You’ve seen my setup with the mk210d for at the dock/garage. One battery gets what little is available when on the water. If I feel my second battery is running low, couple minutes and I switch the cables so it can get some juice of the motor.
That’s a really neat device but I’m not sure you’re going to really gain anything with it.
Ex. if a battery is low you can use the switch to combine both for enough starting power. Real world option, start the motor with the cord.
Ex. On A/C it’s 10 amps or 5/bank. If you’re going to charge on generater, upgrade to the mk220d for 10/bank.
ex. will take up to 65amps off the motor. However we’re talking about maybe 6amps at full throttle and essentially nothing when trolling. Yamaha 25hp 2017 specs