Auto bilge switch

[michael950]

OK, I started this discussion at PWCToday a long time ago (Electricians: Can you ID these relays?).
Anyway I am revisiting this project so here we go:

The attached photo is the relay I am using. It's the one on the left.

Huge thanks to Ollie:

The relay on the left looks like a std. Bosch Relay.
Those numbers tell you what the connections on the bottom of the relay do. Look next to the connections. You will see the numbers again
Here is what those numbers mean.


terminal #85+86 energize the coil of the realy (cause it to fire).


30 to 87a are normally closed (when 85 and 86 are energized, 30 to 87A are open).

30 to 87 are normally open (when 85 and 86 are energized, 30 to 87 are closed.

The way that relay is normally used.

#86 to ground
#85 +12v "signal" (from your switch).

#30 +12v -battery connection (high amperage).
#87 connect to your foglights or whatever high current device you are wanting to turn on.

Those relays have a 30 AMP (typ) current carrying capability. Be sure to size your wiring and fusing with that in mind.

PM me with any other questions.

-O

http://www.pwctoday.com/showthread.php?p=989688#post989688

 

[michael950]

With this info from SJ Bilge Pump

The proper way would be to install a small 12 volt DC relay in the electrical box. Connect the pull in coil to ground and the red wire coming off the rectifier / regulator. Connect the normally open contacts on the relay as you would your normal bilge switch. This arrangement will pull the relay in when the engine is operating, and thus activate the pump.

How can I wire the relay so when the engine is running the relay is energized and activates the pump. I will also be using a rotary switch to keep the pump off when not needed. I will attempt to get the relay into the electrical box and use a spare overheat sensor with sensor cut to use the wires from the inside of the e-box to the outside. If the relay does not fit, I will try to find a micro relay or make the connections on the inside and run outside and get a small project box from RadioShack and seal it up.

I will make splices with bullet connectors (OEM style) from JSS.

I think that is all the info you guys will need.

 

[michael950]

...

#86 to ground
#85 +12v "signal" (from your switch).

#30 +12v -battery connection (high amperage).
#87 connect to your foglights or whatever high current device you are wanting to turn on.

...

-O

Ollie, so basically I need to have two power sources. 1 for #30 which supplies power to the part (#87-foglights/bilge) and 1 for #85 which is switched to activate "energize" the relay.

 

[Ollie Rastabean]

Ollie, so basically I need to have two power sources. 1 for #30 which supplies power to the part (#87-foglights/bilge) and 1 for #85 which is switched to activate "energize" the relay.

#30 you can just connect to the battery (make sure it is fused).

My problem and concern with this setup is how you are going to get the signal to turn the relay on.

With skis being magneto ignition/ charging systems there is no easy way that I can think of to get a high (+12 VDC) signal to turn onthe relay.

John at JSS has a system that uses a pressure sensor to turn the bilge on. The sensor mounts between the pump nozzle + engine cooling line. That is probably the easiest way to do it.

My other suggestion is to just leave the thing on. My SJ stays on all day with 2 Atwood 500s running and I have no issues with battery drain.

-O

 

[WaveDemon]

JSS made one for me that turns on when a pressure sensor sees water in a cooling line or when switched on a three way swith to on. I might be able to dig that thing up somewhere.

 

[WaveDemon]

My other suggestion is to just leave the thing on. My SJ stays on all day with 2 Atwood 500s running and I have no issues with battery drain.

-O

same here, I have a spade connection under the hood that I connect at the beginning of the day and disconnect at the end.

 

[surferdude345]

Thats probably the most confusing bildge set up i have ever seen, keep it simple so when it breaks its easy to fix

 

[michael950]

Yup.