Fitted Inverter but it shuts off power to the van? (1 Viewer)

[Hoovie]

There is a general reason why it is not advisable to have a transfer switch wired directly into the EHU point which would give you EHU or Inverter on all circuits, and it is nothing to do with low current site supply.
If you did it this way (and you left the inverter switched on) and the site supply tripped, your 240V supply within the van would seamlessly switch to inverter. You would not know this and assume you still on EHU, all the time draining the batteries with your appliances, your battery charger, and everything else you may want to use.

 

[Richard n Ann]

I wired ours with a double pole manual changeover switch so I can decide what we're using. I just switch over to ehu for the hair dryer usually.

 

[autorouter]

The problem with wiring the inverter through the normally closed contacts is if you are on a very low current EHU (I've seen a 3A supply in Italy and 6A is very common) and you want to run a high power load from the inverter you have to go outside to unplug the EHU so you can turn the inverter on.

The alternative way is to wire the EHU side through the normally closed contacts and the inverter through the normally open and to the relay coil. With this arrangement you can turn the inverter on while still connected to the EHU, assuming of course the relay breaks one circuit before it close the other - which it should. You can then run your high power load and the EHU will continue to charge the batteries and run the fridge.

Yes, there's something to be said for wiring that way round. Here's a diagram of that method - it just requires the hookup and inverter labels to be swapped.

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[Hoovie]

Yes, there's something to be said for wiring that way round. Here's a diagram of that method - it just requires the hookup and inverter labels to be swapped.

Yup, quite simply changing what goes into the Primary input and what goes into Secondary. (And if somebody wires like this, the answer to the question of "do I have to turn the inverter off when no using it" is basically always yes if you want to use EHU).

 

[Swiss]

Yes, there's something to be said for wiring that way round. Here's a diagram of that method - it just requires the hookup and inverter labels to be swapped.

Looks OK on paper but you have to be very careful if you are using a relay in this way, if you check the spec you will almost certainly find that the contact rating of the NC contacts is very low, typically 3A ish compared to the NC contact rating which is typically rated at around 12 - 25A ish. So I have actually used a 3 pole relay powered when the inverter is switched on to drive 2 double contactors to over come this issue, but the theory is exactly the same though. The Victron power switch has a light on it and clearly visable and only used when required, haven't had any problems accidentally leaving it on.

 

[Hoovie]

Looks OK on paper but you have to be very careful if you are using a relay in this way, if you check the spec you will almost certainly find that the contact rating of the NC contacts is very low, typically 3A ish compared to the NC contact rating which is typically rated at around 12 - 25A ish. So I have actually used a 3 pole relay powered when the inverter is switched on to drive 2 double contactors to over come this issue, but the theory is exactly the same though. The Victron power switch has a light on it and clearly visable and only used when required, haven't had any problems accidentally leaving it on.

You need to edit the above. Quoted "NC" twice and you meant to put "NO" in one of them .


Details matter when it comes to this kind of topic

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[Swiss]

Apologies, you are correct.

NC contacts are usually low rated compared to the NO contacts.

 

[JockandRita]

Yes JockandRita Including your Fridge and Alde but not battery charger, the fridge can be handy but you have to remember if you leave the inverter on for a long period, the Alde would need a lot of solar to be of any use so best keep that switched off

Although available for use via the inverter, it's not for us Martin. See next reply.....

or be very aware to switch them off if possibility of inverter coming on.

That's us, ie, fridge/freezer and Alde to gas first. I have even labelled the inverter remote switch to that effect, ie, DO NOT USE IF ON EHU. This helps to negate draining the batteries through misunderstanding (her) or forgetfulness, (me).

as I'm not sure if a kettle would be too much to expect to work ??

If only the two of you normally Dave, the 800 - 900 watt kettles work a treat off the inverter, and probably draw less than your toaster.

Cheers,

Jock.

 

[funflair]

Although available for use via the inverter, it's not for us Martin. See next reply.....


That's us, ie, fridge/freezer and Alde to gas first. I have even labelled the inverter remote switch to that effect, ie, DO NOT USE IF ON EHU. This helps to negate draining the batteries through misunderstanding (her) or forgetfulness, (me).


If only the two of you normally Dave, the 800 - 900 watt kettles work a treat off the inverter, and probably draw less than your toaster.

Cheers,

Jock.

That's teamwork Jock

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[MisterB]

If only the two of you normally Dave, the 800 - 900 watt kettles work a treat off the inverter, and probably draw less than your toaster.

Cheers,

Jock.

perfect, will start to play when we get back home and try to get it all sorted.

 

[Hoovie]

Although available for use via the inverter, it's not for us Martin. See next reply.....


That's us, ie, fridge/freezer and Alde to gas first. I have even labelled the inverter remote switch to that effect, ie, DO NOT USE IF ON EHU. This helps to negate draining the batteries through misunderstanding (her) or forgetfulness, (me).


If only the two of you normally Dave, the 800 - 900 watt kettles work a treat off the inverter, and probably draw less than your toaster.

Cheers,

Jock.

Ref Kettles and Microwaves, in the US, a lot of people tend to use a Microwave to boil water. Could be handy to cut down on applicances? not sure if it is power-efficient though.
I don't carry an electric kettle in my Motorhome but I do have an Induction Hob and I use that for electric water boiling and it is just as efficient as a dedicated electric kettle (another way to cut down on different applicances )

 

[JockandRita]

I do have an Induction Hob and I use that for electric water boiling and it is just as efficient as a dedicated electric kettle (another way to cut down on different applicances )

Yep, got one of those as well, ranging from 200 Watts to 2000 Watts.............but not used it off the inverter yet. I might have a play with that idea Hoovie, just out of curiosity.

Cheers,

Jock.

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[Hoovie]

Yep, got one of those as well, ranging from 200 Watts to 2000 Watts.............but not used it off the inverter yet. I might have a play with that idea Hoovie, just out of curiosity.

Cheers,

Jock.

remember these cycle power like microwaves usually so your 1000W may not be big enough? the 2000W I used in my last camper between 1000-2000W cycled upto full power, when under 1000W, it would cycle on/off upto 1000W.

 

[MisterB]

An Automatic Transfer Switch would involve the same wiring as the manual one you posted a link of above, yes. So if you decided you are able to fit a Manual One, yes, you would be able to fit an automatic one.
Obviously the innards in the box are different, but that is unimportant, and you can site it somewhere out the way, so auto is much more convenient, but they both do the same job.

cost wise, they all vary in price. The ones I make start from around £40 but as features increase the price increases accordingly. You have have them plug and play (for example, I do one for a Hymer that just plugs directly into the WAGO AC socket on the other side of the EHU external socket, so it takes nearly a minute to install) or hard-wired if you want to connect into a consumer unit, or have multiple outlets. Yiu can incorporate remote control so the inverter will only operare if the battery is at a certain state of charge.


A key feature is WHERE you fit it and understanding the consequences .... a typical UK Site Hookup is 16A - that is a lot of power in relative terms inside a motorhome. when you are hooked up you might use a microwave, a toaster and a kettle all at the same time. Ignoring the battery question intially, your inverter is likely to be only able to handle one of those at a time, so while it is a relatively easy fit, there is still a need of HOW and WHEN to use. once that clicks, brilliantly convenient to just be able to plug something in to whatever socket is best and just have it working.
When I bought my new (to me) Motorhome last year, I had no doubt I would be fitting a Victron Multiplus (which has an ATS built in) in it, as it was so useful in the campervan I had built. just a mattery of deciding WHICH Multiplus.
Bringing back the batteries ... you have already had comments about the battery sizing. this is the other factor and there are some things you just should not run on an inverter - such as room heating, as it will just suck the power out of any battery setup, or the battery charger (just end up in a loop using the battery to charge the battery) so ideally want a EHU-Only circuit for those, or be very aware to switch them off if possibility of inverter coming on.

End of the day, an ATS of some sort is (IMO) a great little feature to have. This is a Consumer Unit I built with an integral ATS and Remote Control input

hi, can you advise me on a suitable relay please? i have spare places on the current consumer unit in the van and could easily fit a relay in there or preferably in a separate enclosure and then wire up the EHU suppy and the Inverter supply to either side of the relay - the inverter is a 2000w pure sine wave (4000w peak power)

i would also look at ensuring the heater/water heater only operates when on 240v by only allowing that circuit to become 'live when on EHU as you advised

CU+ATS+Remote by David, on Flickr
One half is EHU only, one half is Auto-Select EHU/Inverter, all in the one unit for a self-build camper installation.