Originally Posted by rwidman
The isolator doesn't consume any current (amps) or power (watts), but an isolator does have a voltage drop of about.6 volts across the diodes which prevents fully charging any of the batteries. Replacing it with a battery combiner is a good idea.
The problem can be over come with a Smart Regulator such as the Balmar ARS-5 or the MC-612. They have a sensor that goes to the B+ of the house and thus they will adjust the Alt voltage to what ever it needs to be to overcome the isolator diode and line drop. So if you have an isolator off of the Alt that splits the house and the start you can remove the isolator and go directly to the house B+ out of the regulator and then use an Echo charge to handle the start battery. If as in my case the Alt goes to an isolator that splits to the 1-Both-2 selector and the Windlass / Bow Thruster 8D. The sensor and the charge wire that go to the selector can now go directly to the house and an Echo Charger to the start battery. The 8D Windlass/Bow Thruster will get the same voltage as the house by way of the up stream isolator.