Help !!

[richinnc]

I need some help!!!! Anyone????

I am putting in a dual battery system on my 2019 Crest 1220 SLC. I am using the Blue Seas Add A Battery 120 AMP capable system. It comes with a switch and an automatic charging relay that senses when either battery gets low and charges it. Every thing is sorted out but one little wire.

Let me give you the instructions and see what you guys think…

“Connect a wire from the quick connect terminal marked SI (Start Isolation) to the terminal or wire running from the start key switch to the starter solenoid. Make this connection through an in-line fuse of one to ten amps. This connection can be made at the start key switch or at the starter solenoid, but must be to the line that is positive only when cranking. Connection to a line that is positive while the engine is normally running will prevent the charging relay from working properly.”
I know where is SI terminal is and I know what gauge wire to use. What I am not sure of is should I go with the connection at the switch…or…at the solenoid. Which would be “easier”?? I am running a Suzuki DF150.

Also, I have called and talked with a Blue Seas tech rep and I still don’t understand if this has to be hooked up to a wire that goes essentially dead after you turn the switch….WHY DO I NEED IT !!??
Anyone???? HELP!

[Fishscalz]

I think the wire temporarily disengages the charge/power sensing, because when starting the engine, it's a relatively big power surge.
It may make things go a bit haywire if the unit it sensing while cranking, and after cranking the unit goes back to normal sensing once the engine is running.

As far as the connection, the closest is usually the easiest, and that is how I would proceed.

Good luck

[trigger22]

You’re isolating the charge circuit during cranking because you’re putting out a ton of amps during startup and you’re preventing a surge across that circuit.

I personally would put it off of the switch as that’s usually the easiest. Here’s a diagram (this might not be your diagram) but will work for explanation in this post. Your directions say to put it on the wire that’s only hot during start, so in this case you’ll put it on terminal S of your switch (yellow). Be sure to reference your own wiring diagram for colors and terminal positions.

[richinnc]

Great stuff. Thanks T-22.