Alternator overcharging ?

Joker2 · #1 05-28-2011, 08:15 PM

Got a new Optima Blue top battery this year went out and noticed when going 2000 or more Rpm's my voltmeter ( new ) goes up to 17 / 18 volts. Checked it with a known good meter at the battery while underway. sure enough it read 17.5 V. Didn't have this problem last year with old battery, I didn't change anything as far as electronics go. How bad is this and how do I fix it, or at least troubleshoot the problem ? Thanks

THEFERMANATOR · #2 05-28-2011, 11:17 PM

OPTIMA batteries are of an AGM design that have very low internal resistance and will run pretty high voltages compared to a lead acid battery in an unregulated charging system. If this is with your 150 EVINRUDE though, sounds like you have a voltage regulator issue. Check the connections espescially the ground at the regulator is the first thing I would do. You shouldn't get much higher than about 14.5 or so if the regulator is working properly. I know AGM batteries don't take well to running at high voltages for extended periods of time and will die a short death doing so.

Joker2 · #3 05-29-2011, 06:09 AM

Thanks , I will check that out.

Joker2 · #4 06-05-2011, 07:44 AM

I was wondering why my fishfinder is not shutting down when the Alternator is putting out 17.5V, it's just a cheap $120.00 Lowrance lcd unit ?

THEFERMANATOR · #5 06-05-2011, 10:14 AM

Quote:

Originally Posted by Joker2

I was wondering why my fishfinder is not shutting down when the Alternator is putting out 17.5V, it's just a cheap $120.00 Lowrance lcd unit ?

Alot of marine electrronics can run on both 12 or 24V as some boats run 24V systems in them.

phatdaddy · #6 06-05-2011, 12:50 PM

i think one of my garmin units has an operating range of 10-20 volts

Joker2 · #7 06-05-2011, 02:13 PM

OK Thanx

Joker2 · #8 06-11-2011, 05:55 AM

My mechanic took out the brand new CDI voltage reg. he put in when he rebuilt the motor and put back the original OMC one and it has been working fine, (15V max ), he told me the CDI's are crap and he isn't using them anymore.

THEFERMANATOR · #9 06-11-2011, 10:22 AM

Quote:

Originally Posted by Joker2

My mechanic took out the brand new CDI voltage reg. he put in when he rebuilt the motor and put back the original OMC one and it has been working fine, (15V max ), he told me the CDI's are crap and he isn't using them anymore.

I got news for your mechanic, CDI makes them for BRP now. It's just the luck of the draw wether you get a good one or not. Even OEM parts fail out of the box.

spareparts · #10 06-12-2011, 08:37 AM

what Ferm said. New BRP parts are CDI parts re boxed in BRP boxes(the leave them in the CDI box)