[BroadHopper]

Interesting about 2018. I have the 1-both-2 off combiner with no ACR on board. Originally #1 was the starter & #2 was the deep cycle. #2 is connected independent of the 1-2 switch to the bilge switch and the Mercathode. Mercathode runs all the time, thus draining the #2 battery.

Because the batteries were different, the starter will fully charge first and the generator will continue to charge the deep cycle thus shortening the life span of the starter battery. In fact one year, the positive battery post on the starter actually fried! Lucky it did not catch fire. So I would have it charged on both for about 15 minutes and switch to 2 to fully charge the deep cycle.

When I heard of dual-purpose batteries, I switched both to dual purpose and leave the combiner switch to both at all times. Seems the batteries last longer and charge evenly.

If you have the Mercathode option, you should turn it off if you valet.