I am planning a solar installation on a friend's 320 Tab. As has been noted, there doesn't seem to be any manufacturer supplied electrical schematics available. I have accessed a few owner generated schematics on this forum that are helpful, but not complete. Unfortunately I don't have ready access to the trailer to be able to use my multimeter to check out some of the wiring to answer a few questions I have. I was hoping some some owners who have delved into the wiring might be able to shed some light on a few questions I have.
1. The owner generated schematics indicate there is one positive lead from the trailer junction box to the trailer battery which passes through the battery disconnect switch. (In the junction box, this positive battery lead is electrically connected to the WFCO converter battery charging line (thru panel fuse) and the seven prong plug from tow vehicle. This indicates to me that the tow vehicle battery cannot charge the trailer battery while towing unless the battery disconnect switch is in the shut position. My supposition is in conflict with the owners manual electrical section which states "The charge in the 12 volt batteries can be replenished, depending on the tow vehicle, from the tow vehicle alternator thorough the 7-way cord. The charge will flow to the batteries regardless of the battery disconnect switch position. Likewise, if on or off, the solar panel is still charging the batteries."
Have owners noted if the battery disconnect switch position affects the ability of the tow vehicle to recharge the trailer battery? Has anyone found a schematic for wiring to supplement Rick Parco's beautiful 2016 schematic/info sheet?
2. It is not intuitive to me how 12V power from the trailer battery gets to the 12V loads. It would make sense that all 12V loads are powered via the 12V fuse panel in the WFCO Power Converter. This is certainly the case when the 12V DC is being supplied by 120VAC power thru the converter. Is the trailer battery connected electrically to the WFCO Power Converter 12V output upstream of the fuses? This would make sense so that load fuses would be in line regardless of source of DC power (Converter or trailer battery or tow vehicle battery). If this is the case, what is electrical connection from trailer battery to upstream of the DC load fuses? Is the electrical connection thru the battery charging fuse/circuit in the DC fuse panel? I.e., does current flow both ways thru fuse circuit depending on whether trailer battery is being charged from shore power or shore power is not connected and trailer supplying DC loads?
3. How does the 40A reverse battery protection fuse in the DC fuse panel of the WFCO tie into the power distribution?
I hope to have more access to the trailer to be able to try and figure some of this out, but was hoping to get a head start with other owner experience and input.
Thanks for you patience wading through these questions.
Steve S
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I'm on-the-road without full access to my electrical wiring files
So these answers depend more on memory than (owner created) documents.
The Manual Section you are referencing is old/out-of-date/wrong.
However, solar panels are indeed normally wired to the battery so the Battery Disconnect Switch position does not prevent solar charging.
Other owners have created schematics similar to Rick Parco's with different style or levels of detail.
Some can be found within threads but not on the Resources Page. {or my traveling laptop }
I for one do not know how the Two 12VDC sources are actually connected inside the Power Center, just know the 12VDC Fuses are active. And yes, current can/does flow both directions to/from battery via its fuse.
Do know it works as designed and will blow if the trailer battery is installed backwards.
Which protects both the WFCO and Battery from damage.
TV: '17 Colorado V6 Z71 4x4, Tow Package, GM Brake Controller
Adventures: 54 Nights: 341 Towing Miles 43,780
Cheers
(I'm guessing) The lead gets to WFCO box where it is wired to both the 30A battery charging fuse downsteam side AND to the 40A reverse power fuse. On the other side, the 40A fuse is connected to the DC distribution bus for supply to all DC loads (except Battery charge 30A fuse which is connected to a separate converter battery charge ckt and would be silly anyway).
With trailer battery wired properly and no shore power, 12 VDC flows from trailer battery, thru battery disconnect switch, to junction box, to WFCO, thru 40A reverse pwr fuse and onto 12VDC distribution bus, then thru individual ckts to lights, fridge, etc.
With shore power available, 120VAC is converted to 12VDC and sent to distribution bus and off to the loads thru the ckt fuses. Converter also sends appropriate near 12VDC to 30A battery charging fuse back to trailer battery for charging.
If battery was hooked up backwards with shore power energized, there would be current surge thru 40A fuse back to trailer battery...this explains reverse pwr fuse ckt.
Not quite sure what voltage on DC bus would be with shore power charging trailer battery since output of battery charging ckt thru 30A fuse floats on trailer battery and therefore is electrically present back on DC distribution bus via 40A fuse.
At least that is what makes sense to me. I may contact WFCO people to see if I can get confirmation or what the actual setup is. Or open up WFCO unit to eyeball the wiring. Haven't found a WFCO converter - distribution panel wiring schematic yet. Not that it matters too much, but I like to know how stuff works.
Thanks again.
Same wire, different direction. Any "switching" is just the result of this reversal of voltage potential.
With trailer battery only powering WMFO, DC loads remained powered with 40A fuse pulled, but not with 30A fuse pulled. Thus, as noted above and contrary to my previous supposition, DC power is applied to DC distribution bus via 30A battery charging fuse. 40A fuse not in the circuit between trailer battery and DC loads.
With 120 VAC only powering WMFO, DC loads were deenergized when 40A fuse pulled, but remained energized when 40A reinstalled and 30A fuse pulled. Thus, 40A fuse is between AC/DC converter output and DC distribution bus.
It makes more sense to me now, at least.