Club 80-90 Forums

WOW

I am impressed by your knowledge but that just went way over my head

what i need is a chart really so going off mocki's conversion is this correct

6 amp site = 1500 watts
10 amp site = 2500 watts
15 amp site = 3750 watts

if i stay well under these values ill be ok..right?

That's in VA (Volts * Amps), assuming the ac Voltage is 250V, eg:-

2.5 kVA = 250 V * 10 A

where as:-

Power = 2.5 kVA * Power Factor

I think I have got the power factor slightly wrong when it comes to fan heaters (I think it's actually about 0.95), I had simply assumed it from an electric motor (I haven't done that sort of maths for nearly 16 years believe it or not).

For most modern day appliances (such as flat screen teles, satellite recievers or anything that uses a switched mode power supply) the power factor can largely be ignored (it is very close to 1), so in most cases the guide you mentioned should easily be sufficient.

However, for inductive load based devices such as kettles, fan heaters, etc the power factor of those devices will be somewhat less than that (eg. from about 0.7 to about 0.9-ish).

I hate to add further confusion to this but a kettle is a purely resistive load and therefore has a power factor of 1. I'm very dubious of the 0.7 - 0.95 power factor of a fan heater as the vast majority of the power is taken by the heating (resistive) element. The only inductive aspect is the fan which is tiddly in comparison and I doubt it would drag the power factor out by any appreciable amount. I haven't looked at one closely but surely the manufacturer would also fit a capacitor to counteract the inductive reactance of the motor too.

Practically, I think you can pretty much ignore p.f with domestic appliances. Just my tuppence worth.........

so if i take it as every appliance has a power factor of 1 and the wattage on the box must be the maximum that it will draw, then sticking to these guidelines and the campsite ratings i shouldnt leave anyone in the dark

and does everyone agree with the conversion chart above ???

They appear to be based on a mains voltage of 250v whereas it's 240v. Even that has changed as it's now supposed to be 230v but it's never been that low whenever I've tested any. The figures will do as a rough guide though.

ok ill re-do em at 240v and hopefully if anyone else is unsure this can be a guide for them too....or is just me who worries
and once again..thanks guys

Wouldn't surprise on sites if voltage was less then 240/230l, especially if several hookups are running heaters, kettles, etc. And if voltage drops, amps drawns goes up.

Not for straight resistive loads it doesn't!

Might do on things like laptop power supplies that use switch mode power supplies, but anything else will just work with less heat/light/efficiency etc.

Just found this amongst some info I have, may be of interest, but pretty much what has been said. A friend of ours was out on New years eve at a site and they had problems with power where so many people were using max heating, the main site fuse was glowing red, they had to go round and get a few people to turn down / off some heaters that were running almost pointlessly in open awnings. You have to dress for the weather. There is NO bad weather just BAD clothing, as I was told as a lad.

AMPS
Amperes - or amps - refer to the quantity of electrical current flowing along an electrical cable. The pressure that pushes it along the cable is measured in volts. Multiplying the volts by the amps gives the amount of energy an appliance uses, expressed in watts (W).
In the UK, normal mains voltage is 230V, though it can vary slightly. The highest amperage of an electrical appliance is 13A, so based on the formula, this becomes 230 x 13, which equals 2990 watts.
The maximum amps available from the hook-up on a UK site is 16A; often it's less - 10A or 6A. Also, although a nominal 16A may be available, it is unlikely that this amount will reach your unit if other users are also drawing current.
Hooking up, you need to calculate the total amperage you can draw without tripping out the mains. Add up the wattage of all the appliances and then divide it by 230. Thus a 2kW heater, 125W fridge, 750W kettle, 50W TV, plus two 40W lightbulbs, totals 3005 watts, which, when divided by 230 gives you 13 amps. So if the site's supply is less than 16A, switch some items off to avoid tripping out the mains.

6A X 240V = 1440W and 80% safe usage is 1152W
10A X 240V = 2400W and 80% safe usage is 1920W
15A X 240V = 3600W and 80% safe usage is 2880W

The formula for converting Watts to Amps is : Watts = Amps * Volts

The formula for converting Amps to Watts is : Amps = Watts / Volts

SAFETY WARNING : It is a smart Idea to only use 80% of your the circuit breakers capacity this gives you a little leaway for error !

With temperatures of -9 this week I had 2.4Kw of heating , telly, laptop, mains lighting, etc with no problems on the campsite I use each week and that was more than enough to keep me well and truly warm. My Autohomes circuit breaker has two trips and these have different current limits pre-set. My breaker always trips before the campsite hook-up in the UK but most campsite hook ups have a re-set that you can access anyway. If using high wattage appliances best not to form any excess hook up lead into a coil, also make sure that your hook up lead is man enough for the job. Just remember to switch the heater to a lower heating output when you use your 2.4Kw kettle!

when we go to our favourite campsite in the new forest sometimes we trip the post. i think we had our little convector heater plugged in but probably belting out at full chat heating the planet, the electric kettle plugged in and maybe the tv on as well, not a big deal unplug one the devices, reset the trip and away you go.

shanco73 wrote:when we go to our favourite campsite in the new forest sometimes we trip the post. i think we had our little convector heater plugged in but probably belting out at full chat heating the planet, the electric kettle plugged in and maybe the tv on as well, not a big deal unplug one the devices, reset the trip and away you go.

OR

u step the voltage up to 660v which inturn lowers the amps being drawn which means u can power alot more with out using that much power..

this is what im going to do to get the most out of my batterys...


good ay!!!

Erm power is power...

If you up the voltage you down the current (amps), but the power remains the same.