12 volt electrical system

3

34chriscraft

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Joined
Jun 11, 2007
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26731
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My 12 volt electrical toilet doesn't work. I have identified the battery it runs off of and the battery tests fine with a volt meter and load test. However, I am not getting enough volts from the battery to the toilet switch. I am only getting 1.36 volts at the distribution panel and only .07 volts at the toilet switch. Any ideas?
 
Loose/corroded connection somewhere; don't forget the ground lead and the ground bus. Is everything else on that dist. panel working?
 
quote:
Originally posted by stmbtwle

Loose/corroded connection somewhere; don't forget the ground lead and the ground bus. Is everything else on that dist. panel working?

Click to expand...


Thank you for your reply - yes, everything else is working but everything at the panel is at 1.36 volts.
 
i would run a jumper from the panel to the toilet...see if it works. that would isolate your problem

i agree with willie, the ground could be the problem as opposed to the positive so check both.

if one is bad i would change both out any way as they are probably routed in simular locations.
 
If you connect your -ve voltmeter wire to any other ground than the one provided at the distribution panel, surely that will determine if your bad connection is in the positive or negative wiring. ie if you now get 12VDC then the problem is in the negative (ground) wire...if it is still 1.36VDC then it is in the positive.
Assuming you mean the DC distribution panel and you only have 1.36VDC there, then I don't see how other items connected to that distribution panel can work. You will need to check the wiring backwards from the panel to the battery for a loose or corroded connection.
David
 
Thanks for the responses - here's what I know after running a few tests-

-I can get the toilet running if connected directly to a battery
-same for running a jumper from the positive battery post to the toilet motor (ground connected as it normally is).
-I can get 12 volts at the distribution panel if testing off one ground bus bar and 4 volts on the other and 1.36 volts connecting to a screw ground not connected to a ground bus bar.
-I can't get the toilet to run when connecting a jumper from the distribution panel to the toilet motor. The circuit actually trips.

Since I could get the motor running when jumping the positive connection without doing anything with the ground, I believe it is the positive cable that has a bad connection somewhere. It's too bad because tracing that is going to be a nightmare.
 
You may be confusing the toilet problem when it appears you have an electrical distribution problem.
You say that:-
"I can get 12 volts at the distribution panel if testing off one ground bus bar and 4 volts on the other and 1.36 volts connecting to a screw ground not connected to a ground bus bar."
This would indicate to me that the -ve ground where you only get 4VDC and 1.36VDC are not right.
Normally the battery is connected to a +ve bar at the distribution panel. Thereafter, that +ve is distributed to the circuits on that panel via identified c/b switches. The -ve's are connected to a common bar which is also grounded.
If you get 12VDC between the +ve and the common -ve ground then the circuit from the battery to the distribution panel is OK. If only 4 or 1.36VDC is present then the circuit from the battery to the distribution panel is faulty. You will need to determine this first before leaping into any circuit AFTER the distribution panel. In short, ensure you get 12VDC at the distribution panel first.
Once you establish that 12VDC is available then you can check each c/b switch by connecting between the output of the switch and -ve ground and switch ON and OFF to see power goes thru the switch. If that is OK and the toilet does not work, the fault is in the +ve wire to the toilet pump, as you clearly made it work with the jumper wire from the battery using the boat's -ve.
I'm not sure where you connected the jumper to and tripped the c/b because that does not seem right, you might have shorted something to cause that.
David
 
You certainly have more experience and knowledge then I but the one thing I am having trouble understanding is if it was a problem with the ground then why could I get the toilet working without touching or modifying the ground and bypassing the postive wire by using a jumper wire directly from the battery to the toilet motor and I could not get the toilet working when directly connecting a jumper wire from the positive wire that connects to the switch in the distribution panel to the toilet motor?

In both scenarios the ground connection was the same and one worked and one didn't. Either way I will check both and will eventually find out what is wrong and will let you know. Thanks.
 
Jeff,
I think my previous sentence agrees with your theory:-
"If that is OK and the toilet does not work, the fault is in the +ve wire to the toilet pump, as you clearly made it work with the jumper wire from the battery using the boat's -ve."

I'll try to explain in a different way but it is difficult without using a schematic, nor knowing your exact system:-

If you have a +ve 12VDC coming out of the c/b or c/b/switch for the toilet, at the distribution panel, then the +ve wire connections, or the actual toilet operating switch is faulty. You have proved that when you jumped from the battery to the motor, using the boats own -ve return line.
My previous advice was to determine that you DO have 12VDC at the distribution panel. Otherwise, you would be wasting time chasing the problem downstream to the toilet.
Hope this helps, but please keep us info'd on progress.
David
 
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