[IAEP] [Testing] [support-gang] 12-Year-Old XOs (even 18-yesr-olds)

John Watlington wad at laptop.org
Tue Sep 13 02:03:45 EDT 2011

On Sep 1, 2011, at 12:55 AM, James Cameron wrote:

> On Wed, Aug 31, 2011 at 05:43:28PM -0700, Caryl Bigenho wrote:
>> So... the RTC battery probably went dead? Will charging the machines
>> for several hours also recharge it?  I had them on charge overnight
>> the other day so maybe that took care of if.
> No.  The charging only happens when the laptop is on, as far as I can
> tell from the circuit.  It doesn't happen when the laptop is suspended.

On XO-1 and XO-1.75, the RTC battery is only charged when the
laptop is actually turned on and not suspended.   On XO-1.5, the
RTC battery is charged even when the laptop is turned off.

All laptops will preferentially power the RTC from the main battery or
DC input, if present.

> However, a small amount of charging will run the clock for quite a long
> time.
> I don't have a clue how much charging is required to charge the clock
> battery from a fully flat state.  Perhaps Richard knows.

We charge that battery very slowly to extend its life.   Best estimates
based on the manufacturer's data is that you should reach 80% of full
charge after 20 hours of charging, and 95+% after 30 hours of charging.

> I searched for ntp-set-clock using Google:
> 	site:wiki.laptop.org "ntp-set-clock"

I learn some new function of OFW every week!
It looks like that function requires the presence of an access point called "OLPCOFW"
which provides DHCP and connectivity to an NTP server with name "time", "",
or one of the various NTP pool servers.   Did I misrepresent it ?


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