Battery Isolator


Junior Member
I have a Battery Isolator that I am trying to figure out what the extra post is on it.

It has 4 post. One is connected to the Alternator and the other two are connected one each to the two batteries.

There is a label on the side that shows the 4 post and labels them as:

A E 1 2

A = Alternator (or supply)
1&2 are the batteries.

Anyone have any idea what E is for?

The post E is right next to the post A which are both in the middle.

o o o

The sticker has the company name as "Valley Industries" which appears to only make hitch and hitch kits. "Multi Battery Isolator 90 amp" is listed on it. Model number 5277-81.

Battery Isolator

Take your continuity tester and check from post E to the case of the isolator. I'm guessing (and this is only a guess) that it is a ground terminal. Incidentally if this is the case the E stands for Earth as a reference to ground.
call me Krazee