[C320-list] 10V battery-how?, alt to Exide, charging different batteries?

[David Swanson]

Pat,

As others have noted, I would replace both of the batteries at the same time and make sure that your auxillary (or "starting") batteries are the same chemistry.  

This spring, I installed a Xantrex LinkPro and a G24 auxillary ("starting") battery before we took a several week vacation to Catalina Island.  My set up worked very well, although I never really had to use the auxillary battery (it is nice to have as a piece of mind).  I found a lot of great advice on our C320 website, the C34 website, and Sailnet.  What I did was:

1.  Fabricated and installed a custom G24 starting battery tray and mounted it forward of the existing pair of D4's under the starboard salon seat.
2.  Wired the existing Exide D4's in parallel for the main house bank on switch position 1.  I believe that combined that these batteries have 2x160=320 A-Hr capacity for the house bank.
3.  Wired the new G24 to battery switch position 2.
4.  Wired a Xantrex Echo charger from the main house bank to the new G24 starting battery.  The Echo Charger is a simple device that follows the charge voltage of the main batteries and charges the starting battery when the main bank is charging.  It limits charge current to the auxillary battery to 15A.  It is a deceptively simple and reliable device.
5.  Installed a Xantrex Zapstop fuse on the alternator to protect the diodes in case someone accidentally switches the battery switch off while running the engine.
6.  Installed a Xantrex LinkPro to monitor battery use.

Overall, my set up worked very well for our trip to Catalina.  As expected, our refrigeration (we have two in our C320 MK II, one in the top down icebox and the vertical Waeco refrigerator) uses up the bulk of the battery power, so we turned off the "ice box" refrigerator and used ice in this compartment.  My refer used about 40A-Hr to 50A-Hr per day as others have noted.  With the LinkPro we were able to watch our power usage closely and even had the ability to watch movies in the evenings while on a mooring (TV and DVD player used about 15 A-Hr for a 2+ hour movie). 

When trying to charge using the engine and the stock 60A Hitachi alternator, I was only able to put back about 18A to 20A for the first hour or two of runtime of the engine.  So, my next project will be to install a Balmar 3-stage charge controller to try and get more efficient charging capacity our of my stock 60A alternator.

Anyway, I hope some of this information helps you and others who might be following this thread.

Dave Swanson
SV Emily Ann
2007 C320 MK II, No. 1107

  
On Aug 17, 2010, at 1:39 PM, Pat Ireland wrote:

> 10V battery-how?, alt to Exide, charging different batteries?
> 
> One battery registered a bit over 10V when checked on Sunday.  Charged for
> about 10 minutes and checked again.  Both batteries registered close to
> 13V.
> 
> Upon inspection, one of the battery terminals showed some corrosion, so I
> cleaned all of the connections.  While the ground was off each battery, the
> voltage registered about 10V.  When all assembled, both batteries registered
> about 12.75V.  Both batteries started the engine with no problem.
> 
> It looks like we initially had one battery isolated from the buss wit.h
> corrosion.  The charger broke through that corrosion to establish
> continuity.
> 
> Is that analysis likely correct, or is it more likely that the battery has
> an internal short on one cell that was removed by the charger?
> 
> Given option 2, it's time to replace the batteries.  Really like the Exide
> commercial option, but no dealers in the area.  CA is sunny but not all is
> rosy.   Is the Exide sold under any other brand?  Interstate has an 4D-XHD
> that sounds quite similar.  1000CCA, 1250CA......  Any possibility that it
> is the same battery?
> 
> Also, the normal advice is to replace both batteries when one goes bad.
> Logical, except, that with the addition of a starting battery in position 1
> and connecting both 4Ds as a house battery in position 2, you get two
> significantly different batteries.  How does the charging balance?  I can
> understand the mode of operation where you keep the two banks isolated, but
> It was my understanding that both banks get charged regardless of switch
> position.
> 
> DC Challenged, Pat, 801

David Swanson
kswanson123 at comcast.net