To date, I have replaced 7 WTFCO's. Two got Xantrex XADC 40. Great converter, too bad they quit making them. Two with Xantrex TrueCharge 40 and 60. Also great but expensive as they have temp compensation, power factor correction and are somewhat programmable. The last 3 got PD which walk all over the WTFCO when boondocking and in long term storage.