[Tom]

Your buss bar in the electrical panel is likely split so each of the inverters had their own dedicated circuits. I you go to a single inverter to handle what two handles you might have to run a heavier wire from the single inverter or combine the two wires now used to handle the extra current and you might have to join the two existing inverter powered buss bars.

[Joe]

Jon on the battery side, Nick Hessler wired me per modern convention so that the 4 batteries are one big bank (the + and – to both inverters are tied together as re the 2 banks in the DC panel.

On on the AC input side each inverter is fed from the breaker panel with a different phase of the 2-phase input.

On on the AC output side each inverter drives a different side of the bus.

my understanding is that the dual-input / dual output 3000 unit would handle a split phase input and output and all I would lose is some overall wattage.

Only difference from from a straight 3-wire hookup is each phase has its own neutral from the fuse box I would have to combine the two 2-wire cables back into a single 3-wire cable to run into the inverter.

BTW, here is a picture of the carnage. In inspecting the other inverter I found that they soldered the two wires together and then coveren with a wire nut. Been 40 years since I soldered by the joints looked dull which if I remember means a “cold” joint so perhaps that is the culpret:

[Archived]

Based on your description of how you are hooking things back up I think you are correct. When using two inverters you have to keep their outputs on separate buss bars unless they can sync phases with each other, but when you use one you no longer have that issue so combining legs is appropriate.

[Tim]

Liam: What does “SI/DO units but are connected as SI/SO” mean? What does the “cold” mean? How should have the connection have been made to do it “right”?

What do you think of WAGO Lever Nuts? For use with stranded and solid wire connections on 12volt, 24volt, and 120 volt both low amp and high amp applications.

http://www.wago.us/wago/press/press-releases/overview/detail-1122.jsp

[Archived]

My model of inverter can accept a 2-wire 110V SI (single in) input. That is a hot (black wire), cold (white wire) plus a bare ground.

My inverter is a DO (dual output) in that it has a 20amp output and a 15amp output.

When the prior owner upgraded, he chose a “parallel stacked’ configuration.

The 50A shore power and generator are 3-wire 220V. That is a red wire in addition to the black and white. Just as in your home, the black and red hot wires drive the left and right side of the breaker panel bus.

So in a parallel stacked configuration one feeds the black leg to one inverter and the red leg to a second. You get twice the capacity. Given that, and the fact that the bus only has so many inverted outlets, the 20a output of inverter 1 powers the driver’s side of the bus and inverter 2 drives the passenger side. The 15a output of both inverters is un-used.

So each SI/DO inverter is used as a SI/SO.

The new 3,000 watt inverters are DI/DO which means that a single inverter can be driven by a 3-wire 220V input. I spoke with Xantrex, and it is now a lot clearer how this DI/DO unit works. The second input is simply a “passthrough” meaning the only thing it does with Input #2 is the transfer-switch function. The charging circuit draws power only from Input #1.

In terms of the connector you show, I would not use them. They are based on spring tension. This is a similar system to the “push-in” holes in the back of home outlets and power switches which were intended to save electricians the time to form a loop and tighten a screw. After 25 years, I have needed to replace at least half of these in my house as the copper wire cold-flowed or the spring tension weakened causing a faulty connection.

I believe that those devices are now no longer manufactured. Go to Lowes and pick-out a $5 Legrande outlet (right next to the cheap $2 outlest and you will notice they have a push-in capability – but the way it works is you tighten the screws and a clamp inside tightens down hard on the straight wire. Look in your breaker box. Every single connection is a terminal screw that can be torqued.

In Germany where I lived for a few years, if you remove a ceiling light – you will find that the 3 wires are connected to a white “molex strip” which has six screws and the 3 house wires and three light wires but-up into that connector. Brilliant system as each time you change a fixture, you don’t muck with the original house wiring and more importantly, you don’t wire-nut a stranded light wire to a solid house wire (which as I said before is illegal in wiring DoD equipment as it is unreliable). You won’t find ANY wire nut on the space station!

For 12 or 14 guage wiring in my home, I use those same molex strips and you can find them at lowes. Come in big strips and you cut them.

In reqiring my inverters I am going to use “Alumicon” connectors. These were invented to repair houses with aluminum wiring. They are designed for Aluminum-aluminum, aluminum-copper or copper-copper connections. The holes are also filled with a dialectric grease to prevent corrosion. While I don’t need the protection from “dissimilar metals” they provide – they are an easy to find “screw-terminal wire-nut” if you will. They accept up to a 10guage wire wich is what was used to wire my inverters.

Sorry for the rant, but it is amazing the things that building codes mandate (you now have to caulk the crack in between two wood studs (like a king and jack stud around a window) so a microscopic amount of air can’t infiltrate – but yet you can still take a few stupid shortcuts in electrical wiring. If you wonder why that Canadian guy “Holmes on Homes” is always ranting about open junction boxes, look at the picture above and immagine that little meltdown didn’t happen inside a completely enclosed metal case. I would have been posting pictures called “bus fire”.

[Archived]

Thanks for taking the time Liam. That was very helpful and educational. I’m not an electrician or electrical engineer. But I have been doing basic 12 volt and 120 volt for years and now 24 volt. I can remember when I discovered “backstabbing” of outlets. I thought how convenient. Then after joining the Garage Journal Forum I read many posts from experienced electricians condemning backstabbing with the reasons why well documented. After having a problem with two outlets in our house and finding them backstabbed with arcing I was a convert. When I engage an electrician to do something for me one of the first questions I ask is “Do you backstab or backwire?” I figure they know right off the bat that they aren’t dealing with a rube.

Through the GJF learned the difference between backstabbing and backwiring. I think the better quality outlets you advocate use backwiring to secure the wire under a plate on the side of the outlet that is then torqued down. Thanks for sharing the information about AlumiConn connectors (they apparently aren’t cheap!) I also learned there is apparently a tool I didn’t have and didn’t know I needed …. torque screwdriver.

Those seem like they are the ticket for a secure connection. I’m not a good wire nutter.

Do you use the Molex strips in electrical boxes on 120 volt cicuits? If so. do you do anything to protect the individual lugs?

We watch Mike Holmes shows regularly and are amazed at the hack jobs that he runs into. Very educational for anyone who isn’t knowledgeable about the building trades and would like to learn more. Oftentimes the best way to learn the right way to do things is to see them done the wrong way first.

I expect in a few years we’ll see the debute of “Rowe on RVs” where the show will focus on Jeff Rowe showing us hillbilly modifications made to Prevost coaches brought into his shop and how to fix them right.

[Archived]

If anyone wants to see coaches that have been butchered look at some older coaches that have gone through multiple owners and which have been under loved. It is amazing how many ways owner-mechanics can come up with to “fix” something. Or maybe it is the work of RV service places that work mostly on pop-top campers who are doing the repairs. Regardless of who is doing them the end results are bundles of wires that have just been cut and are dangling, or air hoses removed and capped, or maybe it is the number of wires that are just laying around or draped on top of things and which might be the quality of Christmas tree lights.

I would hate to be Jeff or anyone else that has to reconstruct the damage done by people that shouldn’t be allowed to work on coaches.

[Mike]

Jon, I totally agree. Very first long trip with my bus the water pump burned-out and I thought “no worries, just hook-up a hose and use park water pressure”. Well turns out the prior owner stubbed-off the plumbing behind the panel. Had to push water backwards through the water softener to save the trip.

Post-Script on the inverter story:

I spoke with a super freindly guy at “Inverter Service” and he said when they repair inverters they try to install a terminal strip so that folks don’t use wire nuts.

I mentioned I wasn’t crazy seeing that the other end of the 110V wires attached to the circuit board with spade connectors. He said, yes those can work lose over time as well.

[Tradewinds Coach & Marine]

Liam said “I mentioned I wasn’t crazy seeing that the other end of the 110V wires attached to the circuit board with spade connectors. He said, yes those can work lose over time as well.”

What is the preferred method? Ring terminals?

---

Tradewinds Coach
Kyle Bennett (Service)
Brian Miller (Sales)

[Archived]

I would have preferred that the 110V leads be either soldered to the circuit board or attached with a ring-tongue to a screw post.