Powering Van 230V From On Board Inverter

[nut17]

There is an interesting thread running on another forum at present on the above subject and it prompted me to run past the experts here the potential dangers involved.

Copy of my post on that forum:

We have our van set up so that it can be powered up via the on board 1200w PSW inverter. I have the inverter hard wired to an all weather 16AMP plug under the van. (Same as used in NZ camp grounds) I have made up a short cord to link the two outside sockets. Our van, being an NZ spec Jayco has a switchboard with a main RCD and four separate circuits. Prior to plugging in this system, I ensure that the 230v hot water service is switched off along with the mains charger and the AES fridge is manually switched to gas. I then use the four circuit breakers to selectively send the power to the parts of the van where we need it - ie washing machine, electric blankets etc. I have a good battery monitor/ computer and keep a close eye on the battery state of charge. Prior to this installation we used to run extension cords the length and breadth of the van to achieve the same results. We never attempt to run any high current drain devices for any length of time, only the Nespresso coffee machine and the pop up toaster and maybe a hair drier!! The last three items are operated from a dedicated 230v outlet wired separately to the inverter.

The Nespresso machine is rated at 1200w and the inverter is drawing approximately 120 Amps at 13v for about 1.5 - 2.0 minutes to make a cup of coffee. This corresponds to about 1 amp hour taken from the battery according to the monitor. The lithium battery copes with this high demand without fuss and even when down to 20 - 30 % remaining still holds 12.8 volts while making a coffee

I have had a registered electrician inspect the current set up and we still comply with the electrical standards in NZ.

Link to thread: http://www.caravanersforum.com/viewtopi ... 51#p481151


Cheers Chris

[oldtrack123]

There is an interesting thread running on another forum at present on the above subject and it prompted me to run past the experts here the potential dangers involved.

Copy of my post on that forum:

We have our van set up so that it can be powered up via the on board 1200w PSW inverter. I have the inverter hard wired to an all weather 16AMP plug under the van. (Same as used in NZ camp grounds) I have made up a short cord to link the two outside sockets. Our van, being an NZ spec Jayco has a switchboard with a main RCD and four separate circuits. Prior to plugging in this system, I ensure that the 230v hot water service is switched off along with the mains charger and the AES fridge is manually switched to gas. I then use the four circuit breakers to selectively send the power to the parts of the van where we need it - ie washing machine, electric blankets etc. I have a good battery monitor/ computer and keep a close eye on the battery state of charge. Prior to this installation we used to run extension cords the length and breadth of the van to achieve the same results. We never attempt to run any high current drain devices for any length of time, only the Nespresso coffee machine and the pop up toaster and maybe a hair drier!! The last three items are operated from a dedicated 230v outlet wired separately to the inverter.

The Nespresso machine is rated at 1200w and the inverter is drawing approximately 120 Amps at 13v for about 1.5 - 2.0 minutes to make a cup of coffee. This corresponds to about 1 amp hour taken from the battery according to the monitor. The lithium battery copes with this high demand without fuss and even when down to 20 - 30 % remaining still holds 12.8 volts while making a coffee

I have had a registered electrician inspect the current set up and we still comply with the electrical standards in NZ.

Link to thread: http://www.caravanersforum.com/viewtopi ... 51#p481151


Cheers Chris

Hi Chris
See my reply on that forum

quote"Hi Chris
Do you still understand that your van RCD may not be fully operational with that set up ?[unless the inverter has been modified,or you have one NZ method, not approved for Aus , which has an earth to neutral bond within the van][end quote]

Peter

[dapope]

Our swagman is set up to do that also. I have a 3 way switch next to the inverter marked mains, gen and inv. I take my choice and light up. I also need to turn off the charger

[T1 Terry]

We plan a set up similar to Brian's, the inverter runs 24/7 and if the mains are connected it transfers the load to the mains and the inverter becomes a battery charger, all automatically done. Rather than the earth/neutral link switching to make the RCD's operate when powered by the inverter we will use the combo RVD/RCD circuit breakers on each major circuit, then RCD's to act as main switches in the sub section after the combo switch. This way, if a combo switch is triggered we can turn off all the sub circuits, reset the combo switch and turn each sub circuit on to determine where the fault is.
All the lighting will be 12v so in the event of any 240v circuit fault tripping the relays, at least we will be able to see what we are doing
I had toyed with the idea of just an inverter and a separate charger, the charger being the only thing powered by the mains, I think Peter & Margaret's OKA is set up this way.

A question for Oldtrack and Super Sparkie, if the vehicle is never connected to the mains, is an earth/neutral link permanently made in the bus legal?

T1 Terry

[oldtrack123]

Terry Quote"A question for Oldtrack and Super Sparkie, if the vehicle is never connected to the mains, is an earth/neutral link permanently made in the bus legal?[End quote

Hi Terry
Now, That is an interesting question
MY interpreatation would be
IF THERE IS NO MEANS of connecting to mains supply
& ALL is permanently fixed &wired
The situation is the same as a fixed installation & the CHASSIS /"earth"to neutral bond can / should be made in the van .
But with the RVD / Combo, That is not needed, as you are defeating the FIRST stage of protection that the Combo gives


The RCDs would only be effective IF the FIRST line to frame fault developed BEFORE the RCDS
Edited @ 5.50 EST22/12


Peter

Now I'm of to bed ,for another hospital visit tomorow

[T1 Terry]

Thanks Peter, that was the way I saw it, this was going to be my original system before the combo RVD/RCD came along, it was the only way I could see to get around the multiple class 1 appliance issues and needing to switch neutral links. The neutral link issue was the main concern, if connected to the mains the neutral link would have to be a the supply side, but if the supply failed the UPS side of the inverter would kick in, but now there would be no neutral link, virtually unprotected circuits with multiple class 1 appliances connected.
It appears that this how the Victron Multiplus units operate, if they sense an earth/neutral link on the supply line they automatically open the link they make internally, but if the supply fails or is insufficient they supplement the supply, as far as I see it, this supplemented supply is not protected, if there was a fault and the supply RCD tripped, the Victron inverter would immediately take over all the supply.
As far as I can follow from the schematics, supply power is required to close the double pole relay on the supply line. When the supply failed the relay should open, once the line was broken to the supply neutral the earth neutral would be broken, this should be sensed by the Victron and an internal link made, this would then make the on board RCD’s functional. The issues I have is the whole system relies the supply relay opening both contacts, that circuit sensing there is no longer a link and making the link internally, otherwise the neutral link would remain open, no protection at all offered by the on board RCD’s as there in no earth neutral link at the supply, the inverter. What happens when the supply comes back on, would it sense the neutral link at the inverter as a short to ground and trip immediately?
There are a lot of very well known brand motorhomes set up exactly this way I believe the owners and the people responsible for setting them up don't see the same potential problems. I think Rich make a copy unit sold via the Jay Car outlets, no idea just how complete the copy is, maybe this is copied as well.

T1 Terry

[oldtrack123]

Thanks Peter, that was the way I saw it, this was going to be my original system before the combo RVD/RCD came along, it was the only way I could see to get around the multiple class 1 appliance issues and needing to switch neutral links. The neutral link issue was the main concern, if connected to the mains the neutral link would have to be a the supply side, but if the supply failed the UPS side of the inverter would kick in, but now there would be no neutral link, virtually unprotected circuits with multiple class 1 appliances connected.
It appears that this how the Victron Multiplus units operate, if they sense an earth/neutral link on the supply line they automatically open the link they make internally, but if the supply fails or is insufficient they supplement the supply, as far as I see it, this supplemented supply is not protected, if there was a fault and the supply RCD tripped, the Victron inverter would immediately take over all the supply.
As far as I can follow from the schematics, supply power is required to close the double pole relay on the supply line. When the supply failed the relay should open, once the line was broken to the supply neutral the earth neutral would be broken, this should be sensed by the Victron and an internal link made, this would then make the on board RCD’s functional. The issues I have is the whole system relies the supply relay opening both contacts, that circuit sensing there is no longer a link and making the link internally, otherwise the neutral link would remain open, no protection at all offered by the on board RCD’s as there in no earth neutral link at the supply, the inverter. What happens when the supply comes back on, would it sense the neutral link at the inverter as a short to ground and trip immediately?
There are a lot of very well known brand motorhomes set up exactly this way I believe the owners and the people responsible for setting them up don't see the same potential problems. I think Rich make a copy unit sold via the Jay Car outlets, no idea just how complete the copy is, maybe this is copied as well.

T1 Terry

Hi Terry
You have most of it pretty right
especially with the VIctron change over neutral bonding with loss of mains power & the reason why some have received shocks even though they have had RCDs fitted
Too early for me to be thinking too hard
A busy morning ahead before heading off to see SWMBO

2.5h to 3hr round trip

Will come back tonight with some point by point replies
Ps :see edit to my first post


Peter

[John M]

My biggest concern with the 240v on board system is that case of an accident there is a possibility of live circuits, granted the on board RCDs should render them relatively safe, however I think there should be some form of signage to make emergency workers aware of this possibility.

[homeless]

I have warning sign on all corners of my bus advising that in an emergency to turn off the battery isolator and it gives the location.

Cant post an image as I like to keep it simple now so have not set up for posting images.

Regards
Brian

[norman]

Ya mean the batterys flat in the camera....