battery power

Discussion in 'Tech/Mech General' started by aba, Aug 17, 2011.

  1. aba

    aba

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    hi i have just unplugged the mains out of the electroblock to get an idea of just how power hungry items fitted to the van really are.

    as it is now going dark we have the over cabinet LED rope lights on (about 10 metres)
    a 12volt 10 inch tv and a 12volt Comag sat receiver the display on the control panel says -13.9A and the battery after 10 minutes of this says 12.5 volts with the load on

    under the drivers seat is 1 exide gel battery rated at 80AHr

    so from what i understand i have really only got 40AHr available before the battery reaches 12volt and is therefore "flat".

    so am i correct in assuming that the battery will be "flat" in around 3 hours with this usage??
    if so then why do the manufacturers fit only 1 battery to a 6 berth motorhome and only an 80AHr one at that??
     
  2. Reallyretired

    Reallyretired Funster

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    From your figures you are correct, however I am surprised that those items are using nearly 14A.

    My TV (17inch LCD) which is quite an old one uses 2A, and my LED lights only 1-2 A depending on how many are on.

    Have you tried turning your items on individually to see what the usage of each item is?
     
  3. hilldweller

    hilldweller Funster Life Member

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    14A - never. Unless that rope really is 33 feet long and steaming hot. Can you turn it off. In fact log each load separately.
     
  4. wizzer59

    wizzer59 Funster

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    To make as much profit as possible they will fit the smallest cheapest battery that will do the job (just!):thumb:

    Tim
     
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  5. aba

    aba

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    i have turned things on 1 at a time and the main culprits are the lights
    the tv and sat box are using 1.9A together
    the LED lights above the lockers in the front of the van which equates to 6 metres of led rope light uses 7.6A and a further 4.5A for the rear lights.
    all lights in the van are Led apart from the spot lights which are 10 watt halogen capsules and the 2 in the cooker hood which are them MR11 10 watt spots.

    bearing in mind the heating system in the van uses a fan and a water pump as it is the Alde wet system.

    it seems pointless having a battery at all at the moment as if i am only going to get maybe 2 hours from it especially in winter.
     
  6. aba

    aba

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    have you seen the price of those Exide gel batteries :Eeek:
    i would have rather they fitted the 5 numax 100AHr i could have got for the same money as 1 of those
     
  7. hilldweller

    hilldweller Funster Life Member

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    What have you got there, a tanning shop or a motor home ?

    Surely the makers didn't fit such strange lighting.
     
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  8. aba

    aba

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    it is factory fitted in a space above the lockers with a translucent strip to let the soft light (which is not that bright) illuminate the roof to give a relaxing warm glow. they call it mood lighting or something like that.
    infront of every locker door there is an Led downlight but these are cool white and contain 3 Led's each and significantly less power hungry but cold and bright i have looked into changing these for warm white but they look like a complete fitting not a changeable lamp and as there are 15 of those it would be expensive to say the least.

    i think in total there are 10 meters of the mood lighting which appears to be about 24 Led's per metre so thats 240 Led's
    15 of the locker Led units 3 Led's per unit
    4 fittings in the door way 2 x 6 led units and 2 x 12 led units all used to be 10 watt halogen
    4 fittings in the kitchen 6 led's per unit used to be 10 watt halogen
    2 fittings in the bathroom 12 led's per unit used to be 10 watt halogen
    2 in the cooker hood (not led)
    10 spot lights (not led)
    and 1 awning light 12 led unit used to be 20 watt halogen
    so thats the lighting and if i hadn't changed the halogens for led then i would have maybe got 2 hours out of the battery
     
  9. hilldweller

    hilldweller Funster Life Member

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    It is a tanning shop.

    Clearly never intended for wild camping.

    It can cost you a fortune in solar and batteries to make that workable.

    It's the extravagant use of power I thought only the yanks understood.
     
  10. Reallyretired

    Reallyretired Funster

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    If I had mood lighting using that lot it would be a bad mood :Angry:

    I should just turn it off except on EHU
     
  11. aba

    aba

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    the germans have it pretty well sewn up with this one although i suppose we could just use a couple of the spot lights to get by on a weekend although i remember at the newark spring fair i had to run the engine for a while on the second day as the battery had got low and when we set off to come home the battery was showing 10.2 volts so its no good for shows either.

    i have been wanting to change the battery for maybe a couple of 110 AHr batteries and it looks like i'm going to have to as to run the engine or a genie on the second day just to get thru the next night isn't really an option.
     
  12. hilldweller

    hilldweller Funster Life Member

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    It's all self defeating. Bigger batteries mean longer charging times, terrible on a gennie. In other words you delay the flat batteries a day but take that much longer to recharge. I wonder what charger you have, 20A is sort of normal, to put 110Ah back in is around 7 hours, that's your genny running all day or night.

    The root cause is power usage out of step with off hookup living.
     
  13. keith

    keith Funster

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    Got to agree with Brian, it's a ridiculous amount of lighting, installed to sell the van not to use it off hookup.

    It looks all fine when they demonstrate it and no doubt looks very swish, but I have seen very few vans that are set up to be totally self sufficient for wild camping from new. We all add to the systems to make them better but of course at a cost.

    The other reason for a small battery is weight, 2X110 will be substantially heavier and reduce the payload.
     
  14. JeanLuc

    JeanLuc Funster

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    There has to be something wrong, either with the electrical installation or the meter indicating power usage. Your earlier post indicates a current draw of 12.1 amps for the lighting alone. That's equivalent to 14 or 15 10W halogen bulbs - more than enough for very bright lighting in any normal sized motorhome - in fact, as Brian says, you have a tanning shop on wheels.
    I would suggest a serious conversation with the dealer to ascertain that there is not a fault somewhere. Your only realistic solution to longer self-sufficiency without re-charging is to reduce the power consumption.

    Despite what I have just said, and regardless of the lighting situation, I would have thought a single 80Ah battery was a bit mean for a six-berth MH. There are only two of us in a 6.4 metre van and we have two batteries. They were originally 80Ah gels but I replaced them with 2 x 110Ah Elecsols. I chose Elecsol because they were the same height as the Exide gels and would fit in the battery tray. A lot of flooded lead acid batteries are too high to fit. We have no LED lighting: ours has a combination of halogen spots and fluorescent tubes. Without hookup, we can last a minimum of 5 days in summer and 2-3 days in winter when the temperature is well below freezing and the Truma hot air is running 24 hours a day. Recently we have had a solar panel fitted so I am expecting to extend that somewhat, albeit by not a lot in winter.
     
  15. aba

    aba

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    i am using the electroblock panel which shows the drain on the battery.
    as i said in a previous post the led rope lights installed above the lockers equates to about 10 metres with approximately 24 led's per meter and presuming these are 1 watt led's thats 240 watts output.
    the van is 8 metres long and has a payload of around 800kg so extra batteries are not an issue.
    im not sure on the charging output of the electroblock although it must be in the 20amp area although it will charge the battery and supply electrics in the van at the same time.
     
  16. hilldweller

    hilldweller Funster Life Member

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    Never assume when you can calculate.

    You've already said 7.6A = 90W and 4.5A = 55W.

    So your 240 LEDs are 90/240 = 0.375W each if driven efficiently, which I've never seen in an LED rope, they just use crude resistor current limiting for cheapness and simplicity.
     
  17. pappajohn

    pappajohn Funster Life Member

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    my view on why they fit just one battery of average capacity....

    the manufacturers assume you will follow the mainstream and use campsites....not go it alone for days on end off H/U.

    that makes the battery nothing more than a dump/stabilizing capacitor for excess charger/power supply current.
     
  18. callumwa

    callumwa Read Only Funster

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    For mood lighting, no need for miles of LED's...........:RollEyes:

    Try 3 or 4 tea light candles....... and a nice bottle of red.......:wine:.......:Blush:

    NO DRAIN on the battery whatsoever.........:thumb:

    just remember to extinguish candles before you go to bed...........:yawn:
     
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