Originally Posted by pietbez
thanks everyone for all the help and suggestions.
i think i have found the problem. i decided today to disconnect the load and let the batteries charge at full capacity. I sat next to the bank for a few hours to monitor
as the morning sun became hotter the charge controller also became hotter, to the point where it would shut down, cool down and reboot. it went into a loop of shutting down, cooling
solution: i mounted a 12v desktop
PC fan on the heat sink.
voila! problem solved
my bank is currently at 14.8v and equalizing.
thanks again for all the replies, what a great forum you guys have here.
The fan is NOT
a cure to your problem....
Your controller is using a local internal ambient temp
compensation feature, which is really a pretty poor design, especially in a controller with poor cooling
which results in incorrect voltage adjustments..
I would urge you to look into an external temp sensor that mounts directly to the batteries and a controller that allows you to program the temp compensation gradient. At 42C, 14.8V is far too high a charging
voltage. At 42C (measured at the battery
case NOT the controller or air temp) the max charge voltage should be 14.3V.
For Trojan batteries the temp compensation is -0.005V per cell
or -0.03V per 12V battery
for every degree C above 25C.
So for a 12V battery:
42C - 25C = 17
17 X .03 = 0.51V
14.8V - 0.51V = 14.29V