battery?

Discussion in 'General RVing' started by racefan, Mar 29, 2006.

  1. racefan

    racefan New Member

    Have a 30ft 5th wheel that i bought off older gent he had put 3 really exspensive deep cell batterys in it but now they wont hold a charge how should i go about testing them ? The old guy ran a electrical repair shop fixing starter and every thing electric i have hade this about 2/3 years now
     
  2. Kirk

    Kirk Senior Member

    battery?

    I would start by lifting the negative cable from the post of each battery. Check the electrolyte level of each cell in each battery and bring it to the proper level by adding distilled water(not demineralized). The charge the batteries with a good, three state battery charger. Once charged, let the battery sit for 8 hours or so, with the cable still lifted and then check the resting voltage. It should be about 12.7V or so by a quality digital meter. Then allow the battery to sit for another 24 hours and check it again. It should not have dropped any more than 0.2V, maximum. Do the same for several days. If the voltage keeps falling, the battery has a problem. If it does not stabilize at some point at or above 12.5V it is probably time to think of a new one. You can also have a battery load tested at your local battery shop.

    ________________________________________________________________
    Percent -- Voltage-- Specific
    Charge ********* Gravity
    100 -- 12.70 -- 1.265
    -95 -- 12.64 -- 1.257
    -90 -- 12.58 -- 1.249
    -85 -- 12.52 -- 1.241
    -80 -- 12.46 -- 1.233
    -75 -- 12.40 -- 1.225
    -70 - - 12.36 -- 1.218
    -65 -- 12.32 -- 1.211
    -60 -- 12.28 -- 1.204
    -55 -- 12.24 --- 1.197
    -50 -- 12.20 -- 1.190
    -45 -- 12.16 -- 1.183
    -40 -- 12.12 -- 1.176
    -35 -- 12.08 -- 1.169
    -30 -- 12.04 -- 1.162
    -25 -- 12.00 -- 1.155
    -20 -- 11.98 -- 1.148
    -15 -- 11.96 --- 1.141
    -10 -- 11.94 -- 1.134
    -05 -- 11.92 -- 1.127
    -00 -- 11.90 -- 1.120
    Based on use of 50% battery capacity.
    True full discharge eqaual 10.5V
     
  3. Browzin

    Browzin New Member

    battery?

    Being Kirk supplied the specific gravity charts above, I would use a Hygrometer and check each cell. If you have a bad cell/cells you will know it very quickly then. Just follow Kirks charge recommendation an then check with the hygrometer, all questions answered.
     
  4. s.harrington

    s.harrington Senior Member

    battery?

    Most deep cycle batteries in the groups 24 or 27 need to be replaced after 3 years with a few exceptions. Most can be desulfated and run a couple of years longer but at a lower reserve amp capacity. If your converter has a conditioning cycle (charge wizard) it can prolong the battery life considerably. Only the newer RVs have this. The best way I know to desulfate a battery is to charge it at about 50amps for 12 hours (cook it off) and then reduce the power to approximatly 6 amps to complete the charge. In some cases you actually have to chamge the battery acid.
     

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