The real knock of the typical automotive 2-battery system is charge position and sense position.
In my Rams, the system senses from the driver side battery, and charges the passenger side battery (which carries over the the driver side).
This system works perfectly most of the time, but if the driver side battery starts getting weak, the system will cook the passenger side battery by ramping up the alternator to compensate.
Sensing and charging the same battery in a dual can result in one battery being neglected, however. Neither system could be considered unreliable, either. They just both have their own little faults.
Diesels do not have isolators for one simple reason: Both batteries are starting batteries. On a cold day, doing long cranking events while you have a super hungry grid heater going requires a lot of juice. There's no point in isolating them.
In my Rams, the system senses from the driver side battery, and charges the passenger side battery (which carries over the the driver side).
This system works perfectly most of the time, but if the driver side battery starts getting weak, the system will cook the passenger side battery by ramping up the alternator to compensate.
Sensing and charging the same battery in a dual can result in one battery being neglected, however. Neither system could be considered unreliable, either. They just both have their own little faults.
Diesels do not have isolators for one simple reason: Both batteries are starting batteries. On a cold day, doing long cranking events while you have a super hungry grid heater going requires a lot of juice. There's no point in isolating them.