Hi Bill,
Thanks for posting. I'm not an electrical engineer so please bare with me. I would really like to know what happened to avoid a similar situation.
You wrote that the charger failed and allowed the positive lead of the battery bank to connect with the boats bonding system and discharge very rapidly. That seems odd, the wires going from the charger to the batteries are pretty small I would think they would fry.
Do you know what brand/model charger failed?
Also, the battery bank discharged with enough current to cut the 1 1/2" SS rudder post in a day and a half? That seems like a long time for the batteries to last without completely discharging.
Do you know what happened to the other boat's zincs and prop? Seems they would go before rudder post.
What happened to the Eboat?
Again I'm no electrical engineer so please forgive my lay-manly questions :-).
Thanks, Mark
--- In electricboats@yahoogroups.com, "ipsbishop" <IPSBISHOP@...> wrote:
>
> I'm Bill Bishop, and I wrote the piece about the small sailboat "With a hidden secret". What I know, is in part hearsay, but this is the general outline. It was a custom built 24 day sailer that was constructed by the Landings School. It had a substantial bank of batteries (I suspect they were also being used as ballast), and three battery chargers. One of the chargers failed, and in the process the positive lead of the battery bank somehow got connected through the charger, and then in some way to the the ships bonding system. I do not know for sure if the battery charger was even plugged in at the time (shore power), but it is easier to create this scenario it is not. The current passed through the bonding system (aka ship ground system, sea water connected with the rudder post of the vessel next door as a ground, (the day sailer had seawall on the other side), and from there the circuit was completed through the ground lead of the next door vessels connection to the shore power system. This was certainly an unusual failure. I do know that if the battery bank had direct path to the vessels ground, and then onto the marina shore power system, the bank would have very rapidly (to say the least) discharged. It may have also been leaking positive DC into the marine ground system if it was plugged in, but galvanic isolators on the other boats would have prevented damage to other vessels. It was electrolysis, from the water, that caused an 1 1/2" SS shaft to be nearly cut off, and it appeared this happened in just a few of days. Odd accident yes, and the first time I had seen something like it, so in selecting a battery charger, don't stint on quality. ABYC has a very comprehensive set of electrical system design codes, that should be adhered to. I am a big fan of electric drives systems, but big battery banks can bite you, or your vessel hard, if you don't use good electrical practices when designing, and building them. Thank you for reading, Bill Bishop
>
> http://themarineinstallersrant.blogspot.com/
>
> --- In electricboats@yahoogroups.com, Jeff ryan <jryancraft@> wrote:
> >
> > Check abycinc.org. They set standards for boat systems. Jeff
> >
> > --- On Wed, 5/19/10, oleliver <oleliver@> wrote:
> >
> >
> > From: oleliver <oleliver@>
> > Subject: [Electric Boats] Electric Boat Wiring Fails - Harms other boat
> > To: electricboats@yahoogroups.com
> > Date: Wednesday, May 19, 2010, 3:24 PM
> >
> >
> > Â
> >
> >
> >
> > http://bit.ly/cxgWWC
> >
> > All,
> >
> > Anyone know anything about this? Especially from the what not to do department.
> >
> > Are there any good resources or list of codes to follow for setting up an AC/DC system on a vessel?
> >
> > Regards,
> >
> > James
> >
>
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