Batterty Isolators - Is there a consensus?
There's another thread on battery isolators, and here is a quote from that thread on testing a diode type isolator: "Should be around 14 at the outer lugs and around 14.7 at the B+ lug" Presumably, ...
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MEXICOWANDERER wrote:
...Unless a Field Effect Transistor type power relay is manufactured incorporating a host of protective circuits (over, under voltage, transients, short circuit, reverse polarity and thermal shutdown, it cannot be as reliable and rugged as a mechanical relay. No way in hell. The insane amount of transient voltage spikes generated when a starter motor solenoid collapses the field inside a starter motor is the bane of any electronic device. DO NOT DO THE FOLLOWING! If a person should be touching a starter motor battery post connection when the ignition key is relaxed, the resultant transient voltage will knock them on their ass. It is far worse a jolt than a spark plug shock. It is not the POSITIVE transients that do damage in a starter motor circuit. It is the negative transients, and guess what...the ground side of a starter motor is not switched.
The newer FET designs are very robust, as are all of the electronics in newer vehicles.
I have had FET battery Isolator devices for years in a few different campers and never had any issues - no contacts to burnish...
