Alternator not charging after nearby lighting strike

[Tmacmi]

I posted earlier that our boat went through a very close lighting strike.

Thankfully everything checked out OK.

However now it appears that the batteries are not charging under the alternator. They charge from dock power.

Would it be possible that the alternator was damaged by the strike?

[BillKny]

Yes.

Diodes are very susceptible to voltage spikes. If you are VERY lucky this will be the only issue you find..

[Calif.Ted]

And when diodes go out you still get voltage but no amps, I think you can get it checked at most autoparts places like autozone now.

[Nicholson58]

Three alternators in three lightening hits. Each time it was diodes. Find an automotive or truck rebuilder for alternators & starters. Cost is $60-$120. If you have an external regulator such as Balmar you may have lost it too. Take the regulator with you to the shop.

[Tmacmi]

How do I know if there is a external regulator? It’s a Beneteau 331 with a Westerbeke 27.

[Nicholson58]

https://balmar.net/

Look for the external device near the alternator & bundled into the wiring harness. Read up on these. They are kind to your batteries and extend their service life.

[Bill O]

Originally Posted by Tmacmi

How do I know if there is a external regulator? It’s a Beneteau 331 with a Westerbeke 27.

What alternator do you have in it now?

[gfrazier]

Check the voltage out with a meter

[JPA Cate]

Just take off the alternator and take it to the auto/truck electric place. They can quickly tell you if it's the diodes (which it probably is), and they can fix it for you. And you won't get it done cheaper somewhere else.

Ann

[singlespeed]

You are extremely lucky if that is the only electrical damage you have sustained. Ours was a near hit and we were still finding electronics failing six months later, that did not have any indication even three months after the strike.

If you have an external underwater grounding plate, dive over the side and closely examine it for holes or scorch marks. If any are present, you are in for a lot of "fun".....

[lordgeoff]

Originally Posted by Tmacmi

I posted earlier that our boat went through a very close lighting strike.

Thankfully everything checked out OK.

However now it appears that the batteries are not charging under the alternator. They charge from dock power.

Would it be possible that the alternator was damaged by the strike?

Take your alternator to an auto shop and have it checked. Get them to check/replace the bearings while they are at it. Always a good idea to carry a spare alternator (or two)👌