On my sailboat, I have a 2S2P setup of four 6v 230Ah East Penn GC2 lead acid batteries for total 460Ah of 12v. I have attached 2x50w panels in parallel (I will be adding 2 more for a 2S2P setup) via a Victron SmartSolar MPPT 75/15 controller. I’m confused regarding what my tail current setting should be, (among other settings). Victron documentation states 4% of bank Ah, but that would be 18.4A, and I have yet to see the charge current surpass 7A when in full mid day sun. What am I missing?
Also, should I be accounting for my alternator and 30amp shore power charger output when setting charge voltages on the controller?
Also, should I be equalizing the batteries monthly? What settings?
Attached are screenshots of my controller settings. Does this look right? Much thanks for any guidance. I don’t want to mess up my batteries or system.
Your battery datasheet should have details of absorption and float voltages so I have no idea on these. Such a small charger will not be able to equalise such a large bank so disable it and set it to the same voltage as absorption. The solar really only is a trickle charge for this bank so setting the tail current to 1.5% should be OK if these are AGM. The solar will work alongside the other chargers OK.
Much thanks for that. They are lead acid batteries. Should I still set the tail for 1.5% and equalization to match absorption voltage?
Does the temperature compensation of -30mV/°C and Re-bulk voltage offset of 0.10V make sense?
Try the 1.5% and if it never reaches it then set it higher, some lead avid allow through some current even when full.
Again, no equalisation as the controller is too small.
The value I know for agm is 24mV/degC. A quick look on line for lead acid gives 18 to 24mV/degC. Drop it to 21 to be in the mid range.
