Have got part of the setup, (MP11 Cerbo,BMZ battery MPPT450/100) working now. Solar is charging battery and battery is communicating with Cerbo, battery now 61V 100%. On MP side getting low battery LED, and the absorption, bulk, inverter on, LED’s, illuminate periodically. Does this regardless if AC present. Getting VE Bus error 15. Cerbo not showing any info from the MP, other than it has communicated it is present and that the AC current limit (31A) is set. Don’t think I have installed ESS assist properly and the issues here I believe are all connected so could do with some guidance please. Not managed to find a good example of ESS assist example yet.
You really need to get someone experienced to help you, or pause for a bit and sign up to professional.victronenergy.com and do the free video training.
You seem to have bitten off a bit too much to chew.
This is expensive gear, getting it wrong can be costly and unsafe.
Something strange here I have replied to a different but very similar posting here. That is not visible, neither my reply. So has someone been editing?
Thanks for that, I have looked previously as what is on there and just had another look and there is a webinar running tomorrow on ESS except unfortunately it is in a language foreign to me. There is a lot of info on how to use it, but not the detail in configuring it for the system. I’ll get there though.
Start with a firmware check and possible update (including VC and ve config)
Error 15 - VE.Bus combination error
Summary
A combination error of VE.Bus products, firmware versions or commands has occurred
This error can occur for example when:
An Interface-1140 with old firmware is combined with a new Multi firmware
When external BMS commands are send while a VE.Bus BMS is connected
The connected VE.Bus product firmware versions are incompatible. (This can in most cases be solved by updating the firmware.)
Recovery: auto-restart once the error is gone.
Brill many thanks for the link worked a treat no communication issue, no low battery LED. 10 min job in end. There was no need for firmware updates had latest versions. Was a bit alarmed when I switched AC on to the inverter for 1st time loud clanking presumably of relays. Exporting a bit this morning, a piece of meat in the oven cooking on sunshine and battery. Great!! Don’t know why I did not pick up on that procedure I had seen it ages ago but for some reason went down another route, probably because felt was drowning under pages and pages of info. So can’t thank you enough for the prompt.
I do have a simpler issue still needing some thought though. Best I do another posting,
Dafydd 
Lol yeah is a bit to chew on in the beginning.