Wire size for additional house batteries

[Khalid]

Hi forum,
I’m adding 2 house batteries to my new 255XE.

Due to the lack of space in the back (bc of the ballast tanks),I will need to place the additional batteries under the bow seat which requires 15-20’ cables. What size cables should I use?

Thanks in advance!

 

[RobbieO]

Marine Grade Tinned Battery Cable 2 AWG ( Size 2 Gauge ) Red - Copper Flexible Stranded

www.batterycablesusa.com

 

[Khalid]

Marine Grade Tinned Battery Cable 2 AWG ( Size 2 Gauge ) Red - Copper Flexible Stranded

www.batterycablesusa.com

Thanks! The dealer tech said 6 AWG

 

[HangOutdoors]

Recommend looking at a wire gauge chart and familiarizing yourself. It will give you gauge per length per amps. It comes in handy. Like this one below. It also depends on how many continuous amps you will be pulling. One size does not fit all in different scenarios.

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

 

[RobbieO]

Thanks! The dealer tech said 6 AWG

Well, thats what I would do. But @HangOutdoors is right, you should use the chart to decide.

 

[HangOutdoors]

@RobbieO wasn't discrediting your advice at all, was mentioning the charts. Will be helpful in the future as well.

 

[ripler]

I've mentioned this in other threads, but the charts are misleading. The amperage a wire can carry depends on it's construction. You need to know the wire you are buying and it's current carrying capacity and then size it accordingly. Here's a good example of what I'm saying below with cable from Knukonceptz. As the chart shows their 1/0, 4 and 8 awg cables have 3 different amperage ratings and it's all based on the cable makeup. If you are using the exact wire that's specified on the charts, then you will be fine.

 

[adrianp89]

I wouldn’t do anything less than 0 gauge. You spent 100k on a boat, no reason to cheap out now lol.