240 versus 12 volt

Discussion in 'Motorhome Chat' started by Vlad The Impaler, Jul 5, 2012.

  1. Vlad The Impaler

    Vlad The Impaler Funster

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    Hi all still trying to work out the power set up for my recently acquired motorhome.After much appreciated advice am thinking about a 1500 inverter,b2b charger and a 120 battery.As far as batteries go I have a couple of questions.Does a 240 telly throu an invertor drain a battery quicker than a 12 v one.Apart from tv poss only charging iPod and phone,no microwave ,hair dryer ,iron etc,so with b2b charger will one battery be sufficient. Finally blown bulk of savings on van so does anyone know of someone around leics or bury area who could help with install for a reasonable fee:BigGrin:Here's hoping.....steve
     
  2. Gromett

    Gromett Funster

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    Yes. You are converting from 12v to 240V (which has some conversion losses) Then you are converting back down to whatever voltage the TV uses again with conversion losses. Far better to have a TV that has an external power supply then getting a proper DC-DC converter which will have far fewer losses.
     
  3. Wildman

    Wildman Read Only Funster

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    Hi Steve, where to start.
    1) 240v TV via an inverter will use more power/drain the battery quicker. Having said that if it is a small inverter rather than a gert great big one the overhead will be small.
    2) Why do you need a 1500W inverter. I run my TV/sat box etc using a 150W inverter, the overhead is one tenth that of a 1500W.
    I would get a 12V TV and use the van for a bit before adding anything else, everyone uses a van differently and have different power requirements. A B2B charge is fine but remember you have to charge the first battery, run that flat and you will have problems starting the van.
    If you have a leisure battery think about getting a bigger one or even a second. It will be charged via a relay anyway and protect the engine battery.
    WAIT and SEE what you need instead of rushing out to spend all of your hard earned cash. Get yourself to the Rutland show and meet a few funsters, see how they manage.
    (note the overhead I refer to is the power used by the inverter on its own, never have it permanently switched on). If you want to find out more about 12v/240 in vans consider getting on the list for the seminar in Aug/September, assuming I get enough response)
     
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  4. Terry

    Terry Funster

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    Sound advise from Roger (wildman) :thumb:
     

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  5. Vlad The Impaler

    Vlad The Impaler Funster

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    Word doc

    Hi got an iPad can't download word doc pls can u copy and paste to a MSG for me at.
     
  6. jonandshell

    jonandshell Funster

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    Wildman misunderstands the operation of a battery-to-battery charger.

    It only charges the leisure battery with the engine running. It will NOT drain the starter as he suggests.
     
  7. JeanLuc

    JeanLuc Funster

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    All good advice so far, particularly 'wait and see'. If you are new to it all, you will not yet be able to make good judgements about what you really need.
    As a basic rule of thumb, IF you need more 12V capacity, the first step is to add another leisure battery. How much will you use the van off hook-up? We hardly ever hook-up so have 2 x 110 Ah leisure batteries and a 135W solar panel. Also a small generator for winter, but that rarely gets used. If you will normally use campsites and be hooked into 230V, you don't need to worry much about extra 12V capacity.
    The B2B charger is a good idea if your usage pattern is fairly short stops (2-3 days) followed by fairly short trips (say 50 miles or so). It puts a high charge into the leisure batteries quickly. If you plan to stay still for longer, the B2B will be less useful as you will need to run the engine to charge - not a great idea; a solar panel and/or small generator will be better.
    Do you really need a 1500W inverter? Considering the list of appliances you DO NOT plan to use, what on earth will draw 1.5 kilowatts? With inverters choose the smallest size you need (allowing a bit of headroom). We have a 150W pure sine wave model that is ample for charging devices and running a fan in hot weather. That way you put less demand on the leisure batteries.
    Keep asking questions, but my suggestion is to take time to think about what you are actually going to do with the motorhome.
     
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  8. Terry

    Terry Funster

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    SIMPLE GUIDE TO 12 VOLT LCD TV FOR MOTORHOMES
    LOTS OF TVS WORK OFF 12V---ASDA, TESCO, COMET, CURRYS ETC.
    MAKE SURE IT SAYS 12V ON THE BACK
    MAKE SURE IT HAS A PLUG TYPE AS IN PICTURE not four pin etc,


    THESE PLUGS ARE READYLY AVILABABLE OFF GAMES CONSOLES ETC,
    YOU CAN USE YOUR 240 LEAD ON HOOKUP OR MAKE UP A LEAD FOR 12V VIA CIG LIGHTER OR CROC CLIPS (PORTECT WITH IN LINE FUSE)
    OR WIRE TO YOUR ARIEL PLUG

    IDENTIFY POSS AND NEG THEN MAKE UP YOUR LEAD
    IF YOU WANT TO YOU CAN PROTECT WITH A VOLTAGE STABILIZER
    OR AS IN MY CASE JUST WIRED DIRECT TO ARIEL PLUG.
    IF USING VOLTAGE STABILISER YOU MAY FIND THAT IF VOLTAGE DROPS TO 12.V IT WILL NOT WORK, BUT IF NONE USED YOUR TV MAY WORK AS LOW AS 11.5 V (LONGER)
    AS VOLTAGE DROPS THE PICTURE WILL GO OFF BUT STILL HAVE SOUND, SO PLENTY OF WARNING TO CHARGE YOUR BATTERY BEFORE ANY DAMAGE OCURS.
    To sums it up simply--------
    There are always conflicting opinions on whether it is safe to use a 12v TV directly from the van 12v supply. I see the argument this way:

    Using an inverter from the van battery to provide 240v then powering the TV via the mains adapter is inefficient and uses considerably more power. I tested my current TV last week and there was a 25%+ difference in consumption. It is therefore better to use the 12v direct if possible.

    The first point to make is how much did you pay for your TV? If it's a £350 super-duper model then perhaps it may be worth splashing out on a voltage regulator or going for the inverter option. If you paid £50 for your TV then why not just wire it straight into the 12v and risk it? In most cases the TV will be absolutely fine.

    The second point is why not be versatile? The risk of the van battery voltage exceeding the safe input voltage of the TV only applies when the battery is being charged, ie: when the engine is running or when on hook-up with the charger powered up. So why not adopt the following strategy?

    a) Don't use the TV when the van engine is running unless you use it via an inverter and mains adapter.
    b) If you're on hook-up either use the TV via its mains adapter, straight from a 240v socket or turn off the battery charger when the TV is in use.

    Seems perfectly simple and logical to me - and saves both cash and battery capacity.
    May I add I have been using several lcd TV without a stabiliser-wired to the Ariel socket both on EHU and charger on without problem for the last 7/8 years-the battery will work as a pretty good stabiliser. Also ran the van while the TV was on but as I am driving I don’t watch the TV with engine running.
    :Wink: terry
     
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  9. Reallyretired

    Reallyretired Funster

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    I use a 1500w inverter but I run hairdrier and electric kettle (low wattage) from it. A TV is best run off 12v, but if you need to run it through an inverter a little one will be fine.
    Also bear in mind a 1500w inverter will draw about 150A from the battery at full power, a single battery will not be adequate.
     
    Last edited: Jul 6, 2012
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