Steve Savage submitted this article to RVtravel.com when he was a Master Certified RV Technician with Mobility RV Service.
Question: I have heard the batteries in my RV are more important than almost everything else in the RV. Why?
Answer: What you have been told is spot on. There is no way I can over-emphasize how important the batteries in your RV are.
The house systems in every RV depend on 12-volt power, and some systems will not work without a good battery (for example some slide-outs), even when plugged into the shoreline. I have found many RVers have a difficult time understanding what components require battery power and which require the RV to be plugged in. It is perhaps easier to say the systems that do not require batteries.
As a rule, anything – other than the entertainment system and the microwave, including any air conditioner with a thermostat on the wall – needs the batteries. That is because the controls all work on 12 volts. When plugged in, the converter can handle most of the 12-volt loads; however, when loads peak the battery comes off the bench and provides the additional power.
Simply put: When things don’t work, check the batteries and fuses first!