What will happen if isolator fails?

[New Comer]

I would like to ask you if battery isolator fails, will that hurt the car or the car battery? Will I still be able to use the car battery as if there is no isolator? I understand I won't be able to properly charge the second battery if the isolator fails, but I don't want it to hurt the car battery or the car.

 

[Gr8ful]

It it fails you may run the starter battery down where it needs a charge or jump.

 

[highdesertranger]

from my experience when they fail they usually fail open which means simply the don't charge the house battery. however there is a chance that they would fail closed in which case it might kill the start battery. btw I have replaced dozens of the isolators because of failure, they all failed open. to be fair I have replaced very few solenoids for failure, they just seem last longer. highdesertranger

 

[becida]

It it fails you may run the starter battery down where it needs a charge or jump.

Of it won't charge the house batt. 

it just connects the house & vehicle battery together for charging. The vehicle batt will always get charged when the engine is running & the alternator is doing it's thing.

 

[New Comer]

Thank you all for answering my question.