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Over The Network

Battery charging basics

We're often asked about battery charging and how low can a battery be discharged. Forum staffer Gary (aka rvroamer) offers this advice.

The battery charger in older RVs will tend to overcharge the batteries and boil the water from them, especially if left for extended periods. If you have one of these older converter/chargers, you might want to replace it with a modern unit from Progresssive Dynamics or Iota that will regulate the charge better and preserve your batteries.

This table shows the approximate battery charge level based on the measured Specific Gravity or the DC Voltage (with no load):

  CHARGE      SPECIFIC     DC
LEVEL % GRAVITY VOLTS
100 1.277 12.73
90 1.258 12.62
80 1.238 12.50
70 1.217 12.37
60 1.195 12.24
50 1.172 12.10
40 1.148 11.96
30 1.124 11.81
20 1.098 11.66
10 1.073 11.51