Is my battery calculation correct? + questions

[chellie]

Hello—am I calculating correctly? I now have a Jackaroo mod that takes a 21700 so I ordered the Molicel 21700 P42A. Someone on the forum helped me out once before and here is the calculation I used. I figured in at 30 watts –I am usually between 23 and 30 watts

30 watts/3.2 battery cut-off voltage/.9 - 90% efficiency = 10.4 Amps
(30)(3.2)(.9) ---max wattage to be used is 86.4

What about my 2 battery mod --is that calculation for each battery. For example, I ordered a Geekvape Aegis X that takes 2 batteries so If I had that same calculation would my wattage be 86.4 per battery?

 

[Baditude]

Figure your top wattage output by the amp rating of the battery, or vice versa. 15 amp battery good for up to 45 watts. 20 amp good up to 60 watts. 25 amps good for 75 watts. 30 amps good for up to 90 watts. Two batteries doubles the wattage of a single battery.

 

[Punk In Drublic]

Hello—am I calculating correctly? I now have a Jackaroo mod that takes a 217400 so I ordered the Molicel 21700 P42A. Someone on the forum helped me out once before and here is the calculation I used. I figured in at 30 watts –I am usually between 23 and 30 watts

30 watts/3.2 battery cut-off voltage/.9 - 90% efficiency = 10.4 Amps
(30)(3.2)(.9) ---max wattage to be used is 86.4

What about my 2 battery mod --is that calculation for each battery. For example, I ordered a Geekvape Aegis X that takes 2 batteries so If I had that same calculation would my wattage be 86.4 per battery?

Your calculation for determining the current draw for the single battery device is correct.

Same equation can be used for multiple battery devices, but we need to account for the amount of batteries being used. So in your case using 30 watts and your new GV Legend X this would be

30 watts/the amount of batteries/cut-off voltage/ device efficiency (roughly 90%) = current draw on batteries.

30/2/3.2/0.9 = 5.2 amps per battery.

To understand how much power can be used while keeping within your battery CDR limits, multiply the CDR rating by 3. And if using a multiple battery device, it would be CDR rating x 3 x # of batteries. Example. LG HG2 = CDR of 20 amps, x 3 = 60 watts. Two LG HG2 = 20 amps x 3 x 2 = 120 watts

 

[chellie]

@Baditude @Punk In Drublic

OK. got it. Thanks. I ordered the 21700 and I also ordered a bunch more 18650's. I have always used Samsung 25R and am trying the Molicel 18650's,

 

[Punk In Drublic]

@Baditude @Punk In Drublic

OK. got it. Thanks. I ordered the 217400 and I also ordered a bunch more 18650's. I have always used Samsung 25R and am trying the Molicel 18650's,

@chellie – both the Molicel P42A and the Samsung 25R are excellent choices with loads of headroom for your usage. BTW….it’s 21700 – your keyboard seems to be sneaking in the number 4