The 12volt Side of Life (Part 1) Mark S. Nemeth.

Welcome to the page of all things 12 Volt! The information here was either excerpted from various sources on the web and in the public domain, or results directly from my personal experience. When researching battery specs for this page, I was amazed at the wide variance in some of the information. For instance; the charts that show voltage related to state of charge... almost every chart I looked at had different voltage values. I had to make a judgment call and pick the chart that best matched my own observations on my own 12 volt system. I tried to keep "opinion" to a minimum in the interest of putting out good, useful information, but where the sources of the information differ, I had to make an opinion call. Just so you know... the data on batteries contained herein is the best I can come up with, but may not be gospel. Some of the suggested RV modifications require you to be at least a little handy... Don't undertake any project beyond your capabilities and be especially careful anytime you are working in proximity to the batteries. They can be really dangerous if treated wrong... acid is caustic and batteries can explode if a spark or open flame ignites the hydrogen gas they produce. Shorting the output terminals of a battery can create huge sparks and sprays of molten metal (can you say "welding"?) When working with batteries, you need to have plenty of ventilation, remove jewelry, wear protective clothing and eye wear (safety glasses), and exercise caution.  Whenever possible, please follow the manufacturer's instructions for testing, jumping, installing and charging. Use proper care at all times and don't EVEN try to sue me if you screw up... I warned you! Please see the disclaimer before proceeding!

 (For a printable GIF of this table, Click HERE.)
Open Circuit  Battery Voltage
Approximate  State-of-charge
Average Cell Specific Gravity
12.70 / 6.35
12.45 / 6.23
12.24 / 6.12
12.06 / 6.03
11.89 / 5.95
OK, folks... that takes care of part 1 of the 12 volt Side of Life. Hope you found it helpful! Part 2 deals with Inverters, Solar systems, Monitoring, Wiring, Lighting and some great do it yourself projects for your RV.
Continue on to Part 2.....