harold1946 wrote:
Those batteries are not deep cycle, they are a hybrid deep cycle/starting battery. Not the best choice for your application. A true deep cycle is needed.
At 70 AH each that gives a total of 140 AH and you need at least 140 watts of solar. Rule of thumb is 100 watts of solar for each 100 AH of storage.
If the controller or solar panels do not have a blocking diode the batteries can discharge back through the panels at night.
Understood that the batteries are not true deep cycle -but for the moment I would be delighted with 70ah usable. I agree that I'm probably a bit light on solar watts - even for 140ah total capacity. However, unless there is some phantom load pulling the batteries down, I can't see how my miserly power usage would have consumed 70ah overnight. And, if the panel/controller was simply too small to replenish the prior day's usage, I would have expected it to be in bulk charging mode (max amps) all day long. Instead, it thought it was done by mid-day and went into float mode.
I've never heard of the blocking diode. I would assume that a Go Power controller would prevent the panel from drawing current at night. But, who knows? Hopefully, the clamping amp meter will help me understand where the power is going.
