Recently connected up our new system as follows (UK system, approved by DNO)
AC coupled PV (from existing FIT setup) feeds into house Consumer unit
Multiplus 2 5000/50-70 (latest firmware) Connected by AC in from consumer unit
Cerbo GX (latest firmware)
ET112 grid meter, hardwired
Fogstar Rack battery system 48v (3 x 100Ah Lifepo4 batteries 15kw) Connected by Canbus cable type B . The cells contain 16 x grade A Eve cells and use PACE BMS. (The batteries are set up to use the Victron protocol and report on the GX as Victron)
Using ESS assistant all setup to store excess PV, and invert when drawing from grid
All appears to work as it should....however after 48 hours, having had lots of nice sunny weather started to get lots of cell imbalance warnings, cell overvoltage warnings etc.
I found that by enabling DVCC and setting a maximum charge voltage of 54.8v, the number of overvoltage warnings subsided, but still got imbalances.
Using the battery software and supplied cable, i was talked through adjusting the point at which cell balancing begins.
over a number of days, the difference between cell voltages became wider, with a couple of cells hitting 3.65 volts way before the majority, and that was causing the alarms, and ultimately the battery would go offline.
Interestingly if you look at the nice lcd screens on the rack batteries , number one(master) reports 92% SOC, whilst 2 and 3 report 99%. (seems quite a large difference)
So today as a last resort, i have disabled DVCC, and rebooted the sytem to reset the VE bus, and lo and behold after a couple of hours of sunshine, the batteries are all back to the matching SOC on their screens, and when you use the software to look at the battery cells, you can see they are far more balanced, in fact it shows the balancing at work.
So question is....is it safe to leave DVCC disabled as it appears to work smoother...so far, or am i doing any harm?
I have scoured forums, and pestered Fogstar who now dont reply to emails or phone calls.
