Batteries not charging

a70eliminator

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Hi. New to me 84 sea ray 5.7 maiden voyage today noticed only 11ish volts on the gauge, got back for the ramp and shut her down and tried a restart the motore barely tunied over confirming no charge, so now i pulled the alternator and it actually looks like newis here a backyard way to.test? autozone was no help at all.
 

silverbul

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Hi. New to me 84 sea ray 5.7 maiden voyage today noticed only 11ish volts on the gauge, got back for the ramp and shut her down and tried a restart the motore barely tunied over confirming no charge, so now i pulled the alternator and it actually looks like newis here a backyard way to.test? autozone was no help at all.
i would start simple, clean battery terminals, make sure alt belt is tight, charge batteries. an old trick is start engine, remove negative terminal from battery while engine running, if it dies, alt bad, if it keeps running, maybe bad batt. jmo
 

airshot

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Look around and see if you have an alternator/ starter rebuild shop in your area. They will know how to test it. Today's auto parts shop know very little unless you can find one with an old timer behind the counter. The minimum wage younguns have no idea.
 

silverbul

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Look around and see if you have an alternator/ starter rebuild shop in your area. They will know how to test it. Today's auto parts shop know very little unless you can find one with an old timer behind the counter. The minimum wage younguns have no idea.
lol
 

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a70eliminator

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i would start simple, clean battery terminals, make sure alt belt is tight, charge batteries. an old trick is start engine, remove negative terminal from battery while engine running, if it dies, alt bad, if it keeps running, maybe bad batt. jmo
Yes...thought about doing exactly that soon as I get a set of muffs
 

dubs283

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remove negative terminal from battery while engine running

Don't do this.

Causes a pretty serious risk of damaging the regulator in the alternator along with other electrical components

Do clean the battery connections and any other you can see and use a voltmeter. Check the voltage of the battery prior to running the engine. Start and run the engine and check battery voltage while engine is running. Compare the values. Should see around 13.5 - 14.5 volts at 1000 rpm. If less or same as battery initial voltage there's an issue. Could be a broken wire/poor connection, could be bad alternator, etc
 

flashback

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When the engine is not running you should see about 12.6/7 . And when running like mentioned above, 13.5 14.5 v. And clean both ends of the cables.
 

nola mike

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i would start simple, clean battery terminals, make sure alt belt is tight, charge batteries. an old trick is start engine, remove negative terminal from battery while engine running, if it dies, alt bad, if it keeps running, maybe bad batt. jmo
Btw, don't do this on anything with electronics
 

a70eliminator

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One would think if the battery connections were corroded and or loose the starter wouldnt work. I removed the alt which looks to have been replaced still has the stickers clean & shiny, i leaning towards a bad connection somewhere beyond the terminals, its a dual battery set up with a switch for bat 1-2'-1&2 so theres a bunch to investigate & honestly from what Ive seen the last owner was a hack ....drywall screws..really ugggh.
 

silverbul

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Don't do this.

Causes a pretty serious risk of damaging the regulator in the alternator along with other electrical components

Do clean the battery connections and any other you can see and use a voltmeter. Check the voltage of the battery prior to running the engine. Start and run the engine and check battery voltage while engine is running. Compare the values. Should see around 13.5 - 14.5 volts at 1000 rpm. If less or same as battery initial voltage there's an issue. Could be a broken wire/poor connection, could be bad alternator, etc
sorry but i say bulls@(t
 

silverbul

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The negative battery terminal on a car battery.

An alternator keeps the vehicle's battery charged and helps power the vehicle's various electrical systems by converting mechanical energy into electrical energy.
To test an alternator by disconnecting the battery you simply remove the negative battery cable from the battery's terminal with the engine running. If the vehicle's engine stutters or stalls, the vehicle's alternator is likely malfunctioning.
A failing alternator is a serious mechanical issue that needs to be fixed immediately or it will leave you stranded.
Although not recommended in modern vehicles due to risk of damaging the complex electrical and computer systems, there is an easy method to quickly narrow down your electrical problems to alternator failure. fyi do it at your own risk. i have never ever had a problem. so do as you will.
 

stresspoint

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The negative battery terminal on a car battery.

An alternator keeps the vehicle's battery charged and helps power the vehicle's various electrical systems by converting mechanical energy into electrical energy.
To test an alternator by disconnecting the battery you simply remove the negative battery cable from the battery's terminal with the engine running. If the vehicle's engine stutters or stalls, the vehicle's alternator is likely malfunctioning.
A failing alternator is a serious mechanical issue that needs to be fixed immediately or it will leave you stranded.
Although not recommended in modern vehicles due to risk of damaging the complex electrical and computer systems, there is an easy method to quickly narrow down your electrical problems to alternator failure. fyi do it at your own risk. i have never ever had a problem. so do as you will.
WARNING : always check the wiper blade condition and vehicle serial number before removing a battery terminal with the motor running.(y)

OP , FWIW testing alternator output this way (lifting terminal) will not surge an ECU anymore than the faulty charge circuit already present.
 

Bt Doctur

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i would start simple, clean battery terminals, make sure alt belt is tight, charge batteries. an old trick is start engine, remove negative terminal from battery while engine running, if it dies, alt bad, if it keeps running, maybe bad batt. jmo
That might have been true in generator days but NOT with alternators. Not seeing a sense voltage it could cause it to go wild up to 28 volts.
 

silverbul

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That might have been true in generator days but NOT with alternators. Not seeing a sense voltage it could cause it to go wild up to 28 volts.
its a simple test, not rocket science, no, not back in the generator days, nothing to burn out, nothing will blow up, your cat will be all right. dog will still poop in the yard.
 

silverbul

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im not going to get into all the new tech vs old tec but if you remove the neg bat terminal, only thing will happen now days that it will reset the computer.
 

nola mike

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its a simple test, not rocket science, no, not back in the generator days, nothing to burn out, nothing will blow up, your cat will be all right. dog will still poop in the yard.
This is truly terrible advice. Anybody reading this, if you think that there aren't better ways to test your alternator (really, a multimeter between the alt output and ground)... there are. You can 100% fry an ECU doing this. Not as much of an issue in these engines, but don't generalize 1960's troubleshooting to a modern engine
 
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