Batteries-Ratings & Size

This is part two in my series on batteries. In part one I explored the different types of batteries used for RV’s. In this post I will do an overview of batteries-ratings and size.


Batteries are rated in one of two ways Amp Hours or Reserve Capacity. RC is the most common rating today.

  • Amp Hours (AH) .The amp hour rating is basically, how many amps the battery can deliver for how many hours before the battery is discharged. Amps times hours. 5 Amps X 20 Hours = 100Amp Hours or 20 Amps X 5 Hours = 100 Amp Hours.
  • Reserve Capacity (RC). Reserve Capacity rating is the number of minutes at 80 degrees F that the battery can deliver 25 amps until it drops below 10.5 volts. If you want to figure the amp hour rating you can multiply the RC rating by 60 percent. RC X 60 percent.

RC rating is established by the Battery Council International (BCI). Some manufacturers use a 15 or 22-amp discharge rate rather than 25-amp discharge. The lower discharge level allows a higher number of minutes to be displayed on the battery label which does not reflect the true RC minutes at a 25-amp discharge. According to interstate batteries

 

BATTERY CHART CHEAT SHEET The battery group size number listed for each battery in our chart represents the maximum dimensions of the battery and they are as follows: Maximum LENGTH x WIDTH x HEIGHT

  • Group 24: 10.75” x 6.82” x 9.4”
  • Group 27: 12.1” x 6.82” x 9.25”
  • Group 29: 13.2” x 6.75” x 9.2”
  • Group 30: 13.5” x 6.82” x 9.25”
  • Group 31: 13” x 6.82” x 9.44”
  • Group 34: 10.25” x 6.82” x 7.88”