low battery shutdown

[James Cameron]

On Mon, Feb 22, 2016 at 09:15:54AM -0500, Martin Langhoff wrote:
> On Mon, Feb 22, 2016 at 9:12 AM, <[1]peter at easthope.ca> wrote:
> 
>     When my XO 1.5 shows about 33% charge, the system shuts
>     down with no warning.  This is normal behaviour?
> 
> Not normal behaviour. It is consistent with a battery that has
> reached the end of its usable/reliable life _or_ a battery that has
> unbalanced cells.

The former, not the latter.  By the time of the XO-1.5 the battery
packs have a cell balancing feature built in.  (I've opened some and
found the internal design had changed without us knowing.)

The early shutdown is an inconsistency between calculated state of
charge and actual state of charge.

If a couple of full charge and discharge cycles don't fix the
inconsistency, the battery is close to end of usable life.

I agree with Paul that power-logs will be useful if Peter wants to
dive deeper into the technical causes.

-- 
James Cameron
http://quozl.netrek.org/