Victron System is Shutting Down

Hi Folks,
First time posting. I've had some problems with my Victron system on a recent trip, which has led to some questions/confusion. Maybe you can help clear it up for me.

System Components- 2 @ 206 ah SOK's. Victron Multiplus 3000, Victron MPPT, Victron Orion, Cerbo GX. DIY install in 2015 Winnebago View.

On recent trip, I became aware that one of my SOK's was completely shut down, which left my battery bank (I think) with only a 50 amp discharge capacity. This created some understandable limitations, but wasn't my main concern.

WHEN CONNECTED TO SHORE POWER, or when running my onboard generator- when I would call for Air Conditioning, my victron system would shut down. The color monitor from the Cerbo would just look like a TV that someone pulled the plug from the wall. It would quickly and continually flicker thereafter until i discontinued my call for air conditioning. What I believe was happening was that the call for power to the A/C was being taken on by the lone battery which being shut down by it's bms. Sensing charge from the solar it would quickly try to reboot, and fail again. Hence the flicker. I reviewed my Victron settings over and over again trying to figure out what I had wrong. Everything looked correct. What could I have overlooked?

Here's what I'm confused about. Some people have told me this is the way it should work and that I need to get my batteries working correctly. I don't get it. The batteries should be irrelevant, right? The shore power should fully pass through the inverter and power up to 30Amp that the service is designed for right? I should be able to hook this thing up to a lawn tractor battery if I wanted, right? What am I missing?

Thanks in advance.
Keith in PA

The load should pass through to shore power/generator unless your pulling more than 30a, then it will utilize the Power Assist function (if configured) and pull excess power needs from the battery.

We’re you able to confirm that the inverter was in pass through mode prior to turning on the A/C? What were the load levels prior to the A/C firing up?

How can I confirm pass through mode? The loads were mild, phone chargers and such.

Are you asking if it was in "charge only" mode? If so, no it was in standard "on" position.

The cerbo display would show AC In/generator power in the top left square.

yes, it shows shore power in top left.

Sounds like two issues. Possible inverter settings issue, with poorly maintained batteries.

What’s the point of hauling around those SoK batteries if they don’t stay topped off.

When on shower power why aren’t they getting a full charge? Isn’t that the point of the multiplus?

I take it this is a 12v system?

What’s the size of the rooftop AC unit? I image it’s a non inverter based unit so it has a large inrush?

If you turn off one battery and try to replicate does it consistently happen? If so, does the issue go away if you turn the second battery back on?

79Westy said:

Here's what I'm confused about. Some people have told me this is the way it should work and that I need to get my batteries working correctly. I don't get it. The batteries should be irrelevant, right? The shore power should fully pass through the inverter and power up to 30Amp that the service is designed for right? I should be able to hook this thing up to a lawn tractor battery if I wanted, right? What am I missing?

Click to expand...

Assuming 12V. Assuming 30A AC input limit setting in MP.

It's very likely that a single rooftop AC unit is going to exceed 30A when the compressor starts up unless a soft start is installed. With the MP in the middle, it's going to sense this and engage power assist. When power assist is engaged, it supplies MORE than it expects to ensure the shore power breaker doesn't trip and then it backs off.

A single SOK can only deliver 100A before it engages over-current protection... that's only 1200W. The inverter is probably trying to supply notably more than that, so it shuts down. With two batteries active, powerassist may function normally.

Recommend you disable powerassist and see if you can start your A/C purely on shore power.

As far as I knew both batteries were fully functional. I didn't connect to the bluetooth bms for each prior to the trip though now I wish I had to confirm they were working. There's no other way to identify that one is shut down. Unless you have a trick. When the batteries are working, they're always topped off. I rarely plug in. The rooftop AC is the stock non-inverter unit. It pairs nicely with the 30 amp system and onboard onan generator. It's not over-sized for the system if working properly.

Adam De Lay said:

If you turn off one battery and try to replicate does it consistently happen? If so, does the issue go away if you turn the second battery back on?

Click to expand...

I'm currently trying to revive SOK #2 on my bench now. will test this when I get it in, but again I don't feel that I should have to, ya know...?

sunshine_eggo said:

Assuming 12V. Assuming 30A AC input limit setting in MP.

It's very likely that a single rooftop AC unit is going to exceed 30A when the compressor starts up unless a soft start is installed. With the MP in the middle, it's going to sense this and engage power assist. When power assist is engaged, it supplies MORE than it expects to ensure the shore power breaker doesn't trip and then it backs off.

A single SOK can only deliver 100A before it engages over-current protection... that's only 1200W. The inverter is probably trying to supply notably more than that, so it shuts down. With two batteries active, powerassist may function normally.

Recommend you disable powerassist and see if you can start your A/C purely on shore power.

Click to expand...

disabling power assist didn't resolve the problem.

Fyi


Love to know the cell voltages of the units, you paid the big bucks for a serviceable battery id say open it up and see what’s lurking in those cells.

79Westy said:

disabling power assist didn't resolve the problem.

Click to expand...

Exact same behavior including GX flicker?

Do you have any assistants running?

sunshine_eggo said:

Exact same behavior including GX flicker?

Do you have any assistants running?

Click to expand...

Exact same behavior with powerassist enabled or disabled, RV loses all DC and AC power abruptly. Sorry, I don't know what you mean by assistants?

79Westy said:

Exact same behavior with powerassist enabled or disabled, RV loses all DC and AC power abruptly.

Click to expand...

That's really odd. This is true 30A power?

Try disabling the UPS function.

Maybe let us see your settings?

79Westy said:

Sorry, I don't know what you mean by assistants?

Click to expand...

Assistants are additional functions you can load into the inverters that add new functions and change their behaviors.

sunshine_eggo said:

That's really odd. This is true 30A power?

Try disabling the UPS function.

Maybe let us see your settings?



Assistants are additional functions you can load into the inverters that add new functions and change their behaviors.

Click to expand...

Nope, everything is just within the available stock settings.

79Westy said:

Nope, everything is just within the available stock settings.

Click to expand...

Are you saying you're using the defaults? If not, can we see them?

Is VRM active? Can you share your site?

Attached

LMK if you still need the link, i'll have to figure that out if you need it. This is currently into a normal 15 amp plug but the problem can be replicated on 30 amp and/or generator.

I would expect disappointment on a 15A plug, but not on the generator.

Recommend you disable dynamic current limit and powerassist. Give it a shot on the generator.

On generator,, dynamic current limit and powerassist disabled. Same result. Complete shutdown, but this time the patch cable to my laptop instead of the cerbo and received the two attached notifications.

Curious. Ripple means swings in the DC voltage that impacts the inverter's ability to deliver power. Low battery is obvious. Normally, this would mean thin wires or a loose connection causing excessive voltage drop. Expect a BMS protection event would look the same.

1000% certain all your battery to inverter connections are solid?

What's killing me is why the inverter is doing anything. It should just sit there doing nothing but charging while in pass through mode.

Maybe try setting AC input current to 50A and disabling the charger?

will try this recommendation in the morning and report back. I'll take a look at all of my connections as well. Do the transfer switches ever go bad in these. Perhaps that's not the best way to describe my question...

79Westy said:

will try this recommendation in the morning and report back. I'll take a look at all of my connections as well. Do the transfer switches ever go bad in these. Perhaps that's not the best way to describe my question...

Click to expand...

It could certainly happen. Without looking it up, I think that ATS is 50A for 6kW of 120V pass-thru.