Adding More Solar Panels
i'm looking at Amazon at the Windy Nation 100w and the Eco Worthy 100w panel both are 100w, specs are close 17.4 working volts 5.75 max working amps versus 17.9 working volts and 5.56 working am...
Forum Discussion
There is also the type of batteries to be charged and their spec voltages. If new batteries coming soon, are they to be chosen to match what the controller can do or should the new controller match what the intended new batts will want?
If two banks, one AGM and one Wet, then two different controllers with own settings could be handy.
I would want the Vabs to stay there till dark and not drop to Float if the batts are not up to True Full (not the fake full at 97% often quoted as being "full")
But that has to happen before supper when the battery draws start up again. Mr Wiz uses his generator at that time, but we don't need to with the propane fridge.
So the Solar30 set to 14.8 should be able to do the whole roof collection and the Xantrex could go back to being the spare?
Even if you find a controller with two settings, the Float setting range might not go as high as the Vabs setting range. With mine, I have to pick the Float as high as it will go 14.5 which it drops to as soon as it reaches the 14.8 Vabs setting. (This particular controller spends no time at Vabs once it gets there)
The EP Solar controllers both MPPT (Tracer) and PWM (LandStar etc) have their standard charging profile where it gets to Vabs of 14.6 and stays there two hours and then drops to 13.8 till dark.
The $15 eBay controllers I have tried go to 14.4 and stay there till dark. That would be fine unless the batts want 14.8.
I do not understand the term "working voltage" unless they mean Vmp which only applies to MPPT. The panels with PWM will be at battery voltage plus line loss. So despite any differences in Voc or rated "working voltages" they will all be at that same batt V plus individual line losses. They might have different "overheads" but would that ever show up?
One thing when looking at Vocs is the heat coefficient for voltage, which can be different for panels, so this might bring different or even the almost the same Vocs closer together or farther apart depending.
Seems like voltage matching is a muddle and not much to be lost anyway in terms of daily AH if they don't quite match? Close is "good enough"?
If two banks, one AGM and one Wet, then two different controllers with own settings could be handy.
I would want the Vabs to stay there till dark and not drop to Float if the batts are not up to True Full (not the fake full at 97% often quoted as being "full")
But that has to happen before supper when the battery draws start up again. Mr Wiz uses his generator at that time, but we don't need to with the propane fridge.
So the Solar30 set to 14.8 should be able to do the whole roof collection and the Xantrex could go back to being the spare?
Even if you find a controller with two settings, the Float setting range might not go as high as the Vabs setting range. With mine, I have to pick the Float as high as it will go 14.5 which it drops to as soon as it reaches the 14.8 Vabs setting. (This particular controller spends no time at Vabs once it gets there)
The EP Solar controllers both MPPT (Tracer) and PWM (LandStar etc) have their standard charging profile where it gets to Vabs of 14.6 and stays there two hours and then drops to 13.8 till dark.
The $15 eBay controllers I have tried go to 14.4 and stay there till dark. That would be fine unless the batts want 14.8.
I do not understand the term "working voltage" unless they mean Vmp which only applies to MPPT. The panels with PWM will be at battery voltage plus line loss. So despite any differences in Voc or rated "working voltages" they will all be at that same batt V plus individual line losses. They might have different "overheads" but would that ever show up?
One thing when looking at Vocs is the heat coefficient for voltage, which can be different for panels, so this might bring different or even the almost the same Vocs closer together or farther apart depending.
Seems like voltage matching is a muddle and not much to be lost anyway in terms of daily AH if they don't quite match? Close is "good enough"?
