Author Topic: What Gauge of battery cables for Coach batteries?  (Read 687 times)

Heather Johnson-Dunnings

  • BAC Member
  • *
  • Posts: 3
  • Thanked: 1 times
What Gauge of battery cables for Coach batteries?
« on: September 28, 2022, 01:40:41 AM »
Team,
I need to replace the Battery Cables as I replace all the Coach Batteries and need to know what Gauge Battery Cables for the Coach Batteries. I am removing battery racks to clean and repaint and repair a missing roller.  Any other recommendations are welcome.
Heather
2000 Beaver Solitaire’s Lalique (#3 of 14 produced)
CAT 500 HP Diesel
2000 Solitare Lalique
C12 500 hp

Steve Huber Co-Admin

  • Administrator Group
  • *
  • Posts: 3271
  • Thanked: 2482 times
Re: What Gauge of battery cables for Coach batteries?
« Reply #1 on: September 28, 2022, 08:04:20 PM »
Why do you need new ones? If the ends are corroded you may be able to cut off the corroded section and add a new lug if the cable has enough slack. Whatever you do, don't add a splice and section of cable to an existing cable.

Otherwise, best to measure the conductor or take a sample to compare. Your cables are probably 00 AWG. Home Depot and Lowes carry cable that should work but you'll have to add the lugs, etc. Suggest you crimp the lugs on the cable then fill with solder. Will need a torch to get enough heat. https://www.amazon.com/s?k=cable+crimping+tool&crid=31CNUK16MFWU8&sprefix=cable+crimp%2Caps%2C378&ref=nb_sb_ss_deep-retrain-0-ops-acceptance_1_11

Probably easier to take existing cables to battery shop and let them build new ones.

Here's diameter of various cables:
AWG gauge   Conductor Diameter Inches   Ohms per 1000 ft.
00                       0.3648                                   0.0779
0                       0.3249                                   0.0983
1                       0.2893                                   0.1239
2                       0.2576                                   0.1563

Steve
« Last Edit: September 28, 2022, 09:44:43 PM by Steve Huber Co-Admin »
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

Heather Johnson-Dunnings

  • BAC Member
  • *
  • Posts: 3
  • Thanked: 1 times
Re: What Gauge of battery cables for Coach batteries?
« Reply #2 on: September 29, 2022, 01:27:54 AM »
Thank you!  Two of my cables diameter is different than rest. I believe they have been replaced and I am working to put everything back to factory install. Thank you for the information
2000 Solitare Lalique
C12 500 hp

Steve Huber Co-Admin

  • Administrator Group
  • *
  • Posts: 3271
  • Thanked: 2482 times
Re: What Gauge of battery cables for Coach batteries?
« Reply #3 on: September 29, 2022, 02:41:58 AM »
Are the 2 cables connected to the posts of the house or chassis battery bank? Is one black and one red? A photo would really help. Do you know where they go from the batteries? Reason for asking is load can determine cable AWG.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

John Fitzgerald

  • BAC Member
  • *
  • Posts: 52
  • Thanked: 12 times
Re: What Gauge of battery cables for Coach batteries?
« Reply #4 on: October 03, 2022, 11:49:29 AM »
I second the battery shop advice.  My local battery shop that deals with trucks will build me a cable for less than I can buy the materials for, at least the last time I went there.  They will also know the correct cable gauge for your system if you tell them the details. 
Thanks

John Fitzgerald
1995 Beaver Marquis Garnet
300 Cummins 8.3
1995 Jeep Wrangler Rio Grande

Eric Maclean

  • BAC Member
  • *
  • Posts: 945
  • Thanked: 333 times
  • Karen and I would like to wish you all happy trail
Re: What Gauge of battery cables for Coach batteries?
« Reply #5 on: October 03, 2022, 01:01:46 PM »
As Steve pointed out the size of the cables is dictated by the load (Amp draw) and the length of the cable .

Because we are working with DC ( Direct Current ) and low voltages the volt drop becomes an issue as the load increases or the length of cable increases.
The inverter / charger is a good example of a voltage sensitive device,  if at high load the voltages are pulled down too low on the inverters input the inverters control board will shut it down as if the batteries were dead .
Inversely if the charger is trying to charge the batteries at a high rate the volt drop would cause a lower than expected charge voltage at the batteries.

As Steve pointed out there may be two different loads connected to the same battery bank each having its own load characteristics and requiring different cable sizing .
It is important to know what the cables are going to operate the Amp demand and the length of the cable run to determine the cable size.

The following link will help determine the size of the cables needed for a given length and load.
Remember here there is no such thing as too large a cable the bigger the better as it reduces volt drop.
Also remember that when calculating the length of a cable you have to calculate both directions to and from the battery bank.

https://www.bluesea.com/support/articles/Circuit_Protection/1437/Part_1%3A_Choosing_the_Correct_Wire_Size_for_a_DC_Circuit


Hope this helps
Eric
« Last Edit: October 03, 2022, 01:13:18 PM by Eric Maclean »
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Steve Huber Co-Admin

  • Administrator Group
  • *
  • Posts: 3271
  • Thanked: 2482 times
Re: What Gauge of battery cables for Coach batteries?
« Reply #6 on: October 03, 2022, 06:38:08 PM »
Eric,
The Solitare is pretty much an all electric coach with a residential reefer, etc. It came stock with 14 6V coach batteries so the cabling is probably fairly extensive. Since we don't have any diagrams of it in Coach Assist, we need to rely on the owners for Solitare related info. Overall it is built on a modified Marquis chassis.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp