Replacing WFCO converter

[rickst29]

Wow, that's a lot to digest rickst29! Looks like some good advice and things to think about here. I'm going to have to take some time and read through this a few times. Next time the trailer is open, in a couple of weeks, I'm going to have to test to see what my output voltage is in lithium mode. I'm still trying to wrap my ahead around why multiple stage charging for lithium is not good like it is for SLAs. A concern with that is being plugged into shore power for several days at a site, pumping potentially 14.6v into it nonstop. I realize the BMS should shut it down, but I would think it still preferred to have a lower trickle charge like when set for SLAs.

Changing out my already purchased battery isn't an option I'm going to consider, but some good advice for those considering options. Unfortunately, my battery does not have the ability to connect to the BMS to make adjustments, so I'm stuck with what I've got, which is a LiTime 100ha.

One thing I don't quite understand is the need for a 4awg wire, which seems excessive. How is a 10awg wire okay at when the converter will still push 14.4v in boost mode? It seems your saying that even though the converter is capable of 55 amps, the SLA will not accept that current but the lithium will. I'm surprised to hear the battery type can affect the amount of current the converter is pushing. Maybe I'm misunderstanding. As I said, I'll have to read through this a few more times.

Looking at boost mode, maybe an option would be to not put the converter in lithium mode, then just use the pendant to set the output at 14.4v when desired. But then that would require me opening the shells to set my voltage each time I plug in when stored, which is not an option in my garage. Lot to think about!

If the battery's BMS is no good (neither readable nor controllable from a cellphone), then it (the battery pack) should probably be replaced. I had a pre-built battery like that a long time ago, with a bad BMS: I later ripped the box apart to extract the cells as 'salvage'. I uised those cells in a home-built pack with new bus bars and BMS, I still have those cells in use today.

But its slow to cut into those sealed up plastic cases using a hacksaw. Brand New and BETTER 100A cells only cost about $50-60 each, it isn't worth your time to savage the old ones -- and you should probably go bigger anyway, 200A or larger per cell.

 

[Knotty-TMO]

I should have been more clear about the wiring part. My main point was, if you are going to upgrade to lithium, it's best to upgrade the output of the charger to 8G (6G is better). That will allow full output of the charger for ultimate battery charging without overheating the original wires. All of the PD chargers that I got only had an empty positive and negative DC port that was capable of accepting 6G wire (or smaller). You insert your 6G wire into the empty port and clamp down on the wire with an allen wrench. If you use 6G wire, will will need to get 6G lugs and a crimper for 6G wire.

When I wired my charger, I ran 6g wire back to my battery's positive and negative busbar (essentially directly back to the battery). I then ran the original 10G wire from the the power center's back to the battery busbars to power the the DC part of the converter's power board.

I replaced my 75 Ah flooded battery with a 230 Ah LiFePO4 and swapped the WFCO charger for a PD4655. With the battery mounted in the original location (up front) there is a significant voltage drop due to the stock 10 AWG battery wire in the TM. I'm guessing it is the reason I haven't blown the fuse in the WFCO panel or the fact that mine has a 40 A fuse and not the 30 A noted in this message thread. No blown fuse is good but voltage drop is bad and is slowing down charging.

I want to move the lithium to the rear of the TM and change out the wiring to 6 or 8 gauge as described but my PD4655 came with soldered in 10 gauge battery wires, in contrast to the screw in wire ports Wavery noted. I don't really see a way to to make the larger battery wires work.

Wavery, Rick or others, do you have any suggestions?

 

[rickst29]

Knotty, my older 4655 was the same as you describe. Here is a good scheme which can provide maximum charging current to the batteries. It also provides increased protection for the WFCO fuse board - by removing battery charge current from traversing the Board.

You should buy a pair of fully insulated 4-way "power distribution blocks". When Amazon and EBay (and other sellers) put these into categories, they are often described audio equipment. (That's because they are widely used in building high-powered car audio installations). Here's a pair at Amazon, although some reviewers didn't like the quality: Amazon.com

Clip the PD output wires fairly short (12V and frame ground,be sure not to accidentally clip any of the wires used for connecting 120-VAC). Butt-connect the shortened ends from the PD board) into longer and larger stranded wire segments. In my own TM,I used AWG-6. I split the strands from each wire to create a lot of overlap, then I soldered the joints and pulled shrink wrap over them. Tin the free ends, which will go into the Distribution blocks.

I recommend using white "ground" and red "12-VDC", even though they are not standard colors - the color meaning of any non-OEM added "black" wire within a TM will be very unclear to the next owner.)
- - -
With the PD board now providing large and fairly long output cables, pull the WFCO unit out from the bathroom wall by a few inches. Pull your new and large battery "12V" cable from your storage location, with one end reaching into the "under the tub seat" area behind the WFCO mount. Attach that wire into one of the power distribution blocks. It's fuse should be at the other end, next to the batery packs, but you should "tin" the end of this cable before locking into a power distribution block. You might make this wire much larger than the PD wires, because the blocks each probvide one port for a big wire (either 1/0 or 2/0 AWG might be a good choice here). Also pull your new and large grounding wire from the batteries, into the other power distribution block. Again, tin the cable end first. (That block supports grounding current at zero voltage).

Set your PD Board into the WFCO box, and pull the wires back to reach into the distribution block ports. Lock them in place. From the WFCO fuse Board, which handles only 8-AWG maximum on the large 12V input connectors, pull two tinned RED stranded wires back to the 12V Distribution Block. You wwant those wires to be exactly the same length, so that the current through each will be approximately balanced. Lock them in, maybe soldering ring adapters on those wire ends to help them fill in the 4-AWG ports better.

In home wiring, NEC does not allow the use of two small wires to handle high current into a large appliance. But in the TM, the 12V fuse board will not accept a single larger cable. The use of 2 wire 8-AWG will provide slightly better efficiency when both are providing current - but if current exceeds 40A on one port and its fuse blows, the 40A fuse on the other port should also fail immediately - because the load current wil alltry to use that path instead. The use of two wires might allow a bit more total current for DC appliances while both wire paths are active (maybe 55A total), but the paired fuses will both blow in rapid succession if 40A is reached on either of the wires.
- - -

The OEM configuration required current from the PD to traverse the Board in order to "go out" on the battery charge port, and adding solar became even more odd. With the power distribution blocks, You can attach your solar controller output wires on the blocks, avoiding the 20A limit of the "downstream" WFCO fuse board fuses. The grounding block can also support better sharing for the dual frame grounding connections (which ar made behind the WFCO, with wires leading the the frame under the "street" side of the bathroom). In my OEM wiring, each of those wires was on a single small grounding bus, any "load balancing"or "back-up" capability could occur through the a very strange use of "alternate paths" through smaller DC grounding wires supporting individual circuits.

 

[Knotty-TMO]

Knotty, my older 4655 was the same as you describe. Here is a good scheme which can provide maximum charging current to the batteries. It also provides increased protection for the WFCO fuse board - by removing battery charge current from traversing the Board...

Thanks Rick. Shortening the PD4655 DC wires and then extending them with larger ones is just what I was thinking. To make sure I understand your description of all the wiring, I made a basic drawing. Can you take a look at it and see if it agrees with what you were thinking?

Also, on my 2518 the WFCO is on the rear wall between the bathroom side and sink/drawers side.

PS - As a test I moved my lithium to right in front of the panel and attached it to the normal WFCO terminals with short 10 gauge wires. With the battery at 85% capacity, I plugged the trailer into AC and measured the current through the battery wires with a clamp on meter and via the batt's Bluetooth BMS (surprisingly they matched). When first plugged in, the meters were reading 45 A but they did not blow the 40 A fuses. After maybe a minute, it dropped to about 38 A. Makes me wonder if I should just replace the two 40 A blade fuses in the WFCO with 50 A and keep the standard wiring, but with larger conductors butt spliced onto the PD4655 wires and larger batt. wires?

 

[Wavery]

This is exactly how I wired mine also.

 

[Knotty-TMO]

This is exactly how I wired mine also.

Thanks for the confirmation.

 

[rickst29]

First with regard to your test: Your 45A to 38A result (in comparison to PD4655's ability to push almost 60A) might have been due to increasing resistance. It might have also been limited at the LiTime non-programmable BMS.n the LiTime battery box.

10-AWG wires pushed that hard will have increased power loss (voltage drop AND heat generated within the overloaded wire strands. But copper is an excellent conductor for heat, as well as electricity. While excessive heat was being generated along the short lengths of cable (due to excessive current), a large amount of that excess heat was probably being transferrd into the terminals at the ends of the cable segments.

Copper doesn't just conduct electricity very well, it is is great conductor of heat. So the cable stayed relatively cool by heating up the PD Board and WFCO circuit board - which isn't a godd thing for those units either. PD might have choked down the amount of current while detecting increased board temperature, but it's hard to guess with so many factors at work.
- - -
The absolutely certain thing, though, is that you should NEVER use a 10-AWG cable into a circuit which allows more than 30 Amps through that wire. (The only exception is cables built with high temperature silicon insulation, they can run at more than twice the temperature of "normal" insulation materials But even in that case, thin cables with silicon insulation waste a lot of power - the 'waste heat' is generated in the copper strands, and the better insulation does not prevent the voltage drop of the coppercable carrying high current - it only avoids burned insulation leading to short curcuits, firest, and othe rbaad things. You MUST use 8-AWG stranded into those WFCO boards if you leave the fuses at 40A, and you should not increase the fuse size to 50 because the terminals won't accept the 6-AWG wire size needed to support the level of current.

The fuse 'maxmium current' must ALWAYS be lower than the cable 'maximum current". ALWAYS -NO EXCEPTIONS. NEC frowns on the use of two fuses on one wire segment, although downstream GFi/GFCI units are legal. The 40A WFCO box fuse for the 10-AWG terminal wire must be replaced with only 30A if the wire size is only 10-AWG.

 

[rickst29]

I won't try to repair the diagram, but here are the changes which it needs to include:

(1) '12V+' from the battery MUST have a fuse added before (or within) it's termination at the new "Fused Distribution Box". The BMS unit only disrupts the path into the battery pack along the GROUNDING cables. Although they are expensive I use a Class-T "fast acting" fuse at the junction of the "+12V" output cable of my thr4ee battery packs. Mine allows 600A, but that is a hard and very fast limit - a "fast acting" fuse doesn't wait for a big wire inside to actually melt. You can go with something smaller, maybe 300A, until you want to add a bigger inverter. If you do add an Inverter, this fuse must allow the peak DC current maximum pull - maybe when starting a downstream appliance such as an Air Conditioner, at initialization, or maybe when turning on the Inverter (connecting it to DC power). I have made posts about high 'Inverter Turn On' power elsewhere (maybe in TMO, or maybe in DiySolar). My own Inverter does that surge upon initial connection to 12V, the "power switch"only enables the 120-VAC Inverter components. I only needed to handle it once.

(2) If you actually fuse inside a fused mini-distribution box,you should use a mega-fuse design. But, you will need to keep total current low - probably less than 150A, because almost none of those pre-built fuse boxes can push more than 150A across the power plane between in the "main in" port and the multiple fuse block legs for the separated "downstream" ports. (The main in" can accept a 400A Mega fuse, but it won't handle all that current in practice - the actual board burns out before the fuse. DON'T DOT THAT!)

(3) The Mini-Distribution (with or without Maxi Fuse slots built in) needs to be 4+1, so that you can use dual ports into the WFCO fuse Board while still having a port for the PD and other big port for the Solar Controller. Each 8-AWG, exactly the same length, going into the "Battery" and Converter" 12v ports of the WFCO fuse board.

(4) If your battery will be handling more than 100A, you need to be more specific in creating the "grounding bus" connections into the frame. TM provided just two 8-AWG wires for that on one or two "mini" bus bars behind the WFCO, you need bigger and better connections to either the frame or big Inverter - using really big wires where current will exceed 40A, and the bars themselves probably need to be heavier.

 

[rickst29]

This is exactly how I wired mine also.

I hope not -- see my 4 numbered items above, they are significant problems.

 

[Knotty-TMO]

I won't try to repair the diagram, but here are the changes which it needs to include:

(1) '12V+' from the battery MUST have a fuse added before (or within) it's termination at the new "Fused Distribution Box". The BMS unit only disrupts the path into the battery pack along the GROUNDING cables. Although they are expensive I use a Class-T "fast acting" fuse at the junction of the "+12V" output cable of my thr4ee battery packs. Mine allows 600A, but that is a hard and very fast limit - a "fast acting" fuse doesn't wait for a big wire inside to actually melt. You can go with something smaller, maybe 300A, until you want to add a bigger inverter. If you do add an Inverter, this fuse must allow the peak DC current maximum pull - maybe when starting a downstream appliance such as an Air Conditioner, at initialization, or maybe when turning on the Inverter (connecting it to DC power). I have made posts about high 'Inverter Turn On' power elsewhere (maybe in TMO, or maybe in DiySolar). My own Inverter does that surge upon initial connection to 12V, the "power switch"only enables the 120-VAC Inverter components. I only needed to handle it once.

(2) If you actually fuse inside a fused mini-distribution box,you should use a mega-fuse design. But, you will need to keep total current low - probably less than 150A, because almost none of those pre-built fuse boxes can push more than 150A across the power plane between in the "main in" port and the multiple fuse block legs for the separated "downstream" ports. (The main in" can accept a 400A Mega fuse, but it won't handle all that current in practice - the actual board burns out before the fuse. DON'T DOT THAT!)

(3) The Mini-Distribution (with or without Maxi Fuse slots built in) needs to be 4+1, so that you can use dual ports into the WFCO fuse Board while still having a port for the PD and other big port for the Solar Controller. Each 8-AWG, exactly the same length, going into the "Battery" and Converter" 12v ports of the WFCO fuse board.

(4) If your battery will be handling more than 100A, you need to be more specific in creating the "grounding bus" connections into the frame. TM provided just two 8-AWG wires for that on one or two "mini" bus bars behind the WFCO, you need bigger and better connections to either the frame or big Inverter - using really big wires where current will exceed 40A, and the bars themselves probably need to be heavier.

Rick, thanks for the additional info. Taking each point in turn:

1) Are you suggesting a terminal mount fuse block for the positive battery terminal? For my situation, I think 300 A would be more than sufficient or perhaps 200 A to match the battery's BMS. I can easily upgrade later if I were to add an inverter and more batts.

2) At this point my total current should be well below 150 A.

3) I'm not finding any distribution boxes which use mega-fuses that have anything other than 8 ga outputs but I need 6 ga to the converter. Agree on the 4+1 in order to send 2x8 ga to the WFCO. Per the WFCO wiring diagram, it can technically accept 6 ga at the DC lugs but with the limited space I'm sure that would be difficult if not impossible

4) Agree that grounding to the frame is a bit of an issue. I haven't looked into that yet. Below are pics of the wiring behind the WFCO in case you're curious.

 

[Knotty-TMO]

 

[rickst29]

A fuse block (even for a single fuse) which can handle 200A or more is going to be extremely expensive. My own TM is wired quite differently, because the batteries and the Inverter are underneath the front dining bench - there are no rear compartments in a 2619 for either batteries or other storage, there is only the bumper storage behind the rear wall of the bathroom.

I have 3 batteries, rather than one. My 600A "big safety fuse" lugs accept 3/8 bolts, with overall cross section 40mm x 5mm (tinned copper). A fuse holder with comparable cross section would cost around $100. It would also be at least 8" long, due to the need for another pair of bolts handling the wire lugs, and this fuse wouldn't fit - I would need to buy an ANL style fuse instead of this too-tall round one.

So, what I did instead: My three short "Battery +" cables (AWG 2/0) have large lugs, they are bolted directly on the "upstream" lug of the fuse (2+1, top and bottom of the fuse lug.) On the other fuse lug ("downstream"), I have a pair of super expensive silicon-insulated cables - also 2/0, both going to the +12V input leg of the Inverter. That "downstream" fuse lug also has a 1/0 cable on one side (sitting above one of the 2/0 cables), that cable becomes the "upstream" link for a large distribution block with fuses.

All of that stuff is under the bench seat. That large distribution block (with ANL fuses) provides an 80A fused link back to the WFCO area. Another fused link connects the "up front" solar controller with a 40A fuse, that unit has 600 nominal watts of solar panels above the front shell. Another 40A fuse provides an exterior 12V power point (via covered Anderson connectors) underneath the front of the floor, curb side.

Back behind the WFCO, the 80A fused cable comes in from the front (It reaches this location back through liquidtite conduit, mostly running through the street side frame box. but also through short segments at the ends - reaching up behind the WFCO, and up into the front seat storage area.) The "behind the WFCO" 12V distribution block is un-fused. The block also attaches wires for the PD converter, a smaller solar controller (for the rear shell panel) and the two WFCO fuse board supply wires.

- - grounding - -

I have re-used the OEM grounding block up front, cleaning and tightening it's connection into the frame. (It originally connected the up-front batteries on the tongue, using an 8-AWG white wire.) That provides battery-negative grounding for all of the DC grounding connections. I have dual 500A coulomb-counter monitors up front. Although the 3 battery packs are thje same size, one BMS allows 250 maximum continuous current, using 3 sets of P-' and 'B-' cables to handle that load. The "B-" shunt for that monitor's shunt connects those 3 BMS wires. The other two BMS units are limited to 200A maximum, their 'P-' wire pairs are connected to the "B-" wires on the second coulomb counter shunt.

The Inverter has two short 2/0 cables on the "input grounding" lug, I routed one cable directly to each of the coulomb counter shunt "P-" bolt down connector blocks. Because they are bolted together at the inverter 12v grounding lug, they always have the same voltage - even if the Inverter is disabled or broken, that lug will still function as a 2-wire bus bar. A couple of additional "grounding wires" with terminal lugs are bolted together, with one big shared wire (size 1/0) going from that bolted stack to the "P-" side of the "250A" coulomb counter shunt.

These short inverter grounding cables are silicon insulated - capable of extremely high current, but super expensive and super-hard to buy anywhere.

 

[rickst29]

With regard to the new diagram - the added wire to the WFCO goes into the other +12v port. IIRC they are marked "batt" and "conv" for battery versus converter.

Per my long post above, you are probably correct in showing an inline fuse mount near the battery, and the small number of fused power distribution units which can handle even 150A on the common "upstream" side of the fuses are very hard to find, and pretty expensive.

 

[Knotty-TMO]

With regard to the new diagram - the added wire to the WFCO goes into the other +12v port. IIRC they are marked "batt" and "conv" for battery versus converter.

Per my long post above, you are probably correct in showing an inline fuse mount near the battery, and the small number of fused power distribution units which can handle even 150A on the common "upstream" side of the fuses are very hard to find, and pretty expensive.

Normally, the battery would be connected to the POS+ port, while the converter connects to NEG- and +VCC. I believe the chassis ground is also connected to NEG-. The two 40 A fuses between the upper ports and the lower battery port are labeled "reverse battery protection fuses". Since my battery is now effectively connecting directly to the converter, via the distribution box, I don't see a need to connect a wire to POS+ and the fuses will no longer be used.

Your inverter and extensive solar require much higher amperage capability than mine. I opted for a combinded 4 port distribution box that accommodates both the fuses and ground bus and is rated to 200 A. I'll have a 200 A terminal fuse block on the battery's positive terminal. Then two 3' 4 ga wires (pos and neg) to the combined distribution box. After that it will follow my drawing.

Here's what I ordered:

Terminal fuse block: https://www.amazon.com/dp/B0BY7VYFV5?smid=A2SR0RN9LFDA0T&ref_=chk_typ_imgToDp&th=1

Power Distribution Block: https://www.amazon.com/dp/B0B3X9TB8G?psc=1&smid=A2SR0RN9LFDA0T&ref_=chk_typ_imgToDp

 

[rickst29]

Although that mini-ANL fuse block does not have any critical reviews on Amazon, its look-alike clones under other brand names have complaints about (1) low power handling and (2)failing set screws.

mini-ANL fuses can be clamped pretty tight, if the set screws don't fail. But the thickness of the arms isn't enough to handle high current amounts, and I've seen a mini-ANL fuss which claim high current capability (e.g., "100A") which use TINY solder dots to connect the arms to the actual fuse strip. Melting solder can make a mess in the small confines, creating a short circuit upon burnout (instead of the desired super-high resistance gap).

I became very suspicious about the super-thin arms (bright brass, not tinned copper) on a "400A" rated mini-ANL, which I purchased for the TM, so I actually tested it. Even with a moderate sized single fuse block adding a good deal of brass surface area to spread the heat from the "arms" into surrounding air,, the tiny arms warmed up very quickly, and the temperature of the mini-ANL fuse containment (between the arms) exceeded 250C pretty quickly, even though I was pushing less than 300A of current through the fuse.

That inner "fuse containment" part of the mini-ANL burned out after less than a minute, with horrible black smoke and (IIRC) failed solder between the outer bars and the inner fuse strip. I disconnected the test load immediately, without attempting to check whether failure started with melting solder (maybe 325 C) or burning plastic, but both were involved in the burned out mess before I could shut down the test -- barely one second after smelling smoke.

I therefore conclude that no "mini-ANL" can possibly support 400A for very long. In high-powered audio audio, peaks of 400A can occur pretty frequently - but the average current is vastly smaller, so the fuses might actually work with a moderate level of safety. But they only fail by melting a gap into the fuse link.

More reliable protection devices (such as modern DIN circuit breakers, AFCI breakers, and class-T one-time-only fuses) use electronics and/or small magnetic switches to assure that the devices will perform according to the requirements. Those requirements are specified as curves of overcurrent amount current versus time before breaking the circuit, and they are required to break the circuit without creating an internal short. (DIN rules specify different curves and catastrophic failure minimum current values for differenent "classes" of DIN breaker quality. But even the laziest of those DIN classes classes must never experience "catastrophic failure"from a surge of less than 6000 amps. My cheap ANL failed with only 300A as a constant current, no lightning strike or 20x higher "peak load" was needed to make it burn catastrophically.
- - -
60A? Maybe. But not 4*60A running concurrently on that nasty little fuse board, the upstream bus can't do it.

 

[rickst29]

Rick, thanks for the additional info. Taking each point in turn:

1) Are you suggesting a terminal mount fuse block for the positive battery terminal? For my situation, I think 300 A would be more than sufficient or perhaps 200 A to match the battery's BMS. I can easily upgrade later if I were to add an inverter and more batts.

2) At this point my total current should be well below 150 A.

3) I'm not finding any distribution boxes which use mega-fuses that have anything other than 8 ga outputs but I need 6 ga to the converter. Agree on the 4+1 in order to send 2x8 ga to the WFCO. Per the WFCO wiring diagram, it can technically accept 6 ga at the DC lugs but with the limited space I'm sure that would be difficult if not impossible

4) Agree that grounding to the frame is a bit of an issue. I haven't looked into that yet. Below are pics of the wiring behind the WFCO in case you're curious.

Thanks for the pictures! the 3rd photo (back of WFCO) shows several wiring choices which I hate:

(A) the "DC" frame grounding wires from 12V circuits (lots of white wires, left side when viewed from the back) have been brought forward - into the box interior. They should not be there! IIRC, Even WFCO now puts the grounding bus lugs on the back of the case. PD has done it the correct way for a long time.
A separate bus bar (a single long one, or a pair of shorter ones) should be placed in the free area behind the WFCO box. These are all frame grounding wires, there should never be ANY voltage difference between that bus bar and the aluminum skin (or the frame, or the floor, or the outer skin of a solar controller, or water pipes, or anything else which is "loose" back there).

When brought forwards (the bad choice) hey clog up the entry hole and a smaller bus bar with a lot of "grounding stuff" which shouldn't be near the DC fuse board at all. If a wire falls loose or breaks off in the front, or its insulation gets worn at the entry hole, bad things might happen - that loose or damaged wire could contact a 12V wire end.

From the photo, it is also unclear whether any of those wires is large enough to serve as a main frame grounding connection. The "grounding wires" should have two shared connections to the frame, at least 8-AWG each. (If you use two smaller bus bars, they should be connected to each other with 8-AWG. Each one gets one of the frame interconnect wires - safely assuring that they both function as one bigger bus.)

From this frame grounding bus, pull one green-insulated wire (8-AWG, if the WFCO safety grounding bus lug can handle it, 10-AWG iof the WFCO safety grounding bus bar can't take a 8-AWG wire) into the WFCO 120 volt section. Attach that green wire on the small bus bars for safety ground wires (the bare wire bus, NOT the 120-volt "neutral return" bus full of white wires !!!)

Then pull one small white wire from the frame grounding to the "negative" port on the 12v WFCO fuse board - that grounding link allows the fuse board to turn on the little LEDs if/when one of the 12V fuses gets burned out.

( Main wires on the 120-VAC side ore either missing or colored strangely. You haven't shown the front side wiring in the WFCO, but 120-VAC create a concern for me: I see a single large oranange/red wire, a smaller white wire, and no bare or green safety ground at all. Although the 3 conductors within the TM 30A cable can be broken out before entering the box, I would recomend using that cable ike a bigger 20A Romex - left unbroken until after it has entered the WFCO box. If it is broken out ahead of time (maybe because the holes were drilled too small?) then the green (or bare) wires into that section MUST be made more obvious - both the 30A safety ground(into the 120-VAC main power cable) and the 20A safety ground from the "frame-grounding" bus. When you connect TM to the grid, the safety ground pin at the campground socket MUST interconnect the TM frame to the actual ground bar (into physical earth) at the camground main service panel.

USA electrical coce (NEC) banned 2-wire AC fro m new home construction over 60 years ago, it can only be used for cheap and low-power lamp cords. If your TM was built with just just one white wire pretending to be both "current carrying neutral" AND safety ground", RIAA should probably be advised of the problem and the factory needs to be slammed. Please show a front-side photo of the 120-VAC section, include the two bus bars.

 

[Wavery]

I hope not -- see my 4 numbered items above, they are significant problems.

I was just referring to the way it was wired (fuses not withstanding).

I use a 225A, Class T fast blow fuse right on the pos battery terminal. I use 175A Mega fuse between my distribution block and inverter and a 30A Mega fuse between my distribution block and converter panel. I use the proper (solar) DC circuit breakers between my solar controller and distribution block.

Amazon.com

I hope not -- see my 4 numbered items above, they are significant problems.

 

[rickst29]

I was just referring to the way it was wired (fuses not withstanding).

I use a 225A, Class T fast blow fuse right on the pos battery terminal. I use 175A Mega fuse between my distribution block and inverter and a 30A Mega fuse between my distribution block and converter panel. I use the proper (solar) DC circuit breakers between my solar controller and distribution block.

Amazon.com

Your fuse choices are EXCELLENT, Knotty should buy a fast class-T just like yours.

A battery BMS which might allow 200A continuous (Knotty's bad one isn't programmable) should normally have either a fast class-T instant-killer fuse of size between 250 and 300A, although your smaller Inverter might not handle 120-VAC peaks and start-up As agressively (on the DC input side) as mine does. If Knotty follows our instructions and switches to THAT one, they offer 250A for the exact same price.

 

[Knotty-TMO]

I'm not dealing with the levels of current you guys are. No inverter and only 100W of solar. I do appreciate all the comments and am learning a lot. My stuff arrives Monday, so I will probably build it out as I had described but will take both of your advice and change out my battery terminal fuse to the one Wavery suggested in the near future.

 

[Knotty-TMO]

USA electrical coce (NEC) banned 2-wire AC fro m new home construction over 60 years ago, it can only be used for cheap and low-power lamp cords. If your TM was built with just just one white wire pretending to be both "current carrying neutral" AND safety ground", RIAA should probably be advised of the problem and the factory needs to be slammed. Please show a front-side photo of the 120-VAC section, include the two bus bars.

Rick - Here's the requested pic of the 120 VAC section of the WFCO. Note, the PD4655 was removed when pic was taken, so you won't see the wires coming up from it. The closeup pic, shows the orange wire coming in with the standard three conductors. Coming through the same clamp connector is a larger gauge white wire, which must be the frame ground. Note they put a wrap of green tape around it.