Charging GC2 with Rogue MPPT Solar
Charging a pair of USB2000 golf carts with the Rogue MPPT 3048. US battery says the absorb voltage should be 14.7V (for 2 GC2 in series) held for 2-3 hrs, with charge terminated by max time or when...
Forum Discussion
brulaz wrote:
When in storage I set the float voltage to 13.1V as recommended by US Battery. But then the Rogue waits until the battery voltage drops to 0.5V less (or 12.6V) before going into MPPT mode.
I didn't notice this to happen, and I don't think this is supposed to happen with any controller in the way you describe it.
When there is none or very little loads (you said "storage", right?) - then Rogue maintains this Float 13.1 as long as there is any sun in the sky. There is always self-discharge current and some minor loads like LP detector, so in daytime the Rogue is always running, supplying enough current to maintain 13.1V.
Rogue will only let the battery voltage drop below Float 13.1 when there isn't enough sun to maintain 13.1 (or whatever Float you've set).
You may notice that around sunset when there is not enough current from PV to maintain Float, Rogue will turn the MPPT mode on, and yes, it will wait until voltage drops to 0.5V below Float, before running MPPT. Then, when there is no more sun in the sky, it will run MPPT for a few more minutes, catching the last few lumens of daylight, while the voltage slips lower and lower (because there isn't enough light), and then it will go to sleep.
I "think" that Rogue, same as any other MPPT controller, will also run MPPT when, while being in Float, you suddenly turn some high load on. So high that the panel can't supply enough current to maintain Float. Didn't happen with me, because I don't have such high loads to run, but logic dictates that this is how it should be.
As BFL13 hinted, too much information can be stressful ;)...
