Fridge or Freezer on a Boat?

Discussion in 'General Electronics Chat' started by Garth, Jul 20, 2014.

  1. Garth

    Thread Starter New Member

    Jul 19, 2014
    Would a 2,000 Watt Inverter start and run a Small Refridgerater or Small Freezer on a boat using 12 volt boat batteries on the boat ??..
  2. shakilabanu


    Jul 8, 2014
    Depends on how small your fridge is but 2000w is a good amount of power to run a small fridge.
  3. colinbeeforth

    New Member

    Sep 7, 2008
    Hi Garth,
    please be very careful with fridge/freezer and inverters. Most motors demand up to 5 times running current as initial inrush current. If your inverter can supply the total needed, it might be ok. If it can't supply enough, it may start the compressor some times, sometimes is may not, especially if the compressor output has back pressure. Stalled compressors will usually overheat and blow a thermal overload quickly. Some will reset when it cools, others won't - and you ruin the compressor. Best thing by far is find a supplier who will let you bring your device to their store and actually test their inverter. It's much easier to prove it doesn't work on their premises before you pay cash, than try to get your money back when it doesn't work on your premises. Yeah, it's a hassle, but I guarantee you won't lose money this way.

    The best fridge/freezers to use for mobile purposes is the Engels style (not recommending the brand, it's just a recognisable style) normally used in four wheel drives. They are modest in their power demands and will often run from 12 or 24 volts. They use the minimum power to achieve the end result and use much more insulation to ensure low power usage. I'd highly recommend 24 volts, as the inrush surge is halved. You can get good efficient switched mode 24VDC power supplies quite cheaply, but make sure they are the constant current protection type, as foldback protection won't start a DC motor for nuts.

    I highly recommend you check out the 4WD and camping forums, people there have solved these problems before, it might save you reinventing the wheel and losing cash.

    Cheers, Colin
    Garth likes this.
  4. Brownout

    Well-Known Member

    Jan 10, 2012
    It really should be fine for most applications. Refigerators use a couple hundred watts, so the 5x rule should not be a problem. Look at the consumption of the particular unit. On the other hand, using a modified sine wave inverter as opposed to a "true" sine wave inverter might cause some additional power consumption and heating of the compressor motor, or the motor might not start at all.