Apologies in advance, this may be a long first post …
We live on our narroboat and usually constantly cruise the system. We will be in a marina for the next 3 months (minimum) as my wife needs an operation. Therefore we have access to shore power, the usual 16 Amps @ 230v.
Given it is summer I would like to maximise the use of solar and use the grid only for heavy loads and backup/charging if/when the batteries get too low.
We have a Victron based system, with a Multiplus 3000, 12v, 120 - 16. Its on v552 firmware (there is a later version but I have no need to update at this time). We have a Cerbo Gx and an MPPT SmartSolar Charger too. Appx 600w of solar (currently). The batteries are LiFePO4 (EVE cells) and we have 942 AH installed with a REC BMS.
I know that there is an option in the Multi to “Limit internal charger to priorites other energy sources” which, from what I can see does part of the job. The manual for this is here https://www.victronenergy.com/media/pg/Solar_&_Wind_Priority/en/index-en.html. This option seems that it will only use the battery bank for the 12v stuff but will always use the shore power for the 230v stuff.
I would like to use the battery bank through the inverter for some 230v loads, and this seems possible using the Virtual Switch labelled “dedicated ignore AC input” and setting appropriate values as shown in this blog post https://panbo.com/maximizing-solar-production-with-victron-gx/. Obviously my values would be different to those shown!
However we have our immersion heater wired into the AC 2 outlet, and we control this using two assistants, specifically “programmable relay - use ACOut 2 relay”. One to turn it on, and one to turn it off, both driven by SOC %. And this works very well for us. The immersion has a physical isolation switch. Trouble is, if I enable a VS (any VS), it disables (and removes) the assistants. I cannot see how to control this relay from any of the VS options, and it appears you can only choose one. Also if using the “dedicated ignore AC input” option, it disables the AC2 Out whilst on batteries. We can safely use the immersion on batteries as it only pulls 1KW. so this option is a non-starter for us.
I can manually switch the inverter into “Inverter Only” mode using VRM or on the Cerbo and this works to a degree but is inelegant and means remembering to switch back to “On” to enable the charger! It is an all or nothing type solution, and I would like to be able to use mains when loads are higher than say 1500w.
I prefer to avoid using something like Node-Red too.
Has anyone done this or know a way to achieve this?
TIA
Paul.
