Author Topic: Coach Battery Replacement  (Read 7425 times)

Cary Rodriguez

  • BAC Member
  • *
  • Posts: 3
  • Thanked: 1 times
Coach Battery Replacement
« on: November 13, 2024, 10:39:11 PM »
Good Day Beaver Heads!

     Almost sounds like a Grateful Dead post.  ;D   The wife and I picked up a 2003 Beaver Monterey Ventura a few months back and are replacing aged items a little at a time.  I am looking to replace my coach batteries and was wondering if 2 of these would be a good choice: Super Start Marine Battery Group Size 27 - 27DCM from O'reilly's.  I currently have four 6V batteries but looking to simplify things. Many thanks.

Cary

Bryan Beamon

  • BAC Member
  • *
  • Posts: 382
  • Thanked: 134 times
Re: Coach Battery Replacement
« Reply #1 on: November 14, 2024, 01:14:21 AM »
Cary, the amp hours on a group 27 battery are 72 to 90 amp hours while a good 6volt wet cell is 210AH . Plus the lead plates in a 6volt battery ate much more robust. The battery bank of 4 6volt is 400AH+ which is more the double the two 12 volt marine batteries. Unless there are other considerations suggest you stay with the 4 6volt battery set up
C & Bryan Beamon
2006  to present
2007 Contessa 42ft Cat C-9 400hp
1996 to 2006 97 Beaver Patriot Camden

Joel Ashley

  • BAC Member
  • *
  • Posts: 2449
  • Thanked: 769 times
  • OSU Class of '73, Oregon Native. RVing 40 years
Re: Coach Battery Replacement
« Reply #2 on: November 14, 2024, 06:29:02 AM »
Bryan’s right that you want 6v deep cycles for their total amp hour capacity.  Some thoughts:
1). Take a couple clear photos of your current battery wiring configuration and make a paper diagram, so you can correctly reinstall wires;  unplug the Coach and throw a dark cloth over the solar panel to avoid sparking when handling battery connectors;
2). Consider getting the 6v deep cycle Interstates that Costco sells - they are one of the better deals;
3). To be finally rid of corrosion and water top-ups like I am, AGM house batteries should be on your radar despite their extra expense.  Just be sure your inverter and solar chargers can work with them.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Cary Rodriguez

  • BAC Member
  • *
  • Posts: 3
  • Thanked: 1 times
Re: Coach Battery Replacement
« Reply #3 on: November 14, 2024, 02:49:40 PM »
Bryan and Joel,

     Many thanks for your replies.  I will go ahead and stick with the 4 6V batteries.  I have already taken photos of the wiring and also made a drawing of the battery layout just in case.  Thanks again.

Cary

Fred Brooks

  • BAC Member
  • *
  • Posts: 1663
  • Thanked: 744 times
  • RVIA Certified Luxury Technician 49 years, Retired
Re: Coach Battery Replacement
« Reply #4 on: November 15, 2024, 09:34:37 PM »
  Cary,
  Here are some more considerations as you enjoy your adventure. When you connect 2 deep cycle 6 volt batteries in series you will double the voltage to 12 volts but not the amperage rating. So your system with 4 -6 volt deep cycle batteries will be 2- 12volt batteries in parallel with 420 to 440 amp hour rating. A fully charged 12volt system resting will yield 12.8 volts. These batteries should never be discharged below 50% of their capacity which is 12.3 volts. Failure to do so will damage their life span. Another consideration is Peukerts law when discharging batteries. When discharging lead-acid batteries the rule is between 25 and 30% loss of capacity dependent on rate of discharge. If you operate within these parameters the batteries will last 4 to 5 years if you do the maintenance. Make sure you cover any solar panels when you disconnect the batteries. Failure to do so may damage the solar voltage regulator. Hope this helps, and welcome to the forum. Fred
Fred & Cindy Brooks
2000 Marquis, Jasper
C-12 Wild Cat (U of A)
2014 Honda CRV
Proverbs 3: 5 & 6

Cary Rodriguez

  • BAC Member
  • *
  • Posts: 3
  • Thanked: 1 times
Re: Coach Battery Replacement
« Reply #5 on: November 17, 2024, 03:35:25 PM »
Hey Fred,

    Many thanks for the recommendations.  I really appreciate it.

Cary
The following users thanked this post: Fred Brooks