Charging Issue

[jeffmacdonald]

History
Spent night on the hook. Next morning boat would not start. Friend came out brought me new battery. In my haste I reversed polarity and cycled through battery switch. Boat stated but from that point on I had no power. when I hooked up to shore power all electronics once again functioned. Thinking I had bad batteries I removed them (2) and had a friend charge and load test. Both were bone dry and when charged only had 11amps. Replaced bad batteries with Gel type from Cost co. Hooked up batteries both put out 13.5amps respectively. Switched selector to Bat. 1 got 13.5 amps. Switch to bat. 2 I got about 12amps and cabin lights dimmed and a alarm sounded. Left to charge for a day or two. Came back and same scenario. Started motor and I smelled smoke, 3=4 minutes had elapsed before I shut down the motor and found my alternator was extremely hot. It was at least 30 min. before I could remove it from the engine.
Took alternator in to shop and was told it was fried. Replacement for Toshiba LR 160-735 60amp is $750.00 from dealer on the other hand a automotive cranking 40-45amps is $118.00. This is a Yanmar 3ym20 with 30 hours on it.
Questions-
Will it work (providing specs are the same and what will I be giving up?)
Can anyone tell me by the chronology what I might have done.
Thanks, Jeff
I probably somehow have violated the "question rules here but please have Patience.

 

[jeffmacdonald]

Got It! Thanks for all the feedback

 

[Stu Jackson]

It's not that no one answered

it's that no one answered perhaps because of the all of the questions. Dry batteries? Toast, so how can we help from here? $750 or $180? One's way too high, and you don't discuss of explain whether you want to upgrade your charging system with a replacement alternator. Long term trickle charging and fried dry batteries are what you did wrong. and you already know that.

"Hooked up batteries both put out 13.5amps respectively. Switched selector to Bat. 1 got 13.5 amps. Switch to bat. 2 I got about 12amps and cabin lights dimmed and a alarm sounded. Left to charge for a day or two."

It's Volts not amps you were measuring. Left after an alarm sounded and did the same thing two days later and wonder why you're having trouble? That's like doin' the same thing wrong time after time and wondering why the results don't change.

I though this was a spammer's question. Sorry no one answered because the series of truly basically stupid mistakes and lack of understanding of V and A seemed to imply an "I'm pulling you legs with this BS, folks." If you weren't, we apologize. If you weren't, you need to start reading some basic electrical books.

So, what's the question?

 

[Paul17512]

Electrical Issues

Jeff,

This is what I gather from reading your post.

Your batteries went dead after spending the night on the hook.

Had batteries tested and both were "dry" and unable to accept a charge. I'm assuming these are Lead Acid batteries.

Replaced batteries but accidently reversed the polarity (pos to neg and neg to pos) when hooking them up.

Did you try to start the engine with the batteries hooked up backwards or did you only cycle the battery 1/2/all/off switch before you realized it? Your engine shouldn't have started with the batteries hook up backwards if these are the batteries you use to start the engine. Did you run your engine with the batteries hook up back ward? Did you cycle the 1/2/all/off switch with the engine running?

assumptions:

after correcting your polarity error, you started your engine and smelled smoke. How long was the engine running before you smelled smoke. Where was the smell coming from? The alternator or other electrical components in the boat? Did you blow any fuses or trip breakers?

you have a quality marine type battery charger on board that charges your batteries while you are on shore power. Does everything work correctly on the boat when plugged in? Do you still smell smoke/hot electrical?

Answers: (from what I know so far)

Your alternator

$750 dollars is way to much money for that alternator. Do some research on line (google the alt you are looking for) and I think you will have better luck finding a replacement. I never shopped for that particular alternator, but I bet you can find a replacement for under $200. DO NOT USE AN AUTOMOTIVE ALTERNATOR IN YOUR BOAT! These are much cheaper but are not certified for marine use because there are not ignition protected. Marine alternators are tested in a flamable chamber to ensure they do not provide a spark that would cause an explosion in a enclosed area. Automotive alternators are not. Many boats carry flamable gases and liquids (LPG stoves) in enclosed areas that automobiles dont.

your electrical issues.

I'm guessing from the info you provided you have a short somewhere on your boat (lights dim when you select a power source). Don't have enough quality info to guess when that short occured, why it occured or how you can go about looking for it.



If you can answer the questions I've asked and provide more clear info, we might be able to help you more.

Paul

 

[Stu Jackson]

Jeff,

Something remains wired very incorrectly. Upon my fifth re-reading of the original post, the bat 2 position seems to be the initial culprit. Paul's reply reflects the same confusion I had, and my initial reply remains valid.

Walking away from a boat that "smoked" with the charger left on is not prudent.