How to make a 2-stroke 75 yamaha charge a battery HELP PLEASE!!

pedroeguiguren

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Joined
Mar 27, 2013
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I hired a mechanich to do the conections in order to make my 75hp yamaha 2-stroke 2010 engine charge a simple 80 amps 12 volt battery.

- he said the conection should be made from the green cable that comes out of the "rectifier, regulator" (really dont know the name yet) that has 3 cables that come out.. (Red, Green, Green/white stripe). SO this green cable to the Red battery end and the other one to "ground" the thing is he was wrong!! after starting the engine the cables burned and melted!

Later an expert on the matter said that the conection must be done from the Red cable that comes out of the engine "regulator, rectifier" to the positive end of the battery and the other one to ground, and that should send an electrical charge form the engine to the battery to charge it.

BUT!! its not chargin the battery.. How do I tell if this rectifyer is damaged or did I just failed to do the proper conection??

And also how many amps should a 75hp engine send to charge normaly? and how many volts?

Thanks a lot!!!
 

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: How to make a 2-stroke 75 yamaha charge a battery HELP PLEASE!!

That motor should have a charging system in it by default. You shouldn't have had to make any connections yourself. If your rectifier was fried (as they easily can be) you just need to replace it. If it's not the rectifier it could be the more expensive stator but it's more often just the rectifier. I don't know the amperage but outboard charging systems aren't real strong. You generally want to start out with a fully charged battery and only rely on the motor to keep it topped off. Mine is 12V at rest and creeps up to around 14 or so after some time running. Do you have a tach? Tachs read the charging system pulses so they are pretty quick and easy indicator of charging system issues. I ran for a full season with a dead rectifier (because I usually topped my battery off at home) and didn't notice I had an issue until I hooked up a tach and it didn't work.
 

pedroeguiguren

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Joined
Mar 27, 2013
Messages
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Re: How to make a 2-stroke 75 yamaha charge a battery HELP PLEASE!!

I ran for a full season with a dead rectifier (because I usually topped my battery off at home) and didn't notice I had an issue until I hooked up a tach and it didn't work.

Thanks for the answer!! you are right I had the battery installed for 20 days and dropped only from 80 amps to 30amp. the thing is I just installed a satellite device to track my boat while it is running through the estuaries. It is used to carry Food and supplies from one of my shrimp farms to the other so I need to be able to look at it from my office.

the device drains very little battery so the small amount of charge the engine generates should be enough.. only that it is not charging.. over here I can get the replacement for about 110 dollars.. I dont know If its a simple task to do it myself, and according to what you say it is probably fryed from the first instalation that was made incorrectly.

Im buying the replacement tomorrow. so a regular multimeter should show me a difference from the 12.5v the battery sends to somwhere around 13v when I start and run the engine at high rpm??
 

pedroeguiguren

Recruit
Joined
Mar 27, 2013
Messages
3
Re: How to make a 2-stroke 75 yamaha charge a battery HELP PLEASE!!

That motor should have a charging system in it by default. You shouldn't have had to make any connections yourself. If your rectifier was fried (as they easily can be) you just need to replace it. If it's not the rectifier it could be the more expensive stator but it's more often just the rectifier. I don't know the amperage but outboard charging systems aren't real strong. You generally want to start out with a fully charged battery and only rely on the motor to keep it topped off. Mine is 12V at rest and creeps up to around 14 or so after some time running. Do you have a tach? Tachs read the charging system pulses so they are pretty quick and easy indicator of charging system issues. I ran for a full season with a dead rectifier (because I usually topped my battery off at home) and didn't notice I had an issue until I hooked up a tach and it didn't work.

Almost forgot! No Te engine does not have any tachometer or anithing, as a matter of fact It doesnt even have a steering wheel. I just use the lever from the engine its kind of uncomfortable but It has to do for now until I fix a smaller old Boston whaler I have lying around, Im planning to place another 75hp yamaha 2-stroke engine on that small boston whaler to go faster from one place to another! haha
 
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