On 1/17/2011 3:30 PM, Ed wrote:
On Jan 17, 1:32 pm, Eric wrote:

It looks like a good choice for your situation. Did they say how much
current it drew from the source battery when it wasn't charging the
glider battery?


I didn't ask, and it doesn't seem to be available on the website.
Since it's generating a constant float I imagine that it is not
inconsequential. I'll find out when it arrives. I'm not an electrical
engineer, but my guess is that the converter will shut down at some
low voltage like 11.9 v and drop the source battery out of the
picture. That's why I wonder if I need to keep the solar charger in
the mix. The question then becomes should I have the 5W solar panel in
parallel with the main aircraft battery to take over the topping of
the battery (output side of the converter), or should I try to keep
the source battery above the lower limit using the solar. The unit is
also flexible enough that if the source power is interrupted it will
figure out where things stand and pick up the charge at the right
place. There's an interesting charge state digram on the website that
shows this. I may need to think about a timer that only allows the
source battery to be available for a certain amount each day so that
it lasts longer.

The self-discharge rate on the typical SLA is low enough, you could
forget about more charging for a month, once it was fully charged.
Unless, of course, your temperatures average over 90-100 F. But,
putting that little 0.3A panel on would keep it topped off.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)