My Victron system has been running smoothly and reliably for 4 years.
In spring, I added a further 2 kW of PV power via an MPPT 150/60. Since then, I keep getting the following error message:
“High cell voltage”
The MPPT then switches to the yellow area or to “Absorption”.
Why would the cells suddenly become unbalanced, or one cell reach too high a voltage, specifically after connecting the new MPPT?
Could it be that the additional MPPT is feeding too much power or current into the battery around midday, when the battery is already almost full, causing one cell’s voltage to rise too high?
Does anyone have any idea what could be causing this, or which settings I should check first?
Could be a few reasons, but without supporting data and history, it is guesswork.
It may be a case that your batteries now get to spend more time at top of charge, balancing.
You would need to look at historical charts for charging.
What version is your GX? New versions have a modified charging algorithm for pylontech to help prevent these issues.
You could also have developed, or had but not noticed, a cell issue. You would need to pull the min/max voltage charts to see.
A connected mppt under dvcc control cannot overcharge your battery.
Typically, high voltage alarms resolve themselves with enough time on charge.
There are ways to encourage balancing, assuming that is actually an issue, by limiting CVL manually and then slowly raising it.
Take the end ones and put them in the middle and the middle ones on the end.
The current sharing problem is the main one now that you have more charge power. They have aged now, you will start to see the long term effects of the long stack set up.
