Johnson 115 - High volts kicks off debth finder

[midtvedt]

Hi Guys - My 1998 center console has 2 volt meters - one shows battery charge (bad/good/full) and the other goes from 1 - 18. A new problem developed when the boat is running, this gauge runs up & maintains 18 volts and continues to trip my fish/depth finder. A mechanic replaced the rectifier. Next time out was still running near 18V, but never tripped fish finder, ( don’t know if this is related, but overnight I charged the batteries - built in duel charger unit - the battery charge level gauge just says good charge, not fully charged, anyways), next day problem was worse than ever...

 

[MCM]

Re: Johnson 115 - High volts kicks off debth finder

How old are the batteries? if their bad or close to it they may not be able to take a charge. I would think after overnight they should have been fully charged.

 

[imported_Curmudgeon]

Re: Johnson 115 - High volts kicks off debth finder

You still have a motor problem, voltage should regulate between 13 and 15, or so. If it's hitting an honest 18v, that's why your FF is tripping (and it's not doing your batteries any good, either).

 

[jaybirdtx]

Re: Johnson 115 - High volts kicks off debth finder

Replace the voltage regulator.

 

[midtvedt]

Re: Johnson 115 - High volts kicks off debth finder

Originally posted by OkieBoatMech:<br /> Replace the voltage regulator.

The engine does not have a voltage regulator - the mechanic assumed to the problem was the rectifier..

 

[bassinva]

Re: Johnson 115 - High volts kicks off debth finder

Check the actual output with a d/c volt meter to verify the gauge is accurate.I have learned over the years do not always trust a gauge !!!

 

[midtvedt]

Re: Johnson 115 - High volts kicks off debth finder

Originally posted by bassinva:<br /> Check the actual output with a d/c volt meter to verify the gauge is accurate.I have learned over the years do not always trust a gauge !!!

When I go above idle speed, it runs up to 18V and trips/turns off my depth finder. Then if I slow down to idle again the volt meter will still register at 18 untill I adjust the electric moter trim, and then it will drop just low enough for the depth finder to work (at idle speed only)

 

[jegervais]

Re: Johnson 115 - High volts kicks off debth finder

Your engine, as you have noted has an unregulated charging system. Simply put, there's a stator, a rectifier, some wires/cables and a battery. Not many parts to it...<br /><br />I've seen this before and (so far) every time it's been related to battery condition. Either batteries were in their death throws, or had recently been replaced. <br /><br />A load test confirmed batteries which needed replacement. <br /><br />In the second scenario, even though the battery was "new" it was of too small capacity to handle the unregulated charging system. Going to a larger capacity battery cured the problem (for example changing a 400CCA for a 600CCA).<br /><br />-John

 

[midtvedt]

Re: Johnson 115 - High volts kicks off debth finder

Originally posted by John from Illinois:<br /> Your engine, as you have noted has an unregulated charging system. Simply put, there's a stator, a rectifier, some wires/cables and a battery. Not many parts to it...<br /><br />I've seen this before and (so far) every time it's been related to battery condition. Either batteries were in their death throws, or had recently been replaced. <br /><br />A load test confirmed batteries which needed replacement. <br /><br />In the second scenario, even though the battery was "new" it was of too small capacity to handle the unregulated charging system. Going to a larger capacity battery cured the problem (for example changing a 400CCA for a 600CCA).<br /><br />-John

John - You are correct, the mechanic mentioned that it is an unregulated charging system... I did not realize that the battery condition would affect the volt meter and in turn trip the depth finder?

 

[jegervais]

Re: Johnson 115 - High volts kicks off debth finder

The thing with battery condition, is that it must be capable of absorbing the full output of the (unregulated) charging system. If it's past prime or too small capacity, you get the problem you're now experiencing. <br /><br />One afternoon at a dealership I once worked at, we encountered this same problem. We tried several "new" batteries off the rack and all produced the same over-voltage condition. As soon as we put a larger capacity battery in the boat, the charging system worked normally again.<br /><br />It appears that your battery may not be taking the full output and that is why you see the higher voltage (18). Many newer depth finders & gps units have the over-voltage protection and shut themselves off to prevent damage to the electronics.<br /><br />If its an old battery, I suggest a load test. Or if its 4 or 5 years old, just replace it. If it's new, consider going to a larger capacity battery. <br /><br />The other option is to attempt to retro fit a voltage regulator (not always possible - depends on model number of motor). This is usually a costlier option, but the fix is permanent.<br /><br />-John

 

[midtvedt]

Re: Johnson 115 - High volts kicks off debth finder

Originally posted by John from Illinois:<br /> The thing with battery condition, is that it must be capable of absorbing the full output of the (unregulated) charging system. If it's past prime or too small capacity, you get the problem you're now experiencing. <br /><br />One afternoon at a dealership I once worked at, we encountered this same problem. We tried several "new" batteries off the rack and all produced the same over-voltage condition. As soon as we put a larger capacity battery in the boat, the charging system worked normally again.<br /><br />It appears that your battery may not be taking the full output and that is why you see the higher voltage (18). Many newer depth finders & gps units have the over-voltage protection and shut themselves off to prevent damage to the electronics.<br /><br />If its an old battery, I suggest a load test. Or if its 4 or 5 years old, just replace it. If it's new, consider going to a larger capacity battery. <br /><br />The other option is to attempt to retro fit a voltage regulator (not always possible - depends on model number of motor). This is usually a costlier option, but the fix is permanent.<br /><br />-John

John - thank you. They may very well be the original batteries (one for the electric motor). I'll keep my fingers crossed that it is the less costly fix!