Solar-Battery System Design


I would like to have a solar/battery system with the following specifications.

2x 100W solar panels, probably wired in series, each with the following characteristics:

  • Vmp = 18.9V
  • Imp = 5.29A
  • Voc = 22.5V
  • Isc = 5.75A

A battery pack consisting of 15S1P LiFePO4 26650 cells (3300mAh capacity, 1C max charging current), 48V nominal battery pack voltage.

The solar panels would be the system's only power source, so the charger circuit would be thought of as in-situ with load.

  • Would ADI's recommendation be to use LT8491 for charging the pack from solar panels, along with 3x LTC3300-1 and 1x LTC6812-1 for cell monitoring and protection?
  • What would recommendation be for adding in gas gauging?
  • If I needed to scale this to multiple parallel strings of 15S cells, how would this scheme change?
  • For in-situ charging as described in Figure 24 of LT8491 datasheet, if load is drawing more current than what the charger can provide, then the balance of current is made by battery, correct?

Thanks!