K2 vs. StarkPower LiFePo4 batteries

On Tuesday, February 3, 2015 at 7:00:07 AM UTC-8, Jim White wrote:
At 11:33 03 February 2015, wrote:
We have been selling the Starkpower battery for more than a year now.
Start=
ed out very cautiously - selling only a few to a few of our steady
customer=
s. We have now sold several hundred with no complaints. They really are
gr=
eat and are exactly the same size as the battery they replace.

One caution is you must use the special charger (inexpensive) that shuts
of=
f when the battery reaches a fully charged state.

Tom Knauff
Knauff & Grove, Inc
Ridge Soaring Gliderport

www.eglider.org

Tom, I want to fit Stark batteries to my ASW27 and am aware of their advice
re charging. Problem is that three years ago I fitted at great expense
Strobl solar panels with their OS4 charge controller. This controller is
designed for two SLA batteries and produces approx. 800ma shared between
the batteries. With SLA this will bring them up to full charge over time
and maintain them at c. 13.6 Volts. The panels have an open circuit max
voltage of 17V.

When flying I draw at least 800ma so the panels are just helping to
lengthen the operating time of my batteries so I do not see this would be a
problem but with the instruments turned off the panels would probably be
trickle charging. What is your opinion? If the internal battery circuitry
is managing the battery would that not shut down the charge when full?

I suppose that I could add a circuit to turn off the power completely at
14.6v but that would be a pain.

Any knowledgeable advice welcome.

Jim

Call Starkpower. They are very helpful on the phone. Since the LFP charger shuts off at 14V, the 13.6 set point of your regulator is probably fine - but it may depend on how it is regulating.