confused

[zach103]

im guessing this is a simple to fix and its a dumb question but here it goes...

I cant get power to the switch panel.. i have one of the big switches for the battery.. i tested the battery and got 12v .. when the battery switch is on it reads nothing. but when its flipped off it reads 12v.. i have two big cables going to that then two small ones from the battery to the bilge pump.. when i move the float switch the pump turns on so i know theres power comin out of the battery..

i checked all the fuses in the boat and their all fine..

any ideas??

 

[NW Redneck]

Re: confused

How and where are you measuring voltage? A volt meter reads the DIFFERENCE in voltage. If you put the leads of a volt meter on the + wire from the battery into the switch, and the other on the out terminal on the switch, with the switch OFF (open) you should read 12v. With the switch ON(closed) you will read 0v. If you connect one lead to the -(neg) terminal of the battery and leave it there, then you can use the other to test different points and find out where you are losing power.

 

[zach103]

Re: confused

alright ill try that... just wondering why it would read 0 when its the circuit is closed? wouldnt it read 12v when the circuit is complete? im young so im not to good with all thiss.. sorry for bein a pain

 

[Silvertip]

Re: confused

Not if you have the negative meter lead and the positive meter lead in the positive circuit. Put the negative lead on the negative battery terminal and leave it there. Now measure at the terminal going into the switch. You should see 12V. Now touch the red lead to the output of the switch. With the switch on you should still measure 12V. Get the drift??

 

[JB]

Re: confused

Betcha got one of those "tight and looks good" connections that isn't electrically connected so common in boat electrical systems.

 

[NW Redneck]

Re: confused

just wondering why it would read 0 when its the circuit is closed? wouldnt it read 12v when the circuit is complete?

Like I said, you are measureing the DIFFERENCE in voltage. Let's say you have a 12v switch, and you have leads on either side of that switch. When the switch is ON, there is voltage running straight through that switch as if it was just a piece of the wire so you would be reading 0 volts as there is no difference in voltage. Turn that switch OFF and now you have voltage coming in, but nothing coming out so you would be reading the difference in voltage (12v on one, 0v on the other).

Clear as mud?

 

[zach103]

Re: confused

i get it now.. ill try that out

 

[NW Redneck]

Re: confused

Good luck! Just remember:
Source - switch - load - return

Source - your battery's + terminal
switch - to control the 'load'
load - could be a light, motor, horn, etc.
return - your battery's -terminal (or engine block, ground buss, etc, they all connect to battery neg)

Of course there could be fuses or gauges in between, but that is your basic circuit. Just remember to watch what you're touching both with the test lead, and with your digits! You'll either get a new hairdoo, or be buying new parts! Be careful!