[C320-list] Electrical Problem

[Joseph Aberdale]

My thanks to all for your helpful comments.

The battery, battery switch connections and starter connections were  
fine.  A battery load test showed that the batteries were fully  
charged. Still, the engine would only weakly turn over, not enough to  
start it.  I removed the starter and had it bench tested.  It was  
drawing 180 amps.  Taking it apart revealed that one of the three  
brushes was completely destroyed and a second brush was almost  
destroyed. I checked with my Yanmar dealer and learned that a new  
Hitachi starter [original equipment] would cost me $359.  The auto  
electric mechanic who tested my starter sold me the exact same  
starter for $150 and commented that the difference in price was due  
to the "marine" label put on it by the Yanmar dealer. A lesson learned.

Joe Aberdale
#908

On Oct 22, 2011, at 11:23 AM, Robert Seastream wrote:

> Did the mechanic 'load test' your batteries or simply check them  
> with a voltmeter?  Voltmeters can't show current delivering  
> capacity.  Four year old batteries should be OK, unless they were  
> in a chronic 'undercharged' state.  This can happen if (like me)  
> you're on a mooring during the season without access to shore power  
> and must rely on the stock alternator to charge the batteries  
> during (usually short) motoring periods.  The stock alternator is  
> rated for 55 amps and delivers about half that once derating for  
> engine heat is considered.  I replaced mine with one rated for 125  
> amps.  It charges my batteries from 25-50% to full charge in ~2  
> hours; much faster than the 4+ it used to take.  I also have a  
> Honda EU2000i generator should the need arise.  We bought our 2002  
> in November 2005; I replaced the batteries in April 2008 to give us  
> a known baseline.
>
> Bob Seastream
> Intuition # 906
>
> On Oct 22, 2011, at 9:51 AM, Joseph Aberdale wrote:
>
>> I have a very perplexing, troubling electrical problem that I  
>> would very much appreciate your help with.
>>
>> My 2002  320 has two 4D banks of Interstate batteries that are 4  
>> years old. For the past month I have been experiencing the  
>> following.  If I don't start my engine once every 3 days, there is  
>> not enough power in the batteries to turn it over to start. I then  
>> have to use shore power to start it. Recently, I motored the boat  
>> for 2 hours to get to the marina that hauls it out for the winter.  
>> Upon arriving, the mechanic checked the batteries and determined  
>> that they were fully charged and did not have any dead cells. I  
>> turned the battery switch to "off" and had all of the circuit  
>> breakers on the panel off as well. The bilge pump is not hard  
>> wired to the batteries. I returned 3 days later and found the  
>> batteries had some juice but if the engine did not start  
>> immediately, there was not enough juice to try to start the engine  
>> a second or third time. I then connected the shore power cord and  
>> it would not start the engine. Several hours later with the shore  
>> power cord still connected, there was enough juice to turn the  
>> engine over just twice.
>>
>> Could something be drawing down the batteries even though all of  
>> the breakers are off?  Are the batteries bad after 4 years because  
>> they cannot maintain a full charge for 3 days? Your thoughts and  
>> help are appreciated. Thank you.
>>
>> Joe Aberdale
>> #908
>