Help with getting the Victron MultiPlus II to work with a generator

[Messier11]

I just finished the last step of Off-grid build based around 16S 280AH Eve batteries, a Victron MultiPlus II 48/5000 Inverter/Charger and solar panels.

In the last step, I connected our old AC gasoline generator. I didn’t get it to work. This is the readings I got on the AC side entering the MultiPlus:

I could hear the loud “clunk” from the MultiPlus a couple of times which is supposed to indicate that it starts charging. But it sounded like it turned off automatically right away. I could see no amps going into the MultiPlus II.

I tried to bring down the Max AC input from 10 to 4 Amps in the settings for the MultiPlus and also enabled the Weak AC power setting.

This is the AC generator I am using:




I read the Victron FAQs for generator and they flagged that it might be hard to get it to work if the generator is of poor quality. This generator is pretty robust and strong, but perhaps on the older side?

Anyone have experience with getting the MultiPlus to charge with inverter power? What does it take from a generator? Am I far off?

Is there any way to increase the quality of the AC output of the generator?

 

[sunshine_eggo]

Have you read this thoroughly and conducted all recommended actions?

https://www.victronenergy.com/live/multiplus_faq

Have you done all of these?






Have you disabled powerassist?

Have you tried it in charger only mode?

Have you tried a different generator?

 

[DJSmiley]

You need to configure the settings as above to start with. For example I see 48Hz, so you need the wide frequency range for sure.

Also, the inrush current might struggle your generator to compensate for it, and the MP might be the faster one to respond.

If the settings above don't work, you can add a 500-1000W halogen bulb (or small heater) to give the generator some base load.

Many of them run much smoother with a base load and than having a big load, than from no-load to a big load.

 

[Messier11]

You need to configure the settings as above to start with. For example I see 48Hz, so you need the wide frequency range for sure.

Also, the inrush current might struggle your generator to compensate for it, and the MP might be the faster one to respond.

If the settings above don't work, you can add a 500-1000W halogen bulb (or small heater) to give the generator some base load.

Many of them run much smoother with a base load and than having a big load, than from no-load to a big load.

Yeah, I saw that somewhere else too. I have a tunnel fan that ventilates the generator so get some constant load.

 

[Messier11]

Have you read this thoroughly and conducted all recommended actions?

https://www.victronenergy.com/live/multiplus_faq

Have you done all of these?
View attachment 103384

View attachment 103385

View attachment 103386

Have you disabled powerassist?

Have you tried it in charger only mode?

Have you tried a different generator?

Thanks, lol I feel a little dumb, read to the heading saying “Grid tab” and thought all info about generators were over.

 

[Messier11]

So I tried the above and with two different generators (identical generators, but the other is a couple of years newer, 10 hp instead of 9hp, and in better shape).

I get it to charge with both generators with the new settings — but the MultiPlus shuts down without warning after say 30 sec.

The second generator is much more stable, it runs at 250v 52hz without load and goes down to about 242/50hz when the load is on and doesn’t jump much at all. I set the maximum AC input to 4 amps.

A little confusing, and I don’t see anything in the VRM under Notifications. Is there another deeper/better log?

 

[Messier11]

Hm, from the JK BMS, this is probably the issue right ?

 

[DJSmiley]

What is the max current your BMS is set to (and is able to handle)?

The Victron 48/5000 charges up to 70A, which is approx 3400W excluding losses
Your generator is 4000VA. Thats going to be close. Especially if the inverter has no ramp-in, its highly likely the generator is not going to do well with a continous load like this.

General recommendation is to stay at or below 50-60% continuous load.

Also, your BMS must support it. If the MP does 70A, and you're getting 40A from solar for example, the total charge current is 110A.

Depending on the BMS and other chargers involved I would decrease the Victrons charge current to 50A or so.

 

[sunshine_eggo]

under charger tab cut charge current to 80% of that allowed by the JK.

 

[Messier11]

What is the max current your BMS is set to (and is able to handle)?

The Victron 48/5000 charges up to 70A, which is approx 3400W excluding losses
Your generator is 4000VA. Thats going to be close. Especially if the inverter has no ramp-in, its highly likely the generator is not going to do well with a continous load like this.

General recommendation is to stay at or below 50-60% continuous load.

Also, your BMS must support it. If the MP does 70A, and you're getting 40A from solar for example, the total charge current is 110A.

Depending on the BMS and other chargers involved I would decrease the Victrons charge current to 50A or so.

Yeah, and since the power of the generator is “self syncherous’ — ie runs harder and burns more fuel with higher loads — I see no reason whatsoever to max it. I will listen to the engine and try to determine at which load it sounds like it’s working fairly effortlessly and go with that. Probably down towards providing 6-7 amps 230v AC which means the charge current will be about 30 amps unless I am missing something. That means a theoretical 9 hours to charge “100%” of my 280ah 48v battery. I will only use the generator winter time and will never use more than 3kwh per day when it’s cold outside. I will probably have to run the generator for like 3 hours every 3-4 days.

The BMS shut down the MultiPlus because for some reason the standard charge setting was 25A. I will raise that to 100A. The BMS is meant to protect the batteries which easily can be loaded with like 100-200As at least unless I am missing something. I don’t need the BMS to protect the charger/generator.

 

[Lilikoi_Heavy_Industries]

I don’t need the BMS to protect the charger/generator.

You need to tell the charger to send the correct amount of amps for your battery bank... If your charger is sending the correct amount of amps but your BMS is throwing an alarm, look at your BMS issues.

EDIT: Have you verified the charger voltages are correct for your batteries also?

 

[HRTKD]

I have the Multiplus 12/3000 and an on-board Onan 5500 watt generator (16 years old, with 800 hours). My LiFePO4 batteries (two 280 Ah with 120 amp Overkill Solar BMS) are NOT communicating with my Multiplus. I can charge my battery bank at 120 amps no problem. The generator doesn't struggle. When the PV system is in the sun the charge amps to the battery can get up to 200 amps.