Low Battery Inverter Shutdown

[caymaanedge]

680ah LifePo4
Victron 2x120 pass through inveter
1140w solar

My inverter has been shutting down due to “Low Battery.” However the SOC is at 73% and the discharge floor is at 20%. Here’s are some screen shots of my settings.
Ideas?

 

[wpns]

How is the wiring between your batteries and your inverter? Voltage drop could explain that.

Also, voltage is a really poor way to determine LFP SOC, any chance your equipment will do closed-loop RS485/RS232/CAN comms?

 

[Q-Dog]

What is your charger's absorption voltage?

 

[caymaanedge]

The wiring is all new, sized properly and in good shape. I don’t know about the closed loop reference.
I believe the charger absorption voltage is 14.4v per battery mfg.
System has been in place for three years but this shutdown has now happened twice in the last two weeks.

 

[caymaanedge]

All Victron components
Smart Solar
Inverter
Smart Shunt

 

[caymaanedge]

I just ran the generator, early here for solar, to get the batteries back to 80%. Inverter won’t go on a says Low Battery.. this is a screenshot of the VE bus Smart for the inverter. It shows 17%SOC. Is there another battery setup in the inverter that could be set with the wrong battery capacity?

 

[Q-Dog]

What is the voltage of the battery right now? What is the low voltage disconnect of the inverter?

 

[caymaanedge]

Battery Voltage is 13.3v. Smart Shunt shows 80%SOC
Inverter is showing 13.3v and 17%SOC
I do not have a readout for SOC Floor from the inverter on my phone so I’ll need to connect laptop and review settings.
Thanks for the input.

 

[justinm001]

Can almost guarantee this is wiring issue. Voltage drop at the inverter means it's pulling more power than the wires are providing. Happens all the time when AC starts without an easy start.

My 15k domestic AC has a LRA of 67amps, that's 8000w. My 12v system runs 4/0 cable to my Quattro 5000w inverter. It'll try and pull as much as 670amps through the cable and voltage drops.

Because the power is only needed for a second the wiring limits how much power can pull from the battery so it doesn't trip the BMS but I get low power alerts at the inverter.

I also found that even though I have a lynx1000a power distribution that some fuses can only handle so much current and seems to be the bottleneck. So a 300a fuse will pass 600a for a second without blowing because it takes a certain time for them to blow....but it'll still limit that current.


If not this. The inverter doesn't care about your shunt or battery settings unless you have some assistants or something. It only cares about the voltage it's getting. Do you have a cerbogx? If not then the inverter can't even see anything from the shunt or batteries.

If you have a cerbogx see what the voltage is at the inverter itself. If not use a voltmeter and check the wiring at the inverter.

A cerbogx will log everything on all devices and will show you exactly what every sensor was reading at that time. So you'll see the shunt voltage and the inverter voltage, if the shunt is 12.5v and inverter is 7v then it's the wiring or lug connection to the inverter

 

[caymaanedge]

No cerboGX
Wire is 4/0
The inverter is reading the correct voltage, 13.3v, it’s just showing it as a Low Voltage and shutting down. I just checked all the wire connections between the Inverter, Smart Shunt and Lynx and they are solid.

I think need to get laptop attached and check all inverter settings.

 

[42OhmsPA]

Individual cell voltages are good?
You're sure one isn't dropping and causing a disconnect?

 

[caymaanedge]

No cerboGX
Wire is 4/0
The inverter is reading the correct voltage, 13.3v, it’s just showing it as a Low Voltage and shutting down. I just checked all the wire connections between the Inverter, Smart Shunt and Lynx and they are solid.

I need to get laptop attached and check all inverter settings.

 

[justinm001]

No cerboGX
Wire is 4/0
The inverter is reading the correct voltage, 13.3v, it’s just showing it as a Low Voltage and shutting down. I just checked all the wire connections between the Inverter, Smart Shunt and Lynx and they are solid.

I need to get laptop attached and check all inverter settings.

So right now the inverter is saying low voltage but you manually checked with a voltmeter at the inverter lugs and it's reading 13.3v? If it gets a low voltage shutdown I believe you need to manually switch it off and back on to reset each time.

You need to find out what happens when the low voltage is triggered. What's running or what's causing it. If all Breakers are off and no AC loads and still the low voltage then check your 12v side

 

[caymaanedge]

Yes I checked voltage at inverter and it’s 13.3v
There was a 120v load running when it shutdown. Once it was just the fridge and once it was a small heater. Both well within the 3000watt inverter capacity. When I got up SOC was 80%+ and it decreased with the loads I described until it shut down an hour later.
When I login to SmartBus it flashes Low Voltage warning. Shows 13.3v and 17%SOC at the inverter.
I ran generator to get the voltage up a touch, above that Low Voltage warning, and inverter restarted. Solar is now kicking in and SOC is rising so no further issues.
So I believe now the SOC setting in the inverter is not correct. I need to get laptop out and connected and check all the settings.

 

[justinm001]

Ahh I see it's vesmart not shunt you're looking at.

You must have the monitor battery option checked. Not sure if you can use that with DC loads. I believe this option monitors power coming and going as if nothing else is connected so power from solar or DC loads doesn't register.

 

[Q-Dog]

On your Battery Settings, under "charged voltage" you have 13.3v. That should be set just under the absorption voltage, so 14.3v would be a better setting. This does not affect battery capacity, it just tells the battery monitor when to set the battery to 100% SOC and makes the counting more accurate.

 

[TomC4306]

I need to get laptop out and connected and check all the settings.

Been saying that for about an hour now...
Gonna do it or what?

 

[justinm001]

Been saying that for about an hour now...
Gonna do it or what?

If he had a cerbogx he can just download and view the config remotely... Just saying

 

[TomC4306]

I just checked all the wire connections between the Inverter, Smart Shunt and Lynx and they are solid

With an actual torque wrench?
Or just a visual perusal?

 

[TomC4306]

If he had a cerbogx he can just download and view the config remotely... Just saying

Or Solar Assistant.