[Noisebridge-discuss] Status of the LiPO batteries on the hack shelf.

[Martin Bogomolni]

More information about the batteries (
http://www.evernote.com/pub/noisebridge/HackShelf#95cb7b4f-a6bb-4580-8752-5d43c668c5d6
)

I just put two random cells on a LiPO charger/conditioner and got the
following results:

One battery had fallen dangerously low in charge (2.1v) and the other
was okay (3.0v).   The battery charger gave me a 'low voltage, are you
sure you want to cycle this battery?" warning, but was able to recover
the cell.

Cell 1:
Starting voltage 2.1v
Charged voltage 4.235v
Settled voltage 4.104v
3 charge/discharge cycles, battery capacity measured at 340mAh

Cell 2:
Starting voltage 3.0v
Charged voltage 4.235v
Settled voltage 4.204v
3 charge/discharge cycles, battery capacity measured at 405mAh

Both batteries are still connected to the charger and cycling some
more.  When they have finished, I will plot the average of each cells
charge/discharge rate and internal resistance, use gnuplot, and post
it to the wiki.

I am worried that a random battery pull resulted in a cell below 3.0v.
 2.7v is considered the lowest voltage a liPO cell should be allowed
to reach while in storage or during a discharge cycle.   I recommend
we test the remaining cells for their current rest voltage and attempt
to recover any that have dropped below 2.7v.

-Martin