Inverters!

Discussion in 'Tech/Mech General' started by Papa Smurf, Mar 31, 2008.

  1. Papa Smurf

    Papa Smurf Member

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    Hi guys and gals,
    I need another question answering I'm afraid - and where else is there to go but the friendliest RV forum to ask it?
    Inverters - (probably a 1800w which will obviously require permanently wiring in)
    Do you have to run a second ring-main of sockets, or can you "splice in" to an existing 240v ring? And do inverters always
    kick-in, or, are they intelligent enough to only do so if they sense that there is no "hook-up" supply present?
    Finally, any personal recommendations for decent makes / suppliers please?

    Thanks,
    Papa
     
  2. Road Runner

    Road Runner Read Only Funster

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    I have a question to?

    Does a small inverter take less from the battery working flat out rather than a big one with no where near working at it's full capacity?
     
  3. Geo

    Geo Trader - Funster

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    Have a good read HERE guys:thumb:
    Geo
     
  4. Road Runner

    Road Runner Read Only Funster

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    But it's in Australian though :Eeek:

    Can you translate it for me please Bruce?
     
  5. Geo

    Geo Trader - Funster

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    Here's an American one for you john Here
    and there's more HERE
     
    Last edited: Mar 31, 2008
  6. Bryan

    Bryan Read Only Funster

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    They can indeed be spliced into the existing ring.

    You can get a 'clever' swith (I'm sure sterling power do them) that works like this:

    Hookup? Yes? Great I'll use that :Smile:
    No Hookup, but Genny on? Okay, I'll use that :Smile:
    No Hookup or Genny? Okay I'll use the batteries throught the inverter, but I'll kill the power to the fridge and the battery charger as they'll kill the batteries too quickly:Smile:


    I would definately get the switch If you decide to go for inverter powered 240 etc.

    HTH

    Bryan

    (Just did a quick search and found this - Sterling Auto Power Selector Switch by Sterling from Kingslock Chandlery online shop- That's what I meant :thumb: )
     
  7. olley

    olley Funster

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    hi £170 for a switch!! their is a cheaper way, plus its easier to wire up.

    Your Rv has already got a switch for the genny, either manual or auto-changeover, try starting it and if you EHU has been wired correctly its pins will be dead, this assumes you have had a proper 230volt conversion done. If the pins are live you have a problem, because if you were on EHU and started your genny the two feeds would mix which wouldn't be good for your genny.:Sad:

    The inverter needs to be as close to the batteries as possible as an 1800watt one can draw over 150amps on full chat, it will also need a fuse, I think Sterling recommend a 300amp for this size inverter.

    Next run the 230volt supply from your inverter to your electric locker and mount a blue socket on it. Now when your not on EHU you plug you EHU lead into the socket and run from the inverter, this is cheap and foolproof you can't be connected to both at the same time and all your fuses and RCCD still protect you.:thumb:

    You will need 2.5mm 3 core flex, and if like me you need to run it externally flexible conduit and possible 2 bulkhead fittings, £30 should cover it.

    My pic. shows a socket and plug, you only need the socket, the plug is for my 230v charger.

    Olley
     

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  8. Road Runner

    Road Runner Read Only Funster

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    What concerns me with this system is wont the fridge and water heater (if you have a hot rod) try and run from the Inverter?
     
  9. Terry

    Terry Funster

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    Hi John try to use the smallest inverter for the job :thumb: A wolloping 1800w inverter will drain batterys faster than I type :Rofl1: (take note PPSmurf):Rofl1:Why not go the simple way everything 12v :thumb: anything requiring more power do without:Rofl1::Rofl1::Rofl1::thumb:
    terry
     
  10. Terry

    Terry Funster

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    :Rofl1: Am I reading smurfs mind in that the next question is how big a solor panel/charger ?:Rofl1: for all the batterys:Doh::Cool::thumb::Rofl1::Rofl1:
    terry
    sorry papa could not resist
     
  11. Bryan

    Bryan Read Only Funster

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    They will John, for all of the 5 minutes they take to chomp their way through your batteries :Rofl1:



    That's why I'd go for the switch I detailed - it automatically cuts power to the battery charger and fridge (and hotrod if you wire it up so).

    Bryan
     
  12. olley

    olley Funster

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    Hi your fridge can be selected for LPG only on the "Mode" button and I would have thought you would have a switch for the water heater, what I forgot to mention is you will also need a switch to turn your charger off. :Blush:

    However if like me you have a fuse box with separate fuses for the 230v and 110v systems, you simply trip the 110v fuse and then neither fridge, hotrod or charger will work as they are all part of the 110v circuit.

    Fitting an auto-transfer switch as Brian suggests is a good idea, but not if you are unsure about electrics, as I think papa maybe.

    Olley
     
  13. Papa Smurf

    Papa Smurf Member

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    Thanks guys - lively discussion!

    I have solar - (Phenix 100w) and have 2 x 110ah batteries to which I will be adding a further 2 giving leisure capability of 440ah. And this is because we will be doing a mix of hookup and free camping.

    I know f...nothing about electricity, save it can bite you, and, if you get it wrong, be expensive to fix the mess you've made. I would love to have gone all 12volt, but failed:cry:

    So, the intelligent switch sounds the best solution (at least I might as well have a piece of electronics that's clever), even though it's costly, it will allow me to sleep at night.

    I presume that a switch will only operate a single inverter, and not several small inverters which only get used as needed btw?

    Papa "burnt to a crisp" Smurf
     
  14. Road Runner

    Road Runner Read Only Funster

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    Out of interest when I had mine converted to a 240volt ring main didn't include the genny. Is it difficult or expensive to convert.

    At present keep a 240 suitcase genny for the 240 volt thinghys.


    ==========================================================================

    Use a 150 watt inverter to run my TV and sat box but thinking of fitting a 500 watt one to make things more flexible.
     
    Last edited: Mar 31, 2008
  15. olley

    olley Funster

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    Hi Papa you can't join inverters together, unless they are specifically designed to be able to do this with a "phasing cable" this ensures the phase is identical on each inverter. I believe you can do this on Victron's, they cost over a grand.:Eek!:

    Even with the intelligent switch you will still need some means of turning off the 110v side.

    Olley
     
  16. olley

    olley Funster

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    Hi John do your 110v sockets work when you connect the 230v EHU? If they do then you have a tranny, if its a proper one and not a yellow site box you should be able to reverse feed it from the genny to give you 230v

    Olley
     
  17. Road Runner

    Road Runner Read Only Funster

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    My leccy was done properly and 110/240 all work, just 240 v not on genny
     
    Last edited: Mar 31, 2008
  18. Thepips

    Thepips Trade Member

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    On both my Georgie Boy and my Monaco the socket ring main is on it's own circuit. The Monaco is a bit sophisticated with a charger/inverter and I haven't worked out how it all works. The Georgie Boy, though, had the inverter connected into the socket ring main only.
    It's pretty complicated stuff
    There was an automatic switch between generator (110v) and shore supply (220v). So if the generator was running the shore supply was disconnected.
    The shore supply was split into two. One went to a step down transformer to supply the 110v circuits as the air con, microwave and fridge were still 110v. The other side fed the 220v sockets.
    The generator output was also split into two. One feeding the 110v appliances and one running through a step up transformer to the 240v sockets.
    Finally (betcha thought I'd never get there:Rofl1:) another a mains relay stopped the inverter being brought into the circuit if the there was mains already in the circuit. The relay was the same brand as the inverter. Despite racking my brains I've not been able to recall the manufacturer. It'll come to me though.

    Hope that helps

    Regards
    Doug
     
  19. olley

    olley Funster

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    Hi John surprised the 230v doesn't work of the genny then as its not much more wiring when your doing the conversion.

    Yours will probably be wired as follows: The incoming 230v from the EHU goes into a fuse box with RCCD then out to the 230v ring, their will also be a feed to the 230v-110v stepdown tranny, the 110v side would then be joined to the old EHU fitted by the yanks which feeds into the auto-transfer switch.

    In its default position power goes from the tranny to the 110v ring, start the genny and it pulls the contacts and disconnects the tranny. To convert yours you would first need to ascertain that you can back feed the tranny (ask the guys who did the con.) if you can then you need to do some rewiring and add a relay to prevent the EHU becoming live. Another option is to fit a 110v-230v step up tranny, again I would have a word with the guys who did the con. maybe get them to do it??

    Get it wrong and you can serious damage to your genny, yourself and your pocket.

    Olley
     
  20. pappajohn

    pappajohn Funster Life Member

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    both will still draw the same current john, the big 'un will run cooler thats all.
    checked mine this evening for current draw when turned on but nowt connected, it draws 2 amps at turn on dropping to 3/4 amp after a short warmup period so they do 'use' some battery even when idle.

    john.
     
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