How to wire auto-switching inverter

[fran&frank]

I am contemplating upgrading to a inverter/charger with auto switching and power assist. I have a 2016 FC FB with stock inverter that has dedicated outlets that only work when the inverter is on. So I am trying to think through the wiring needed to take advantage of the auto switching and power assist features if I put a new inverter/charger in. So do I need to add a sub-panel that would power all the circuits I want powered by the inverter either from batteries or shore power? Do I keep my original panel as a main panel, with a breaker to provide AC power to the inverter, while keeping perhaps dedicated lines for my water heater, fridge, and second ac unit that I don't want powered by the inverter and my batteries? Can anyone point me to a source for a sub-panel suitable for 4 circuits? --Frank

[DaveP]

Hi guys,

You need to put an automatic transfer switch on the incoming 120 volts coming in from the street to a separate breaker box, so it switches between the street line voltage and the inverter. In a (new) separate breaker box panel, you need to have the incoming street-side 120 volt line feeding your inverter’s 120 AC input and any circuits you want to keep off of the inverter. The 120 volt AC output from the inverter needs to be wired back to the panel that has the circuits you want to have the inverter power (or pass through the street line voltage). You will need to run 6 gauge to 10 gauge wire (depending on the length of the run and the amperage) for the incoming AC line to the inverter (from the new box) and the output of the inverter back to the circuit box that powers the circuits you want to run on the inverter. To accomplish these separate 6 to 10 gauge lines, you may have to run electrical conduit on the bottom of your trailer depending on your AS model. It is not for the faint of heart. Spend a lot of time reading up on this before you undertake it or have a professional do it for you. I am in the process of doing my own system right now.

Here is what the basic circuit looks like from Magnum.

Good luck. Keep asking questions.

[cabinetmaker]

I'm guessing you do know Airstream is now providing this on 2017's? My new trailer has only one plug for both. It switches automatic when inverter button is pushed...no more unplug from 120v shore power plug and replug to inverter plug right next to it. New Airstreams have only one plug now for both. Not all plugs are inverter powered and shore powered. They are marked. I have 4 such plugs.

[lewster]

Originally Posted by cabinetmaker

I'm guessing you do know Airstream is now providing this on 2017's? My new trailer has only one plug for both. It switches automatic when inverter button is pushed...no more unplug from 120v shore power plug and replug to inverter plug right next to it. New Airstreams have only one plug now for both. Not all plugs are inverter powered and shore powered. They are marked. I have 4 such plugs.

I too noticed this on a new 26U that I recently upgraded. There is a dedicated 120VAC outlet in proximity to the inverter and it was plugged in to that outlet. ALL WFCO inverters have had this feature (automatic pass thru of 120VAC shore power) but Airstream has left the 120VAC cords taped and not used until now. Still not sure if they are doing this across the board, or just in select models like the 26U.

If the inverter that you choose has an imbedded auto transfer mechanism, than you can easily power it with a dedicated outlet from your 120VAC breaker box and then use the inverter's output to power selected 120VAC outlets that form their own circuit like is done in the 26U.

In this fashion, you get 3,4,or 5 dedicated inverter outlets that will be energized when the inverter is on and you are off-grid, yet these same outlets will be powered from shore power via the inverter's pass-thru feature.

If you want to energize your entire trailer and the 120VAC distribution system, then you will need a new main panel if you wish to use your present panel as the sub-panel. This involves quite a bit of re-wiring, but is not impossible to achieve. I put these systems in Airstreams every day, and usually install only inverter/chargers with the required re-wiring and new panel boards. Also, it is definitely NOT necessary to run any cables outside your Airstream, as I have never had to do this on any of the over 150 Airstream installations that I have done. There is usually ample space for cables inside and below existing cabinetry.

It also depends on the size of your battery bank and the capacity of the inverter that you choose. Using an inverter/charger changes EVERYTHING, and definitely requires a new main/sub-panel arrangement with direct battery connections as well.

[Troutboy]

I think most of the new inverter/chargers have the switching built in. I am in the middle of a solar upgrade and I ripped out the stock AS power equipment.

I am installing an all victron systems since I am doing lithium batteries and I want to be able to run my AC off of one generator Honda EU 2000 if I need or go to the dessert.

I am installing a progressive dynamics dual panel, it has two 30 amp main circuits with subs for each.

Shore power feeds the left side, off that 30 amp main, I have a 30 amp breaker feeding my new 2400 watt inverter, it also feeds the water heater and the fridge when on 110.

The inverter accepts that 110 in, then inverter 110 out feeds the right side of the panel, to a 30 amp main circuit, with subs for all other 110 equipment and outlets, 4 in total. The inverter (victron multi-plus 12/3000) will switch automatic, and when plugged in will allow pass through to the right side of the panel (the sub). I know magnums do this as well.

There are others that have more experience than I do here, but I feel this actually isn't that much of a big deal if you have electrical experience. I am using 10 gage wire from inverter as my runs are short and my service is 30 amp. If you have 50. Amp service you will need 6 awg wire.

I am doing this all in the trailer, not running anything under. There is plenty of room inside and with the right wire, no need for conduit.

I am writing up another post and will post my wiring diagram, or pm me and I will send it.

Good luck, and keep asking, it's how I learned as well.




Thx
Troutboy, aka Rich

[fran&frank]

Thanks everyone for the helpful replies. You confirmed my suspicion about the need for a subpanel after the inverter and the need for some re-wiring, but it sounds manageable to me. If I use my existing panel as one of the panels, can anyone point me to a good option for a new box to use as a main or sub panel? Alternatively I'll also consider a new dual panel like Rich mentioned. --Frank

[DaveP]

Frank,

I used a Square D Homeline 100 Amp 6-Space 12-Circuit Indoor Surface Mount Main Lug. It was the smallest box I could find at Home Depot that had more than two space. I needed more to separate off some circuits from the inverter (like the air conditioning).

[68 Overlander]

Not sure which distribution panel you have now but Progressive Dynamics makes a split 50/30 and a 30/30. Also, Square D and Eaton both make a 70 Amp, 4 position panel you could use as a sub.

[DaveP]

Thanks! Found the 70 amp Square D online (Home Depot). Will be much easier to fit in. Returning the 100 amp box.

[youngpeck]

Originally Posted by Troutboy

I think most of the new inverter/chargers have the switching built in. I am in the middle of a solar upgrade and I ripped out the stock AS power equipment.

I am installing an all victron systems since I am doing lithium batteries and I want to be able to run my AC off of one generator Honda EU 2000 if I need or go to the dessert.

I am installing a progressive dynamics dual panel, it has two 30 amp main circuits with subs for each.

Shore power feeds the left side, off that 30 amp main, I have a 30 amp breaker feeding my new 2400 watt inverter, it also feeds the water heater and the fridge when on 110.

The inverter accepts that 110 in, then inverter 110 out feeds the right side of the panel, to a 30 amp main circuit, with subs for all other 110 equipment and outlets, 4 in total. The inverter (victron multi-plus 12/3000) will switch automatic, and when plugged in will allow pass through to the right side of the panel (the sub). I know magnums do this as well.

There are others that have more experience than I do here, but I feel this actually isn't that much of a big deal if you have electrical experience. I am using 10 gage wire from inverter as my runs are short and my service is 30 amp. If you have 50. Amp service you will need 6 awg wire.

I am doing this all in the trailer, not running anything under. There is plenty of room inside and with the right wire, no need for conduit.

I am writing up another post and will post my wiring diagram, or pm me and I will send it.

Good luck, and keep asking, it's how I learned as well.




Thx
Troutboy, aka Rich

I would appreciate seeing your wiring diagram if you can post it here. Thanks.

[Troutboy]

Frank,

Got your note and will reply later this evening. First day back at work and slammed!

Randy above mentions the split 30/30 from progressive dynamics. You will find that Lewster has also used this with success, he recommended it to me. I purchased the 30/30 and a new 12v distribution panel from Randy at Bestconverter.com.

I'll post the wiring diagram tonight as well
Thx


Thx
Troutboy, aka Rich

[Troutboy]

Okay, here is my wiring diagram for a AS travel trailer (not an international or coach). The wiring can be different for coaches because of the alternator and starter battery. I worked with AMsolar to buy the equipment and develop the wiring diagram. I am not a professional and do not warrant/guarantee the accuracy of this diagram.

I have not updated one aspect of the 110 panels. I plan to remove the refrigerator circuit from the inverter subpanel, to the shore main panel. I will redraw this up.

This document was created in keynote, and I think I have a PowerPoint version as well. PM me if you want the source file, I am happy to send it.

If anybody sees any glaring issues, please let me know. Again, this is a different configuration from a coach setup posted on amsolars website. It also requires that the output D.C. Voltage be modified on the Orion DC/DC converter. Check out a recent post on the amsolar website under install that describes the Orion modification and reasoning for this install. It's under a AS 25 foot install video.

Also, many thanks to Lewster, who helped to guide me through the lithium/solar process, Larry ldbrodsky who recently did an install like this and provided great input, Louis (Switz), who also helped with info and photos of his 23D project.

I hope this helps some others as they contemplate the design of a system.

FINAL NOTE: I do not have wire Gage's/sizes on this drawing yet, as I am in the process of system lay out in the actual trailer and will update t once the exact locations and positions of equipment is known.

And I should have said this is for install of a 2017 FC 23D, and the wiring diagrams for 2017 stock flying cloud were used as basis for AS integration etc.




Thx
Troutboy, aka Rich

[wulfraat]

Will you be adding a cold weather disconnect relay controlled by your 702 monitor? Can the Victron inverter charger also be programmed not to charge below freezing since it is connected to the load side of the bms?

Nice diagram btw!

One other thing that confuses me is that both pre and post Orion converter negative leads are both connected to the same negative 12v system bus.... can't quite get my head around that. I have no doubt it's correct wiring just have a hard time visualizing the energy flow with the pre/post D.C.-D.C. Converter voltages.......

[Troutboy]

I'm not doing the cold disconnects. The main thing is not to charge when cold, so I will make sure the system is shut off in winter and not in use.

My understanding of the Orion is to disconnect the chassis from the TV. So note that the Orion inputs are from the TV plug, then the Orion outputs go to the input side of the battery system, thus separating the two. You can do it oppisite as well, that's the coach setup on amsolar website. Again, I'm not an expert here and this was also the most confusing part to me. The amsolar guys reviewed it after they told me how to do it, and I had them proof it conceptually.

I think I also saw somewhere where Lewster said the Orion serves to make sure you don't fry the BMS, so you ha e to separate the TV systems from the trailer. You can do this on the input side to the BMS or on the output side. Just have to pick one and do it right.

The amsolar guys have been awesome in helping and making sure I understand what to do.

I was questioning whether I could find all the parts and pieces on my own cheaper. And I could in some cases, but with the December sale they had, the price was right in line, and the support is awesome. Even if the cost is slightly more, the support makes up for it in a big way.


Thx
Troutboy, aka Rich

[lsbrodsky]

My install follows the coach drawing on the AM Solar website. I saved a few bucks and a lot of AC rewiring by using the existing AC and DC distribution panels in my 25. I did install a new ATS because of the unreliability of the WFCo used by Airstream and I did install a small subpanel with a 30 amp breaker for the AC feed to inverter/charger. There was no way to use the single 30 main feed in the existing panel because of the bus bar arrangement. Both the ATS and the new breaker are installed in the small locker under the bed, next to the distribution panels. The old converter charger is in place but disconnected.
Larry

[fran&frank]

So if I re-use the current main panel as a sub-panel fed by the inverter, for the main panel can I use a two-space four circuit main lug panel and use on space for a single pole 30 amp breaker to feed the inverter/charger, and the second space with a single pole duplex 20 amp breaker to provide separate circuits for the water heater and 2nd AC unit? In this set up there is know main breaker, but I'm not sure its needed, because there will be one at the shore power source? The alternative is I need a main breaker panel with a 50 amp main, and then the above circuits below it, but these are usually larger panels, and I'm trying to keep this first panel as small as possible while still being safe.--Frank

[DaveP]

Frank,

I wish I had a picture, but that is exactly what I did. I used a small 4 circuit panel for the shore power input to the shore power panel buss bar, and a 30 amp breaker to feed the Magnum input 120v and the another 20 amp breaker to output to the A/C circuit. The 120v output from the Magnum goes to the 30 amp input on the old subpanel (which was the shore input before being repurposed). Easy and minimum cost. If you want more detail, let me know.

[Troutboy]

Progressive dynamics makes a great dual main breaker box that fits in the same space. You have to add a dc box as well, but thy also fits. If you search the forums you can find links to it. I'll try and post pictures when I am back home this weekend. Lewster has posted in this before as well.

[fran&frank]

Thanks Dave and Troutboy. I'm aware of Progressive dynamics dual main breaker panel and may use it, but depending on where I put my batteries, it might make since for me to have the new main panel at a different location than the subpanel fed by the inverter. --Frank

[Mgieselman]

Thanks Troutboy for the detailed diagram, I already have the same setup sans the lithium batteries and was wondering what I needed to upgrade.

One question, in the AM Solar "Signature" wiring diagrams they use 2 or 3 depending on coach vs. travel trailer BP-100 low voltage disconnects. Any ideas if the Blue Solar controller, CCGX and Multiplus will turn off on low voltage?