Recommended Battery Isolator for 220 Amp Alternator in Class A Motorhome

Updated 10/17/2022 | Published 10/15/2022

Question:

I have two 6 volt golf cartinch batteries in my 30foot Class A motorhome as house batteries. I know there is an isolator being used, can hear it clicking. A couple of years ago, I replaced the original 130 amp alternator with a 220 amp one when it became obvious the original one was failing. Everything was fine, and a year ago I replaced my 6 year old golf cart batteries Batteries Plus. But this year, Im on my annual trip South, and suddenly notice digital meter that while going down the road those golf cart batteries two 6 volt wired in series are reading in the 11 volt range instead of the previous 13 volt range, and wonder if the years old isolator is failing. Reading about isolators on your website it looks like the isolator needs to be rated ABOVE 220 amps. Am I correct on this? Thanks for reading.

asked by: Ron H

Expert Reply:

In regards to battery isolators, they should be rated at or close to the changing amperage rating of your alternator. They don't really need to exceed this as it's very unlikely your alternator will ever reach its max charging amperage. I recommend the Redarc Smart Start Battery Isolator part # 331-SBI212 which is rated at 200 amps. This isolator has a ton of great features like the ability to connect to an LED (not included) that can be mounted in your cab for easy viewing of diagnostics. It comes with a tow year wrranty.

expert reply by: Conner L