"Bill Andersen" wrote in message
news:Atqdb.7221$Rd4.6684@fed1read07...
Already had the battery, switch and an isolator;


The phrase: "If it ain't broke, don't fix it" comes to mind here. With the
isolator, you can leave the switch on just one battery and both batteries
will still charge. The downside of the isolator is that unless the voltage
regulator has remote sense it can significantly reduce the rate of charge
you will get. Based on your description of the loads, however, this doesn't
seem like it would be a big concern.


Anybody have any suggestions or preferences of isolator/combiner?


One issue with the battery combiner is that they are subject to failure.
The combiners have a current limit, and if you exceed that limit you can
destroy the combiner. The combiner connects the two batteries, and a sudden
heavy load on one can start to draw current from the other until the
combiner disconnects. Repeated disconnects under heavy load can take its
toll. You may not realize that it is no longer working until your "reserve"
battery is dead.

The isolator only deals with the current from the alternator. If it is
sized according to the maximum output of the alternator, it should never see
an overload, hence they are much more fail safe.

If you need or want the additional charge rate, then go with the combiner.
Otherwise, I would stay with an already installed and working system.

Rod McInnis