I did look at a few battery options. There are several that contain the BMS and all the circuit protection within a sealed unit. This has the advantage of being able to be swapped directly into the place of a lead acid battery and not require any external wiring or protection. However, I quite like to mess about with things in detail and am quite happy with electronics. I also like the Victron products I already have. Therefore, I went for the Victron batteries and added the extra circuitry required. The maximum recommend discharge rates of my batteries is 90 amps continuous (270 amps is the maximum continuous) and 900 amps for a 10 seconds pulse. As I have 3 batteries paralleled that allows 270 amps continues and 2700 amps for 10 seconds!!! I have fitted 100 amp fuses to each battery as I can’t really see me needing more than 300 amps, even when winching.