll be sending you some logs, if it is ok
>> to you.
> After looking at your bat-debug log I've realize that the extra diagnostic
> info is only present in f-series firmwares with my newer EC code.
> I'm forwarding you an e-mail with a copy of q2f02 that I worked on while
> trying to solve some problems with batteries in another deployment.
> q2f02 will be behind q2e41 in terms of OFW but has EC code with extra
> battery diag info.  For battery testing there should no difference between
> the 2.
> Its also available here: (Just never announced since a new e-series release
> happened right after)
> So install f02 on your test laptop and re-run bat-debug-log after you have
> first run 'p2' and the logging to disk should work.  I don't need any more
> see-bstate info.
> so the steps:
> install f02
> remove battery
> boot
> stop at ok
> insert usb drive (or boot with it inserted)
> run 'p2'
> run 'bat-debug-log'
> insert battery
> run for a couple of minutes then hit a key
> send me the log.
> I'll try to get a f03 out soon with the latest of everything but I've got
> gen 1.5 bring up tasks that I need to attend to.
> --
> Richard Smith  <richard at>
> One Laptop Per Child

Ing. Emiliano Pastorino
LATU - Plan Ceibal
Av. Italia 6201 CP: 11500, Montevideo, Uruguay
Tel: (598 2) 601 5773 int.: 213
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