Even though the WFCO is standard equipment on some fairly expensive trailers and 5th-wheels, both TMO's electrical experts (e.g., Bill), and somewhat qualified "amateurs" (e.g., me) are not impressed by the circuit layout, components, or behavior of the WFCO.
Some TMO people have replaced them (or, in particular, the Charger/Converter section) with better systems by Progressive Dynamics or PowerMax. Usually in response to a WFCO failure, but at least once (in my own case) as a preventative upgrade: to avoid ruining a vacation with a WFCO failure, and also to extend battery life. My PowerMax is built better, and the "Float" logic works correctly. The PD is probably even better than Powermax, and also offers a push-button "bulk mode" controller. (That's
extremely useful, if you want to recharge your batteries from a Generator running for just an hour or two.)
WFCO's mainboard/daughterboard layout and components make it more prone to fail than the higher-quality replacements. One common point of failure is the main "power filter" capacitor: WFCO uses two small ones, each failure-prone and unable to share internal capacitance with the other, while PowerMax uses one BIG one (
more than twice the size of each WFCO). WFCO's "daughter board" (the logic section) has about 3x more components than the PowerMax, with correspondingly higher MTBF (Mean Time Between Failures). In operation, WFCO's logic problem is a failure to reach Float stage. TM trailers seem to present enough "phantom loads" (e.g., the stereo system draws a tiny bit to remember it's presets, even when powered off) to prevent the WFCO from
ever switching to "Float", and that issue can lead to cooked batteries.
A Thread, chock-full of information about this, is
http://http://www.trailmanorowners.c...ad.php?t=14155. RIWight and Brulaz present their measurements and ideas, along with mine.
This is never a make-or-break decision in buying a TM, either new or used. It's an easy upgrade, especially if you replace just the Converter section (leaving the original WFCO fuse panel/power distribution section in place.) If you do it, the "best" place to purchase any of the upgraded replacements is bestconverter.com.