Battery or Converter/Charger issue?

BAK · 03-07-2019, 08:32 AM

Has anyone had any compatibility issues with the converter/charger and AGM batteries?

I unintentionally let my Interstate flooded battery completely discharge last year due to not having electrical hooked up and bought an AGM battery from Cabela's to replace it.

The first trip out after replacing the battery in the RV, about two days in, I noticed the lights dimming and the battery meter on the wall showed only 2 red lights. When I took my volt meter to the battery I noticed the voltage was slowly dropping. It appears the WFCO 55 amp converter/charger was not kicking in and charging the battery to keep up with the power draw. My temp fix was to run to the automotive store and buy a 15 amp battery charger. This worked to keep the battery up until the heater kicked at night. By the morning the charger showed the battery at about 30% charged. The day before we left to come back home I bought a replacement in Houston and it seemed to fix the problem. Once home I pulled the battery and kept it in the garage on a trickle charger for the last two months and just re-installed about three weeks ago since I now have shore power on the trailer. When I went to start prepping the trailer for our spring break trip I noticed the battery charge level dropped and the lights are dimmer just like last time. Its not kicking in and charging the battery.

I'm at a complete loss as to what it going on. I took the old converter/charger apart and I see no signs of anything burnt. The circuit board still looks new and the components all look as new. No blown fuses either. I'm going to put the old one back together and bench test it with a flooded battery to see if I can get it to kick in and charge and hope its just the battery causing the issue since we had no issues with keeping the battery charged before.

Anyone have any input on what else I need to do to troubleshoot this issue?

Barry

**JRTJH** · 03-07-2019, 08:52 AM

First, did you check the "reverse polarity" fuses (the two RED 40 amp ones) that are located either to the left of the 12 VDC distribution panel fuse row?

Second, sometimes fuses will fail and will not show a visible defect, so did you check the fuses with an ohmmeter?

Third, is the battery wiring properly connected to the battery AND to the battery cutoff switch?

Fourth, are the two "30 amp DC mini-breakers" working properly?

Fifth, have you had the battery "load tested" at a facility with the proper equipment to diagnose the battery and verify it is good/bad?

Sixth, have you disconnected the battery from the converter/charger and measured the voltage "at the battery terminal wiring" (not the battery, the cables connected to the trailer) for 13.6 VDC?

Those are the steps I'd take and if you don't find anything with the above, please report what you found and confirm the condition of the above checks and we can go from there.

My guess is that you've "killed" the battery by discharging it "below 30%" and/or have a blown "reverse polarity fuse" or "DC Mini-breaker".

MerlinB · 03-07-2019, 09:21 AM

AGM batteries require a higher charging voltage than lead-acid wet cell batteries. 14.8 volts is recommended to achieve a full charge.

MarkEHansen · 03-07-2019, 10:11 AM

You need to check that your converter/charger supports AGM batteries. It probably doesn't. This has been mentioned on this site before (not too long ago) so a search will likely yield some answers.

BAK · 03-07-2019, 10:39 AM

Quote:

Originally Posted by JRTJH

First, did you check the "reverse polarity" fuses (the two RED 40 amp ones) that are located either to the left of the 12 VDC distribution panel fuse row?

Second, sometimes fuses will fail and will not show a visible defect, so did you check the fuses with an ohmmeter?

Third, is the battery wiring properly connected to the battery AND to the battery cutoff switch?

Fourth, are the two "30 amp DC mini-breakers" working properly?

Fifth, have you had the battery "load tested" at a facility with the proper equipment to diagnose the battery and verify it is good/bad?

Sixth, have you disconnected the battery from the converter/charger and measured the voltage "at the battery terminal wiring" (not the battery, the cables connected to the trailer) for 13.6 VDC?

Those are the steps I'd take and if you don't find anything with the above, please report what you found and confirm the condition of the above checks and we can go from there.

My guess is that you've "killed" the battery by discharging it "below 30%" and/or have a blown "reverse polarity fuse" or "DC Mini-breaker".

1&2) yes. both fuses checked good with the ohm meter. I also checked to make sure no corrosion or junk was built up on the fuses and that they were seated properly.

3) The battery wiring connection is good and cut off switches checked. However, I did add a heavy duty marine cutoff switch in the battery compartment. I connected it directly to the ground side of the battery connection. Not sure if that should make a difference. Switch was taken out and apart and I verified it's working properly and even took it out of the equation and it didn't help.

4) The converter/charger circuit breakers seems to be working properly. I unplugged the converter/charger from the back of the power distribution box and there is 120 AC power at that outlet. Plugged the converter/charger back in and the fan ran for a second then cut off.

5) I haven't had the battery load tested.

6) I didn't measure voltage at the distribution panel with the battery disconnected but it was 12.4 and dropping with the battery connected. Which to me indicated the charging side of the converter wasn't kicking to keep the system at 13.6. I would assume if working properly, once it saw a drop in voltage it should kick into charge mode and boost the voltage to cover demand and charging.

I can't believe that I would have two bad inverter/converters in this short of time. I went 30 nights of camping earlier in the year before changing the battery and adding the additional cutoff switch without an issue. Maybe I just got a bad battery to begin with?

I should be able to bench check the old unit this week with a flooded battery so that should hopefully help narrow down the issue.

BAK · 03-07-2019, 11:10 AM

One thing I did think was odd is that the old and the new converter/charger (same exact model) have two 40 amp ATC fuses however there is a label on the back of each unit that says only use 35 amp or lower fuses. Odd to have a mfg to have a warning label that contradicts what they install from the factory.

**JRTJH** · 03-07-2019, 11:50 AM

Here is a link to the WFCO Theory of Operation information: http://wfcoelectronics.com/wp-conten...eration-v2.pdf

I do know that if a battery is connected to the converter, the output of the battery is "read" by the converter and circuits in the converter will "shut down/step up" the voltage output to meet the "battery output" so if you haven't disconnected the battery, shut down the converter, waited about 1 minute, turned the converter back on and read the voltage at the battery terminals, then you may not have completed the troubleshooting steps correctly and are getting a "false indication".

As an example, if the converter senses a "fully discharged battery" it will not charge the battery at "full capacity" until it slowly brings it up to a minimum charge. So, theoretically, if your battery is at 30% charge, the WFCO wouldn't provide 13.6 VDC to the terminals as that would possibly damage the "discharged battery"... That may be why you didn't read 13.6 or 14.4 VDC with the battery connected ???? (just a hunch, not a statement of fact about your situation)

There is a comment in the link that says "Only the WFCO WF-6800 series converters are capable of supporting GEL batteries. Some people consider all AGM and GEL batteries as "AGM type". Are you sure you've got a "true AGM battery" ?or is it possible that you're using a VRLA GEL battery marketed as an AGM battery?

It seems strange (but not impossible) that you'd have two WFCO converters fail with exactly the same symptoms, so I'd think something else is likely to be causing the issue, although I wouldn't completely rule out the possibility that your converter has failed "again"... Have you contacted the WFCO Tech Support section? They are set up to guide you through any issues and are quite adept at translating symptoms into fixes.... You can call them at 877 294 8997

BAK · 03-07-2019, 01:00 PM

John, thanks for the link!

As soon as I get home I will follow the procedure for testing with the first converter/charger pulled out. Luckily I have an old (non-AGM) battery that I can hook up after the initial "no-load" check that will allow me to put a load on the unit afterwards. Depending the outcome tonight, I'll test the one that's installed in the trailer this weekend and compare the results between the two.

In looking at Cabela's website, it shows to be an AGM battery but without having the battery in hand, I can't verify that its not the VRLA GEL.

I'm hoping it's a battery issue since that is the easiest fix. I'm pretty much out of options and warranty if it's not the battery... This issue didn't materialize until I swapped out the battery and added a second cut-off switch so it's a good possibility it's a battery issue.

Barry

BAK · 03-07-2019, 03:28 PM

Well I was able to bench check the first converter/charger and it showed an output of 13.68 VDC with no battery connected.

I then hooked the unit up to two different batteries and the output at the converter/charger still showed a steady 13.68 VDC but I did not see any step up in output voltage with either of these batteries. Unfortunately, battery #1 was already at 12.57 VDC and battery #2 was at 12.52 VDC so they may not have been discharged enough to kick the charging cycle into stepping up the voltage output.

The WFCO information doesn't state at what the battery voltage has to drop down to before it kicks into BULK MODE (14.4 VDC) nor does it talk about any voltage increase in ABSORPTION MODE which appears to be the standard operating mode. In ABSORPTION MODE it only talks about increasing current draw (I assume amperage) to keep up with the load on the electrical system (12 VDC).

I guess I'll head out to the trailer this weekend and measure the voltage output at the converter/charger without the battery hooked up as well as measure the voltage on the battery. I'll probably just buy a new Interstate Deep Cycle battery while I'm in town and install it. Hopefully that solves the issue. If not I guess I'll be carrying my good 30A battery charger with us so I can keep the battery charged.

**JRTJH** · 03-07-2019, 04:49 PM

That's good news (I think)...

Now, if the installed converter/charger works with a conventional lead acid battery, then it sure looks like there's an issue with your "AGM" battery maybe not being an "AGM" but a VRLA Gel"... (a wolf in sheep's clothing) ...

Frank G · 03-07-2019, 05:04 PM

I feel your pain, but there are hundred's of thousands of us out here, including myself, that get along just fine with a simple deep cell battery and the onboard converter /charger. I would think you have battery issues and a incompatibility with the AGM battery. Over the years I have had to replace a couple of converter / chargers. They were easy to diagnose, voltmeter on the battery, and no charging voltage present. This could also be done with a DC Amp meter.
Back in the day I had a small "Snap-On" dc amp meter I carried in my pocket, when a customer came in complaining about charging issues it was a simple 30 second diagnosis to tell them they needed a generator rebuild or voltage regulator replacement.

You may also like: