Battery isolator AND and manual perko switch??

Need help on an install! Please let me know if this is a good idea.

I've got a stinger sr300 battery isolator, and a manual perko switch. I want to set up 2 batteries via the isolator on one side of the perko, and have an extra battery that I can switch to JUST IN CASE, I somehow drain the other two batteries. Is this a good idea? Will it cause any electrical problems? I'll be putting it in an 02 super air.

Comments and suggestions are appreciated. Thanks!

i'm sure you can wire it to work but if the isolator is working correctly, it's kinda overkill. unless you wanna put on a concert and need a back-up stereo battery, the isolator will prevent your starting battery from ever being drained by the stereo.

so, that third battery might get used for the stereo or lights, but you won't need it to start the boat.

A buddy of mine has a huge stereo system plus lights "neon red" in the boat with the perko switch and two batteries and never had it go dead even after listening to the stereo all day. I personally think it is a great idea to have two batteries but weighting them is the only thing.

I would think that it would work fine, as long as you are careful what you power off the third battery. You would probably want to have it in more or less stock configuration, not running all your accessories.