Voltage is 2 volts differance at gauges??

[U Rest U Rust]

I throw a test meter on the batteries and it reads 13.5, my GPS with the shore power battery charger on will read 13.5. turn off the shore power and start engine, gps reads 12-12.3. even when cruising the gps will read 12 or so. So now I ankor the boat and play the stereo, gps reads 10 volts or so. check batteries, 12.0. Engine starts fine.

both batteries are new, battery switch is fine ( i opended it, no corrosion) the gound buss bar on the power panel is tight and looks fine. gps is new.

Alternator is fine as well.

any ideas???

Thanks
Jim

89 mercruiser 5.0

 

[tommays]

Re: Voltage is 2 volts differance at gauges??

Well you need to check the voltage at the battery with the motor running it should be in the 13 to 14 volt range

your shore power charger could stay ahead of a bad ALT with two batterys if your only out for the day


If your GPS is wired into the standard boat wireing than check the 10 pin plug with the hose clamp around it that connects the motor and boat

It looks well sealed BUT all the dash power(50 amp breaker on the motor) and guages run through it and the pins get funky and cause voltage drop



Tommays

 

[U Rest U Rust]

Re: Voltage is 2 volts differance at gauges??

Thanks Tommays

were is the 10 pin connector located?? Is it at engine or panel??

 

[tommays]

Re: Voltage is 2 volts differance at gauges??

it is on the motor


Tommays

 

[U Rest U Rust]

Re: Voltage is 2 volts differance at gauges??

Thanks again. will check it later today...

 

[bruceb58]

Re: Voltage is 2 volts differance at gauges??

Get your meter out with some long leads. While running the engine, measure the voltage from the ground of the battery to the ground in the dash. Do the same from the positive terminal of the battery to the positive voltage of the dash. Both should measure 0V. If not, you will know which leg has the voltage drop in it.

 

[U Rest U Rust]

Re: Voltage is 2 volts differance at gauges??

Boy, that connector took 1/2 an hour to get off. You were absolutley correct about how it looked fine, but was not. When I finally got it off the connectors did look OK, but the female side had a bit of corrosion in it. Cleaned it all up with a wire brush and electrical contact cleaner.

Huraaaahh, eurika, It fixed the problem. GPS and voltmeter now read the same as battery and when I give it gas, it goes up to 13.5.

Looks like project 98 is done.......

Thanks once again for all help guys.....