Leisure battery discharge.

Discussion in 'Tech/Mech General' started by Sid52, Aug 24, 2013.

  1. Sid52

    Sid52 Funster

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    When I switch on the control panel, and then check the battery discharge there is a drain of -1A. This is with all the other control switches off, ie water pump, lighting, oven fan and auxillaries.
    If I turn on the lighting switch the discharge rises to -2A
    If I turn off the lighting switch and turn on the pump switch it rises to -1.5A
    With both lighting band pump switch on the discharge is -2.5A.
    The oven fan and auxillaries switches are fine.

    So the next thing I do is remove all the fuses and repeat the above. The battery discharge is the same.

    To eliminate chances of a self discharging battery I have tried two other batteries I know hold charge, with the same result.

    I know the discharge is real as the battery will flatten within a few days.

    With my limited knowledge I have now run out of ideas.

    So to summarise, with all fuses out,
    Switching on the panel shows -1A.
    The lighting switch adds -1A
    The pump switch adds -0.5A
    Total -2.5A

    Any clues or answers received with gratitude!
     
  2. TheBig1

    TheBig1 Funster Life Member

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    it may just be the panel itself that is either drawing current or not calibrated right
     
  3. meanders

    meanders Funster - Life Member Life Member

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    Hi.

    Two potential issues (no pun intended).
    1. The panel itself takes power. When you leave the van for a while, remember to turn the panel off.
    2. The only accurate way of measuring the drain from a battery is to put an ammeter in line with the load. However, even with the best, you will get some loss to drive the meter itself.

    That said, 1amp is very high. Ours shows .4 with nothing on. Do you know to what precision the panel is displaying the current? The only way to be sure is to connect a multimeter in series with the load. You could borrow a good quality DC clampmeter, but as this relies on the Hall Effect, I suspect it would be no more accurate than what you have.
     
  4. Sid52

    Sid52 Funster

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    The battery flattened after a few days when I left the panel on and with the pump and lighting circuits switched on, so there is real current drain.
     
  5. Sid52

    Sid52 Funster

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    I assume a meter across the battery terminals would measure the discharge and that would give an indication of the panel calibration?
    However I know that there is real discharge as the battery flattens within a few days. What is also perplexing that activating the lighting and pump switches, even with all fuses removed, increases the drain to -2.5A.
    That means just leaving the panel on at night (8hrs) while asleep will consume 20amps!
     
  6. pappajohn

    pappajohn Funster Life Member

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    control panels are getting far too complicated for what they really are...a series of on/off switches. and meters.

    a 2.5amp load will flatten an 85ah battery in 16 hours...not 2 days.

    a 1amp load will flatten it in 42 hours.

    after 2 days discharging and not immediately recharged will leave a knackered battery.

    i would start with the battery and ignore the panel for now.
    turn on the lights for 10 mins to remove any battery float voltage then disconnect the neg (earth) terminal and check battery voltage with a digital meter

    check the voltage 24 hours later...if its dropped more than a few millivolts i woulld suspect the battery.

    it isnt advisable to just wade in checking things at random...start at the beginning.

    .
     
    Last edited: Aug 24, 2013
  7. Sid52

    Sid52 Funster

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    Actually, it could have been earlier than 2 days as I'd not checked in the interim.
    It's good advice to start at the beginning, so the battery is now disconnected, and voltage reads 12.8v. Will check tomorrow afternoon.
     
  8. pappajohn

    pappajohn Funster Life Member

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    [/B]
    let the battery stand for 2 hours then note the voltage again.

    12.8v is a little high and should be 12.6v to 12.7v so the battery may be holding a little residual voltage from the charger which will soon deminish giving a false overnight discharge reading.
    if it then still shows 12.8v it may be a little inaccuracy in the meter and nothing to worry about.

    if nothing else, it eliminates the battery a s faulty
     
  9. Sid52

    Sid52 Funster

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    So to summarise, with all fuses out,
    Switching on the panel shows -1A.
    The lighting switch adds -1A
    The pump switch adds -0.5A
    Total -2.5A



    Checked the battery and reading hasn't deviated from 12.8v
    So it seems I have some significant battery drainage even when all the fuses are removed.
    Is there likely to be anything drawing power that doesn't go through the fusebox, or is it possibly a faulty control panel?
     
  10. StitchUp

    StitchUp Read Only Funster

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    You don't measure the current drawn by placing a meter across the battery terminals, you'd need to connect the meter inline e.g. remove the pos+ conection, place one meter probe on the battery terminal and the other on the connector just removed. Ensure the meter is set to an appropriate Current scale.
     
  11. cranky

    cranky Funster

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    I believe that the pump may draw power when switched on as it has a coil to energise even when it is not operating. The other stuff no idea.
    Actually I've got no idea at all I'm just guessing:BigGrin:
     
  12. hilldweller

    hilldweller Funster Life Member

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    If you are saying that you get 2.5A discharge with "all" fuses out, then you must have missed some.

    With just the panel on, so assumed 1A discharge. First test is set meter to 10A range and with the battery terminal off connect between battery terminal and battery. Do you see 1A then up to 2.5A ? This will at least show if the panel lies.

    I'm wondering if there is a light you can't see switched on.
     
  13. Wildbill

    Wildbill Funster

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    I am thinking of fitting LED light to our new van
    Just got my old battery from the caravan it’s an old forklift battery I think but still had 12.5 volts showing after 2 years big surprise so puting it to work to see how long it will last on my 12v flat screen TV

    if it works it's off in the new van with the other two batterys frome the old van
    pay load may be up but wont be short of power:BigGrin:
    will have to make vented box me thinks why dont we have a DIY smile?:Doh:
     
  14. TheBig1

    TheBig1 Funster Life Member

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    you wont regret fitting LEDs as mentioned on the other thread:thumb:

    be careful mix and matching old batteries as one duff battery will ruin the other/s very quickly
     
  15. Sid52

    Sid52 Funster

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    I need to get a decent ammeter. The one I bought from Maplins only DC and AC voltage but only measures AC current.
    Any recommendations, not too expensive please. Excuse my lack of knowledge, but should I get a clamp meter or something to measure inline?
     
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