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  1. #1
    Join Date
    Dec 2005
    Location
    Far S. Cornwall
    Posts
    12,983

    Default Leisure battery/fridge question

    In a campervan, which I bought so no knowledge of wiring detail. It has a solar panel, MPPT controller, and something that clicks regularly down near the start battery when the sun is out.
    On hols, with only the waeco fridge on, the battery would be dead an hour after the sun went. The fridge would start up in the morning with even minimal light on the panel. Avon 631, can't find if it's deep cycle or not, I disconnected it and after 24 hours it shows 13.2 volts.
    I threw a sheet over the panel, turned everything on, the fridge draws 6A as described on the spec, without it there is a 0.3A drain. Where's my leccy going? The panel will handle the fridge and a peltier cold box at 48w no problem.

  2. #2
    Join Date
    May 2005
    Location
    up on the moors.
    Posts
    33,209

    Default Re: Leisure battery/fridge question

    Have you got a VSR or similar battery charging device being used to split the charge to two batteries ?
    I think, therefore I am. I am, therefore I sail.

  3. #3
    Join Date
    Apr 2002
    Location
    Cornwall
    Posts
    8,590

    Default Re: Leisure battery/fridge question

    If battery shows 13.2 volt no load, turn on fridge and watch the voltage, it should fall slowly, if it falls rapidly you are surface charging the attery, you need to bench charge, or replace battery. If voltage remains the same the fridge is supplied from alt battery.

    Brian
    Kddpowercentre VASR charge

  4. #4
    Join Date
    Apr 2005
    Location
    Exmouth, Devon
    Posts
    712

    Default Re: Leisure battery/fridge question

    Avon are reasonable budget battery but I wouldn't want to run down past 50% very often. Is is 631 or actually 635?

    What size is the panel? Needs to be 120W to keep up with fridge and cold box together unless fridge is clever power efficient type. Check battery voltage at start and end of day with everything off.

    The 0.3A draw is probably the VSR being held closed.
    allGadgets Marine
    www.allgadgets.co.uk

  5. #5
    Join Date
    Dec 2005
    Location
    Far S. Cornwall
    Posts
    12,983

    Default Re: Leisure battery/fridge question

    Fridge def from leisure bat, as tested the A draw between terminal and cable when it fired up. Bat is kept charged by the panel. Yes the panel is enough for fridge and cold box, 10A in all. VSR is the click on the start battery end. Yes I checked the bat over 24 hours disconnected, dropped to 13.2v. After 7 mins of fridge the bat seems to have settled at 12.46-12.49v, still 12.48v after 11mins. Van has not been driven for days. Panel is covered over. So could be surface charge...?

    edit 12.5 now, battery is 681.

  6. #6
    Join Date
    Dec 2005
    Location
    Far S. Cornwall
    Posts
    12,983

    Default Re: Leisure battery/fridge question

    Perversely, after 30 mins the bat is at 12.51v. When I checked it in the early hours on hols it was down to 9v. Only difference is when fridge gets down to temp it cycles on and off. Working fine, freezes water in the ice box.

  7. #7
    Join Date
    Apr 2002
    Location
    Cornwall
    Posts
    8,590

    Default Re: Leisure battery/fridge question

    Quote Originally Posted by fisherman View Post
    Perversely, after 30 mins the bat is at 12.51v. When I checked it in the early hours on hols it was down to 9v. Only difference is when fridge gets down to temp it cycles on and off. Working fine, freezes water in the ice box.
    You do not appear to have a problem, probably under charged battery at first , now charged up, but 12.4 / 12.5 volt would be okay with fridge running, if you see 12 / 12.1 with fridge on you need to charge.

    Brian

    rian
    Kddpowercentre VASR charge

  8. #8
    Join Date
    Mar 2010
    Location
    Ammersee, Bavaria
    Posts
    4,677

    Default Re: Leisure battery/fridge question

    If you are measuring 9V on the house battery, and it is happening regularly then I think your house battery may be scrap - if not now, then very soon.

    Fridges are very power hungry, you said it draws 6A but dependent on how cold you set it, how good the insulation is, and how efficient the condenser etc. it will be cycling on and off all day (and night) and will probably come out somewhere around 0,85 kWh in a 24 hour period (12v, 6A, approx 50% duty cycle). The solar needs to be able to generate this energy during daylight hours (obviously). The battery is effectively a buffer which stores the energy and releases it over a 24hr period to meet the demands of all the electrical gear. A panel providing an average of 48W will need to run for 17 hours
    to provide 0,85 kWh ... I don't know where your van is, but 17 hours of useable sunshine seems a bit optimistic.

    The 0,3A that is going astray could be a car alarm, the electrical control panel or any other camper-van related goodies (gas heating?). Camper vans tend not to have a seperate battery isolator like boats - at least the ones I've used didn't - they also tend to be set up for mains hook-up.

    For comparison, I need 0.8 kWh a day to sit at anchor and do nothing (fridge, lights, some electronics), I have 300W of solar panels, a 370Ah battery bank, the boat is in the Adriatic - in summer. With this arrangement, the batteries cycle between 90% (dawn) and 100% and are fully charged in 2-5 hours of daylight dependent on intensity.

    It would be a good idea to do a power budget and check the optimal solar panel size and battery size for your intended use and location - before you replace the battery.

    PS: Check and see if your fridge is 230V/12V/Gas .... if it can run on gas then the solar and battery requirements will be drastically reduced.
    Last edited by Baggywrinkle; 22-05-19 at 11:27.
    The best argument against democracy is a five-minute conversation with the average voter.

  9. #9
    Join Date
    Dec 2005
    Location
    Far S. Cornwall
    Posts
    12,983

    Default Re: Leisure battery/fridge question

    Fridge is 12/24v. I have ample power in the sunshine, or even on a dull day, so the battery only comes in at night. Soon as it's light the fridge fires up from the panel and the battery comes up to 13v+. Just in the dark it seems to go quickly. I will run the fridge tonight and see if I can log the voltage drop. Fridge is definitely 6A, I put a tester in the circuit, how cold it is set just dictates time fired up. On test today it was running constantly having been just turned on.
    If the battery is OK I will double up in parallel.

  10. #10
    Join Date
    May 2001
    Location
    North Wales, sailing Aegean Sea or Menai Strait
    Posts
    21,698

    Default Re: Leisure battery/fridge question

    If you can run a fridge drawing 6 A from a single battery I think you are doing well. My fridge draws 3-4 A from 3x 120 Ah batteries, voltage usually down to 12.4v first thing. When we only had 2 x 120Ah the voltage was often 12.0v first thing.
    Answers to some technical queries at new website http://coxeng.co.uk

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