Hello everyone,
For the last few months I've been trying to debug an issue and I think I got to the bottom of it but I need some advice.
# The Setup
This setup has been running flawlessly for the last 3 years +-, issues started a few months ago.
Assume that everything is up to date and configured according to the Victron - Pylontech guide.
- 2 X Pylontech US2000 batteries (updated to latest firmware, 94% health)
- MultiPlus 48/3000/35-50 (running latest version)
- BlueSolar 150/70 (running latest version, external control, power cycled 1 hour to make sure)
- BMV-700 (running latest version, not strictly necessary in this setup)
- CCGX (running latest version, some doubts about some settings)
- Generator 7KW
This is a 100% off grid setup.
# The Issue
- PV will charge correctly up until 60-65% then slow down and stop at 72% (reads idle on the battery) --> BMS will mark that it's sill accepting 50Ah 53.2V
- When charging with the generator it will charge to 100% at 35A but as soon as the generator is on, MPPT will produces 0A instead of supplementing till 50A like it used to.
# What I think is happening
So after going through all the settings, update the batteries with Pylontech etc... My current assumption is the problem is with the MPPT and the voltage it's reading.
I've been testing all day and I'm seeing a big difference in reported voltage by the MPPT compared to the real voltage read from the other devices and a multimeter. So we have 3 reading marking 50V and the MPPT saying 52.4V
This means the battery isn't getting charged fully and sits Idle after a generator charge:
This makes sense if the BlueSolar thinks it reached the max 52.4V while really it's at 50v and why it would turn off when it sees the generator charging the batteries at what it thinks is 53.2V.
And the MPPT reports networked operations at :
BMS is reporting it accept 53.2V and 50 A until it gets charged with the generator to 98%+-
There is almost no difference between min and max cell on Pylontech, less than 0.02V.
# So solutions I can think off:
- Fix the MPPT voltage reading, no idea how to do that, cables are secured and seem to be in good conditions / not heating up.
- Set the MPPT to charge with a 2V offset, but I don't know how to change the max CVL which is forced by Victron at 52.4V.
Any ideas are welcome, this has been on my mind for many months and I feel like I'm getting there but I don't know where to go from here.
Thank you for reading.
