12v - what electric bits can really be run?

Discussion in 'Motorhome Chat' started by Minxy Girl, Feb 21, 2014.

  1. Minxy Girl

    Minxy Girl Funster Life Member

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    There have been several queries on the forum about wanting to use hairdriers etc on 12v which has got me wondering just what could be run from our existing set-up which is:

    1 x 75w Alden solar panel
    2 x 100 amp Leisure batteries

    As we extremely rarely use any campsites, preferring wild-camping or a CL on an odd occasions (without hook-up), we have a Gaslow 11kg refillable system but obviously as we are 'generating' free electricity whilst travelling and on holiday abroad in the summer sun with our solar panel (hopefully!) what would we be able to realistically use/run, either in 12v or 230v form via an inverter?

    I'm thinking along the lines of the standard remoska, or a small oven, small halogen oven etc ...

    Any ideas?
     
  2. Wildman

    Wildman Read Only Funster

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    forget anything that relies on a heating element, cooker, hair dryer etc do the sums for yourself. You have 2 x 100 amp/h batteries, max 50% use means you have 100 amps useable power that is 100 amps for one hour (mind you you would need cables the size of tree trunks to take that amount of power, hee hee). Power consumption on devices is given in Watts so Watts divided by 12 will give you the consumption in amps per hour. Most heating devices will see your batteries flat in 30 mins. Hair dryer for a few mins if you must or a microwave again for a few mins is the most you are likely to get away with if you still want other functions in the van to work. The solar will give a max of around 4 amps midday mid summer with the panel pointed directly at the sun any other time of the day or year will give a fraction of this in the UK the percentage will improve the further South you travel. In the winter expect it to fail to keep up with internal battery resistance losses when there are long periods of cloudy skies.
    A halogen oven say 1300W will use around 100amps in 1 hour. A chicken will take half an hour to cook. So 50 amps gone from the battery. On an average day the best your panel will produce is 3 amps per hour so you would need 16 hours charging at that rate to replace that 50 amps could take a few days. Engine charging is not efficient unless you have a B2B charger fitted.
     
    Last edited: Feb 21, 2014
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  3. SomeoneElse

    SomeoneElse Funster

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    :BigGrin:To run anything like an hair dryer you need 230 volts. Therefore an inverter is necessary. However running an inverter for anything other than briefly, ie a few minutes will flatten you leisure batteries PDQ.
    Fortunately hair dryers only need to be run for a brief time each day. I found a 800 watt dryer, with some help from this forum, and initially decided on a 1000watt inverter.
    I now know the dryer needs 70amps feeding the inverter, so let's say it is run for 6 minutes, that is a tenth of an hour, so uses 7 Ah a go. We'll with the capability of your batteries.
    Now when I looked around I realised that an inverter could also run our 900watt travel kettle, our toaster (900watts) and if updated a bit our microwave, it's takes 1250watts.
    I therefore opted for a 1500watt inverter, it had to be a pure sine wave jobbie to cope with the microwave, but we have complete independence of mains leccy.
    Of course the kettle, toaster and to a large extent the microwave can be replaced by gas when the solar isn't producing too well.
    Works for us, YMMV.
    Gordon
     
  4. Minxy Girl

    Minxy Girl Funster Life Member

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    Thanks Gordon, only thing missing is what leisure battery power you have! :RollEyes:
     
  5. SomeoneElse

    SomeoneElse Funster

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    We have a 2013 Bailey Approach and Bailey supplied it with a 105Ah battery (Varta lfs105 if you need to look up the spec). I have added a second identical battery.

    The solar bit in my post is theoretical as my solar panels (2 x 130watt) are still in the shed, awaiting some suitable weather to fix them. We have used the inverter several times to power the kettle, particularly when using the tunnel as the gas is turned off. The microwave has been used also when travelling around France between aires without undue discharge on the battery.

    The hair dryer will get used more this year now that the affect of the Chemo has worn off and Linda's hair has returned.

    I also have a NASA battery monitor, the battery state percentage is pretty naff but the voltage and current meters are useful to keep an eye on the batteries.

    Our microwave is rated at 1250watts the inverter says it's supplying 1.28kW and the monitor says the batteries are delivering 127amps, but five minutes are enough to reheat a meal so the batteries soon recover. It's really all down to how you use your appliances and what comprises you are prepared to make in your life style.
    In our case we wanted all the options and will work with whatever gets throw at us.

    Gordon
     
  6. Minxy Girl

    Minxy Girl Funster Life Member

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    Thanks Gordon, that is very interesting!

    I have a small travel kettle and a low powered toaster so I might give them a try, especially the toaster as the gas one is cr*p and I do like toast for breakfast every now and then with some home-made jam. :Smile:
     
  7. ludo

    ludo Funster Life Member

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    Get one of these toasters, they are brill and fast! Trust me, you will not be disappointed.

    http://www.ebay.co.uk/itm/BRIGHT-SP...Goods_Camping_Accessories&hash=item5ae05155bc
     
  8. ludo

    ludo Funster Life Member

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    Why hammer your batteries and struggle with inverters? My advice would be, get a good, quiet, reliable generator, Honda EU20i Portable Generator. 2000 watts to play with.:thumb:

    You can cook whatever you want and how you want. Dry your hair without problems. Then, you have 230v power anywhere, even at home during a power cut!:thumb:
     
  9. magicsurfbus

    magicsurfbus Funster

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    You can get 12v hair driers and hair straighteners if required - not perfect but no need to run an inverter.

    We're solar powered (85W panel, 110Ah battery) and our inverter is disconnected and gathering dust - we cook and run the fridge off gas and do everything else with 12v. It's worth getting at least one of those 12v 3 socket extension gizmos with a USB socket included which is handy for recharging phones. I recharge my Mac laptop with a compatible 12v charger unit I bought off eBay - Apple's official product costs way too much.

    I sometimes take along one of those car starter power packs which I charge from the dashboard socket whilst driving. Comes in handy if you need portable 12v power anywhere.
     
  10. pappajohn

    pappajohn Funster Life Member

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    i agreed fully, but for convenience you cant beat an inverter.

    Plug in, switch on.

    Gennie is preferable if you plan on longer useage....watching tv for an evening or charging batteries etc but just 10 mins for a microwave or hair drier....not worth opening the storage locker.
     
  11. Puddleduck

    Puddleduck Funster

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    Thanks for this great thread. My OH needs to run medical equipment and I have just checked the rating. At 12V it draws 2.5 amps. So with a 100 amp battery fully charged and running it down to 50%, without running anything else we'd get 20 hours of equipment use - enough for a couple of overnights and a safety margin. Ideally we'd have two batteries of course.

    Very reassuring. Now I need to contact the equipment manufacturer for a 12V power supply.
     
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