I wanted to be able to charge my starter battery as I spend a week off grid fishing in France. Opening doors in my transit custom Tourneo (8 lights already changed for LED bulbs) uses power from the battery and therefore runs it down.
I have also installed a leisure battery which I use for a fridge that I have in the van.
To power the leisure battery I have a 175w solar panel and MPPT 75/15 and DC-DC Charger from Victron. Looking into the options to power both batteries using a split charger with bluetooth similar to the MPPT controller.
Victrons answer is the the PWM controller with old charging technology and no bluetooth.
I thought of using 2 MPPT’s but was told that they would not work with one solar panel and that a second solar panel would be needed.
I decided it would be possible if I could separate the solar supply using a voltage sensitive relay (as in the Victron DC-DC charger). I searched the internet and found what I needed with and high and low voltage switch relay. I wired it all up and used the relay to switch the solar power from the leisure battery to the starter battery.
The leisure battery has priority. When this reaches 13.3V it then switches to charge the starter battery. If the leisure battery voltage drops below 12.8V then the relay switches the solar power back to the leisure battery.
All theory put into practice and it works!! See wiring and installation picture.
PS I need to tidy up the wiring a bit.
