Originally Posted by Dougsee3
This could be right or wrong?
30 years ago it was explained to me that a battery isolator main use was to control the charging of two batteries or banks.
If one battery bank was bigger than the other.
Or one of the batteries have a wiring gauge difference, or as well as a different or longer distance from the charge source.
The battery isolator would vary the charge rate between the two batteries, so that the closer battery would not over charge while trying to charge the further battery. Over time charging both batteries would come to a full charge.
When the batteries are hooked to the same charging source the further battery puts a load on the system calling for a higher charge rate from the regulator. This can over charge the closer battery and at the same time the further battery never receives a full charge.
I do not know for sure but all this could be done in a Battery Control Center that for e.g. is in my unit? and probably in most others now a days.
An isolator contains two Diodes. Diodes are one way electrical check valves. The power goes in the center and out each side. It can not come back.
Amps go to the "low voltage" battery. If the voltage is up, very little amps go to it.
That's about all they do.
They fell out of favor with interninaly regulated alternators. The regulator could not see the battery voltage and regulate.
Every, well almost every, MH built since the mid 2000s combines different size and type battery banks, moments after starting the engine.
Newer ones combine while plugged in or running the generator, at home or campground.