Our MTTP 100-50 started giving intermittent overvoltage events about 4-6 weeks ago. The MTTP was installed in 2022 ( a few things were not DYI) and worked perfectly until about 6 weeks ago. My Lithionics batteries have disconnected automatically, but the over voltage killed my Webasto heater. (I’ve had other problems with the heater so installed an Espar heater, also not DYI. I opened a ticket with Victron and the dealer (Dixon Marine, not the installer) about 2 weeks ago and no response. I know it was the MPPT because our Multi Plus was not on shore power. I then saw 3 events on the Victron Connect. Sorry, I did not take a pic of the screen.
Does Victron make a product that will take a variable voltage and put out 12v? The ones I’ve bought on Amazon don’t work or eventually break. 
The battery is the system reference, if it disconnects when the mppt has production that is the problem.
This is usually done as a protective event. So it should nit be regular.
Why not rather find the solution for that.
Are they being overcharged? Might just be settings. Why not lower the absorption setting a bit lower to prevent the overcharge protection and disconnect.
The batteries are working properly. They came out of the overvoltage shutoff just fine. The over voltage killed my Webasto heater. I don’t want overvoltage to kill anything else.
The cause of this is overcharge.
So that is the problem that needs to be solved. Then the ither problem will be solved as a result. An overvoltage spike is because the battery reference disappeared and then nothing is there to absorb the power being produced. If the battery remains as a reference this would not happen.
Lower the target voltage on the mppt by about 0.2 or 0.3v.