The folks that told you about batteries freezing neglected to say when an RV battery freezes. Per Trojan...
“The only way that a battery can freeze is if it is left in a state of partial or complete discharged. As the state of charge in a battery decreases, the electrolyte becomes more like water and the freezing temperature increases. The freezing temperature of the electrolyte in a fully charged battery is -92.0F.” Trickle charge them in the RV. Memphis doesn’t see -92F often...lol. Not sure these folks know much about RVing.
http://www.trojanbattery.com/Tech-Support/FAQ/Maintenance.aspx?old=aspx
