New starter battery...I smoked alternator?

[Rockinar]

I have a really simple 28' boat with just a starter and one house battery and 14HP diesel. Have twice put new batteries (lead acid) in it with no issues


Today I go to put new batteries in it and smoked the alternator. Not sure what happened and Im stumped why because cause the system is so simple.

Negative from engine goes to the negative on the battery. Positive cable from starter goes to the 3 way switch. Put the #1 positive cable from switch to positive on starter battery. Put switch on #1......cranked it just to double check that was the #1 cable. It cranked.....and POOF. Smoking alternator.


Am I missing something?? Hate to pay a yacht service company $100/hr to come look at it when its such a simple setup.


How can I test all this with a multimeter?

[goboatingnow]

Doesn’t sound like the alternator wire is connected. Is it wired into the positive starter battery lead

[Nicholson58]

We don know the whole trai of events. Why another new battery?

Guessing: alternator failed, cratered battery. Check the wires and all connections. Learn how to run an alternator test. Balmar has a great trouble shooting guide or probably YouTube video. I have my failed alternators repaired at a dedicated alternator, starter shop. Usually diodes and not expensive. Lightening is tough on the diodes.

[GordMay]

Hope these help.
Basic Alternator Testing ➥ https://www.cruisersforum.com/forums....html#post1264

And:
Page 1 ➥ https://www.cruisersforum.com/galler...r&imageuser=79
Page 2 ➥ https://www.cruisersforum.com/galler...r&imageuser=79

[Bill O]

Originally Posted by Rockinar

I have a really simple 28' boat with just a starter and one house battery and 14HP diesel. Have twice put new batteries (lead acid) in it with no issues


Today I go to put new batteries in it and smoked the alternator. Not sure what happened and Im stumped why because cause the system is so simple.

Negative from engine goes to the negative on the battery. Positive cable from starter goes to the 3 way switch. Put the #1 positive cable from switch to positive on starter battery. Put switch on #1......cranked it just to double check that was the #1 cable. It cranked.....and POOF. Smoking alternator.


Am I missing something?? Hate to pay a yacht service company $100/hr to come look at it when its such a simple setup.


How can I test all this with a multimeter?

So you didn't change any wiring to the starter or alternator and only changed the start battery? Very odd that it would instantly smoke the alternator.

Will have to ask a similar question the the above, how often are you changing start batteries? Do you have any trickle chargers on while you are gone? Do you check water levels in your batteries and refill w/distilled water routinely?
Sounds like you will want to take your alternator into a shop to get it checked out/rebuilt. Hopefully you have a shop where you can ask the technicians questions as to possibly what happened to cause this problem.

[Squanderbucks]

Can you send a diagram of your wiring of the two batteries to the switch?

Two batteries to a 3-way switch to me means each battery has an input terminal to the switch and there is one output - an EITHER Battery 1 or Battery 2 or OFF.

Do you turn on Batt 1 just when starting the engine and then turn the switch to Battery 2 once it is running so the house has current? Or what is your procedure.

For a "Simple" two battery system like yours I would expect something like each battery having it's own On/Off switch.

Does your switch have Field Disconnect protection built in?

There are a few types of battery switches and it seems the subject has fervent supporters for different methods on the forum but we need more info to know what your "Simple" system is really like.

[Squanderbucks]

Quote OP:
"Negative from engine goes to the negative on the battery. Positive cable from starter goes to the 3 way switch. Put the #1 positive cable from switch to positive on starter battery. Put switch on #1......cranked it just to double check that was the #1 cable. It cranked.....and POOF. Smoking alternator."

Battery switches that I am familiar with have Multiple inputs and a single Output. So your batteries get wired to separate terminals on the back and the Output terminal send the "juice" where you want it. If you are connecting the starter cable to the #1 Terminal where is the Positive cable from the battery hooked to the system?

Unless you are hooking both the starter cable (often with alternator inline) to the switch AND the Positive from the Battery 1 to the same pole on the switch (Always ON) then Positive Battey 2 and House Out or Feed to House Manin Panel to the #2 Switch termainal (also always On)

What do you have hooked to the OUT or Feed Position of the Switch?

A diagram of what you have would help.

[stinkpots]

I blew up my alternator last year. It turned out that the 150 amp balmar circuit breaker (instead of a fuse) had failed while the alternator was outputting 100 amps. This circuit breaker/fuse sits between the alternator and the battery bank on the positive lead. This put the alternator open circuit while operating at full output. The result was a dramatic melt down.
I have replaced the faulty circuit breaker with a 150 amp fuse. It was a very expensive malfunction and I will never use a circuit breaker again in this situation. You could check if you have a fuse in the same place?