[C320-list] Battery Logic

[Dean Vermeire]

Hi Jeff,

Thanks for the response.  It hasn't ever made sense to me why both 
batteries aren't connected to the charger.  I guess someone saved a 
little money on wiring.

Dean

On 9/21/2015 4:28 PM, Jeff Hare wrote:
> Hi Dean,
>
> There's really no good reason why you would have a multi-bank battery charger with only 1 output connected.  If the second output is still wired from the charger compartment to the battery compartment, I'd hook it up.  EVEN if you put the batteries in parallel (Both position), it's perfectly fine to have to charger legs hooked up to each of the house batteries.  The charger does not care.
>
> The one positive part of using a Starting battery (vs dual purpose or deep cycle) for engine starting is that you can get away with a smaller starting battery that will be better at starting the engine.  Starting batteries supply more current at a given voltage than dual purpose or deep cycle batteries, so they'll often be able to start the engine when the dual purpose battery won't.  Deep cycle/dual purpose batteries are ok to be drawn down but are damaged by high current loads.  Starting batteries are fine with high current loads (like a starter), but don't like to be drawn down low.  So, if your second 4d battery is always used for starting and not always topped back up, it will probably have more plate damage than the one that is used for lights and instruments.
>
> So... If the wires are there, hook one charger leg up to each 4D battery.   This will not cause the batteries to be in parallel and when the charger isn't running, they will remain isolated.
>
> -Jeff.
>
> -----Original Message-----
> From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Dean Vermeire
> Sent: Monday, September 21, 2015 2:04 PM
> To: Catalina 320 List <C320-List at Catalina320.com>
> Subject: [C320-list] Battery Logic
>
> As any battery discussion, this one starts with a dead battery.  One of the two batteries has gone bad.  I've tested both and identified the bad one.
>
> Our boat is a 2001 model (#847), with the original ProMariner Protech 1220i charger and two #4D 12V batteries, neither of which is a deep cycle battery.  Only battery #1 is connected to the charger, which means that battery #2 only gets charged when the selector switch is on "Both".  This is how the boat was when I bought it.
>
> We sail on a lake in Kansas, so it is not like I will be out cruising for a week.  I really don't need to have two #4d deep cycle batteries and put in a separate starting battery, change the alternator, etc.
> However, I am inclined to replace the dead battery with a deep cycle battery.
>
> So, here are my questions for you battery-minded people...
>
> 1.  Why was the boat wired with only one battery connected to the charger, and would it be better with both connected to the charger?
> 2.  Can you think of any reason why I couldn't have a deep cycle and a starting battery on the same charger, as long as they are of the same battery type (e.g. lead acid, maintenance free)?
>
> Thanks in advance,
> Dean Vermeire
> Moonstruck II (#847)
>
>
>