Current draw of typical caravan appliances.

Sep 29, 2016
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My google-fu has failed me, I remember seeing tables on some web site or other where typical wattages for aplliances were listed.

Anyone know where such a list can be found?

I ask because I am trying to get a guidline total wattage rating for all the equipment I may use when off EHU.

e.g. Blown air heating fan, fridge light when fridge is on gas, lights - led and halogen, 12v Tv, radio, toilet flush, phone charger, radio, and any other general appliances.

EDIT: I forgot the Water Pump :oops:
 
Mar 14, 2005
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As Audio Rob has stated the list he points to only covers mains powered devices. If you are off grid you will be most interested in the 12dc current the appliances use. The current rating of the appliance should be stated on the data plate or in the manufacturers instructions. Some manufactures may also state the Wattage.

There is a simple relationship between Volts Amps and Watts W= VxA (Ignoring inductive load effects)

Items like the fridge, water and space heaters may use 12V dc to operate control circuits , but they will not generate the heat power they need from the battery instead they need to be switched to gas.

To work out how much 12V power you will use, you need to find out two things for each appliance.

A. How much current (Amps) it will use when its turned on
B. How long the appliance will be used for each day (best to work in hours and parts of hours)

Multiply the current usage by the hours and you will get an Amp Hour (Ah) figure for that appliance each day.

Add all the results together to get a Daily Ah demand. That can be compared to the Ah capacity of a fully charged battery to estimate how long it will last.

What might surprise you is the water pump. Just for example a pump may be rated at 5A, but when you look at how long it is used in a day it might only be 12 mins of actual running time, that is 20% of an hour, meaning the pump may only use 1Ah of battery capacity.

But by comparison a filament light fitting may be rated at 1A, but its used for 3 hours so that is 3Ah.
 

JTQ

May 7, 2005
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For going off grid, it is not really the Wattage that is important, but the "energy" Ah you are going to use from the storage you have in the battery, and what any solar system can replace during a typical day.
The water pump for example, draws a significant current, but is only on briefly, each time for tens of seconds, so the amount of Ah is actually very small. Compare this with a TV that typically will be near 2.5 >3 Amps but could be on for hours, and much is the same for lighting, the more so as we move away from the peak season. Then again a light in the loo will be used for a minute or two, hopefully not hours on end, so even if a power hungry halogen still pretty irrelevant.. So lounge lights are where the investment in LEDs is most effective.
Of great surprise to many is the mover, this pulls loads of power, varying a lot as it starts and the difficulty of the ground over which it hauls the van, but again most users will not be driving it for many minutes. Say it averages a 30Amp pull, but the job is over in five minutes, that takes a somewhat surpising 30 x 5/60n = 2,5 Ah, similar to an hour of TV. The mover will find out a sick battery pretty quickly but that's a different issue. Somewhat makes a nonesense of those telling we must fit a 120 Ah battery if we have a mover, no, only if we have a TV and it comes with no self control. :dry:

The yield from solar is a very challenging estimate, clearly the panel size is important but so is its orientation and elevation, the weather and the often overlooked effects from shadows, even minor part shading. If the battery needs it and is healthy enough to take it then through the main season if you work on getting a third of the panels rating over an 8 hour period, thats about what it seems to average out at, but if it is a wet weekend you will get significantly less. IME, solar all goes too challenging as we close in on winter, even with a portable panel and sun tracking it, overcast and the low sun angles being major problems.

So really it is not that important to identify what everything takes but very important to know what the long duration usage kit takes.
 
Sep 29, 2016
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Thank you to everyone for all the very helpful replies.

I came across this web-page, very helpful with lots of useful information and a built in solar related calculator, the links contained within may be useful depending on your needs.

Look under the "electrical " section for further info.

https://www.parkedinparadise.com/
Cheers all.
 

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