XO power management

Richard A. Smith richard at laptop.org
Wed Apr 20 07:07:57 EDT 2011

On 04/19/2011 03:52 PM, Pablo Iguiniz wrote:
> Hello Richard,
> This is Eng. Javier Iguiniz from Ceibal. Ismael has recently changed
> work so I am now taking over part of his tasks, in particular the
> testing related to the XO batteries.

Welcome Javier.

> I tried to catch up with the plan, so we have carried the test to
> another batch of batteries we had here. The initial batch had 50
> batteries and there was all kind of them: newer and older from different
> years.
>  From the 50 units only 28 remained functional, meaning that they could
> accoplished the full charge/discharge test cycle. The damaged batteries
> showed different problems, which I list below:
> Battery not recognized  - "No Battery" reported , LED does not light up.

This failure is possibly recoverable if you have an external 1-wire 

Check these batteries by putting them in a XO. Stop at OFW and run 
'see-bstate'.  If you see a series of 0 1 2 over and over then you will 
need an external 1-wire interface to recover the batteries.  If you see 
more numbers than 0 1 2 then the battery should be recoverable with OFW.

> Battery recognized but error message is shown, red LED blinks

This should be recoverable.  Do you have a XO-1.5 handy?  In the latest 
XO-1.5 firmware 'watch-battery' will tell you what the error is when you 
exit.  So put the battery in a 1.5 and let the LED blink red.  Then run 
'watch-battery' and after it prints a line then press a key to exit.  It 
will print out what the reported error is.

> Bad data retrieved from EEPROM

Please describe this more.  You can get a listing of the EEPROM by 
running 'bat-dump-banks' from the OFW prompt.  Its handy if you have a 
serial port connected so you can log the results.

Also try to put the battery in a XO-1.5 with the latest firmware.  The 
1.5 firmware has code that can try and fix some types of EEPROM 
problems.  If not then we can fix the EEPROM via OFW.

> Never finishes trickle mode
> Battery appears as full but doesn´t allow the XO to start
> Initial tricke mode, does not charge after recover phase

These are interesting.  Only the 4 you show in the spreadsheet have this 
problem or do you have more?  There are only 47 entries in your 

>  From those 28 functional batteries I´m ataching a zip file with data
> collected and a file with the batteries status summary . I hope you
> could find it useful.You may find some files which have a minor data
> process or include a graph.

Your .zip file contains mostly .xls files that have been converted from 
the .csv files.  My processing tools cannot operate on excel files. 
Please send me the .csv files that olpc-pwr-log generated.  They do not 
have to be in separate directories.  You can copy them all into a single 

> At the moment we don´t have many more batteries left. I will try to find
> some more from now on.

I'm confused.  I thought you had hundreds of batteries to process. 
Thats why you needed the fast procedure.

> I saw that there was another side on the investigation regarding the
> information of charge and discharge cycles collected  in EEPROM. I would
> like to know if you had any chance to go further on this point.

I've modified my processing tool to output the lifetime numbers but 
right now they don't appear to be useful.  They don't make sense.  After 
you send the rest of the .csv files I'll summarize the results.

Richard A. Smith  <richard at laptop.org>
One Laptop per Child

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