I recently installed the following off-grid system in a country house that will be used only during the weekends:
- 4 300W solar panels
- MULTIPLUS-II GX 48V
- SMARTSOLAR MPPT 150/35 48V
- 8 Acid Lead batteries of 6V each
Normally I switch on the MP II only when I'm onsite and I need power (once a week so far), during the other days I leave the MP II off. The solar panels and the MPPT are always active (see the screenshot below taken from VEConnect).
I see from the App that every day of the week, even if the MP II is OFF, the batteries are exposed to a charging cycle (bulk, absorption, float). The voltage is raised from 51V to 59V everyday.
That is the behavior suggested from my Victron and battery re-seller.
I'd like to have the confirmation from you that my settings are the best ones in order extend the life of my batteries as much as possible.
Is the daily charging cycle really needed? Wouldn't be better to disconnect the 4 panels during the weekdays and to connect them to the MPPT only during the weekend?
Thanks for your suggestions!