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Power-User

Join Date: Jul 2006
Posts: 243

### How Much Can a Battery Lift?

04/09/2007 7:09 AM

Can someone tell me, if I have a household battery - eg a torch battery - how can I translate its potential energy into available mechanical energy? As an example, a battery I have says it is 1.2V and 2500mAh. Through what distance could that battery lift 1kg? (I'm talking thoeretically - so assuming friction and other losses to be zero). Thanks!

Pathfinder Tags: battery Energy mechanical energy potential
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Anonymous Poster
#1

### Re: How Much Can a Battery Lift?

04/09/2007 9:11 AM

Error report session ended due to lack of data. report error code 63F6G74EE35

Anonymous Poster
#2

### Re: How Much Can a Battery Lift?

04/09/2007 9:22 AM

Just theoretically I'd say the energy in a battery of 1.2V at 2.5 A for 3600 seconds would be...

(1.2 * 2.5) *3600 = 10800 J

So if Force * Distance = Energy then...

(1 kg)*(9.8 m/s^2)*d = 10800

then d = 1100 m

Guru

Join Date: Sep 2006
Location: California, USA, where the Godless live next door to God.
Posts: 3428
#3

### Re: How Much Can a Battery Lift?

04/09/2007 1:56 PM

Only in theoretical deep space with no gravitational influence, friction or inertia to overcome...

You are better off using the available wattage, in your case 3W, as a precursor to mechanical power available. Then take out losses for conversion, i.e. magnetic / resistive / windage / friction etc. A reasonable estimate is 40% losses, so you end up with about 1.8W of available mechanical power. Insert that into whatever mechanical formulae you then need to move your object. Lastly, use the mAh rating to determine how long you can sustain that movement, then take the mechanical movement you came up with times the available time to get distance.

In other words, you can move something very very light for a (relatively) long distance or, with the proper gear ratio, something very heavy for a very short distance.

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Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 5469
#4

### Re: How Much Can a Battery Lift?

04/10/2007 7:49 AM

26ft....

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Guru

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Location: at the beach in Florida
Posts: 5469
#6

### Re: How Much Can a Battery Lift?

04/10/2007 12:16 PM

260ft...?

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Guru

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#5

### Re: How Much Can a Battery Lift?

04/10/2007 9:49 AM

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Power-User

Join Date: Jul 2006
Posts: 243
#10

### Re: How Much Can a Battery Lift?

04/11/2007 6:49 AM

Thanks Kris - exactly the info I was after...

Thanks to other respondents too - (like all engineers, some were very useful, others were just plain innovative).

Anonymous Poster
#7

### Re: How Much Can a Battery Lift?

04/10/2007 7:12 PM

It all depends on how much weight training and body building it has done.

Power-User

Join Date: Jan 2006
Location: Australia
Posts: 254
#8

### Re: How Much Can a Battery Lift?

04/10/2007 8:24 PM

I suspect that the most efficient way might be to convert the sparks to heat and use the heat to expand something, thus providing the lift. From a theoretical point of view it ought to be possible to get very high efficiency, especially if you work on lifting a large mass a very small distance with a small temperature change.

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Anonymous Poster
#9

### Re: How Much Can a Battery Lift?

04/11/2007 3:28 AM

Ignite some gunpowder things will really take off.

Guru

Join Date: Sep 2006
Location: California, USA, where the Godless live next door to God.
Posts: 3428
#11

### Re: How Much Can a Battery Lift?

04/13/2007 12:44 AM

Great idea actually. If you think about it, an auto Air Bag is a small explosive charge (solid rocket fuel) that inflates that bag quite a bit with a tiny amount of electrical energy. Lots of chemical energy of course, but from the standpoint of what you can do with a battery, it's probably the most efficient.

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