Generator input (AC-IN) not being accepted in 48V M-S dual Inverter setup

[pmunnelly (Phil)]

Hi guys, I am having problems getting AC power into my off-grid solar system. It recognises the voltage and hertz but after a few seconds of the generator running the system seems to try to accept the input (I see AC Input 1 in the active input field on the Cerbo and a non-zero wattage) it makes a loud clunking sound and then cuts out. It seems to try again every few minutes with the same result.

No notifications or errors are apparent.

The system works fine apart from not accepting power from my generator.

EDIT: I tried the Weak AC Input option this morning. Checking that box made no difference.

---

I have a two-year-old off-grid house system with the following configuration:

2 x 8KW Multiplus 2 inverters in M-S configuration
2 x MPPT controllers
2 x 16 cell lithium batteries managed by 2 x JK-BMS
Cerbo GX

AC wiring is to both inverters with similar AC cable lengths.

I am using a fairly new Ryobi 2400W generator

Charger Config:

[Ludo]

I don’t believe a 2400w generator can power 2 8000w multiplus, the minimum ac-input amperage is probably higher then your 2.4 kw

[pmunnelly (Phil)]

Thanks for the prompt reply Ludo. Is there somewhere in the Victron documentation that details this limitation? I am happy to go out and get a bigger generator if I have to, but want to make sure it is going to work.

[Ludo]

It should be somewhere in the manual…

To be of any use with your 10kw setup, you’ll need at least a 6kw generator

Multiplus II 5000 drawing too much current from generator

Hello, New user here. I have a problem charging with Honda EU30is and Multiplus II 5000, 230V. I adjust the max allowable current in Cerbo all the way down to 6A, however the Multiplus exceeds the max output of the generator within a few seconds after the charging session starts, and it trips the generator breaker fuse. I watch the Cerbo/BMV700 reporting increasing load past 3000w before the fuse goes, so clearly the Multiplus is aware that it is overloading the generator, and still it is allow…

Don’t forget you have 2 !

[shtonkalot]

Not sure if you are experiencing the same issue as I was but your charger settings have a setting the same as mine that was causing similar relay clunks until I changed it.

The “Charge current” setting relates to the battery charge current. So that is 10 amps at 48v (480W) I raised mine to 70A (Well within limits for my batteries, check yours first) and then had no issue.

I used the VRM to change the generator AC input current limit to suit my generator but it meant the excess unused AC was able to charge my batteries at a good rate and the relay stayed latched. I also wasn’t drawing more than the generator could handle.

Your usage case and setup is different to mine. I have an Easysolar II GX which is essentially a single MultiPlus.

I think it may be worth checking your battery specs (My 2x pylontech 48v batteries can handle 80A each for a combined 160A of DC charge current) and increasing the “Charge current” setting and seeing if it helps. It may not affect you if you are drawing a lot of AC power but it should mean the generator is able to supply more charging current to your batteries.