1980 Evinrude 100hp battery not charging while running...help

[dicarlo]

I have a 1980 Evinrude 100hp, rebuilt the power head last year. Just put it in the water after the winter with new battery, new power packs, reflector, and plugs and wires.

Battery is not charging while running the motor. Being out on a good day battery has drained to 75%. And then hard to crank the motor. Radio is on separate battery, so that isn't draining it. Any ideas? Was not having this problem last year... Also this is happening even after running at WOT for 20min intervals throughout the day.

 

[Fed]

Re: 1980 Evinrude 100hp battery not charging while running...help

Test across the battery terminals with a voltmeter while turned off and running at speed.
Running at speed should show a higher voltage.

 

[emdsapmgr]

Re: 1980 Evinrude 100hp battery not charging while running...help

If you have a functioning tach in the boat, check it out. If the tach operates normally, probable that the charging rectifier is ok. If the tach is erratic or non-functioning, it's probable that the rectifier is bad and that the battery is not being recharged. If you don't have a tach, use a household voltmeter to measure running voltage, as Fed stated. Normal battery voltage is around 12.5 or so. After running for 20 minutes, the measured battery voltage could creep up to 16+ volts. That's normal and what you should be looking for, number-wise in this charging test. Point of clarification: keep in mind that your engine has two sets of coils under the flywheel. Coils to recharge the battery and separate coils to fire the ignition. Two different systems. Since the engine only consumes battery voltage only when starting or using the trim motor, it could take quite some time to actually discharge a fresh start battery with this scenario. You indicate a pretty severe discharge in just one day. Either you are using the trim a lot, are restarting the motor frequently- each day, or the battery could be old/weak.

 

[boobie]

Re: 1980 Evinrude 100hp battery not charging while running...help

Have your battery load tested.

 

[dicarlo]

Re: 1980 Evinrude 100hp battery not charging while running...help

Thanks for the suggestions. As I stated the reflector is brand new, as is the battery. Could this be a possible coil issue? Still have to take it out on the water and test. But the tach works normal as it should.

 

[emdsapmgr]

Re: 1980 Evinrude 100hp battery not charging while running...help

Sorry, I misunderstood. The part you said you replaced was the reflector. The part is actually called the rectifier. With a working tach, I'd take a minute and get the battery load tested somewhere. Could be a bad/weak cell-even though it is new.

 

[jimmbo]

Re: 1980 Evinrude 100hp battery not charging while running...help

What type of loads are you putting on the system? The stock charging system is usually only about 5 or 6 amps at best

 

[emdsapmgr]

Re: 1980 Evinrude 100hp battery not charging while running...help

To jimmbo's post: If the engine has power trim, the stator outputs 10 amps, if it does not, the stator outputs 6 amps.

 

[jimmbo]

Re: 1980 Evinrude 100hp battery not charging while running...help

I stand corrected

 

[dicarlo]

Re: 1980 Evinrude 100hp battery not charging while running...help

So I think I may have found the culprit. Bad Ground from the motor to the battery. The wire was corroded and barely hanging together on one end. To me that makes sense that it might not have had a good enough ground to keep charging the battery. Does this make sense? Other than that the battery load test good. And yes it was the rectifier that was replaced...stupid auto correct on my phone! Gonna test this with the new ground in the next few days. Hopefully this cures it.

BTW yes it is power trim...so 10 amps it is!

Thanks guys