Linking an inverter to the van’s 230V internal sockets (2 Viewers)

[ManTheVan]

Our MH has 230V internal sockets that go live on the rare occasion that we connect to EHU.

As part of the electrics upgrade to LiFePO4, I also fitted a pure sine inverter at the same time, which we use to charge the electric bike batteries. However, the inverter is stand-alone and we plug the bike chargers directly into the inverter.

I know that there must be a way of retro-wiring the inverter output into the MH’s existing 230V internal circuit, and presume this must involve some sort of relay to prevent feedback into the Sterling mains unit.

I would certainly ask a qualified sparky to do the job for me, but am interested to find out what would be involved if I decided to go ahead.

Has anyone else retro-wired something similar?

 

[pacman]

Our MH has 230V internal sockets that go live on the rare occasion that we connect to EHU.

As part of the electrics upgrade to LiFePO4, I also fitted a pure sine inverter at the same time, which we use to charge the electric bike batteries. However, the inverter is stand-alone and we plug the bike chargers directly into the inverter.

I know that there must be a way of retro-wiring the inverter output into the MH’s existing 230V internal circuit, and presume this must involve some sort of relay to prevent feedback into the Sterling mains unit.

I would certainly ask a qualified sparky to do the job for me, but am interested to find out what would be involved if I decided to go ahead.

Has anyone else retro-wired something similar?

Did this on my Adria a couple of years ago after finding a you tube video.
Both the inverter and shore supply are fed into a 230v relay which outputs to your sockets circuits. The relay will keep the inverter isolated and connect shore supply to the sockets circuit. If shore supply is not available the relay will supply the inverter supply to the sockets circuit.
I got the original info off LeisureBit on you tube when he did a series of videos on Lithium Battery installation and you could plough through those to get all the info required for the relay described above.

I've added a link below to a video he has done where he discusses different options for supplying 240v to your sockets from you inverter. May be worth a watch as a starting point.

 

[Cavs]

I've done it following guidance on here. In addition, you need to be sure to rewire anything necessary to avoid the inverter trying to run your fridge, boiler and battery charger. In my case, that involved a slight reallocation of supply from the circuit breakers and a new cable to supply mains to the fridge.

 

[autorouter]

If you only want the sockets to run from the inverter, then it's easier. You can use a simple manual changeover switch, or use a relay that changes over automatically, as in that video. If you are only rarely using EHU, the manual option might be suitable.

For a manual switch, you can use the type that is used for switching between a generator and a grid supply. You'll need a box to mount it in also. Like this one:

https://www.amazon.co.uk/Heschen-Universal-Selector-Changeover-Terminals/dp/B097T3DXV8?tag=mhf04-21

Basically you cut the wire from the consumer unit to the mains sockets, and use the switch to select between the EHU supply and the inverter supply. Only the live and neutral are switched. The earth wires are just all connected together permanently.

That's probably all you need to know if you're getting a sparky to do the wiring. There are possible minor problems if the sockets are supplied by more than one trip switch, but that's unlikely in most motorhomes.

 

[Cush]

If you only want the sockets to run from the inverter, then it's easier. You can use a simple manual changeover switch, or use a relay that changes over automatically, as in that video. If you are only rarely using EHU, the manual option might be suitable.

For a manual switch, you can use the type that is used for switching between a generator and a grid supply. You'll need a box to mount it in also. Like this one:

https://www.amazon.co.uk/Heschen-Universal-Selector-Changeover-Terminals/dp/B097T3DXV8?tag=mhf04-21

Basically you cut the wire from the consumer unit to the mains sockets, and use the switch to select between the EHU supply and the inverter supply. Only the live and neutral are switched. The earth wires are just all connected together permanently.

That's probably all you need to know if you're getting a sparky to do the wiring. There are possible minor problems if the sockets are supplied by more than one trip switch, but that's unlikely in most motorhomes.

This is what I did with autorouter ‘s help (although it’s a power station and not an inverter). I took the ends from the ehu external plug that normally runs to the consumer unit and ran them in to a break before make switch on the output side. Then new length from ehu socket to input along with a cable with 13 amp plug from the power bank. Works well. Just need to make sure that the 240 switches for the fridge, boiler etc are off. I can also disable my onboard charger (which is ) and plug in a Victron ip65 when necessary. All good

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[ManTheVan]

Thanks all. With the video I might even attempt the job myself, as I’ve done all the other 12V stuff.

Really helpful!

 

[EuroTrotters]

Ive done this 4 times.

This system i hace is vía/EHU/Generator (we used to use it on the move *)/engine/solar. Automatically switches between sources.

As we no longer use a generator, as we have 480w solar and victron B2B. I would do it differently .

I would use a victron inverter : charger similar to the one we have, but make use of the dual output. That is, all Mains supplied with EHU and no power to fridge / electric heating etc when on battery .

I will try and find my latest posts.

But I would do it differently next time, as I said

 

[MisterB]

Our MH has 230V internal sockets that go live on the rare occasion that we connect to EHU.

As part of the electrics upgrade to LiFePO4, I also fitted a pure sine inverter at the same time, which we use to charge the electric bike batteries. However, the inverter is stand-alone and we plug the bike chargers directly into the inverter.

I know that there must be a way of retro-wiring the inverter output into the MH’s existing 230V internal circuit, and presume this must involve some sort of relay to prevent feedback into the Sterling mains unit.

I would certainly ask a qualified sparky to do the job for me, but am interested to find out what would be involved if I decided to go ahead.

Has anyone else retro-wired something similar?

Look at the Renogy inverters, they do what you are trying to do. Mine feeds about four sockets via the inverter and then when connected via EHU, the pass through facility makes those sockets (and the others in the van) live via 240v. Works perfectly and easy to do ...
You can see an example on you tube of the 2000w inverter, but we went for a 3000w inverter to power the microwave and kettle at the same time

 

[ManTheVan]

Thank you. I’ll look it up.

 

[TrudeandDall]

If you only want the sockets to run from the inverter, then it's easier. You can use a simple manual changeover switch, or use a relay that changes over automatically, as in that video. If you are only rarely using EHU, the manual option might be suitable.

For a manual switch, you can use the type that is used for switching between a generator and a grid supply. You'll need a box to mount it in also. Like this one:

https://www.amazon.co.uk/Heschen-Universal-Selector-Changeover-Terminals/dp/B097T3DXV8?tag=mhf04-21

Basically you cut the wire from the consumer unit to the mains sockets, and use the switch to select between the EHU supply and the inverter supply. Only the live and neutral are switched. The earth wires are just all connected together permanently.

That's probably all you need to know if you're getting a sparky to do the wiring. There are possible minor problems if the sockets are supplied by more than one trip switch, but that's unlikely in most motorhomes.

I like this idea as I only want the sockets to run from the inverter and definitely do not want to have to manage the supply to the truma and leisure battery charger when the inverter is on
I guess that a relay on the socket output cable instead of the manual switch would work, but providing auto switching.

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[Tombola]

Another vote for the renogy inverter

Just plug and forget .

 

[Moto GBR]

Hi All,

I am looking for some help also. I have looked through various posts and videos and a little confused.
I am looking to use me Renogy Inverter 2000w to power my sockets in the MH if and when needed. I have a couple of questions if anyone can shed some light on this.

I am possibly looking to put a change over relay as per the video.

1. How do I identify the socket only cable from the Sargent EC600 unit to tap into?
2. How would I wire this up?
3. Can I use the Renogy without a change over relay?
4. Is the EHU cable orange inside the MH?

TA for any advise

Steve

 

[WESTY66]

Look at the Renogy inverters, they do what you are trying to do. Mine feeds about four sockets via the inverter and then when connected via EHU, the pass through facility makes those sockets (and the others in the van) live via 240v. Works perfectly and easy to do ...
You can see an example on you tube of the 2000w inverter, but we went for a 3000w inverter to power the microwave and kettle at the same time

Another vote for the renogy inverter

Just plug and forget .

Keep going, I have one in the classified ads

 

[TrudeandDall]

I like this idea as I only want the sockets to run from the inverter and definitely do not want to have to manage the supply to the truma and leisure battery charger when the inverter is on
I guess that a relay on the socket output cable instead of the manual switch would work, but providing auto switching.

All completed, with ease, the only difference to the video is that as we are mainly off-grid, I made our inverter circuit the NC and the EHU the NO switch over circuit.
A real worthwhile upgrade and all is working as expected.
Thanks Autorouter for the idea of just connecting the sockets, rather than working around managing the charger and Truma.

 

[MisterB]

Hi All,

I am looking for some help also. I have looked through various posts and videos and a little confused.
I am looking to use me Renogy Inverter 2000w to power my sockets in the MH if and when needed. I have a couple of questions if anyone can shed some light on this.

I am possibly looking to put a change over relay as per the video.

1. How do I identify the socket only cable from the Sargent EC600 unit to tap into?
2. How would I wire this up?
3. Can I use the Renogy without a change over relay?
4. Is the EHU cable orange inside the MH?

TA for any advise

Steve

With mine, I opened the 240v fuse box/ consumer unit and traced which wires fed into which circuit breakers. Then instead of them going into the consumer unit, I wired those circuits/sockets directly to the inverter, via standard 3 pin fused plugs.

I then ran a cable from the consumer unit (via a now unused circuit breaker) to feed the inverter. Don't forget you also need connections from the leisure battery to the inverter.

The Renogy inverter I bought has a built in pass through

I didn't touch the main incoming cable from the EHU to the consumer unit for that part of the project but did add a surge protection device between the incoming supply and the consumer unit.

Of course everything needs to be done correctly and safely but it isn't difficult, just plan it all out on paper.

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[mgibbons]

Our MH has 230V internal sockets that go live on the rare occasion that we connect to EHU.

As part of the electrics upgrade to LiFePO4, I also fitted a pure sine inverter at the same time, which we use to charge the electric bike batteries. However, the inverter is stand-alone and we plug the bike chargers directly into the inverter.

I know that there must be a way of retro-wiring the inverter output into the MH’s existing 230V internal circuit, and presume this must involve some sort of relay to prevent feedback into the Sterling mains unit.

I would certainly ask a qualified sparky to do the job for me, but am interested to find out what would be involved if I decided to go ahead.

Has anyone else retro-wired something similar?

I came across this the other day which seems aimed at exactly the use case you talk about and send very simple to install - https://www.roadpro.co.uk/product/02i-inverters/cliveway-priority-switch-with-rcd-c7679a/C7679A

 

[Moto GBR]

Would this method eliminate the power to the charger, fridge etc?

TA Steve

 

[Speve]

A victron Multiplus inverter/charger does it all we have a 2000ah and also can work with mains if supply is low on amps

 

[mgibbons]

Would this method eliminate the power to the charger, fridge etc?

TA Steve

Very little changes from a standard setup other than now the power to the 240v sockets comes either from the inverter or EHU with that box driving automatically between them. Look at the instructions and you can see where it is placed i.e. just before the 240v sockets but after everything else.

 

[autorouter]

Very little changes from a standard setup other than now the power to the 240v sockets comes either from the inverter or EHU with that box driving automatically between them. Look at the instructions and you can see where it is placed i.e. just before the 240v sockets but after everything else.

The instructions are misleading if you are not electrically knowledgeable. They show an extremely dated system that is never used nowadays in a motorhome or caravan. I have told Clive Mott about this some time ago, but he seems not to have corrected the diagrams.

Briefly, the diagrams show a system wired like a UK domestic consumer unit, with single pole MCBs and a common neutral block. These are not used in motorhomes and caravans nowadays, because all MCBs are double pole, with switched neutrals not a common neutral.

The Cliveway device itself looks OK, if it was wired into the motorhome system properly.

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[HugoBNB]

If you are on a campsite with say 6A supply, can you run both the inverter and the hook up to share the load to the appliances?

 

[autorouter]

If you are on a campsite with say 6A supply, can you run both the inverter and the hook up to share the load to the appliances?

In general, no. The inverter mains and the grid mains are not synchronised, so can't be combined together to share the load. However a few inverters can synchronise themselves to the mains and combine together to share a load. The Victron Multiplus Inverter/charger is the best, most well-known example, but I believe Buttner and MasterVolt do similar devices.

 

[autorouter]

3. Can I use the Renogy without a change over relay?

The Renogy Inverter 2000 has a built-in changeover relay, so it's a lot easier to wire in. No extra changeover relay is required. Obviously it has a 12V DC input, and a 240V AC output, like other inverters. It also has a 240V mains input.

When the 240V mains input becomes live, the relay automatically switches the inverter 240V output so that it comes directly from the 240V mains input instead of from the inverter electronics. This means the inverter electronics doesn't draw any power from the batteries while the mains input is available, which is usually exactly what you want.

When the mains input is unplugged, the relay switches the inverter 240V output so that it runs from the inverter electronics, taking power from the 12V battery. Again, that is usually exactly what you want.

Of course if you don't wire anything to the 240V mains input, the inverter will only supply power from the inverter electronics, taking power from the batteries, just like a standard inverter.

4. Is the EHU cable orange inside the MH?

Usually not, that's only required for some UK campsites to make it visible on grass when the ride-on lawnmover is on the prowl. In my Hymer, mains wires are white and 12V wires are black, more or less, but the colours vary in other brands.

1. How do I identify the socket only cable from the Sargent EC600 unit to tap into?

The trip switches will be one RCD (with a test button) and one or more MCBs (no test button). First find which MCB switches off the sockets. Then look at the wires coming out of the MCB to see if it looks like the wire to the sockets. If there's more than one wire from the MCB them you might have to use trial and error to disconnect them one by one to see which one it is.

2. How would I wire this up?

Disconnect the wire to the sockets from the MCB. Run a wire from the MCB to the 240V mains input of the Inverter. Then run a wire from the 240V mains output (use a suitable plug) and connect it to the wire you previously disconnected from the MCB. Use a suitable junction box to connect the wires. If you want, you could use a 13A plug and socket: a socket on the wire from the inverter, and a plug on the wire to the motorhome sockets.

Obviously make sure the mains hookup is unplugged and the inverter is switched off before doing any work on the mains. If you're not sure, ask an electrician to do it.

 

[Moto GBR]

Would I be right in thinking that this is the way the wiring would work for the inverter to run the sockets?

TA Steve

 

[MichaelT]

I put a 3 way switch in as in post #4, joined the input to the RCB to wire up to switch where the input from inverter also connects then cable back out to the input to RCB to power the sockets. We rarely use EHU so switch left on inverter setting mostly, only problem is the fridge runs off the same RCB so may need to find if I can separate that at some point but for now if I'm using the inverter for any length of time such as using slow cooker I manually turn fridge to gas. I did a test the other day and with good sun the solar panels gave enough power to run inverter with fridge on and still put 3 or 4 amps into batteries so I can run fridge for free if I want.

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[Cush]

4. Is the EHU cable orange inside the MH?

I can help with this! In my autotrail it’s orange. Have a look at what comes out of the ehu socket on the side of the van.

(I don’t have an inverter, but a powerbank wired in to the Sargent unit via a rotary selector break before make switch. Fortunately I can manually turn the onboard charger, fridge etc off if I need to. )

 

[MisterB]

Would I be right in thinking that this is the way the wiring would work for the inverter to run the sockets?

TA Steve



View attachment 927742

I have some of my sockets fed by the inverter so don't have the junction box, so only some sockets for specific appliances become live when on Inverter but they all become live when on EHU.

Others with far more knowledge than me will comment re your diagram ..

 

[autorouter]

Would I be right in thinking that this is the way the wiring would work for the inverter to run the sockets?

I was thinking more like this. For an inverter like the Renogy with a built-in transfer switch.

 

[MichaelT]

Roughly this is how I did mine

 

[Moto GBR]

In the junction box would this have the wires to the socket, wires from inverter and wires to the MCB Socket outlet so this would make them live when hooked up to EHU?

I am a little confuse on how to pick up the socket wires to use from inverter and EHU.

TA Steve

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