volt gauge question

[1216bandit]

The volt gauge reads low...I checked voltage at the battery while running and it shows about 13.5 volts but the gauge shows about 11 volts. I checked voltage at the battery with engine off and it shows about 12.4 and at the volt gauge terminals I am reading about 10.5. The power to the gauges looks like they are daisy chained so I left the ground from the meter on the volt gauge and tested with the positive from the other gauges and voltage gets higher on the test meter as I move to gauges closer to the ignition switch. Would this indicate a bad connection at some other gauge before the volt gauge? Thanx! Dan
boat is 22' starcraft with a 4.3 mercruiser

 

[JB]

Re: volt gauge question

Your voltmeter is incorrectly connected. The + should be on the ignition switch and the - on ground. There should be no other device in series with it..

 

[j_martin]

Re: volt gauge question

He's not talking about series connection, but other gauges etc are connected to the same wire as it is routed to the voltmeter.

Any voltage drop in the system will be seen by the voltmeter.

3 items:
1. The lead to the volt meter should go to the first drop on the wire from the ignition switch to the instrument panel.

2. The ground likewise should go directly to the ground bus, not be daisy chained with other devices.

3. This much voltage drop in the instrument panel indicates inadequate wiring, or too much load (extras) wired through the instrument panel and ignition switch wiring.

 

[bruceb58]

Re: volt gauge question

You need to check for voltage drops between your battery and your helm. With the ignition on, measure the voltage between the postive lead at your fuse panel and the positive lead of the battery. Do likewise from the ground of the fuse panel to the ground of the battery. You will need to make some long leads to do this. Both should be close to 0V but the two will add up to be your volatge drop at the helm.

If those look OK make the same measurements from the positive of the fuse panel to the postive at your gauge and likewise for the ground.

It is not uncommon to daisy chain grounds, and for power for that matter, in an instrument cluster. Since there is really no current drawn, it is an acceptable practice.

 

[1216bandit]

Re: volt gauge question

Thanx for the tips, I'll check things out further tomorrow...

 

[NYBo]

Re: volt gauge question

Since the voltage drops with each successive connection down the line, you have resistance in the connections. Remove the nut, clean everything up, replace nut and tighten securely, and repeat down the line.