WFCO WF-8955 amps in absorption mode

[mooky_stinks]

I have a WFCO-8955 (55 amp) that absolutely will not go into bulk mode even though it’s a 3 stage converter. Not sure if it’s inadequate wiring or an inadequate converter. It’s always 13.6-13.8 no matter the state of charge of the batteries. What I’d like to know is how many amps is it putting out in this mode. And don’t tell me 55 because we all know that ain’t possible! ??

[JBarca]

mooky stinks wrote:
It’s always 13.6-13.8 no matter the state of charge of the batteries. What I’d like to know is how many amps is it putting out in this mode.

Something else to add, if you "never" see the voltage drop down into the 13.25 volt range, (float mode) sooner or later being at 13.6V (standard charge) "all" the time is a sign you are going to boil out the battery in short order. Check the electrolyte level often to not go below the plates.

If you are camping on shore power for 4 to 5 days and the voltage never drops to 13.25 V, there is a problem. Maybe the WFCO, maybe a bad cell in the battery. This is a separate issue from not going into boost mode.

WFCO's as they age are real good battery killers and other devices in the camper. They seem to die 3 ways. Way high voltage, real low voltage or just plain die and do not work. The first two ways you may not notice until other damage is done. At least when they die totally, they do not kill something else in the process.

[ktmrfs]

typical WFCO operation. Part of the problem is long undersized wiring. But IMHO them major issue is how the WFCO decides to go into boost mode. It stuffs the rated current into the battery and then AT the WFCO OUTPUT looks at the voltage needed to maintain the current. If it is above something around 14V it drops to the "trickle" mode. so... voltage drop along the run is usually enough to never let it go into boost mode. so, your stuck with a 13.6V or so output, and 15-20A.

If you only have one battery, likely never go into boost mode. a huge bank, sometimes. Others have done tricks, turn on a heavy load to keep the battery voltage down low so the WFCO output doesn't reach the trip point initially. Make sure you have very large and short wire to the batteries., usually very hard to do since most trailers have the converter way away from the tongue.

solution.............. replace with a well designed charger, Progressive dynamics, iota etc.

[Learjet]

I've had a couple of WFCO on previous campers...the solution if you really need boost mode is to change out the converter to either and IOTA or Progressive Dynamics with a mode switch so you can manually select boost.

I was able to manual get my WFCO to go to boost by turning it on with a battery checker connected (resistance load of @ 50 amps)...but this is not practical to do and didn't even work every time.

[Grit_dog]

Good responses above.
I never got far enough to figure out if it was a wiring deficiency or just the normal behavior (which apparently can be tricked into working better), as we didn’t use the camper a lot and always had power either with hookups or the generator.
But had I kept the camper, I would have looked into the above suggestions and/or junked it for a better converter.
I had the same issue as the OP. It never went into full charge mode. Never saw more than 13.6V at the batteries.

[red31]

you could certainly measure the amps and will likely find that it varies from near zero on up mainly based on the battery's condition.

[JBarca]

Here is what I have run into with the WFCO on this non going into boost issue.

Part of the problem is wiring within the camper. A long run on no. 6 awg across a 25 to 18 ft run between the battery and the converter limits the converter from going into boost and it also limits the amps from the way the converter senses the battery.

In my case, the factory installed a 30 amp self resetting breaker in that same main feed line to protect the battery, wire etc. They know the converter will never be passing anywhere near the 30 amp breaker limit back to the battery in charge mode. The WFCO's in this setup has real issues going into boost.

My guess is, you may only be getting 15 to 20 amps from the converter to the battery regardless being in boost at 14.4 or standard charge at 13.6 volts. That is what I measured on mine while boondocking.

I did change out my converter from a prior 2 stage American Enterprises to a Progressive Dynamics and it has no issues going into boost, I can even use the wizard and force the modes. BUT, that same small wire that long is still limiting the charge amps even in boost mode.

In order to get the amps up, one needs to move a good power converter real close to the battery and used really large short cables. Then the converter can sense the battery resistance better and pump up the amps also.

It seems that maybe, the standard RV setup with a 55 amp or 60 amp power converter is setup to allow, approx. 20 amps to charge the battery while the rest of the 35 to 40 amps is running the camper. That smaller wire setup is making that happen on a long camper.

Hope this helps

John

[shastagary]

you can read about what others have done to force boost mode here

WFCO 8955 - force into boost mode