Power Wiring Question

[DragonflyBob]

On my Dragonfly 32 (per the recommendation of the builder’s electrical engineer), I am about to install a Victron DC-DC 30 amp Orion charger between the boat’s two (2) house batteries located in the main salon and the bowthruster/anchor windlass battery located in the V-Berth. The house batteries and the bowthruster/windlass battery were originally wired in parallel when the boat was built in 2016 and that is the current setup.

The recommendation is based on the V-berth being about 8 feet away from the salon compartment containing the house batteries. Use of the Orion is per the builder’s current design setup for this boat and the engineer explained to me that this upgrade will provide more consistent and balanced charging voltage for the V-berth battery.

The current battery cable size from the house batteries to the V-berth battery is 2 AWG. The Orion is set up for max 6 AWG cable for the output to the charged battery. All I have to do is disconnect the existing 2 AWG from the house batteries and connect it to a new relatively short 6 AWG cable that will come from the output terminal of the Orion. Is there any performance or safety issue tying together the new 6 AWG cable to the larger existing 2 AWG cable? If there is not, this saves me the task of having to pull a 6 AWG cable from the salon compartment to the V-Berth compartment.

Thanks for any advice/feedback.

[wholybee]

8 feet? Is that a typo? I don't see a reason to have a separate battery if it is only 8 feet away. Usually a separate windlass battery is to avoid a very long cable run.
The Orion will in theory provide a better charge for the windlass battery, if you think that is needed. Are you trying to solve a problem? The connecting 6AWG to the existing 2AWG should not be a problem. It should hopefully already have a fuse, and that fuse should be downsized for the smaller wire.
The Orion is going to limit current to 30Amps. Without the Orion, the current from your windlass was more equally split between the windlass battery, and the house batteries. Now, you will have only 30 amps coming form the house batteries. This will work the windlass battery harder, and it will run out of juice faster. I don't know if that will be noticed in the real world or not. But, you should be aware of it.