[C320-list] Battery Woes

[Dean Vermeire]

Troy,

Thanks for putting so much thought into this.  You've confirmed my 
thinking.  My next visit to the boat is to focus on the charger.  I have 
not taken a good reading of its charging voltage or amperage.  It is a 
ProMariner 12-30 and has been reliable for many years, but that is also 
to say it is many years old.

On the 200 mA draw, I have to believe there is something I'm 
overlooking.  I need to keep digging on that one.

My question on the bilge pump is really why it is wired to one battery, 
rather than both?  Not a big deal, though (unless battery 1 is dead, 
battery 2 has juice, and we're taking on water).

Thanks again,

Dean

On 6/18/2020 11:12 PM, Troy Dunn wrote:
> Dean
>
> Yes, your bilge pump is always on and therefore is wired directly to one of
> your batteries at the back of the selector.  This ensures that your bilge
> pump when correctly set to auto will still operate when your 1/2/BOTH/OFF
> switch is set to OFF.   A fully charged battery does us no good if our boat
> sinks.
>
> 200mA would take almost 2 weeks to draw your fully charged 4D battery to
> 50% SOC...maybe longer.   So, you have something else going on.   200mA is
> still a high draw however...you need to investigate that parasitic load.
> It may lead to finding something more insidious.
>
> I'm starting to wonder if your charger is shot.    In fact this is the most
> logical conclusion so far, but unfortunately much more data/investigation
> is required.
>
> Having two new batteries simultaneously go belly up is not unheard of...but
> it is a low probability event.   Did you check the manufacturer date on
> those batteries?  If the dates are more than a year old then yes you got
> bad batteries because they self discharged and sulfated beyond the point of
> recovery.  Sometimes there is a sticker.  There is also usually a date code
> stamped into the lead post.   The manufacturer usually can tell you how to
> get that code and turn it into a date.
>
> 13.4 V is an incredibly low bulk/absorption charging voltage.   At that
> voltage it will take a long time to fully charge your battery.   A day at
> least I'm thinking.    That number had me scratching my head a lot.
>
> Are your battery cables installed correctly?   There should be no washers
> between the cable lug and the lead battery post.  Stainless steel is a very
> poor conductor compared to copper, lead, aluminum.   Incorrectly installed
> washers can cause serious voltage drop, poor charging, high heat, and in a
> worst case scenario...melt your battery casing.
>
> Check connections at the back of the selector switch,  the battery negative
> connection at the back of the breaker panel, the battery ground at the
> starter motor/engine, and all connections at the charger...check those
> charger connections for signs of overheating too.
>
> If these things don't turn anything up...it might be worthwhile to pull a
> battery and take it back to get a proper load test.   I know that’s a pain,
> but at least you will know if the SOH of the battery is good/bad.
>
> What type of charger do you have?  Some are more prone to early failure
> than others....
>
>
>
> Troy Dunn
> Hull#514
> Wonky Dog
>