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Broken wire at alternator

Posted: June 10th, 2019, 8:51 am
by Craig_B
Took our 1988 Santego out for its first real run since we purchased it this spring.

Had to change the float switch for the bilge pump and while I was crammed into the engine bay I noticed the main battery wire to the starboard engine alternator has rotten away.
I assume since it was already installed it will be ok to repair and reconnect it?
This is my first twin engine boat so I am being overly careful and asking lots of questions before doing any repairs that may have unexpected results.

If anyone can briefly describe how the dual alternators work that would also be helpful. Do they just work together in parallel?

Thanks.

Re: Borken wire at alternator

Posted: June 10th, 2019, 9:08 am
by bud37
Just disconnect your battery power.....make sure that cable has no juice before you reconnect with a new end ( test it, dvm )....that way no sparks or surges.. :-O

Good catch by the way.... :down: They play together nicely.

Re: Borken wire at alternator

Posted: June 10th, 2019, 11:20 am
by km1125
Craig_B wrote:Source of the post
If anyone can briefly describe how the dual alternators work that would also be helpful. Do they just work together in parallel?


Yes, they both just work together to charge the battery (-ies). If you have a 1-2-all battery switch, then they are only charging the battery selected unless you have a VSR - voltage sensing relay - which would connect other batteries while they are being charged.

Sometimes having two alternators charging will mask a bad one, as the voltage will be "normal" while the engines are running even with one dead alternator (or broken wire which it seems you have). The trick is to force yourself you periodically alternate which motor you start first and check voltage on the meter before you start the other one. Then you know each engine is capable of charging.

Re: Borken wire at alternator

Posted: June 10th, 2019, 12:24 pm
by Craig_B
km1125 wrote:
Craig_B wrote:Source of the post

Sometimes having two alternators charging will mask a bad one, as the voltage will be "normal" while the engines are running even with one dead alternator (or broken wire which it seems you have). The trick is to force yourself you periodically alternate which motor you start first and check voltage on the meter before you start the other one. Then you know each engine is capable of charging.


That's a Great idea. I Will definitely do that the next couple of times out.
Thanks

Re: Broken wire at alternator

Posted: June 23rd, 2019, 10:07 pm
by Craig_B
Put a new terminal end on the broken wire and hooked it back up.
Both alternators are now charging. :-D