Victron shunt vs inverter values way off

[Cardude]

I installed a Victron shunt two months ago in an attempt to get better monitoring on my 2-EG4 Lifepower4 48v batteries. When I first started checking the shunt vs the inverter values they were fairly close, but I haven’t checked in over a month and just saw they had diverged quite a bit.

Inverter value is at 55% this morning and the shunt says 69%. Is that normal for them to diverge that much, or do I have something set up wrong?

I tend to believe the shunt value because I started with almost a full charge last night and usually end up around 30% usage overnight, but now I’m not totally sure what to think.

 

[740GLE]

Is there inverter talking to the battery via some sort of coms?

Are the settings of the shunt the same as the inverter?

When was the last time the batteries got to 100%

 

[chrisski]

Can you send a picture of the settings for your Victron Shunt? What type of inverter?

I have a Victron shunt for the RV which I believe the SOC. Took a bit of tweaking to get the data right. Right out of the box indicated accurately the SOC discharged, the problem for me that took the tweaking was not getting the Victron Shunt to jump from 85% to 100% when charging. This was tail current.

I don't know how your inverter measures battery state whether its through the BMS or an internal shunt. If an internal shunt, there could be some system tweaking to be done. I'm still working on getting the SOC reading for my Outback shunt on the house tweaked. If your inverter gets SOC from a battery's BMS, IME BMS readings are not that accurate. Those don't come from a shunt but a coulomb counter.

Plenty of people have EG4 Batteries and should respond soon.

 

[Cardude]

I’m not at the van now so can’t connect to get the Victron settings. Will get those later when I go to the van. Yeah maybe I have it set up wrong.

The inverter is an EG4 3000 AIO unit, and I think it uses the battery BMS?

 

[chrisski]

The inverter is an EG4 3000 AIO unit, and I think it uses the battery BMS?

I can't speak to the EG4 but with my two JBD/Overkill BMS that is on the RV, the BMS does significantly differ from the shunt and I trust the shunt more. One of my BMSs would display 70% when full, while the other displayed 100%. I knew the batteries were full because the Victron Shunt Said 100%, and the voltage had reached the programmed bulk voltage and the current in had tapered to next to nothing, so batteries charged. No SOC reset button on the BMS.

If you do charge the batteries to every day, that should be an easier way to see which is more accurate. I can get data from the MPPTs to see how much power went in, and bounce that against the inverter power out and amount produced by my BMS and battery shunt.

 

[Cardude]

Here is my shunt info

 

[Brucey]

I’m not at the van now so can’t connect to get the Victron settings. Will get those later when I go to the van. Yeah maybe I have it set up wrong.

The inverter is an EG4 3000 AIO unit, and I think it uses the battery BMS?

I would trust the shunt over the 3k AIO or what the eg4 batts report.

 

[740GLE]

My JK says I have 37% left but cells are at 3.33v

My victron smart shunt says 70%, I hope my shut is correct as I head into the over night.

Granted I’ve lowered my SCC charge voltage to 3.42v/cell yet, I never touched my BMS for what full is.