In the Victron instructions it states. “When WeakAC is on, the maximum charge current is reduced by approximately 20%.” And, “If WeakAC is set, the charger will also accept a strongly distorted voltage, at the cost of greater distortion of the input current.”
I assume this means it will reduce the charging current only when an actual weak AC input is detected. And the charger will operate at 100% when AC is sufficient.
Can someone confirm this please?
In short, your assumption isn’t correct. Enabling this function screws up the power factor (the reason for the 20% reduction) for ALL charging. See here:
Have a great weekend!
So if I am understanding correctly choosing “Weak AC” permanently changes the charge algorithm. Too bad.
Thanks Ed.
You’re welcome. It’s definitely a trade-off, and why it’s suggested to only enable it if no other measures work. I’m just curious, are you asking because you have a problematic genset or just out of curiosity?
I have found the smaller Onan generators more often need WeakAC enabled than the larger models (i.e. 12kW) and I’ve assumed that’s primarily due to inertia helping to stabilize the output. I could be very wrong about that. Older generators that have a lot of hours on them seem to be less stable and require WeakAC. Just today we lit up a brand new Onan 7kW commercial series (outputs 120/240) and did not have to enable WeakAC. I can load that generator to maximum continuous output and the Quattros remain synchronized to it, at least for 15 minutes of run time. In production use I will set the input current limit such that the generator outputs a continuous 5600W, even though that will slow down battery charging, just to preserve the life of the generator. I suggested the customer have the factory include a 10kW genset but they opted for a smaller, less expensive model.
I don’t have a specific problem I am dealing with. Not knowing what kind of generator if any the client(or someone they may eventually sell their rig to) will try to implement, I want to program the inverter for all possibilities. In the past I was told by others to just set it in case there is ever an issue. Upon reading the manual, and confirming on this site, I realized this may not be all its cracked up to be.
Copy that. I think you’re better off fine tuning the inverter settings to the specific installation. If circumstances change in the future, it’s better that they come back to you to diagnose why the system no longer behaves the same way. Not only does it help you earn a few nickels, it’s also better for the customer to know what’s changed. Cheers!