How many amps

[Mr Eccleston]

I'm trying to work out how much current is drawn on the 240V side of our power supplies when for example you are charging at 6A on the 12V side.

From my rough calculations, on the 12V side it would be 72W, so therefore on the 240V side it is approx 0.25A.

Just wondering how many people can safely charge through a 13A socket

[Whiskers]

Well my 8.5amp charger is equiped with a 5amp fuse if that is any help?

[bert digler]

Originally Posted by Mr Eccleston

I'm trying to work out how much current is drawn on the 240V side of our power supplies when for example you are charging at 6A on the 12V side.

From my rough calculations, on the 12V side it would be 72W, so therefore on the 240V side it is approx 0.25A.

Just wondering how many people can safely charge through a 13A socket

depends on input volatage 240ish it never is psu ratings cables plug resistance in theory you can run a silly amount but its dangerous 0.25a per unit 52 chargers but expect at least a blown fuse if not a fire

[mark christopher]

good psu's have thier max amp draw on the rear or in the tech details

[bert digler]

Originally Posted by mark christopher

good psu's have thier max amp draw on the rear or in the tech details

agreed its usually in watts so needs to be calculated back to amps watts divided by volts to give amps also bear in mind the amount varies by heat a lot an idea would be if you are doing it as a club maplins sell power indicator plugs these give amps volts power factor and will show how close you are to the limit

[SlowOne]

6A at 12V is 72W. 72W at the 240V end is 0.3A. Isn't it as simple as that?

[mark christopher]

only isnt the uk 230 volts?
http://www.gbaudio.co.uk/data/mains.htm

[ashleyb4]

Uk voltage can vary depending on location, how heavily an particular phase is loaded etc. But it terms of calculations if you do not have a measured value we usually assume 230 for calculation.

Also what are you wanting to know this for??? As Yes in a perfect circuit it would draw 0.31A On the supply side of the transformer. But as with all electrical equipment it is not 100% efficient so there are other losses to consider. So depending on what you need this calculation for and how acurate you need to be depends if you should take these in to account aswell.


So really im asking why are you trying to calculate this???

Ash

[super__dan]

Originally Posted by Mr Eccleston

I'm trying to work out how much current is drawn on the 240V side of our power supplies

Just wondering how many people can safely charge through a 13A socket

ash, see above

[bodgit]

Firstly I am not an electrician but would this home made device work. Seems it would via the multi meter allow you to read the amps as you add extra load on. Please read disclaimers
http://vinayaga-raman.blogspot.com/2...-for-220v.html

[mark christopher]

far safer to use one of these
http://www.maplin.co.uk/Module.aspx?...No=222032#spec

[D20MCK]

Originally Posted by Mr Eccleston

Just wondering how many people can safely charge through a 13A socket

Hi Derek

I'll test my power supplys with my clamp meter and let you know what my psu pull's.

[MRD]

Here ya go




6A @ 12V = 0.28A @ 240v

[SlowOne]

OK, perhaps the next simple answer is "as many as it takes to blow the fuse?" If it's any help we run two pit tables of 10 people each at 12th Nationals off one 13A socket. Each person will have at least one battery on the go, sometimes two, sometimes a soldering iron or several and the odd laptop charger.

[D20MCK]

ok, my psu and charger, charging at 5 amps is pulling 0.38A from the mains.

[Mr Eccleston]

cheers guys, looks like 0.4A is a good enough figure, maybe even use 0.5A just to be on safe side.

Just, looking to make sure we don't overload our circuits at the club, would rather control how many can plug in than trip fuses etc.

Also looking at supplying power outdoors, so trying to calculate how big a generator is required to get average club numbers all powered up.

[D20MCK]

Remember your wall sockets in the hall should be on a 32 amp mcb, it's just 13 amps per plug top

[metalmickey0]

Originally Posted by SlowOne

OK, perhaps the next simple answer is "as many as it takes to blow the fuse?" If it's any help we run two pit tables of 10 people each at 12th Nationals off one 13A socket. Each person will have at least one battery on the go, sometimes two, sometimes a soldering iron or several and the odd laptop charger.

Blimey they must be big tables. Can only get 2 people per table normally. On the fuse bit. If the first plug in the line has a 13a fuse and it hasnt gone pop. Then no probs no matter how many spagetti leads are then plugged in. Works fine werever i`ve gone too