Inverters

[tonyfletcher]

Hi Everyone,

Is there a method, and I suppose what I am asking is not DIY, of using the inverter to power all the sockets in the Motorhome whilst still allowing the mains input to be used (Obviously not at the same time)?

Is anyone aware of companies that can do this?

Cheers Tony

[sshortcircuit]

A very simply way to do it is to plug the output from the inverter into your hookup socket by using a simple extension This would ensure you cannot have both on at the same time.

 

 

[tonyfletcher]

What a simple solution, why didn't I think of it ????

Many Thanks

T

[lennyhb]

Fairy easy to wire a contactor or or power relay into the circuit so when you plug the hook up in the relay/contactor pulls in swapping the circuits over.

[vindiboy]

If you try and run all your van sockets etc off the Inverter ,don't forget that the Fridge will also run off it too, and if it an auto self seek fridge you will have flat batteries in no time, How do you intend to keep your Batteries charged/ I fitted a separate  string of sockets  in my van connected to the Inverter [ 2000 watts ] which I can switch on at will.Connecting through your Hook Up point will affect the Earthing on your van as the Hook Up  Earths via  the Hook UP Bollard and you won't be connected to it .

[sshortcircuit]

vindiboy - 2012-04-26 12:42 PM

 

Connecting through your Hook Up point will affect the Earthing on your van as the Hook Up  Earths via  the Hook UP Bollard and you won't be connected to it .

 

But the inverter is the source and not the HU so what's the problem?

[vindiboy]

sshortcircuit - 2012-04-26 12:52 PM

vindiboy - 2012-04-26 12:42 PMConnecting through your Hook Up point will affect the Earthing on your van as the Hook Up  Earths via  the Hook UP Bollard and you won't be connected to it .

But the inverter is the source and not the HU so what's the problem?[/quote

 The Inverter is not Earthed, you need a  Copper spike driven deep into the ground  and a cable to this  to the Earth point on the Inverter, some Earth their  Inverters to the van Chassis but this does not properly Earth the Van, rubber tyres etc, some don't even bother to Earth the Inverter at all, their choice, you are a long time dead as they say.

[hallii]

I am also interested in the earthing of inverters, I don't earth mine but everything I use off it is double insulated anyway so should be safe. I assume the vehicle chassis, being -ive DC also acts as a "floating earth" for 230v AC?

 

I also assume that since the AC output is electronically isolated there is no need for a proper spike in the ground type earth?

 

This has made me curious though, I will measure what voltage there is from the AC output to vehicle ground.

 

H

 

 

[sshortcircuit]

vindiboy - 2012-04-26 1:17 PM

 

sshortcircuit - 2012-04-26 12:52 PM

vindiboy - 2012-04-26 12:42 PMConnecting through your Hook Up point will affect the Earthing on your van as the Hook Up  Earths via  the Hook UP Bollard and you won't be connected to it .

But the inverter is the source and not the HU so what's the problem?[/quote

 The Inverter is not Earthed, you need a  Copper spike driven deep into the ground  and a cable to this  to the Earth point on the Inverter, some Earth their  Inverters to the van Chassis but this does not properly Earth the Van, rubber tyres etc, some don't even bother to Earth the Inverter at all, their choice, you are a long time dead as they say.

 

The live output from the inverter has to find a return path to the inverter normally via the neutral. A fault in the wiring has to find its way back to the inverters earth via the wiring or the chassis. All these circuits are contained within the motorhome so connecting this huge copper spike is going to achieve what? The inverter has no connection to terra firma so connecting to the EHU achieves nothing.

 

 

[lennyhb]

vindiboy - 2012-04-26 12:42 PM

 

If you try and run all your van sockets etc off the Inverter ,don't forget that the Fridge will also run off it too, and if it an auto self seek fridge you will have flat batteries in no time, How do you intend to keep your Batteries charged/ I fitted a separate  string of sockets  in my van connected to the Inverter [ 2000 watts ] which I can switch on at will.Connecting through your Hook Up point will affect the Earthing on your van as the Hook Up  Earths via  the Hook UP Bollard and you won't be connected to it .

 

Easy enough to switch the fridge to manual in fact I never run mine on auto.

Inverter does not need a separate earth it is an isolated supply and if wiring to the mains input you will have your RCD in line.

[vindiboy]

sshortcircuit - 2012-04-26 1:39 PM

vindiboy - 2012-04-26 1:17 PM

sshortcircuit - 2012-04-26 12:52 PM

vindiboy - 2012-04-26 12:42 PMConnecting through your Hook Up point will affect the Earthing on your van as the Hook Up  Earths via  the Hook UP Bollard and you won't be connected to it .

But the inverter is the source and not the HU so what's the problem?[/quote

 The Inverter is not Earthed, you need a  Copper spike driven deep into the ground  and a cable to this  to the Earth point on the Inverter, some Earth their  Inverters to the van Chassis but this does not properly Earth the Van, rubber tyres etc, some don't even bother to Earth the Inverter at all, their choice, you are a long time dead as they say.

The live output from the inverter has to find a return path to the inverter normally via the neutral. A fault in the wiring has to find its way back to the inverters earth via the wiring or the chassis. All these circuits are contained within the motorhome so connecting this huge copper spike is going to achieve what? The inverter has no connection to terra firma so connecting to the EHU achieves nothing.

 

My 2000 watt Inverter has a dedicated Earth Terminal, this is connected by Cable which I in turn connect to an Earth rod which I drive into the ground at the side of my van, you do whatever you want.

[sshortcircuit]

vindiboy - 2012-04-26 3:05 PM

sshortcircuit - 2012-04-26 1:39 PM

vindiboy - 2012-04-26 1:17 PM

sshortcircuit - 2012-04-26 12:52 PM

vindiboy - 2012-04-26 12:42 PMConnecting through your Hook Up point will affect the Earthing on your van as the Hook Up  Earths via  the Hook UP Bollard and you won't be connected to it .

But the inverter is the source and not the HU so what's the problem?[/quote

 The Inverter is not Earthed, you need a  Copper spike driven deep into the ground  and a cable to this  to the Earth point on the Inverter, some Earth their  Inverters to the van Chassis but this does not properly Earth the Van, rubber tyres etc, some don't even bother to Earth the Inverter at all, their choice, you are a long time dead as they say.

The live output from the inverter has to find a return path to the inverter normally via the neutral. A fault in the wiring has to find its way back to the inverters earth via the wiring or the chassis. All these circuits are contained within the motorhome so connecting this huge copper spike is going to achieve what? The inverter has no connection to terra firma so connecting to the EHU achieves nothing.

 

My 2000 watt Inverter has a dedicated Earth Terminal, this is connected by Cable which I in turn connect to an Earth rod which I drive into the ground at the side of my van, you do whatever you want.

I will try and reply in a way you may understand. The mains supply to the EHU will be connected to a local transformer. This transformer will have 3 windings. One end of each winding is connected to a common point. The common point is taken to terra firma to provide an earth and is also used as the neutral point. Now to receive a shock you must touch the live side of the coil and either tera firma or neutral so there is a complete circuit.. Now your inverter has an earth point but is only related to the inverter and is floating if not connected. If you touch the live output from your inverter it needs a return path but where?. If you connect the inverters earth to the MHs EHU input then the internal wiring will provide a return path but using an earth spike is only of any use if you intend to use appliances outwith the MH which would not be normal use.

[Brian Kirby]

sshortcircuit - 2012-04-26 10:53 AM

 

A very simply way to do it is to plug the output from the inverter into your hookup socket by using a simple extension This would ensure you cannot have both on at the same time.

I think there may be another snag (fridge apart) to this simplicity. Most van systems also liven the habitation, and some the starter, battery charger when connected to mains. So, quite a bit of the output from the inverter will be diverted to trying to replace the current the inverter is drawing from the battery, which is a long winded way of saying perpetual motion has not yet been invented! :-)

 

What is really needed is a relay to ensure that when no mains supply is present only the power sockets run from the inverter, leaving the fridge and battery charger completely isolated. When mains is present, the relay switches to give normal, full, mains supply.

 

There should also be a switch in the inverter 12V supply to ensure the inverter is only in circuit when wanted. They have quite a significant quiescent consumption, so it would be unwise to leave it permanently on when not actually required. For this reason, a prominent warning light indicating the inverter supply is live would be wise.

 

However, unless you have a large van with lot of 230V outlets, I think it may be a better, and almost certainly simpler and cheaper, plan to simply wire a single (or twin), additional, socket permanently to the inverter. Don't forget that a 1 Amp current taken from the inverter at 230V (230W) equates to a bit over 20 Amps drawn from your battery at 12V. If you want to use the inverter for anything of higher consumption, or for extended periods of time, you will need a large battery bank to maintain the 12V supply, and that in turn will require longer to re-charge whether by driving, solar, or when on EHU. There is no free lunch!

[sshortcircuit]

Point well made Brian. The suggestion was based on my own experience with the Sargent unit that requires manual switching on of the charger and manual switching at controls to use/charge starter battery, which is an excellent facility.

 

I have a 150 Watt inverter that supplies a single socket that is used for tv and is operated by a switch and relay. In addition a 2000 Watt inverter supplies a single socket. The incoming cable from the hook up was cut and a plug and socket fitted with the plug attached to the Sergant. This allows me the option to supply the one socket or the complete MH from the inverter. Very rarely is it used to supply complete MH. The large inverter is locate under the bed which is lifted up to gain access and left up when on in order not to forget to switch off. I will give you one guess what the large inverter has been used for.