WFCO Converter/Charger Dead? How to tell?

@MNtundraRet - thanks! I'll do some troubleshooting! You're right, we've mostly relied on the idiotmeter. We have a multimeter onboard, but have generally taken the lazy route (and/or really haven't had much concern about the batteries as we tend to do a lot of driving and they never get very low). I bought one of those little meters that plug into a 12V outlet (which I know also can be problematic relative to accurate readings depending on having charged or used your battery within some period of time), but it turns out I have no 12V outlets in the coach.

So, we've just gotten along for the past four years with little muss/fuss other than making sure the water level in the batteries is fine.

It look's like your only way of checking your batteries is the "Idiot meter".

Almost useless!

Get a multi-meter, if you no not already own one. Take the voltage reading at the battery-terminals first while unplugged. A fully charged battery will read 12.6+ volts (50% charged = 12.1 volts, 30% = 11.75 volts, 10% = 11.3 volts).

Now plug into shore-power. Take reading at the battery(s) again. You should see the voltage rise to 14.4 volts (bulk rate charging for your unit) or at least 13.6 volts (absorption rate charging if the battery(s) were better than 75% charge).

If you see only 13.2 volts the converter portion works but not the charger portion. No increase in voltage means the unit has failed, if the breaker for 120v AC power has not tripped, or the fuses are okay (there is either one or two on the back of the converter/charger).

Please note if your battery(s) voltage is less than 11.0 volts they are likely dead. That means they cannot operate the solenoid to either "connect" or "disconnect" from the 12v dc circuit for charging. Also; the charger will not continue to charge a dead battery. It automatically shuts down.

Start the MH engine. The alternator should allow charging of the batteries since it by-passes the disconnect switch. You should see 14.5 volts, or more, showing charging from the alternator. Once the batteries have been charged with the engine idling for 15 minutes or more, a working converter/charger should start charging batteries if the "disconnect" switch will work to connect the batteries to the circuit. The charger should be allowed to charge the batteries 12 to 24 hours. Let the batteries sit while the MH is unplugged for 24 hours. If the battery(s) read less than 12.6 volts they are sulfated and need replacement.

I suspect you batteries are shot from little TLC. Make sure the water level is okay in all the battery cells. By the way, my WFCO 45 amp multi-stage charger is original from fall 2002. If the charger is bad you will find out by checking

testing without DC voltmeter is pretty simple to point fingers at least.

Turn on your ceiling lights without being connected to shore power. Your ceiling lights should work.

Then connect trailer to shore Power and your ceiling lights should get alittle bit brighter.

Having a DC VOLTMETER is best way to test.
Without shore power connected you should be able to read around 12.6VDC across the charged up battery terminals.

Turning on your shore power you should be able to read 13.6VDC across the same battery terminals. This is telling you all the fuses are connected between the converter/charge and the 12VDC distribution panel. It is also telling you the fuses are good between the 12VDC Distribution panel and the battery terminals...

If you don't see the 13.6VDC then either there is a bad connection, the battery disconnect switch if you have is open, or fuses are bad between the battery terminals and the output of the converter/charger unit or the converter/charger is bad.

There is a 120VAC circuit breaker on the 120VAC Power Distribution panel that feeds the converter/charger unit. Be sure it is closed. If the converter/charger is ON you should be able to measure 13.6VDC at the DC OUTPUT terminals at the converter/charger unit at all times except when it is doing charge mode operations. Then it may read 13.2VDC, 13.6VDC, or 14.4VDC depending what charge mode it is doing at the time....

Let the forum know what your read...

Roy Ken

This is my 4th season.
I've repaired/replaced my parallax twice.
I'd call it a common occurrence.