Diode Fitted To The Bilge Pump

[Taz59]

Guys
My Boat is a 1997 Fourwinns 205 with Volvo Penta 5.7GLi Engine,
I have a single battery and inside the main battery isolator is a Diode that is connected to the bilge pump via a fuse its all original wiring as its on plug and sockets.

Cheers

 

[Silvertip]

So what is your question? Are you certain the "main battery isolator" is actually an isolator and not a "battery switch"? There is a significant difference between the two.

 

[Taz59]

It's the main battery isolator

 

[Silvertip]

Ahh -- you have one battery. Why do you need an "isolator". Does this device have an ON/OFF knob? If so, it is a battery disconnect switch. An isolator typically is used in two battery systems, has no ON/OFF control and isolates one battery from the other to prevent accidental discharge of either one. So we are still not clean what you actually are speaking of.

 

[sam am I]

Too much guess work....Stock Fourwinns setup, he probably has just one battery installed but by default has the "standard/deluxe package" wiring that included dual switch, refer tap, common cathode diode package etc., and is pre-wired as below for a dual feed on the auto bilge pump's main feed.

OP, The diode/s are just to isolate one batteries load from the other(points "1" from "2" on switch) in a dual battery setup and at the same time allow JUST the bilge pump's "auto on" to draw from either/both batteries. This can be a common setup, I run a triple feed setup in fact. Short of a shorted diode(ask/google if you just want to know how to test), as long as your bilge pump's "auto" float switch circuit is working(pump comes on w float switch), don't sweat it, the diode/s are most likely good and not a worry.

 

[bruceb58]

The reason you have a diode is so that your bilge pump can connect directly to your battery and not backfeed power to your boat when your battery switch is turned off and your helm bilge pump switch is turned on.