Since I installed my system I've been looking at ways to prioritise solar over grid without using ESS.
Currently I have programmed my Multiplus with an assistant to ignore ac input if aux input is open circuit and do not ignore ac input if aux is closed.
Then I use my bmv to set it's relay on (allow ac in) if SOC <50% and set it off again when SOC >99%. this is my summer setting. this is a common way to prioritise solar and is suggested by Victron.
I also have an over-ride switch in parallel with the bmv relay for winter which allows ac in all the time and prevents un-necessary cycling of the battery when there's not enough sun.
I'm about to fit another mppt controller (150/45) and have noticed that this particular controller has it's own programmable relay (not all 150/45's have this and some other 150 and 250 versions have it) which can be programmed to operate during daylight.
my plan is to wire this to the multiplus aux input via a three way switch so I have a choice of summer-use bmv relay, winter-do not ignore ac input, and spring/autumn-use mppt to ignore ac input during the day but allow it at night.
note that the normally closed contacts of the mppt relay should be used as they will be open during the day.
I hope this helps others trying to prioritise solar. :-)
