My set up is composed of three panels 125w each connected in series through a bluesolar 75/15 charger and a 285w panel also connected to a separate 75/15 charger. The chargers feed two champion agm batteries each of 200AH and connected in series. The batteries charging is monitored by a BMV 700. My question relates to the tail current interpretation from the battery manufacturer charging curves attached. What should be the tail current to input in the bmv?
For most AGM's the default Victron settings will be fine.
Are you talking about the BMV's tail current setting? This has no effect on battery charging. It is only required to perform a "Synchronisation" to define the batteries as fully charged, by setting the tail current threshold combined with Charged Voltage and Charged detection time. Experimentation is required but again start with the defaults. Solar charging with clouds tend to mess up the process, its a problem you can't program for.
Also the MPPT's have the option to abort absorption early and switch to float by looking at the Tail Current setting in advanced battery settings, if this is reported by bluetooth network from the BMV. Useful to avoid excessive absorption, you could try 10-15 amps and see what happens. Only need a long full absorption to be done every month or so I believe, and the periodic equalisation settings can be tweaked to ensure this still happens.
