Inverter or mains?

Discussion in 'Tech/Mech General' started by Bryan, Dec 17, 2009.

  1. Bryan

    Bryan Read Only Funster

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    Scenario:

    Motorhome has 240v tv, dvd and sky box. When on hookup you can connect them to the mains socket and when not on hookup you have a smallish inverter dedicated for running them from your leisure batteries.

    Question:

    Why not leave them connected to and running from the inverter all the time? When on hookup your charger is charging the battery and powering the inverter anyway so what reason is there to unplug them from the inverter and plug them into the mains socket?

    Obvious answer:

    Your inverter will last longer


    Any more?


    Bryan
     
  2. hilldweller

    hilldweller Funster Life Member

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    Modern inverters should have unlimited life.

    I guess the only question is wiring. If the inverter is properly integrated into the MH and the wiring is tidy use it all the time. If the inverter is two big crock clips sticking out of the floor and a flex running end to end then maybe not.

    I've just put a fixed inverter in for occasional use with one socket but the socket is not placed for constant use - just pop laptops or chargers in as needed.
     
  3. Fatalhud

    Fatalhud Read Only Funster

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    You have to also remember that when not on hook up, if you leave the inverter on, it still drains power, even if the appliances are not connected

    Alan H
     
  4. Geo

    Geo Trader - Funster

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    For Inverter
    1.Save wear and tear on sockets and plugs
    2. Prevent repetitive strain injury
    3. Give you something else to blow up
    4. Confuse next owner
    5.Confuse you
    6. Over complicate a simple system
    7. Be something to get cash back on
    8.Be something else to go wrong
    Against Inverter
    Same as above just add won't in front of all reasons for:Doh:
    Geo
     
  5. hilldweller

    hilldweller Funster Life Member

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    Good point Alan. Some are much worse than others, best to measure it.

    Ours is now in a locker - must remember to fit a visible 240V neon to remind me to turn it off when not in use.
     
  6. vindiboy

    vindiboy Funster

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    I have a 2000 watt inverter in my van ,and we use it to power high wattage items Micro wave .Hoover. hair dryer ,iron etc [ if we are on a site with low amp hook ups 4 or 6 amps for example ] ,power used from the batteries is put back over time by the battery charger, SEEEMPLES.:thumb::thumb::thumb:
     
  7. johnsandywhite

    johnsandywhite Read Only Funster

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    :Cool: We have ALWAYS used our Inverter for ALL our 220/240 volt requirements. TV, Satellite, Video. Having said that. ALL our Internal Mains connections are 110/120 volts and we do have Solar power and loads of batteries. :Rofl1::Rofl1::Rofl1:
     
  8. bashers

    bashers Read Only Funster

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    depends on your inverter technology.

    A major "good" point of this plan would become apparent when you go abroad.

    Your camp-site EHU may drop to 6 or even 3A and those times, you could leave the inverter on permanently and your EHU would power solely your charger

    Then, if you exceed your inverter current, you'll get an alarm or shutdown rather than a trip to the site office and further embarrassment!!
    Plus you can use up to the limit of your inverter

    This is how i run my RV as just the transformer alone can blow a fidgety 6A circuit breaker as i have seen many times
     
  9. MAUBRI

    MAUBRI Funster

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    I have got virtualy the same set up and tend to leave ALL 240v mains items connected to the Inverter,a seperate 16 amp mains charger keeps the battery Banks on permanent float,i.e. 2 banks of 4 X 85amph. when not on mains I have a 130 watt solar panel. They are wired through a 100amp rotary marine switch whereby I can be charging one bank and using the other for the inverter.

    The Leisure battery has its own 100watt solar Panel so is independant.

    Brian
     
  10. haganap

    haganap Funster Life Member

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    my van is set to run completely by 12v and invertrers. I leave everything via inverter and simply plug in to charge up. There is normally more amps in than out in my case.
    Why?

    Because im on holiday and the last thing I want to do is to break me back getting in to a tv unit.:Eeek:
     
  11. chrisoops

    chrisoops Read Only Funster

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    You won't hear the fan on your inverter.
    You will be more efficient, save energy and burn less carbon so humans will have that bit longer to inhabit the planet. (Inverters as well as using energy to cool them, obviously are not 100% eficient otherwise they would not be producing the heat which needs to be disapated, usualy with fins and fan.:Smile:
     
  12. jezport

    jezport Funster

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    You need to be happy that your charger is putting more into your battery than the inverter is taking out.
     
  13. G4GMO

    G4GMO Read Only Funster

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    Obviously I have way too much time on my hands which is why I'm adding my tuppence worth.

    Inverters are very in-efficient which is one good reason for running off EHU.

    Solar panels are also very inefficient (from an ex-colleague who has a very sophisticated setup http://3gcl.no-ip.org/) he tells me they are about 13% efficient and are worse as they heat up.

    I have two 25w panels that help to keep my batteries charged and the batteries hold up well (also charged by the built-in ac mains charger on EHU) when running the 300w inverter for powering the tv and lights.

    So I would say use the inverter when you have no EHU but use EHU whenever you can.
    Not all inverters are made equal. Better to buy a good quality model that gives a good sinusoidal waveform. The cheaper versions, like my £25 300w inverter, don't power sensitive equipment like tv/dvd etc properly but are unlikely to cause any damage.

    Hope this helps.
     
    Last edited: Dec 19, 2009
  14. G4GMO

    G4GMO Read Only Funster

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    Sorry that should have read inverters are not 100% efficient so better to run off mains rather than the inverter with an EHU. ... and you'd rather be charging the battery than not wouldn't you?

    It was late and I was titrred :Smile::RollEyes:
     
    Last edited: Dec 20, 2009
  15. suenmike

    suenmike Funster

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    Just a thought :Doh:

    You techies out there - would the inverter act as a suppressor to voltage spikes and surges?
     
  16. hilldweller

    hilldweller Funster Life Member

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    Yes.

    But does the inverter survive the spikes :)

    It's got a very good chance because the battery is between any spikes and the inverter.

    And the charger is between the spikes and the battery.

    So what should die is the charger.
     
  17. bashers

    bashers Read Only Funster

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    Note to myself; "Another good reason why not to get a combined charger/inverter"
     
  18. hilldweller

    hilldweller Funster Life Member

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    All eggs in one basket sort of thing.

    It's a trade off - the MH manufacturers would love them, just one box to install.

    I was just looking at the circuit of our Electroblok, that is a charger plus switching logic and fuseboard. The charger part does fail and it would be quite easy to strip out the charger bit and replace it with a stock charger if it did, possibly a better long term solution rather than sending a great lump back to Germany.
     
  19. veletron

    veletron Read Only Funster

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    Hi

    An big inverter will act as a nice buffer for short-term large current draws - i.e it will prevent your hairdryer tripping the fuse on a 5A hookup. It might also allow you to get more from an EHU than you would otherwise (in terms of useage).

    They are, however inefficient. If your TV and Sat box combined took say 50W at 240V, this translates into 4.16A @ 12V take into account inverter efficiencies of around 85% and your looking at drawing 4.7A. If you use the TV alot, and have a typically wimmpy charger on your EHU (15A odd) then your batteries might take 33% longer to charge if you are using the TV on the inverter vs if the TV was running direct from the mains.

    That, to me if the main disadvantage, of course, if you have a decent charger (30A plus) feeding a large battery bank then there's no issue.

    What I did is fit a 240V DPDT switch over relay. If I connect EHU, all the sockets run off EHU, while without EHU, all the sockets are connected to the inverter. If you are not into DIY, your local dealer should be able to sort this out for you...

    The other issue with an inverter is where you have a minimal battery bank. A single 110AH or 85AH battery will not let you boil much water using an inverter before the inverter trips due to low voltage at 12V.

    I run a 1KW inverter and 3x 85AH batts, these are charged by a sterling 50A B2B while driving and a 130W panel while stopped. The solar panel provides more than I can use in summer, but way less than I use in winter!

    Nigel
     
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