I have two Orion XS units in parallel operating in Power Supply mode so that they provide a constant output voltage to a bank of specialist cameras from a large lithium battery. The settings of both units are:
Function: Power Supply
Input Current: 50A
Output Current: 50A
Output Voltage: 13.6v
Input voltage lockout: 12.0v
VE networking is disabled (having this on made it worse).
Input and output cables are identical to both units.
The problem that I’m seeing is that randomly one unit will work very hard while the other idles, other times the two work perfectly balanced, there doesn’t seem to be a pattern as to why this happens.
This is what I see on VictronConnect when they are unbalanced;
I assume that you have very short and/or thick cables on the output of the OrionXS’es to the point where both outputs are tied together? This causes both to measure (almost) the same output voltage, independent of the provided current as there is hardly any voltage drop over the output cables. Small differences in temperature or other circumstances might cause the output measurement to differ just a little, causing one of them to work hard and the other to do nothing.
I suspect that using longer (but equal length) cables on the output before they come to a common point might solve this problem as then there is a bigger voltage difference when they have a different output current, causing it to balance out more.
Just for your information (and everybody else), the reason the VE.Smart networking makes it worse is that it adjusts its output based on the reported battery voltage, compared to its own measured output(!!) voltage. So in this case it started to adjust its output voltage based on the voltage reported by the SmartShunt, which is connected to the input(!!) of the OrionXS.
In short, for every VE.Smart network, the battery voltage in the network should always be the voltage of the battery/common point connected to the output of the OrionXS/MPPT/…
The output cables are 16mm and very short (about 10cm), what sort of lenght do you think would be needed to give the effect that you describe? By my calculation if they were 1 metre long and 30A the voltage drop would only be 0.56% at 13.6v, would that be enough for the Orion units to detect a difference? I’m not sure how sensitive they are.
I frankly have no idea what length would be needed. My guess is that 1m would already help as then the voltage drop approaches 0.1V, which is a measurable difference for the OrionXS. Making the cables longer will (most likely) cause the current to be distributed more evenly. The downside is of course that there is a larger voltage drop over the cable and the voltage at the camera end will depend more on the total current drawn.
