Inverter tripping from high voltage from Victron CC

[noobie]

I'm running into a strange over voltage problem with my inverter after just switching to the Victron 250/100 CC

I've just replaced my Renogy Rover 60A charge controller with the Victron 250/100:

Victron energy SmartSolar MPPT 250/100-Tr VE.Can | SCC125110412

Victron MPPT 250V/100A charge controller is the most efficient solar charge controller to increase energy harvest for solar panels. Victron Smart Solar MPPT is Suitable for charging 12, 24, 48V batteries. Shop Online for Victron MPPT with the lowest price in Canada.

volts.ca

I have this inverter which has been previously working fine with the Renogy CC

https://www.amazon.ca/gp/product/B07HCWCF85/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I've only had the Victron for a few days and now that we have had a full day of sun, my battery got full again.
The Victron CC went into absorption mode today and this is when the issue seems to happen.

When it's in bulk mode, there is no issue.

So the issue is that the inverter trips due to high voltage when the CC switched to absorption from bulk.

I saw that when putting a 1800W load(boiling water in a kettle + aquarium pumps + lights), the CC switched back to bulk(as there is cloud cover and it can't power directly on solar). The normal load is about 300W from the aquarium during the day time.

Battery is a 100aH 48V server rack LiFePO4 battery.

When the big part of the load was removed(water boiled and kettle shut off), the CC switched back to absorption pretty quickly.
During this short time, I saw on my Renogy shunt display that the voltage spiked to around 61V.

I am using the built in Victron pre-set(Smart Lithium) for LiFePO4 which has absorption voltage of 56.80V and float voltage of 54.00V
It shows equalization voltage: disabled and automatic equalization: disabled.

Has anyone had this problem with Victron CCs?

Any suggestions on how to remedy this? Should I just set everything to manual settings?
Any ideas why the voltage spikes briefly to around 61V when it switches to absorption mode?

I came across a similar issue reported in this other thread with EPEVER CCs but you'd think Victron wouldn't have this problem?

Inverter cutting out due to high voltage .....

I need to run my koi pond by solar but my inverter keeps tripping out due to over voltage? The system was running fine until we got a sunny day about a week ago and ever since the inverter has been causing me nightmares. As you will understand because it is running a Koi pond pump, aerator and a...

diysolarforum.com

 

[740GLE]

I’d drop the bulk and absorbstion voltages down, Ive always felt victrons defult was too aggressive.

What were the old settings of the Renolgy SCC? I run mine at 3.45v/cell, this would be 55.2 for bulk for your set up.

Are you getting any HVD alarms on the battery?

What gauge wire from the SCC to the battery?

 

[noobie]

I don't have the Renogy settings accessible since it's disconnected but I think the bulk voltage was set to 14.6v*4=58.4 and float 13.8x4=55.2 or so. Renogy settings are set as 12v values and then multiplied internally in the controller to get the real value for your battery voltage(i.e. multiply by 4)
The battery I have seems to call for a fairly high charge voltage of 58.4v

https://www.canva.com/design/DAE0dJakOLM/SVi8aTUZn7F_pNGSGXzoQQ/view?utm_content=DAE0dJakOLM&utm_campaign=designshare&utm_medium=link&utm_source=shareyourdesignpanel

These settings seemed to work ok with this inverter.
Now the Victron settings are defaulting to 56.8 for bulk and 54v for float which is actually lower than the Renogy was set to.

In the Victron Connect app, it shows max battery voltage for today is 59.76v but I'm thinking it didn't catch the high voltage of 61v because this is the inverter over voltage limit and it's tripping many times during absorption phase.

I'm going to try and go into manual mode and just set absorption duration to 0 so it goes from bulk to float for now.

I don't have any HVD alarms on the battery at all. The over voltage situation seems to happen for a split second but it's enough to trip the inverter.
I'm using 2 gauge wire from the inverter to the bus bar and 4 gauge wire from the CC to the bus bar.

Currently I only have 1860W of solar so the wire size should be sufficient.

 

[400bird]

The battery should act as a stabilizer/anchor to hold the voltage stable. If the charge controller can output 61 volts, it's because the battery let it.

How is your system wired? Got a diagram or pics? One alternate to my above statement is too much resistance between the battery and inverter, but no resistance between SCC and battery. Ideally there'd be no resistance in the circuit anywhere.

I agree with lowering the charge voltages. How balanced are your cells at 56.8 volts?

 

[noobie]

During this incident, the battery was at 100% SOC and it wasn't accepting any current at all.
I've noticed the battery will stay in this mode for a while, until it drops below some SOC(that I haven't paid attention to).
For example, it'll be at 100%, not accepting any current, and I draw 1500W for a few minutes. The SOC will drop a bit as some power is pulled from the battery, but it will not accept any more charge right away to get back up to 100% once the load is removed.

I'll have to check the cell balancing again but I've not noticed any large variances at 100% SOC before.

Perhaps this is normal with other batteries but I'm not sure.
I had this similar behaviour with the Renogy in "Boost" mode, which I think is the same thing as Victron's "absorption" phase.

I'll hopefully be able to catch the switch over to absorption with a multimeter but I did see it occur and saw the voltage on the screen of the shunt jump up slightly over 60v. The Victron appeared to be switching between bulk and absorption a couple times and as it did that, the inverter was beeping and briefly lost power.

None of this happened with the Renogy so this is strange that it just started with the Victron.

I've set it to manual settings as mentioned above but will try with absorption now at 15 minutes rather than 0 which was working yesterday, but may eventually lead to cell imbalances I'd imagine.

Here's my setup.
Wiring needs to be trimmed up a bit, as I just dropped in the Victron in place of the Renogy CC and the terminals were in the opposite order so there is some extra length still.

 

[mikefitz]

The voltage spikes are due to the battery entering protection mode, perhaps due to cell over volts, and disabling the charge path. When the cell volts fall with load, to below 'recovery volts ' the battery accepts charge again.
Because the energy in the controller has 'nowhere to go' when the charge path is opened there is a voltage rise.

The Victron is not actually 'switching ' anything. In the bulk charging phase, maximum amount of solar energy is transfered to the battery.
When the volts reaches the absorbtion level, ( boost volts for Renogy) the controller keeps the voltage constant at absorbtion level for the absorbtion period. On time out of absorbtion the volts drop to float.
Renogy charger , using preset lithium values, puts maximum energy into the battery until the battery volts equals boost volts, and then stops charging.

What I suspect you are seeing is that towards the end of the bulk phase, the battery is entering protection. The Victron terminal volts will jump to a high voltage momentary, the Victron regards that bulk is over and puts out constant volts for the absorbtion period.

If the battery showing 100% and there is no charge current until the volts fall slightly, the it must be protection mode, charge path off.
Use expert mode and reduce the absorbtion volts , try 56 volts.

Mike

 

[noobie]

Interesting theory. I'll try lowering the charge voltage again and see.
With a higher voltage on the Renogy, I didn't have this issue and I don't see any faults on the battery itself.
But it's possible it didn't trigger the alarm since it was pretty quick when it was doing that and then the inverter reset itself.
It would run for a bit again and would keep tripping, until I took off absorption completely.
It's strange since the voltage for absorption and the end of bulk should be the same..

We have a lot of partially cloudy days coming up and possible thunderstorms all week so I may not get a chance for this to happen again this week but we'll see.

 

[noobie]

Update on this:

If I set the absorption voltage on the Victron CC to 56.6v then the inverter trips. If I look at the History for that day then the max battery voltage shows 59.14v for some reason.

If I set the absorption voltage to 56.3v then the inverter doesn't seem to trip. Max voltage on this day shows 56.65v.

The shunt and battery BMS both showed that the battery still got to 100% SOC based on the amount of energy pushed into the battery.

Based on the previous theory, perhaps one cell is getting a bit of an over voltage situation at 56.6v and it trips the OVP on the battery. Nothing seems to be noted in the BMS that this happened though so if it did then the BMS isn't registering it.

Absorption time I've set to 20m now, rather than 5m and it seems ok so far.

I'm going to be returning this battery and exchanging it for an SOK battery if the supplier I bought the battery can get their act together and ship me the replacement SOK.

 

[Q-Dog]

Your battery suggests charging at 50 amps. Your old charger could do 60 amps but your new charger is capable of charging at 100 amps. How many amps are you charging at and have you tried to reduce the amps?

 

[noobie]

That's true, both chargers were over sized for one battery. I only have 4x465w bifacial panels at the moment so max 1860w from solar though. I think I remember seeing >1900w in the winter a few times.
The max amps I've seen to the battery is 26.2.
It is slightly above the recommended charge current but the BMS supposedly can handle 100A

The specs they give are a bit strange and seem high

Charge Voltage: 58.4±0.2V
Charge Mode: 0.2C to 56.75V, then 57.75,charge current 0.02C(CC/CV)
Charger Current: 50A
Max Charge Current: 100A
Charge Cut-off Voltage: 58.8V±0.2V

I could just set to 20A I guess as well, but it doesn't generally go >20A very often at the moment.

The main thing that got me asking about this is that the same settings on the Renogy didn't seem to cause an issue. But when I switched to Victron, there was a problem with spiking voltage.