as you all saw last night, the battery in the powertank is beyond charging.
So, this is what we need.

http://www.kendrickastro.com/astro/batt ... tBatteries
and scroll down to the 33ah battery, 150$, surely we can source something similar somewhere nearby for ALOT cheaper then that.
and here is instructions for changing the battery.
http://www.kendrickastro.com/astro/pdf/ ... _instr.pdf
I've the battery out, so when I get another one, I'll be able to put it in straight away.
for the rest of the observing nights, I'll use my own powertank.