Battery not charging

[jlb7244]

My 1986 40hp evinrude with electric start was not charging the battery so I replaced the stator and rectifer with no differance still about 12.2 volts at idle and 12.3 volts at about half throttle, any ideas

 

[F_R]

Re: Battery not charging

My 1986 40hp evinrude with electric start was not charging the battery so I replaced the stator and rectifer with no differance still about 12.2 volts at idle and 12.3 volts at about half throttle, any ideas

You have cleaned and shined up the battery terminals (haven't you?)

Check voltage at the red rectifier terminal. Might not be connected to the battery (broken wire someplace).

Whatever blew the original rectifier may have blown the replacement. Only takes less than a split second. Test it.

 

[jlb7244]

Re: Battery not charging

I did test the rectifer and it is good and I will ck the red lead tommorow, should it have battery volts and when its at half throttle about what voltage should it be yes the battery terminals are nice and shinney and clean

 

[Vic.S]

Re: Battery not charging

Rectifier test is at http://forums.iboats.com/showthread.php?t=190638 but if you use a digital meter use it on the "diode test" range not one of the ohms ranges.

You could also check the stator output. You should get around 12volts AC between the yellow/gray and both yellow and yellow/blue, rising as the revs are increased.

Connecting the battery with the polarity reversed will instantly blow the rectifier.

Disconnecting the battery while the engine is running may also blow the rectifier.

Why did you replace the stator and the rectifier? What indicated that these were faulty


BUT BUT BUT is your battery just low/ If its at half charge it will read around 12.2 volts and it will take quite some time before it charges and you see the volts rise.

Could disconnect the red led and see what you get out of the rectifier with no load. should be 12 ish at idle but rise considerably as the revs increase

 

[jlb7244]

Re: Battery not charging

the test i did was have multimeter hooked to the battery on dc volts. then disconnected rectifier and tested and was ok, took out stator and found a little differance between old and new stator on olm meter the reason I changed the parts was I used to be able to troll all day with an am radio marine radio and depth finder on and still be able to start the big motor at the end of the day and now I cannot. I have not reversed polarity or disconneced battery while running. I will ck stator output tommorow and what should it be?

 

[F_R]

Re: Battery not charging

Sorry, I have to disagree with the suggestion to disconnect the red lead while it is running. That is the same as disconnecting the battery while it is running and presents a very good chance of blowing the rectifier.

I do, however, agree that it takes a while to show a battery voltage increase. If you really want to check charging output in a meaningful way, the way to do it is with an ammeter inserted in series between the rectifier and battery cable. That motor probably only puts out around 5-6 amps, so a low-reading ammeter is needed. The 60 amp ones from the car store won't even budge at 5 amps.

A battery is like a bucket of water. How full it stays is dependent on what you put in it, as compared to how much you take out of it. At idle, you are only putting in a couple of amps at best. How many amps does your equipment draw?

 

[Vic.S]

Re: Battery not charging

Sorry, I have to disagree with the suggestion to disconnect the red lead while it is running

sorry I did not make it clear I did not mean disconnect while running I should have said disconnect then run and test.

Agree an ammeter between rectifier and battery lead is a sensible thing to try.
Most small multimeters have a 10 or 20 DC amp range (usually means changing the input socket for the positive lead on the meter) that will do the job. Make good connections though before starting up because if one comes off for the reasons already given it's likely to blow the rectifier.

As soon as done though swap the meter lead back to its normal socket and switch the meter off or as sure as eggs are eggs you'll pick it up to use as a voltmeter, short every thing out and probably wreck yet another meter!

As FR says at idle the current will be very low, a couple of amps even is probably optimistic. Id be quite happy if I had to get up to a fast idle speed before seeing anything at all provided I could get a good current at higher speeds.