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Itasca55's avatar
Itasca55
Explorer
Aug 12, 2015

coach batteries

I have two 31sg batteries in my 1992 Itasca sunrise . There 1290 ca and 1000 cca each with 200 reserve capacity . How do I convert 200 reserve capacity in to amp hours . I searched and found out 200 reserve capacity Means 200 minutes at 25 amps. Brand is amerastart don't know if there still around . It doesn't say anywhere on battery there amp hours . there date is 2004 and there still working great . It looks like a sealed battery.:h thanks for any input .

Itasca55

4 Replies

  • Ivylog wrote:
    If you convert the 200 minutes to hours and X 25 you get 83 AH which is about right for a cranking battery. A deep cycle battery that weighs that much would have around 125 AH.
    I replaced my 10 year old Interstate 31s last summer as Interstate made me an offer I could not refuse at the FMCA rally in OR... I got to keep them. I put them in a 24V machine I own and they are still going strong. I did find the caps under the hard plastic top of these "maintenance free" and would add a small amount of water every two years. Taking the caps off and checking the Specific Gravity of each cell will tell you a lot about them.


    I have noticed I have alot of reserve power after camping last weekend.
    I plugged motor home in after getting back ( 5 days later )I unhooked it today and let it sit for about 3-4 hours and tested voltage it checks 13.41 volts no charging going on . I did test when it was plugged in 1 hour before I unplugged it and it was trickle charging at 13.71 volts . the day I got back from camping it was charging 14.71 volts
    from the 110v . So everything with charger seem to be working good . far as I know . Did find issue with cranking battery has a slow dis charge even with everything off . That will be next project :)

    Itasca55
  • Ivylog wrote:
    If you convert the 200 minutes to hours and X 25 you get 83 AH which is about right for a cranking battery. A deep cycle battery that weighs that much would have around 125 AH.
    I replaced my 10 year old Interstate 31s last summer as Interstate made me an offer I could not refuse at the FMCA rally in OR... I got to keep them. I put them in a 24V machine I own and they are still going strong. I did find the caps under the hard plastic top of these "maintenance free" and would add a small amount of water every two years. Taking the caps off and checking the Specific Gravity of each cell will tell you a lot about them.


    Was Google searching and found this reserve capacity x .60 = ah
    so 200 x .60 = 120 ah This was for deep cycle batteries .
    I think this must be right . that's some serious amp hours with my 2 batteries total 240 amp hours . thanks for the info . used these batteries last weekend and had tv going bunch of lights fans xm radio going all night etc .
    Batteries said still full charge after 10 hours . I was amazed .
    next time i use them again i will check with voltage meter .

    Itasca55
  • You can do Ivylog's conversion in one step by dividing the reserve minutes by 2.4

    200 / 2.4 = 83.33...

    Tom
  • Ivylog's avatar
    Ivylog
    Explorer III
    If you convert the 200 minutes to hours and X 25 you get 83 AH which is about right for a cranking battery. A deep cycle battery that weighs that much would have around 125 AH.
    I replaced my 10 year old Interstate 31s last summer as Interstate made me an offer I could not refuse at the FMCA rally in OR... I got to keep them. I put them in a 24V machine I own and they are still going strong. I did find the caps under the hard plastic top of these "maintenance free" and would add a small amount of water every two years. Taking the caps off and checking the Specific Gravity of each cell will tell you a lot about them.