How do I fugure amps?

[BradSmith]

So am I correct that to figure amps you would divide volts by ohms? For instance a 3ohm atty with a 3.7 volt battery would give you 3.7/3=1.23 amps?

The reason I am asking is I have been going on candlepowerforums to find the best batteries for my mod. They have run some great tests on the 18650's but it's clear that some are much better at 1 amp and others better at 2 or more.

Any help would be great.

 

[Cee_Jay]

You got it - here's a chart for the other equations. Ohm's Law

and another - Chart

 

[BradSmith]

You got it - here's a chart for the other equations. Ohm's Law

and another - Chart

Sweet thanks, It's been a while so I wasn't sure if I remembered right or not.

according to the graphs I will be going with the ultraFire 3,000mAh for use on a standard atty, with 3.7 volts. The AW2600 seems great for anything pulling close to 2amps.

http://light-reviews.com/forum/down...id=4f059c0cd79235f940e45cca64254895&mode=view

This is just one of the graphs they have them broken down for many batteries at different amps.

Thanks again.

 

[BradSmith]

For anyone interested here are a couple more charts one at 1amp and another at 2amps

http://www.candlepowerforums.com/vb/showthread.php?t=223638

Just scroll down. They are mostly talking about higher amp aplications but it's still interesting.

 

[Rocketman]

Brad,
The AW 2600 cell will handle any vaping application.
Go back and look over the graphs again but don't pay any attention to the end of the curve where voltage starts to drop off (discharge knee). You won't be vaping there anyway. Don't pay a lot of attention to the total milliamp hours at the end of discharge either. Go to the discharge midpoint (about 1200 mah if the cell gave a total of 2400). Look at the mid charge voltage at the current of interest. Interpolate between the currents if necessary.

For example; a 2600mah cell that ran out of steam at about 2400mah has a midcharge of 1200mah, not 1300. Try and find the voltage between 1 and 2 amps at the 1200mah point in the graph. Probably somewhere around 3.6 volts with a lot of cells.

Watch out for the graph of unprotected cells. They will be about 50mv higher than a protected cell through the midpoint. You probably won't be vaping unprotected cells.

 

[Java_Az]

I usually cheat and let this calculator do the math for me

Ohm's Law Calculators

 

[WillyB]

Sweet thanks, It's been a while so I wasn't sure if I remembered right or not.

according to the graphs I will be going with the ultraFire 3,000mAh for use on a standard atty, with 3.7 volts. The AW2600 seems great for anything pulling close to 2amps.
.

According to those graphs the UF3000's performance at 1A is terrible and at 2A it's pathethic. Those tests are a prime examples of why the the UF3000 should be avoided.

Look how quickly the voltage drops compared to most of the others. And note after the volts drop below ~3.4V it's time to recharge anyway.