How do I wire this?

[drewpster]

Below is a simplified diagram of a manual combine switch. I would like to wire an indicator light to show when the switch is closed. Got any ideas on how to do it?

 

[bruceb58]

Re: How do I wire this?

I don't think you will be able to.

 

[drewpster]

Re: How do I wire this?

I was hoping someone smarter would come up with something. I have been racking my brain, diode?, relay?...nothings coming to me. Gotta be an Elec engineer around here somewhere!

 

[drewpster]

Re: How do I wire this?

By smarter, I mean smarter than me.

 

[Boatist]

Re: How do I wire this?

It can be done many ways but I assume you also only want the light on when the key is in the on position. That way it does not run your battery down when the engine is not running.

One way would be to install a battery charge solenoid and connect the two batteries as you have diagramed. Then wire the pick wire to another manual switch. The line from this switch would feed both the battery solenoid and a second wire to your light. Other side of light goes to ground. +12 volt input to the manual switch should be wired to your ingition line so any time the key is off the Solenoid will drop and the light will go off.

Another way would be to wire a double pole single throw switch. One pole would be as you have diagramed. The second pole would go from a 12 volt source thru the switch to your light then the other side of the light to ground. Again I would suggest wireing the 12 volt source to the ingition switch so light goes off when the key is off. Switch would need to be heavy duty to not burn up form current between batteries.

A form of the above could be a dual circuit breaker like you would use in a 220 volt AC breaker for 220 volt circuits in your house. I would suggest at least 50 AMPS. Even with 50 amps the circuit breaker would likely trip if closed when you start your engine. Also if one battery is fully charged and the other is completely dead would likely trip.

The battery charge solenoids like in the top example are usually raited at 250 amps continueous or 375 intermitent. The size and length of wire between battery will greatly affect the surge when you throw the switch. Also if the motor is running will make a big difference in surge.

Also there circuit breaker that have a built in trip circuit you could wire your light to. I do not remember if these a usually normaly open or Normaly closed.

 

[drewpster]

Re: How do I wire this?

My main battery switch panel consists of three SPST switches, a house switch, a start switch and a combine switch.
I would like to wire three indicator lights that will show each switch's position on the dash panel at the helm. (on or off) The house and start switch indicators are simple enough. I will use relays powered by the ignition switch closing the branch circuit powered by the battery switch.
The problem is the combine switch. I do not see how to wire the indicator light without closing the circuit between the batteries.
Does anyone know if blue seas systems makes a dual circuit mini battery switch?

 

[bruceb58]

Re: How do I wire this?

I am an electrical engineer. If you want to use the switch that you already bought and have installed, I don't see how it can be done.

If you want to buy all new switches, then double pole, double throw switches will work.

You would need this one:

http://www.bluesea.com/product.asp?Product_Id=174084&d_Id=7458&l1=7458&l2=

Using an AC breaker is bad idea for this application. Because the RMS value for AC is a 0.71 factor from that of DC, a 50A AC breaker will trip at 35A on DC.

 

[drewpster]

Re: How do I wire this?

I will be using the switches I have even have to do without my pretty little lites. I just wanted to see if there was a way to do it with what I have.