Adding a Dedicated Starting Battery to the C-320

My dedicated starting battery is sitting on a shelf that I added in the space just forward of the forward 4D in the starboard side settee. As a slight port list is typical for many C-320 owners and the space is ample for the purpose, this is a favorite location for many later model C-320 owners where the batteries are located under the middle of the starboard settee. This location is also desirable in keeping the new jumper wires short which reduces resistance and voltage losses.

 

 

 

The goal is to provide an isolated emergency starting battery while making only a few wiring changes right at the battery terminals themselves.  To do this we first hardwire, in Parallel, the 2 existing 4D batteries to become a single large house bank. Then add a starting battery as the new second battery.  The existing 1-2-Both switch will now switch between Starting battery, the House bank, or combine all batteries in the Both position.

 

The wires that are likely to be found on the forward 4D battery terminals are: 

 

Forward 4D Negative (-) Terminal:

1)      A large 1/0 gauge BLACK ground wire going to the aft 4D’s Negative terminal

2)      A smaller 4 gauge BLACK ground wire going to the Windlass ground

 

Forward 4D Positive (+) Terminal:

3)      A large 1/0 gauge RED power going to the battery selector switch

4)      A smaller 4 gauge RED power coming from the battery Charger.

5)      A smaller 4 gauge RED power going to the Windlass breaker

 

Step 1:  Starting Battery Installation

1)      Mount the starting battery and strap it down.

2)      Move the large 1/0 gauge Red (#3 above) from the Forward 4D to the Positive terminal on the Starting Battery.

3)      Move the battery charger cable (#4 above) from the Forward 4D to the Positive terminal on the Starting Battery.

4)      Connect the Starting Battery’s Negative terminal to the Forward 4D’s Negative terminal using a short Black 1/0 gauge pre-tinned cable.

 

Step 2:  Wire both 4Ds in Parallel 

The Negative terminals of the 4D batteries are already connected together by a short cable.  To complete the process of wiring the 4Ds in Parallel, add a new short cable to directly connect both 4D Positive terminals together.  This must be a Red 1/0 gauge cable.

  

The Result:

 

 

 

 

 

Safety Concerns:

 

Recommendations:

For more photos, click on this image to visit the photo album..

 

Jeffrey Hare, Catalina 320 International Association Webmaster

Woodbine II, Hull # 809

 

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