Posted on 05/24/2009 12:42:22 PM PDT by Former MSM Viewer
I just made a stupid mistake.
I connected the positve to the negative and vise versa in my boat...
The alternator smoked...after reversing the cables, totally dead.
Question; Did I only damage the alternator or did I fry the electrical system?
I feel like an idiot doing this to my boat on Memorial weekend
You should have fuses to protect the rest of the electrical system.
At least is wasn’t a moon battery mistake.
Exactly what did you connect ? Did you mean you shorted the alternator leads while it was running ?
oh yeah, thats right...I was so disgusted with myself that I just disconnected and went back in the house...
I can change the alternator if that is all it is,
do you think it fried the battery?
Learned long ago that a boat is a hole in the water into which you throw money.
I connected the pos lead to the neg terminal and v versa
using the ‘a boat is a hole in the water you pour money into’ I’d say its the alternator.
You smoked the alternator diodes. I dont believe you hurt anything else.
I doubt it fried the battery..the alternator is the only thing that shoulda gone out..fuses are there to protect the rest of the electronics..
you may want to check the fuses though and check the main breaker..
so change the alternator?
When the inshore fishing was good here on the coast, it was worth keeping up a boat...not anymore...sold mine about 5 years ago and never looked back.
Yup
If it was just for a few seconds you are probably OK.
Its even possible the alternator isn’t ruined — just hook it up correctly and see if it fires up.
That's the only reason I had a boat.
Those were the days. sigh
i reconnected correctly and it was like nothing was connected...nothing clicked...dead
By reversing the leads you effectively turned your alternator into an electrical motor. It would have blown its diodes when it could not spin.
I would start by changing the alternator diodes — the rest of your alternator should be (fingers crossed) fine.
Bad luck, but it could have been worse...
Unless I’m mistaken (HAH!) the alternator has transistors to switch its field that will fry from a short.
The rest of your system should be protected. The battery might need a charge, but should be OK.
if its an alternator, the odds of finding the correct part this weekend are long...
what a dumb mistake I made...
this wasnt something I was unfamilar with - I was just careless, didnt check first...dammit
Check your fuses. They probably are toasted if you get zilch ...dead
There are no positive/negative terminals in an alternator because it’s an AC generator. Assuming you shorted the terminals while it was running, get a cheap multimeter from Radio Shack /Sears and test for connectivity. If the resistance between the two terminals of the alternator shows infinity, then it’s your alternator. Otherwise it could be the fuse(if it was fused) or something else in the electrical system. But a resistance test should be the first thing to start with.
Sign up for free to join a few hundred boaters who make this, and other, stupid mistakes. http://www.boated.com/forum/forum.asp?FORUM_ID=1
Check the fuses, check the battery, replace the alternator.
My car’s alternator has the brushes and diodes on a single assembly that bolts in and out in about 5 minutes. Wouldn’t be surprised if it’s the same on a boat motor.
Check your fuses, some battery cables have a last ditch fusible section. Time to break out the ohmmeter, disconnect cables one by one until you find where the circuit break is. Possible it is the altyernation-thingie but if so you should smell the baked resins from the winding coils. Also possible you ruined your voltage regulator, if you have a separate one from the altyernation-thingie.
Battery is probably OK. Alternator diodes are almost certainly smoked. Any electronic appliance (other than light bulbs; I mean radios, depthfinders, fishfinders, radar consoles, possibly some engine gauges) that may have been on at the moment of doom is also probably fried.
If you are very lucky, you may have converted the alternator diodes into fuses and their destruction may well have protected everything else. But it’s also possible that you created a massive surge in the system with some attendant destruction.
Strictly speaking, the rectifier and voltage regulator are not part of the alternator. But I suspect that’s where the problem is.
From what he said Im sure the diodes are cooked and possibly any solid state equipment that may have been on when the battery was hooked up.
I would put in circuit breakers or fuses on your electrical system if you don’t already have them (sounds like you don’t), although what amp load you have is hard to know without seeing your system firsthand.
Possibly. In any event you’ve fried the diodes in the alternator. Simpler to just replace the damned thing.
As to any other electronics? Some units will tolerated reversed polarity, some won’t. Only way to be sure is to power ‘em up one at a time. Have the fire extinguisher on standby just in case.
On the bright side, at least you didn’t set a metal gas can down on the battery’s terminals...
Marine alternators are particularly expensive. the greatest likelihood is that the rectifying diodes are bad, there are six plus a possible blocking diodes. The fact that nothing works is a possible good sign. If your system has reverse polarity protection i.e. fuse, circuit breaker, or varistor it could mean that just the circuit protection is open and needs to be replaced or reset. Any polarity sensitive electronics, VHF, FRS, Depth, CD player AM/FM radio, navigation aids, could be damaged also The reverse polarity should not affect incandescent navigation lights. If you have a stand-alone electronic alternator regulator it could have been damaged . The alternator can be repaired the parts are not expensive. The expensive parts such as the stator windings, bearings and the rotor are not damaged. If your alternator were A Delco 10SI the parts would cost about $20.00 and an hours work.
Unlikely. They're built to provide a lot of current for cranking.
Gotta mind that “cable smoke”! Once that gets out of ‘em they usually don’t work too well anymore!
(As others have said, you probably just fried the regulator - could be repairable, but perhaps it’s easier to just get an exchange part. I once had a faulty alternator on a car and got a rebuilt unit ‘part-exchange’ for very much less than a new unit would’ve been.)
Im hoping l can just slap a new alternator in there and be done...but of course, I will need to check/replace all blown fuses.
just hoping it didnt get to any other parts of system...
Marine ‘anything’ costs more...
You are a bad man.
A BAD man!
Thanks everyone
thanks especially for not razzing me for this bone head move
Outboard or Inboard? Make, Model, etc.
Ive owned half a dozen boats over the years when it came to having work done on the motors be prepared to drop your pants, bend over and back into the shop.
Me too. Keep us posted?
I/O Mercruiser Alpha drive 250HP,
Chaparral
Shit just happens sometimes, have a good weekend.
Time to raise the sails...
Yes the alternator is an AC generator but the output goes through a full wave three phase rectifying bridge. The heavy lug is the positive output and the frame is the negative in nearly all modern automotive systems. A continuity check (not conectivity)should not show flow from the red lead (pos) to the black lead (neg) placed on the frame because the internal diodes block backflow.....................
Fuses per se nor circuit breakers are designed to protect against reverse polarity only over ampacity over a designed time interval. Your battery does not need to be replaced. Dont feel bad I did the same dumb trick yesterday on a toyota and I have over 35 years doing industrial electricity, Senility is a curse.
Stop beating yourself over this, take the positive route.
yup the two happiest days are when you buy it and when you sell it
in that case..
are you logged in???
:-)
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.