I plan on running up to three 12|12 30A Non-Isolated DC to DC chargers in parallel in one of my systems and I just want to verify that the way I'm doing it is safe.
I plan on running 2awg cable from the alternator connection to a "LittleFuse" 1-3 way fused distributor (image attached), then from the distributor to each charger via 6awg cable. I'm not certain stepping down from 2awg to 6awg is the best idea, but if that's ok, please let me know.
Wire size depends on both ampacity (the wire's current carrying capcity) and voltage drop.
#6 is fine for 30 amps as long as the voltage drop isn't significant. If the runs are short then this too will be OK. Keep in mind, the DC-DC chargers need an accurate sample of battery voltage and any voltage drop in the wire between the two might cause the charger to enter absorption too soon.
The connection between alternator and DC-DC charger is more tolerant to voltage drop. Again if the lines between the fuse block and the chargers is short, you should be fine with #6. Your use of #2 from the alternator to the vicinity of the chargers is the best way to minimize voltage drop.
Fuse block to Orions, one line per Orion, must handle the 30A.
Orions are designed to work in parallel to increase output current. Eachust be programmed with identical charge parameters.
How big is the alternator? Drawing this current, with other vehicle loads, like lights, may burn out the alternator. There's a Victron video about this on YouTube.
The alternator is a standard 140 Amp. I read that keeping draw under 100 amps is safe enough, but will shorten the life span of the alternator.
According to my calculations the #2 awg (35mm^2) should be sufficient to get to the fuse block, and then #6 awg (16mm^2) from the block to the chargers.
