Johnson charging problems

[Spicy_McHaggis]

My johnson 115 is overcharging my battery. What causes this? I hooked up a multi meter to my battery and watched to see what was happening and why my radio would shut off only when the motor was running. The voltage slowly rises until the voltage gets to high for my amp then shuts itself off. I don't know if there is a voltage regulator or what off of the charging coil or what?? I don't want to blow up my battery or something like that, this can't be good for the rest of the electronics on the boat!

 

[VaBlue]

Re: Johnson charging problems

There should be a voltage regulator in the charge circuit. Don't know where it would be, but the manual will tell you. It will also have troubleshooting steps for the circuit. Otherwise, somebody here with more knowledge than I will probably give you a better place to start...

 

[Vic.S]

Re: Johnson charging problems

You do not give any model details, year and model number !

Some 115 models have a rectifier/ regulator. If yours is one of those it is almost certainly defective.

Others have a non regulated rectifier. They will almost certainly have a lower output stator coil and battery damage is unlikely but a battery that can be topped up when necessary, rather than any low maintenance, sealed or gel types, would be the only sensible choice.

 

[daselbee]

Re: Johnson charging problems

spicy...dude...come on....
Give us some numbers. Model, year, etc.
AND...you say you hooked up a voltmeter, and that the "voltage rises".
That don't help. Post the exact voltage. "Started at 12.5 and rose to 16.4"....something like that...

In other words...details please.

 

[Spicy_McHaggis]

Re: Johnson charging problems

Ok the motor is a '79 115ML, the voltage started out at 12.6 and rose up to 15.6 before the amp shut off and I shut off the motor. I'm almost positive that it is the rectifier just wanted to check before I start replacing parts that aren't broken!!

 

[daselbee]

Re: Johnson charging problems

Good deal, man. Now, we can look up the motor (as I have) and see that you have a simple three wire rectifier assembly PN 390124.
There is no regulation circuitry in that unit.
So, as the motor revs up, the voltage to the batt goes up.
The batt can withstand extra voltage applied, but the electrical accessories may not.

If this is a new to you problem, I bet your batt is old and possibly defective, unable to "absorb" the extra voltage supplied by the rectified engine charging system, and voltage rises...modern electronics go haywire.

 

[phipps]

Re: Johnson charging problems

If this is a new to you problem, I bet your batt is old and possibly defective, unable to "absorb" the extra voltage supplied by the rectified engine charging system, and voltage rises...modern electronics go haywire.

My question is related to this thread, but a little off topic....

Is there any thing that could be installed inline between the battery and electronic components that would regulate the voltage?

 

[daselbee]

Re: Johnson charging problems

Very good question...basically you want to add a regulator inline...

I have dealt with this for years. Recently, I had a reg/rect fail on my Kohler lawn tractor engine...same issue, too much current, over too much time, and blewie..no reg/rect. Too much current was because the blade clutch was failing...but off the subject....

The bottom line is this: If you can find an air cooled regulator/rectifier from any manufacturer...it doesn't have to be marine.....and it accepts two wires input (25 - 30 volts max), and has one output to the batt, it will probably work. I had a guy wanting to know if a Merc reg rect would work...sure, why not?

Air cooled, mounted properly...and don't exceed the input voltage...sure.

Just remember that it gets hot...keep it cooled very well.

I do not know of an OMC approved solution to the issue.

Probably more to add...but it is Labor Day.....

 

[Vic.S]

Re: Johnson charging problems

I do not know of an OMC approved solution to the issue.

Maybe not OMC approved but I have seen outboards, and I am pretty sure Evinrude/Johnson ones at that, with a rectifier and a separate regulator. It may have been on a very recent four stroke model that's a re-badged one. Some other makes I think have a separate (air cooled0 regulator If suitably rated one of those could be added.

Since the battery is not the problem, but other electronics, it would be a simple job for someone with a bit of electronics know-how to make up a regulator based on a Zener diode to control the supply to an individual item rather than using a regulator controlling the whole lot.

 

[daselbee]

Re: Johnson charging problems

Yep....somewhere out there is a proper, engineered rectifier/regulator that will just bolt on up to an older 'Rude...and give you a regulated charging system.

It is out there....get to looking.