High Voltage reading

High Voltage Reading :I get a reading of 16+ on my voltage guage.
My Hummingbird Depth finder reads Low Voltage and My Ship to Shore Radio will sound an alarm and read high voltage when I am running at over 5000 RPM's. What do you think the problem may be. I have been going off shore 15+ miles and am getting a bit concerned. Any help would be appreciated.

Re: High Voltage reading

Without a clue to the engine size, I woukd say that is not equiped with a alternator regulator just a rectifier to correct that problem you will have to install a regulator or live with the problem.

Re: High Voltage reading

Also, on a non regulated system, high voltage indicates your battery needs service or replacement.

Tell us what your engine is, so you can get a more dedicated answer.

John

Re: High Voltage reading

I would check the wiring to the depth finder. If someone put a resistor in that circuit to protect it, then the resistor may be incorrect. With out resistance added to that circuit the voltage should be very near the same as elsewhere on your boat. Some engines have unregulated charging, and the higher the rpm the higher the voltage. A few solutions are to add a regulator, not sure how to do that or where to get one. Add an accessory that takes a fair amount of current to run (as a live bait pump) and see if that drops the voltage readings at higher rpm.Then you can turn it on at higher rpms and off at idle, PITA, but it works. A fiend got some large resistors with a heat sink and turns them on when the voltage goes too high. I believe around 14 volts is where you want to top out. Do this after you make sure the battery isn't on the way out and creating the need for higher voltage. Good luck JH

Re: High Voltage reading

Thanks to all replies:
The motor: 200 Merc. Off shore EFI, 1998-99.
The Battery was left in the boat all winter, but does not appear to have a crack, new last year. Holds a charge.
I keep the live well running, and lights on, but does not seem to change the voltage guage. Guage drops only when trimming the motor, but goes right back to 16+.
Ran it for 8 hr yesterday. 70+ mile chasing fish.... And depth finder stopped reading low voltage after I adjusted the view screen. So still stumped ?
How do I know its the battery ?
CAn the battery blow ?
And am I in danger of frying my electrical system ?
Any thoughts are greatly appreciated.

Re: High Voltage reading

Does the manual tell how many amps can come out of the rectifier? On mine it says 7 - 9 amps. If the battery is fully charged when going high rpm then somewhere around the rectifier output would need to be used to drop the voltage down. I'm interested in the answer since I suspect that I have a similar situation with mine. Have a volt gauge ordered and then will be able to monitor the volts and see if something needs to be done, although I don't run the long durations that you are running, Just maybe 15 mins and then onto the kicker for some trolling. When running, my engine uses no current, the stators other windings make the charge for the spark. The trim motor must pull a fair amount of current, If you can determine what that is then try to match it with accessories, a good coffee maker should just about do it. Just kidding, don't know of a DC coffee maker available, but you could hook up a inverter and run some AC stuff. JH

Re: High Voltage reading

Can you identify your electrical system? A 98 EFI should have a 40 amp dual voltage regulator system. Anything will go under the cover, so it could be anything from a 16 amp rectifier only to a 40 amp water cooled single regulator (yuck) to the dual system.

Question 2. Do you have an accurate volt meter to take actual readings off the battery? You may be chasing your tail for a bad meter.

hope it helps
John

Re: High Voltage reading

thanks again for the info.
going out today to purchase a voltage meter. Plan on checking guage, battery and regulator. Will get back with the info. Hope to take a couple of photos and insert in next reply. Maybe it will help someone else too.

thanks to all