how much does it cost???

[jasonnjane]

how much does it cost to charge a rc car battery?

always wondered this.

[pugs]

not much, if you are charging off a modern switch mode power supply the current draw on the mains side is going to be very low, maybe about 20-40 watts at the most I would have thought(unless you are running at its max current draw), electricity is measured in Kw hours,so you can draw 1Kw(1000 watts) for 1 hour and you will be charged 1 unit of electricity for this (not sure how much it is per unit now) but if you know then you can roughly work it out now

[purpletimbo]

Nothing as I always charge off my full size car, and the extra fuel to recharge it's battery must be too small to measure.

[ashleyb4]

Well Going on the basis that electricty is say somewhere about 5p a unit?

I charge my 5000 mah lipo at 5 amp

13.8v x 5 = 69Watts

Now in theory it should take an hour at 5 amp to put 5000 mah into the cell im sure its not but i aint arguing so thats 69wh > 0.069

Somwhere about 0.3 of a penny.

God ive got to much time on my hands.

A

[pugs]

Originally Posted by ashleyb4

Well Going on the basis that electricty is say somewhere about 5p a unit?

I charge my 5000 mah lipo at 5 amp

13.8v x 5 = 69Watts

Now in theory it should take an hour at 5 amp to put 5000 mah into the cell im sure its not but i aint arguing so thats 69wh > 0.069

Somwhere about 0.3 of a penny.

God ive got to much time on my hands.

A

Thats how many watts you are pulling from the 12v side not the 240v side

[ashleyb4]

Yea but omhs law! As voltage goes down aka the transformer the current goes up. TO make the power the same.

A

[pugs]

Originally Posted by ashleyb4

Yea but omhs law! As voltage goes down aka the transformer the current goes up. TO make the power the same.

A

No sorry it's not the same, if you pull 20amp from a 20 amp power supply it will not pull 20amp from the 240v end, more like 3-5amp, think about it you normally only get a 13amp fuse,trust me I've been an electronics engineer for 16 years. You are right that as the voltage goes down the transformer current goes up but it's the conversion between the two coils, the current draw on the 12v side is at say 20amp(max load) the load is a lot less on the other side because the voltage is a lot higher and if you go into switch mode power supply's it's even more complex

[chris68nufc]

Speaking about electronics.....did u manage to fix my Receiver???

[bodgit]

You need one of these
http://cgi.ebay.co.uk/Electric-Power...item439a3d1e90

[ashleyb4]

I know that but you draw 5 amps and 13.8v which is 69 watts 69/230 = 0.3A

So you draw 0.3 amp on the 230v side

So 69watts

Please point where im wrong im not some idiot that reasearched this on the internet. Im a trainee electrican. Have passed my first year and cuurrently in my second at college. Had 4 destinctions and 2 credits for my 2330 last year and I was electrical apprentice of the year.

A

[pugs]

Originally Posted by chris68nufc

Speaking about electronics.....did u manage to fix my Receiver???

of course I did, I'am clever!!!!!

[chris68nufc]

Originally Posted by ashleyb4

I know that but you draw 5 amps and 13.8v which is 69 watts 69/230 = 0.3A

So you draw 0.3 amp on the 230v side

So 69watts

Please point where im wrong im not some idiot that reasearched this on the internet. Im a trainee electrican. Have passed my first year and cuurrently in my second at college. Had 4 destinctions and 2 credits for my 2330 last year and I was electrical apprentice of the year.

A

When i trained as an Electrical apprentice, one year somebody got Apprentice of the year by being the best at sweeping up, not such a great accolade!! You do seem really clever to me tho Ash. Well done!

[pugs]

Originally Posted by ashleyb4

I know that but you draw 5 amps and 13.8v which is 69 watts 69/230 = 0.3A

So you draw 0.3 amp on the 230v side

So 69watts

Please point where im wrong im not some idiot that reasearched this on the internet. Im a trainee electrican. Have passed my first year and cuurrently in my second at college. Had 4 destinctions and 2 credits for my 2330 last year and I was electrical apprentice of the year.

A

As a rough guide yes, but this does not take into account how much power the power supply uses at idle or how efficient the power supply is and this would change for each different model, the best way would be to pull the load and use a dvm in the live wire to mearsure the current draw and then times that by the voltage to give you the exact power consumption.

[ashleyb4]

OK OK i thought i had made a major mistake here. I understand there will be losses etc in the transformer but the guy wanted a rought idea im sure its not going to make a huge diffrence in this particular calculation.

A

[ashleyb4]

Originally Posted by chris68nufc

When i trained as an Electrical apprentice, one year somebody got Apprentice of the year by being the best at sweeping up, not such a great accolade!! You do seem really clever to me tho Ash. Well done!

Thanks chris i am actually the best at sweaping up as i was the only person that ever did. Everyone else took so long to do there practical asignments i had nothing to do but wait so i started sweeping. God i miss first year second year isnt as much fun I had so much free time i built 8 motor testing rigs for kelloggs.

A

[Marvin]

Ok.

I am charging a 7.4V 5000mAh battery at 5A.

The Voltage supplied by the charger is 8.4V, and the current supplied is 5A (assuming that for the one hour charge, the current level remains the same, even though it doesn't). 8.4 x 5 = 42W.

Most chargers are about 80% efficient so 42 / 0.8 = 52.5W drawn from the power supply. The power supply provides this power at 13.8V, so 52.5 / 13.8V = 3.8A.

However, the power supply is also not 100% efficient, more like 75%, so 52.5W / 0.75 = 70W.

70W is drawn from the mains. 70W/230V = 0.304A.

70W are drawn from the mains in that hour, so 0.07kW. Which, assuming electricity costs 13p per kWh/unit, is 0.91p. So not too much really.

[MRD]

Just hooked my 240v charger upto the power meter and these are the readings:

5300 lipo

5.3A Charge rate

0.24A Current draw

60W Power draw

Apparently its about 13p a unit. I'll let somebody else do the math.

[bert digler]

Originally Posted by Marvin

Ok.

I am charging a 7.4V 5000mAh battery at 5A.

The Voltage supplied by the charger is 8.4V, and the current supplied is 5A (assuming that for the one hour charge, the current level remains the same, even though it doesn't). 8.4 x 5 = 42W.

Most chargers are about 80% efficient so 42 / 0.8 = 52.5W drawn from the power supply. The power supply provides this power at 13.8V, so 52.5 / 13.8V = 3.8A.

However, the power supply is also not 100% efficient, more like 75%, so 52.5W / 0.75 = 70W.

70W is drawn from the mains. 70W/230V = 0.304A.

70W are drawn from the mains in that hour, so 0.07kW. Which, assuming electricity costs 5p per kWh, is 0.35p. So not too much really.

it costs me, squeek, bubble, the monk, matty,t speed turner and who ever else scabs a supply off the genny a fiver a day between us all

[MRD]

Ive used a energy calculator and the official figure for charging a 5300 lipo at 1c for an hour is 0.8p. Job done.