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Converting Ampmeter to Voltmeter

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johnnyeal
Posts: 7
Joined: Tue Jun 06, 2006 11:23 pm

Converting Ampmeter to Voltmeter

Post by johnnyeal » Thu Apr 05, 2018 9:44 pm

Could anyone please confirm the proper way to wire the new voltmeter. This is on a 1967 Super Sport and custom ski boat. I ran a jumper from the temp gauge to the positive post on the voltmeter and a jumper ground from the same gauge to the negative post on the voltmeter . Gauge only indicates 8 volts Battery is 12.6. I am now thinking about running a new lead from the ignition on post to the positive post on the voltmeter. I am wondering if my ground needs to go to a better ground than the daisy chain ground going between the gauges. I have not touched the shunt or voltage regulator but terminated the ampmeter wires that went to the gauge.
Thanks for any help

jim g
Posts: 922
Joined: Wed Dec 14, 2011 10:55 pm

Re: Converting Ampmeter to Voltmeter

Post by jim g » Thu Apr 05, 2018 11:17 pm


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mbigpops
Posts: 304
Joined: Tue Feb 16, 2010 9:18 am
Location: Eastern Massachusetts

Re: Converting Ampmeter to Voltmeter

Post by mbigpops » Mon Apr 09, 2018 7:25 am

Your ground should be fine.

Measure the voltage on your hot side of the ignition switch and if it matches the battery then jumper that to the voltmeter. If that reads 8 volts then you have a problem.

Mark
1953 CC Rocket Runabout "Rocket Man"

johnnyeal
Posts: 7
Joined: Tue Jun 06, 2006 11:23 pm

Re: Converting Ampmeter to Voltmeter

Post by johnnyeal » Mon Apr 09, 2018 10:59 pm

Hello Rocket Man
Thanks for the help I ran a wire from the ignition switch ON position to the Voltmeter positive post and a wire from the main ground to the negative post on the gauge
I have 8 volts showing on the gauge when I turn inthe ignition switch Gauge reads 8 volt and not 12.6 BUMMER
Battery reads 12.6 with multimeter at the battery post
Any ideas as to my problem or what to try. I still have the shunt and original voltage regulator and a one wire alternator
Boats are 1967 Super Sport and a Custom Ski
Thanks Mark

jim g
Posts: 922
Joined: Wed Dec 14, 2011 10:55 pm

Re: Converting Ampmeter to Voltmeter

Post by jim g » Mon Apr 09, 2018 11:31 pm

johnnyeal wrote:
Mon Apr 09, 2018 10:59 pm
Hello Rocket Man
Thanks for the help I ran a wire from the ignition switch ON position to the Voltmeter positive post and a wire from the main ground to the negative post on the gauge
I have 8 volts showing on the gauge when I turn inthe ignition switch Gauge reads 8 volt and not 12.6 BUMMER
Battery reads 12.6 with multimeter at the battery post
Any ideas as to my problem or what to try. I still have the shunt and original voltage regulator and a one wire alternator
Boats are 1967 Super Sport and a Custom Ski
Thanks Mark
A one wire alternator is usually internally regulated. So you should not need the original regulator. If you not sure it is internally regulated. Take it off and take it to a Starter/Alternator repair shop and have them check it. Also have them make sure it is a marine alternator. It could save your life and others.

The wire from the gauge should go straight to the terminal on the alternator. Also if you are not using the amp gauge you need to eliminate the shunt.

johnnyeal
Posts: 7
Joined: Tue Jun 06, 2006 11:23 pm

Re: Converting Ampmeter to Voltmeter

Post by johnnyeal » Thu May 17, 2018 2:19 pm

I still have not solved this question and read only 10 volts on the voltmeter and battery reads 12.2. I have the old voltage regulator, alternator and shunt still installed. Would these items be interfering with the voltage reading?

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