Smart Inverter?

Discussion in 'Self-Build Motorhomes' started by Red_48, Oct 31, 2018.

  1. Red_48

    Red_48 Funster

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    Just learning about inverters...

    Does anybody know of an inverter that can isolate when on shore power, i.e. autosense AC power coming in from the shore (terminating on busbars) and isolates itself preventing AC power coming from both battery and shore?

    Or do they all do this?
     
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  2. eddievanbitz

    eddievanbitz Trader - Funster

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    The ones with automatic transfer do it, ones that don’t can easily be installed that way using and external purchased device or a suitable relay in series

    If you buy an inverter/charger, it will monitor the incoming shore power and auto invert and short fall I.E. shore power supply 6amp and suddenly Motorhome requires 12 amp the inverter/charger will take up the slack to avoid power disruption and blowing the shore power requiring it to be reset

    Don’t forget to install a RCD in series on the inverter output to the 13 amp sockets
     
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  3. Red_48

    Red_48 Funster

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    Thank you Eddie

    Sadly I have already purchased a Victron Energy - Charger 30A 12V which is not an inverter, so I would need to buy a separate unit.

    When shopping Invertors, I know I want a pure sinewave model. This model states it has "High voltage battery stop", is this the same as "automatic transfer"?
     
  4. eddievanbitz

    eddievanbitz Trader - Funster

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    No, that just means it turns off I assume.
     
  5. DBK

    DBK Funster

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    I rigged up an automatic change over relay and wrote a thread about it on here somewhere. Others have also done it and others have fitted manual changeovers.

    The one circumstance when being automated isn't perfect is if you have a very low amp supply. I've come across 3A in a few places. This isn't enough to run a hairdryer or my coffee machine so I had to unplug the EHU cable and run the inverter. You could get around this by adding a switch to force the relay to change instead but the need hasn't arisen frequently enough for me to have bothered. :)
     
  6. eddievanbitz

    eddievanbitz Trader - Funster

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    Or, simply put the AC main on the Normally Closed contacts, so the relay only being energised when the inverter is ON.

    Starting from scratch an Inverter/Charger is the best bet as it would enhance your 3amp up to the capacity of the inverter to avoid any issues
     
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  7. tacr2man

    tacr2man Funster

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  8. peterc10

    peterc10 Funster

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    Eddie when you fit one of those does it render the existing Electrobloc charging of the hab batteries redundant? And does it deal with solar as well?
     
  9. eddievanbitz

    eddievanbitz Trader - Funster

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    The electrobloc charger is disabled. There are no issues with Solar. I have 2 Lithium batteries, 3 x 150w solar panels and the Victron Multiplus 2000/80 and it all works a treat. On my camper there are three very large domestic TV's run from a HDMI distribution unit, a Humax 1Tb Freesat Digi box all mains, so the inverter is rarely off.

    Luckily my wife insists on having a hair dryer and tongs I get Wife approval for all of this, and cost, whilst a consideration is not too high on the list.
     
    Last edited: Oct 31, 2018
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  10. peterc10

    peterc10 Funster

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    Thanks. Only you and Eurotunnel would ever call what you have got a "camper"!!!!!!!!!!!!!!!!
     
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  11. eddievanbitz

    eddievanbitz Trader - Funster

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    :whistle2:
     
  12. peterc10

    peterc10 Funster

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    Out of curiosity do you have a ball park figure for how much that would cost to fit in my 2015 Hymer B678?
     
  13. VanWolf

    VanWolf Funster

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    Just joined and seen this today. FWIW I have just bought a complete Votronic system - kit comes well recommended. The Inverter will use the batteries but as soon as it senses 230V hook up it will switch to that. All the kit came from RoadPro - see RH column on this page for 5%. This is my system;

    Votronic VBCS 60/40/430 Triple = Charger
    Votronic VPC Jupiter 400 = Panel
    Votronic Inverter SMI 1700 ST NVS = Inverter
    Votronic Bluetooth-Connector S-BC

    I am using 2 x 200W panels and 2 x 200Ah Tube Cell batteries.
     
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  14. Red_48

    Red_48 Funster

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  15. DBK

    DBK Funster

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    The usual scheme is to connect the inverter output to the 240v sockets only. In your case through a double pole switch. I used a relay but a manual switch would be fine.

    Edit. Just had a look at your wiring diagram (an annoying process as DropBox tries to get me to install their app - much better to upload the image directly to your post) and you just need to wire in the inverter to the socket side of things.
     
    Last edited: Dec 30, 2018
  16. Red_48

    Red_48 Funster

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    Are you suggesting I need to isolate the shore charger when the inverter is in use?
     
  17. DBK

    DBK Funster

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    I'm struggling a bit with your terminology but I think I understand. :)

    In your diagram where you show the wires going to the sockets is where you need to break in. What you need to find is a suitable double pole changeover switch. The sockets will be connected to what I might call the centre terminals and the switch will either connect them to your "shore power" or to the output of the inverter.

    If you do it this way you could stay connected to say a low amp supply (6A isn't unusual) and this would keep the battery charger running and the fridge while the inverter could be powered up to run a coffee machine or whatever from the sockets.

    You also need a suitable RCD fitted where the shore power enters the vehicle and best practice these days suggests a latching RCD on the output of the inverter too.
     
  18. DBK

    DBK Funster

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    This how I wired my relay but the same idea will work with a manual switch.

    240v wiring diagram.jpg

    In hindsight it would have been better to connect the coil to the inverter output and I will change it to this configuration when it gets a bit warmer. :)
     
  19. VanWolf

    VanWolf Funster

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    That won’t work - you are creating a loop whereby the charger could take power from the inverter to charge the batteries that power the inverter. I suspect something would go bang.

    Without something smart or a switchover your shore power sockets are exactly that and can’t be run from the inverter.

    The Votronic inverter we are using is the line before the charger and any 230V sockets. It senses when on MHU and switches from battery to MHU.
     
  20. Red_48

    Red_48 Funster

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    Thank you. I have amended my diagram to reflect a Single Pole Double Throw manual switch on the positive wire between the existing shore charger and the proposed inverter (see link below).

    This would effectively isolate the shore charger or inverter.

    The switch position would be moved from Inverter to Shore when connected to shore power. But I'm unsure whether the inverter would be damaged if the switch was left set to the inverter when connected to EHU?

    https://www.dropbox.com/s/ecp2x13uqqxrm6v/Inverter.png?dl=0
     
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