XO battery/performance [Devel Digest, Vol 76, Issue 21]

Yioryos Asprobounitis mavrothal at yahoo.com
Wed Jul 4 12:20:27 EDT 2012

--- On Thu, 6/28/12, Richard Smith <richard at laptop.org> wrote:

> XO-1 and 1.5 do not have the manual wrapping code so when
> they reach
> and extreme the counter just stops.  In theory its self
> correcting as
> once you hit a stop then the amount of ACR in the other
> directly would
> be much more and would pull the counter back the other way
> but perhaps
> there's more to it than that.
> This may or may not be the source of your original problem
> but it does
> prevent the power measurement script from getting an
> accurate reading.
> The fix is simple.  Put the battery in an XO-1.5 and
> boot to OFW.
> Then at the ok prompt do the following.  Note that it
> has to be a 1.5
> as batman does not work on a 1.75
> ok 0 bg-acr!
> Thats a zero not an O.
> This will reset the ACR register to zero.
> you can then look at it with:
> ok bg-acr@ .bg-acr
> After you do that then please run another
> discharge/charge/discharge
> cycle while running olpc-pwr-log and resend the results.

"0 bg-acr!" solved the problem of the erratic reading.
Logs look more reasonable now (though there is still a sudden jump from 87 to 96% during charging in one log. 
Battery capacity looks also improved (2.8Ah in one run)
However, the original issue of battery losing ~12% charge per day while in the XO with the laptop off, is there.

I still have the serial adapter connected to one XO-1.75 ;-)

> -- 
> Richard A. Smith
> One Laptop per Child
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