RV Maintenance Tip: Bad Solar Panel

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July 10, 2012

Bob, I have a 2004 National RV Dolphin motorhome with a small solar panel on the roof for maintaining a charge on the two 6-volt coach batteries. The panel’s surface is severely cracking, curling and peeling, so I doubt it’s providing much of a charge. National RV has gone bankrupt, and the phone number listed on the 10-year service warranty for the 7-watt Solar ChargeMaster charger is no longer in service.

I’m not sure where to test the charger’s output or get a replacement panel. I don’t even know whether a new panel will match the charger.

Doug Hillstrom, Colorado Springs, Colorado

BOB: Doug, the panel on your motorhome is probably one of those hand-built jobbies that the manufacturer glued to the roof. If so, it uses a fiberglass backing to inset the cells, which are covered with resin or Tefzel. There’s no glass, unlike most panels. If the top material isn’t baked on properly, it will eventually peel, just as you described.

A 7-watt panel’s value is more psychological than effective. Many owners think they have a panel that charges the battery but, in fact, this type of panel is ineffective. As a rule of thumb, if the panel doesn’t come with a separate charge controller, then it’s inadequate for RV use.

Tests by solar experts have shown that it takes at least 40 watts to do any good charging batteries with internal resistance. That’s a minimum requirement. If you want a panel that will condition your batteries properly (i.e., finish charging), then you should consider a minimum array of 60 watts, with a good-quality charge controller.

If you want to learn more about a proper system for your coach, contact AM Solar at www.amsolar.com or 541-726-1091. These people specialize in solar-panel installations and are RV enthusiasts.

Tech Topics columnist Bob Livingston has spent countless hours exploring the inner workings of RVs and finding ways to make life on the road easier for all RVers, particularly Good Sam members. Got a question about your rig? Send an e-mail to [email protected].

In addition to answering your letters, Bob Livingston is publisher of Trailer Life and MotorHome magazines, director of the seminar program at the Rally and author of Trailer Life’s RV Repair and Maintenance Manual. To purchase the fourth edition of the manual at the discounted Good Sam price, click on www.goodsamclub.com/store.

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