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Inverter switching

Posted: 09 Jun 2014, 18:09
by pfield69
A quick question for any electrical experts out there.

I want to add an inverter to my camper. Can I leave the unit on and switch the supply on or off?

Is there an alternative to using a dead man lead to connect this to a wall socket?

Any recommendations of a good inverter, I can see lots of dodgy one on Ebay

Re: Inverter switching

Posted: 10 Jun 2014, 07:49
by ghost123uk
pfield69 wrote:I want to add an inverter to my camper. Can I leave the unit on and switch the supply on or off?

Yes :ok

pfield69 wrote:Is there an alternative to using a dead man lead to connect this to a wall socket?

What is that ?

pfield69 wrote:Any recommendations of a good inverter, I can see lots of dodgy one on Ebay

Don't buy a Chinese one ! Other than that you pay your money and take your choice ;) I would try and get one with a reputable brand name on it (C-Tech, Sterling, Waeco, Ring, Durite etc)

Re: Inverter switching

Posted: 10 Jun 2014, 08:11
by MidLifeCrisis
Can we ask what you are going to use the inverter for?
I assume that we are talking about a 12v(DC)-to-240v(AC) inverter?
Because...
a) There aren't many things that 'really' need 240V (there is usually an option for a lower voltage)
b) If it does actually need 240v (i.e. heater, hairdryer etc) then the 12V battery usually can't actually supply enough power

Re: Inverter switching

Posted: 10 Jun 2014, 10:50
by AdrianC
ghost123uk wrote:
pfield69 wrote:Is there an alternative to using a dead man lead to connect this to a wall socket?
What is that ?
At a guess, if the van' got multiple 240v sockets and lights, the inverter would have a normal mains plug on the output, which'd then be plugged into one socket and power the whole ring up whilst the hook-up's disconnected.

If I'm right, then it sounds very well named.

Re: Inverter switching

Posted: 10 Jun 2014, 11:14
by CJH
AdrianC wrote:
ghost123uk wrote:
pfield69 wrote:Is there an alternative to using a dead man lead to connect this to a wall socket?
What is that ?
At a guess, if the van' got multiple 240v sockets and lights, the inverter would have a normal mains plug on the output, which'd then be plugged into one socket and power the whole ring up whilst the hook-up's disconnected.

If I'm right, then it sounds very well named.

I put a plug on the end of the supply for my sockets, and connected a socket box to my fusebox. In normal operation the plug is in the socket box, but when there's no hook-up I can move the plug to my inverter so that all the sockets inside the van get the output of the inverter. This is much safer than a cable with a plug on each end, which is what that 'dead man lead' sounds like.

Image

Re: Inverter switching

Posted: 10 Jun 2014, 12:35
by ghost123uk
AdrianC wrote:
ghost123uk wrote:
pfield69 wrote:Is there an alternative to using a dead man lead to connect this to a wall socket?
What is that ?
At a guess, if the van' got multiple 240v sockets and lights, the inverter would have a normal mains plug on the output, which'd then be plugged into one socket and power the whole ring up whilst the hook-up's disconnected.

If I'm right, then it sounds very well named.

Too right :shock: :run

Re: Inverter switching

Posted: 10 Jun 2014, 21:15
by pfield69
Yep, you've all guessed right - plug to plug, I use the same setup when we have power cuts to hook up my generator to the house ring remembering to turn off the main switch. We used it all the time on MoD Exercise :shock:

I only have a few mains powered units - 3 way fridge, battery charger & 1 socket. The socket will be used with random electronic equipment, low power hair dryer and battery charger (cameras & AA batteries etc)

I could do with a mains powered break before make relay so that if site mains is added the inverter is automatically disconnected. I like CJH's idea.

Another question is should I earth the chassis and have rcbo?

For information, my battery can supply 45a at a voltage of 11v.

Re: Inverter switching

Posted: 11 Jun 2014, 07:15
by ghost123uk
pfield69 wrote:Yep, you've all guessed right - plug to plug, I use the same setup when we have power cuts to hook up my generator to the house ring remembering to turn off the main switch. We used it all the time on MoD Exercise :shock:

I note you used the "shock" emoticon there :shock:

pfield69 wrote:I only have a few mains powered units - 3 way fridge, battery charger & 1 socket. The socket will be used with random electronic equipment, low power hair dryer and battery charger (cameras & AA batteries etc)

If you have a 3 way fridge, why on earth (meant in a friendly way) are you considering running it off a 12 volt to 240 volt inverter. That really does not compute ;) Anyway, running it of the battery, and a bit worse off the inverter will hammer your little 45A battery in about an hour (or less) as will the hair dryer, even if it is "low power" ;) Run the fridge off gas ;)

pfield69 wrote:Another question is should I earth the chassis and have rcbo?

Yes and Yes ;)

pfield69 wrote:For information, my battery can supply 45a at a voltage of 11v.

Why only 11 Volts ?

Also, have a read of this thread = https://club8090.co.uk/forum/viewtopic.php?f=39&t=100632" onclick="window.open(this.href);return false;

Re: Inverter switching

Posted: 11 Jun 2014, 08:12
by pfield69
I badly wrote my last reply.

I meant I only have 3 items that use mains. The 3way fridge will be run of main or gas unless moving when the 12v will be used. It pulls just over 10A on 12v so, as you say will kill any battery.

My battery is actually 120ahr battery but if I pull 45Amps the voltage drops to 11v, meaning a 500w inverter is the biggest that can be used.

Thanks for letting me know about earthing. Others have told be not to but I see a big hazard if not earthed.

Re: Inverter switching

Posted: 11 Jun 2014, 08:31
by ghost123uk
Ah, right, understood :)

Re earthing the mains to the body. As far as I see it, the RCD would not work (protecting you) unless it was earthed. But, as this is a fairly critical thing, it might be prudent to double check this ;) Anyone like to confirm ? (I cannot check mine as I don't use a hook up).

Re: Inverter switching

Posted: 11 Jun 2014, 08:42
by AdrianC
pfield69 wrote:I meant I only have 3 items that use mains.

What are they, and how much do they draw?

ghost123uk wrote:Re earthing the mains to the body. As far as I see it, the RCD would not work (protecting you) unless it was earthed. But, as this is a fairly critical thing, it might be prudent to double check this ;) Anyone like to confirm ? (I cannot check mine as I don't use a hook up).

The hook-up's certainly earthed on our Westy.

Re: Inverter switching

Posted: 12 Jun 2014, 20:43
by pfield69
AdrianC, just fridge charger and socket.

Re: Inverter switching

Posted: 12 Jun 2014, 21:35
by AdrianC
pfield69 wrote:AdrianC, just fridge charger and socket.
The fridge won't be running through the inverter, the charger - well, you _might_ have just invented perpetual motion...

So that's just the socket. With what plugged into it?

Re: Inverter switching

Posted: 12 Jun 2014, 21:46
by pfield69
mostly battery chargers (camera, flash gun and torches) and a hair dryer (400w). I wanted to run my coffee machine but that's 100ow peak, 800w constant and the battery can't supply that level of power

Re: Inverter switching

Posted: 12 Jun 2014, 21:53
by Ralf85
You need electric hook up!