Forum Discussion

Katdaddy's avatar
Katdaddy
Explorer II
Oct 27, 2021

And Another Battery Question

We just got back from our yearly trip to the Cades Cove. No hookups in the campground, so we are dry camping. I equalized the batteries right before we left and after resting overnight the batteries voltage showed 90%. We get to the campground and set up and voltage shows 70%. I have a solar panel and it would show the batteries fully charged by the end of the day, but as soon as the sun went down they went back down to 70ish%. Sams Club golf cart batteries. The temps at home before we left when I checked everything was in the 80s. Temps in the mountains were low 60s during the day and low 40s at night. I let the batteries rest overnight when we got home yesterday and voltage back to around 100%.
So, does altitude affect readings? I have a chart that I printed of web some years back that shows voltage readings according to temperature. That chart shows the 12.30 reading at the temps we were experiencing as between 90 to 100%. Is this in any way accurate?
With the solar panel we have plenty of juice, just trying to understand what is going on.
As always, thanks for all your help.
  • TUCQUALA's avatar
    TUCQUALA
    Explorer
    Oct 27, 2021
    Having used GC2 batteries for many years, both myself and my son have seen voltages similar to yours. They seem to charge up fully, and when in use drop down in voltage to around 12.6 or so. Not much below fully charged. The biggest plus for them is that they hold the charge and last longer than most 12V batts for some reason. The real number is what your voltage is in the morning, esp if using furnace in cooler weather. Our 4-1/2 yr old 6Vs will be at 12.2 or so in the morning and recover very quickly when the sun starts shining. Sons act similar. Personally (with no actual proof!!) feel that this is a normal pattern for a true deep cycle 6V pair!!

    Also, hydrometer almost always shows above 1275 when recharged!!! Never have checked in the morning, no problem, no fault!!!
  • Katdaddy's avatar
    Katdaddy
    Explorer II
    Oct 27, 2021
    Batteries are 3 years old and we are very conservative with battery usage. The part that confuses me is the voltage is back up now that we are home. I guess I am going to have to take hydrometer next year to see what it says.
  • 2oldman's avatar
    2oldman
    Explorer II
    Oct 27, 2021
    Voltage alone is not a good indicator of capacity. Your batteries may be old. One solar panel is usually not enough to maintain one battery let alone several, depending on your use. Those temps should not affect things very much.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,195 PostsLatest Activity: Feb 05, 2025