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G8rfisher

1999 Yamaha 115 - Charging Issue (had it mis-labeled at 1995)

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When I unplug my batteries before fishing I am about 12.6 volts. I run 3 batteries, 1 house and 2 for trolling motor.

I have read that when you run your voltage should increase to 14.1-14.6, recently mine only goes down throughout the day no matter how long I run.

I am running a 1999 Yamaha 115 Inshore.

This may sound stupid, do these motors have an alternator that could have gone bad?

Any suggestions?

 

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Those motors have a stator only.  How many batteries are you trying to charge?  You should maintain 14 plus volts while running when only charging the house. Stator is not designed to charge multiple batteries.  

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Are you looking at your gauge or using a volt meter?  

Both my last two boats have had Yamaha gauges that read low compared to a volt meter for whatever reason.  

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I suggest testing your battery. If it's over a couple years old you might consider changing it out. If your engine is generating 14.2 - 14.5 and the battery won't hold it, sounds like you have a battery issue. JMO. 

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You will only see 14+ volts if the motor is charging the battery, if it always output 14+ volts you would over charge the battery.  If you charge the battery at home before going out, then the motor may not need to charge. If it's not charging the gauge will show 12ish volts. So your system could be fine, you will have wait for the battery to run down some so the motor can charge it. Not saying there is not a issue, but it could be that your battery is good and charged. 

This is why I only charge my starting battery about once a month. I think charging the starting battery before every trip could hide a motor charging issue. 

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With in an hour of being on the water, using livewell and powerpole my voltage drops to 10 and never recovers throughout the day, even when I make long runs. To me it seems my boat is running purely on battery.

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With the engine running read across the pos and neg poles of start battery, should be in the 14 volt range.  If not it is possibly the rectifier/regulator.  I had this happen last year because I didn't notice my engine wasn't peeing, there is water jacket mounted on the back side of the rectifier that is fed by the pee stream (at least on my 200 HPDI) and the lack of cooling water flow it fried the rectifier.  The charging system can be kind of hard to trouble shoot.

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Voltage readings will vary a good bit on the same battery at the same time due to resistance in the size of and the length of the wire. If you are reading on a display there will be resistance in the unit.

There are many smarter electrical people here but true voltage readings can be difficult to determine

 

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4 hours ago, G8rfisher said:

With in an hour of being on the water, using livewell and powerpole my voltage drops to 10 and never recovers throughout the day, even when I make long runs. To me it seems my boat is running purely on battery.

Yes, totally agree this is not good, and would indicate something wrong in the charging system. Does the motor struggle to turn over? If you can find a manual for your motor, it will give you some resistance checks to perform on the charging system. 

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Seems odd, you indicate 10 volts but no struggle to start. You said you are reading voltage on the GPS correct? Is it possible the GPS is being powered by a TM battery?

 

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Still having problems with this and I am getting really tired of running out of juice while on the water and not being able to use my accessories.

How do I test the regulator/stator/rectifier on my engine?

Is it possible there is a bad cable coming from engine to battery?

I feel there has been plenty of "modifications" over the years before I bought it and I don't know where to start trouble shooting and it isn't worth spending thousands on, I would rather upgrade to newer model.

Thanks for all the input!

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Resistance can cause a lot of variation in voltage. Measurement at the battery will tell you the voltage of the battery. As you move down the line the resistance of the wire will change the voltage reading. As you get to a display the resistance of the unit will also come into play To check the output of the motor you need to be at the motor not down the line. After you see the voltage at the motor you can move down the line. At each point a large drop in voltage will often indicate a problem, possibly a bad connection or corroded wire.

 

 

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11 hours ago, smilemaker said:

Resistance can cause a lot of variation in voltage. Measurement at the battery will tell you the voltage of the battery. As you move down the line the resistance of the wire will change the voltage reading. As you get to a display the resistance of the unit will also come into play To check the output of the motor you need to be at the motor not down the line. After you see the voltage at the motor you can move down the line. At each point a large drop in voltage will often indicate a problem, possibly a bad connection or corroded wire.

 

 

Where do I start testing? On a 1999 Yamaha 115 Inshore, what am I looking for (Stator, Rectifier, Alternator?), I am ordering a manual but still need to know what to look for. 

Thanks for the help!

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When you put an actual volt meter directly  on the battery (not the Garmin reading) while running what does it read? I would also check all connections to the starting battery. A corroded wire can cause issues as well.

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Assuming your start battery is near the engine you can check across the + and - posts with the engine running and should be in the 14v range.  Also SIM Yamaha has excellent engine schematics to help you locate the essential parts.  Wish you were closer to Cross City ,I would be glad to help.

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8 minutes ago, imsnookyrd said:

Assuming your start battery is near the engine you can check across the + and - posts with the engine running and should be in the 14v range.  Also SIM Yamaha has excellent engine schematics to help you locate the essential parts.  Wish you were closer to Cross City ,I would be glad to help.

I was just in Steinhatchee for 4 days, lol. 

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A schematic of engine would be nice but for basics go to the motor and put the meter on where the cables connect on the motor. From there follow each wire looking for any splices or junctions. Check and compare readings as you work to the  cranking battery. 

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