According to the Victron guide the minimum nr of PylonTech US2000s is 4 on a MultiPlus II 5000. What would be the minimum needed for PylonTech US3000s
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Minimum number of PylonTech US3000's on a MultiPlus II 5000
@jond As a minimum, you should ensure the batteries can handle the nominal and peak draws of the 4000W inverter. It is however not that simple. How long should the system supply your loads and how large will they be? How will the batteries be charged etc I'd recommend 3 minimum for the size inverter and together their 37A nominal rating each should easily cover peak loads, although not for very long.
@ejrossouw I have 3 x US3000s on the system. Their peak is about 2500 watts and the system is a backup system for a home office that uses about 6 kwh a day. I keep getting this error and I am trying to figure out if it is related to the number of batteries or something else.
Err 67 - BMS Connection lost
I posted about it here: https://community.victronenergy.com/questions/50585/err-67-bms-connection-lost-after-firmware-upgrade.html
The latest multi firmware is 474. Give it a try. Make sure the battery firmware is also the latest. Check with Pylontech what their suggestions are. The multi obtains it info from the bms so ... start there. I noticed the high voltage alarm. Without a view on all you settings, I'd struggle to give concrete answers, but this is likely your problem and has to be resolved as it comes from the BMS end and the battery is probably protecting itself.
Cables, if there are self made ones, suspect them too. Check all the settings and switches again. Don't be afraid to "reset" dip switches as one may just not make contact properly.
