can you explain to me whats the difference between energy and capacity in batteries

i need it in homer simpsons simple

I`ll try...

Energy is the ability to do work, often measured in Watts.
when we discus Watts in terms of electricity, it`s made up of Volts times Amps, so a 4 Amp 4 Volt battery will deliver 16 watts (Volts X Amps = Watts).
so your battery will be able to run a 16 Watt radio for 1 hour, or a 32W radio for half an hour, or 64W for 15 mins etc... there is a limit to this however! you can`t carry on doubling it forever (except on paper) because the battery chemistry and physics forbid you from drawing Infinite watts in Zero seconds! LOL

I`ll let someone else deal with capacity because it`s a bit vague in this context.

edited to add: it works the other way as well, you could run an 8W radio for 2 hours, a 4W for 4 hours etc...

Check this out.






So in this metaphor, capacity (mAh milliAmp hours) is the volume of water in the reservoir that all this water comes from.

ty both of you i kinda of get it now. for a flash light on medium brigtness for longer runtime id want more energy?

ps i used to know ohms law .but i forget so much latelty

raggie33 said:

ty both of you i kinda of get it now. for a flash light on medium brigtness for longer runtime id want more energy?

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Basically Yes, but there are rules!, your emitter and driver board only work in a given voltage range, so doubling the Volts would indeed double your "power" but probably blow something up! LOL, the only thing left you can alter is the Current (Amps), so if your battery is a 2000ma, then putting a 4000ma battery of the same voltage in there would double your power also, it just wouldn`t blow anything up

raggie33 said:

ty both of you i kinda of get it now. for a flash light on medium brigtness for longer runtime id want more energy?

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Not really. You'd want more light time. You use medium as opposed to high to stretch the release of your capacity out over time. The Energy would remain constant whether you blow all your capacity on high in, say, 10 minutes, or stretch it to, say, 30 minutes using medium.

raggie33 said:

ps i used to know ohms law .but i forget so much latelty

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V = IR or I = V/R or R = V/I

where I is the current through the conductor in units of amperes, V is the voltage measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms.

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

another way to remember it as a practical example is that 1 Volt across (shorted out with) 1 Ohm will draw 1 Amp, from there you can jugle the numbers around to match whatever you`re trying to work out.

Sorry for stepping all over your replies, Katherine Alicia!

does this seem like a good battery there like 65 cents a battery there lithium they look greatly built
they tested at 4 amps draw at2.77 amp hour and energy 1.45 watt hour

chillinn said:

Sorry for stepping all over your replies, Katherine Alicia!

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not at all! the more perspectives the greater the chance of understanding

i learned from both of you thank you both

Katherine Alicia said:

not at all! the more perspectives the greater the chance of understanding

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I say something similar... if everyone always agreed, nothing would advance.

chillinn said:

I say something similar... if everyone always agreed, nothing would advance.

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I don`t think we actually disagreed in posts #6 and #7, we just interpreted the question differently and naturaly gave 2 different answers, both correct for the individual interpretation., we effectively answered 2 different questions LOL

raggie33 said:

does this seem like a good battery there like 65 cents a battery there lithium they look greatly built
they tested at 4 amps draw at2.77 amp hour and energy 1.45 watt hour

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have you got a link at all, it would probably be easier to answer. there`s all sort of lithium cells, some are useless for flashlights.

Katherine Alicia said:

have you got a link at all, it would probably be easier to answer. there`s all sort of lithium cells, some are useless for flashlights.

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there aa cells buy a company called bevigor. they run like 1.74 volts and rated at 3000 mah they sure gave me more run time then alkaleaks

Watt hrs = Power (energy over time) = Average Voltage under load X Amp Hours (mAh/1000)

Watts = Energy = Amps X Voltage (under load)

raggie33 said:

there aa cells buy a company called bevigor. they run like 1.74 volts and rated at 3000 mah they sure gave me more run time then alkaleaks

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Hmmm... Sounds like a pretty good deal for 65 cents then! though 1.74 volts isn`t a common voltage spec for batts that I`m aware of, I wonder what the chemistry for them is, in particular the cathode material? Are they Primary cells or rechargables?

there throw away litium aa cells