Renogy Rover Li 40a & 30a conflict?

Both have same size arrays of 3x100w panels.
Both wired the same.
One is pulling 0.4a from an array while other sees an actual load.

Is this a conflict I should know about? Did Ibplan my system wrongly?

Is your DC side sitting at the voltage both SCCs are targetting? ie, the chargers are in absorption stage or float stage charging? If so what you are seeing is the slight difference in the voltages both are actually producing. The one producing more current will be producing a slightly higher voltage than the other so it supplies most of the current. If this is the issue it will only affect things when your battery voltage is at the voltage the chargers are targetting in absorption or float mode. Once the load draws the battery down below that point both controllers will provide as much current as they can.

This is not unusual at the lower end of the market. If you put a multimeter on the battery terminals of each charge controller and compare with the battery voltage each controller displays you may find a 0.1V difference. If that's the case you can adjust the set points of one controller to compensate. Note that even though you might be working with the lower reading controller you might find that this controller is actually the one with the higher target voltage so a bit of trial and error may be needed. The voltage regulation is done with a separate circuit to the one that determines the voltage for display.

It is also possible that variations in wiring length and other cumulative resistances are causing the same issue, again with the chargers in absorption or float mode but I'm betting on it being the former - slight differences in the voltages the controllers are actually producing.

Side note: that wiring looks a little light for the potential 25A each charger's 300W array can provide to a nominal 12V battery.

*edit to add note about voltage regulation vs display*

Ah!

My battery bank is chock full (waiting on new inverter cables to make use of them).

So when I draw a load the actual voltages will likely reappear on both controllers?

That'd be a relief. PS How low end are the Rovers? I researched and theybl seemed solid for a small array.

Thanks!

gnubie said:

Is your DC side sitting at the voltage both SCCs are targetting? ie, the chargers are in absorption stage or float stage charging? If so what you are seeing is the slight difference in the voltages both are actually producing. The one producing more current will be producing a slightly higher voltage than the other so it supplies most of the current. If this is the issue it will only affect things when your battery voltage is at the voltage the chargers are targetting in absorption or float mode. Once the load draws the battery down below that point both controllers will provide as much current as they can.

This is not unusual at the lower end of the market. If you put a multimeter on the battery terminals of each charge controller and compare with the battery voltage each controller displays you may find a 0.1V difference. If that's the case you can adjust the set points of one controller to compensate.
It is also possible that variations in wiring length and other cumulative resistances are causing the same issue, again with the chargers in absorption or float mode but I'm betting on it being the former - slight differences in the voltages the controllers are actually producing.

Side note: that wiring looks a little light for the potential 25A each charger's 300W array can provide to a nominal 12V battery.

Click to expand...

So...

The Rovers are more mid-range. There's nothing wrong with them but they don't have the accuracy of the higher end items such as Victron.

Weird but yes: as soon as the battery was just a touch below full again, the readings equalized...ish.