Outboard electrical charging

[LongLine]

Any outboard electrical charging experts out there?

The voltmeter on my fishfinder says I’m charging at 16.5 to 17 volts. Last year it read a solid 13.5-14 volts. It’s a 1984, 75Hp Evinrude. I installed a fully charged dual purpose 650 battery this year. I can’t find in the manual what it should be charging at. I did a continuity check with ohmmeter on rectifier and it seems to check out okay. I.e. resistance in one direction only – all leads to ground. Although resistance wasn’t infinite, it was fairly high.

Possible it’s breaking down and smart to replace it anyways? Any ideas?

Tom B.

(LongLine)

[Fishgill]

Did you check the fennaugulater. I would start there. Just my 2 cents.

[Guest Cheers]

I had high voltmeter readings on my boat's gauge last year.Turns out it was a loose positive ground on the motor.

[cdelong]

the alternator will try to overcharge a "dying" battery. If your battery is on the way out that could likely be the cause. kinda mimics what someone above said with the loose battery cable.... alternator sees the battery as "needing" a charge so it attempts to put out more amperage.

check your battery at rest 24 hours after you run the boat. if it is not at least 12.6v, you should consider getting a new battery.

[borderline 350]

Dear LL,

IF the voltmeter on your FF is accurate, you have lost the internal regulator in the alternator. Charging @ 16 volts will boil a wet cell battery out and dramatically shorten the battery life. Max. alternator outpit should be 14.4 volts....steady rate.

GET a good volt meter and check the voltage at several locations in the boat, while the engine is running at 2000 RPM....steady rate.... If the voltage is 15 or more, you need a new internal voltage regulator.

Sincerely,

Jet Boat Bill

[LongLine]

Bought a new rectifier & a voltmeter. Battery, connections, cables are fine. Found out how to check some components. Old rectifier was shot and unfortunately stator is shot. Just ordered a new one. Hopefully it'll arrive by weekend.

Maybe I can use this as an excuse for getting skunked??? I.E. excesive charge in an aluminum boat????? :roll:

Tom B.

(LongLine)

[L&M]

Have you tried another battery? Could save yourself any more expense.

[bbolger]

regulator most likely or a bad battery or both....

Bruce aka "Throbbin Rod"

[mscheda]

A 1984 OMC does not have a voltage regulator, only a rectifier. Therefore 16-17 volts is expected with a fully charged battery and normally operating charging system. Borderline 350 is correct that this voltage will "boil" a wet cell battery, so keep a close eye on the fluid level of the battery.

Having no voltage regulation is a bit of a cheesy design, but it's reliable and only requires that you do the battery maintenance. My boat batteries typically have lasted 5-7 seasons with a similar setup.

You could look for and connect an external regulator, but more connections and another device could actually reduce the overall reliability of the system. I haven't done that, and probably neither have thousands (millions?) of other outboard owners.

Mark