Deep Draw

January 27, 2013
Filed under RV Tech Q&A

We have a 2002 Rexhall Rex Air 36-foot motorhome. The deep-cycle coach batteries have some sort of drain on them, even when we are plugged into a shoreline. We’ve tried disconnecting them via the switch, and leaving them connected with the same results. We have had service departments check it out and they find no drain. What is going on?
John Thompson | Dallas, Texas

Seems like it may be the batteries. Rather than using the switch, try disconnecting the batteries by removing a negative battery cable from each one. Make sure the terminals and tops of the batteries are clean and dry. Fully charge each battery with a battery charger, and then test each cell with a hydrometer. With the batteries completely disconnected, hydrometer test them every few days. If they don’t discharge rapidly, the problem is in the circuit. However, if they still go down, the batteries with the bad cell readings are defective and should be replaced.
— Ken Freund

Have a technical question about your RV? Send them to Also, check out TrailerLife.TV for expert RV how-to videos.

Print Friendly, PDF & Email


Feel free to leave a comment...
and oh, if you want a pic to show with your comment, go get a gravatar!

Get a FREE issue of Motor Home Magazine

Sign up for your trial subscription and you'll receive a FREE issue. If you like Motor Home, pay just $19.97 for 11 more issues (12 in all). Otherwise, write "cancel" on the invoice, return it and owe nothing.

Terms of Use | Privacy Policy

© 2016 Good Sam Enterprises, LLC. All Rights Reserved.