WFCO WF-8955 Converter

[EddieL]

Can someone explain how my converter can output 14.4 VDC but you can't read it with a volt meter?

The following was copied from my converter manual:

In order to maximize battery life, it is best to charge batteries slowly, keep them topped off with a trickle-charge when the RV is not being used. The 3-Stage “smart” charger continuously measures the battery voltage output and regulates the amount of charge using three modes of operation; Absorption, Bulk and Float modes.

All WFCO power converters are automatic three-stage switching power supplies. The converter senses which mode it needs to be in by checking the RV system voltage.

The converter normally provides a constant target output voltage of 13.6 VDC (nominal) to power all the branch circuits. However, it is current limited, and if the output (load) current reaches its maximum, the output voltage will drop as necessary to hold the converter’s maximum output current level (the Amperage rating) without exceeding it.

If the output current reaches its maximum (normally caused by a discharged battery), this will cause the converter to go into Bulk Mode, which means the target output voltage will change to 14.4 VDC and a timer will start. Although the converter is outputting 14.4 VDC, you will not be able to read that on a voltmeter due to the voltage-current relationship. From the paragraph above, as load current increases, output voltage decreases. The actual output voltage will not rise until the load current is reduced, which happens naturally as the battery charges or if 12 VDC appliances are turned off.

Bulk Mode will be maintained until the current draw drops to approximately five Amps, or until the timer reaches four hours (whichever happens first). Then the target output voltage is changed back to 13.6 VDC for Absorption Mode. Lights that are powered from the output may change brightness slightly at that time.

Thanks,
Ed

[Flybob]

The sentence may be a little vague. It is not saying you will not measure a voltage on the output with a voltmeter, it is saying you will not see 14.1V. This is explained in the next sentence. From the paragraph above, as load current increases, output voltage decreases. The actual output voltage will not rise until the load current is reduced,

A very discharged battery will pull down the voltage on the line until the battery builds up charge.

[HONDAMAN174]

Too bad many of us could never get anything but 13.6 and dumped our wfco units

[EddieL]

13.6v is the highest I've seen from the converter but with an automotive charger I see 14.something volts. That's why I don't understand the WFCO manual.

[TowPro]

Ed, a bad battery can cause a load which will lower the voltage. Also as the load goes up the fan should come on. I have only had 1 WFCO, it lasted 2 years and started to switch high, low, high, low voltages while sitting with no load. mine was a stand alone unit so it was easy to replace. I put in a Boondocker charger.
They make replacement lower sections for the WFCO 9855 that are 4 stage, and have double the warranty.

My brother just installed one this spring and its install and forget. His WFCO was running the fan as soon as you turned on any load (even one bulb), until one friday night they showed up at the camper (sits on permanent site all summer) to find the battery was dead and they lost everything in the refrigerator, plus they had a long weekends worth of meat and produce with them and no refrigerator. (he did get it running again on a battery charger until the parts showed up)