I know this question may be better suited for an outboard forum, but I thought I would give it a shot and see what you all think. I have a 1994 Evinrude Ocean Pro, 200 hp. My voltmeter is reading 18 with the outboard running. If I just turn the key, it reads 13 until the motor cranks, then jumps up to 18. I know this will fry the battery. So, is this a bad rectifier? My tachometer works, so I do not believe it is the stator. Has anyone dealt with this electrical issue? Thanks!
Bad Rectifier?
- Thread starter mboyatt
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If your meter really reads 13 volts with the key on but the motor not running, something is wrong with your meter. You shouldn't read more than 12.6 or abouts for a fully charged good battery. Withe the ignition on but not cranking, the voltage will drop a bit just from the load. Yes it is possible that there is a voltage regulation problem but I think you meter is not working correctly.mboyatt said:
Thank you, seasick. I will purchase a meter to test the output at the battery. I made an error in what I stated previously. The voltmeter was reading 16 when the boat is running (not 18!). So here is an update. I figured I would purchase a new battery since the one that came with the boat was really old. Now, with the new battery I am reading 13 when I turn the key. I am now reading 14 with the motor running. I am headed in the right direction! Maybe it is the gauge that needs to be adjusted or replaced and not the rectifier. Sure would be a whole heck of a lor cheaper. The rectifier is about $200 bucks. :bang
enfish
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mboyatt said:
Reading 13 volts on a new, fresh charged battery isn't out of the norm. Each cell can hold up to 2.2 volts per cell (6 cells total, for 13.2 volts). But typically the battery won't hold that charge for too long and drop down to 12.6 volts (2.1 volts per cell). 14 volts with the motor running is good. But the safe bet it to check with another meter to verify since your readings are moving around.
Thank you for the responses. I plan on going over all wiring connections - to include at the motor- and also testing the reading at the battery. Hopefully this was just a bad battery. Would hate to spend 200 on a rectifier. Thank you again guys! I want to get the boat on the water Friday just to make sure the volt meter doesn't jump up to 16v again at high rpms.
Don't relay on the voltmeter at the helm. They can be way off. You need to use a decent voltmeter at the battery as a reference point.(measuring fathther away from the battery will help identify normal or abnormal voltage drops Your maximum charging voltage should not generally exceed 14.5 or there abouts. As the battery charges, the charging voltage should drop a bit if you have a voltage regulator and it is working. Note that most newer electronis like sonars and chart plotters have the ability to display voltage. The actual number may be off a bit but the relative changes are what is important.
With respect to your replacing the battery, if the battery was able to crank over the motor it was probably not all that bad. Since the voltage read way off before the battery was replaced but closer to normal after replacement, I would suspect a bad connection before a bad battery.
My understanding is that the resting voltage at 68 degrees F of a fully charged lead acid battery is 12.67 volts. I have never seen a standard lead acid 12v battery read 13.2 volts at rest.
With respect to your replacing the battery, if the battery was able to crank over the motor it was probably not all that bad. Since the voltage read way off before the battery was replaced but closer to normal after replacement, I would suspect a bad connection before a bad battery.
My understanding is that the resting voltage at 68 degrees F of a fully charged lead acid battery is 12.67 volts. I have never seen a standard lead acid 12v battery read 13.2 volts at rest.
Thanks, seasick. I am putting the boat in the water Friday for a test under load at 4000 rpm. I will use a tester at the battery and post my results. I can deal with a bad voltmeter. I really hope it is not the rectifier going bad. I have priced those, and they ain't cheap for my motor.