max A in dual battery mods (parallel, series)

[Daisychainvaper]

I have some dual battery mods, some are parallel (istick 100) most are in series (ipv3li, ipv4s).

I think I know that the capacity doubles and the amps halve in a parallel mod (not exactly but roundabout). So drawing 25A of a dual 18650 in parallel with 2x 15A battery should be safe.

What about batteries in series? Still halve the Amps and double the capacity?

Thanks!

Story behind: I have a couple of Samsung 25R (20A) and also some 30Q (15A) now. Is it safe to use 2x 30Q in an IPV4S when drawing 25A out? (95W, 0.15Ohms)

 

[classwife]

Moved to Batteries and Chargers from E-Cigarette Technical


Batteries and Chargers
Discussion of batteries, chargers and multimeters used in association with APVs.

 

[Froth]

Series and Parallel can both draw the same a mount of amps and provide the same sort of vape experience, the difference is that Series does not split the amperage between two batteries, instead it takes advantage of double voltage to keep the amperage the same(depending on the build!).

Example:
Dual 18650 Parallel @ 0.20 ohms = 88 Watts at 10.5A total (4.2V total voltage full charge)
Dual 18650 Series @ 0.80 ohms = 88 Watts at 10.5A total (8.4V total voltage full charge)

You can get the same amperage draw with a series setup, but it requires a higher resistance to provide a similar vape to the parallel setup.

 

[Daisychainvaper]

I am really dull when it comes to this topic obviously or ppl don't understand what I mean

I have a .20 ohms build and vape it at 4 Volts - regardless if it is parallel or series as it is a regulated mod. So 4 volts it is.

This would be 20 Amps then. With how much amps are the cells "loaded" in a parallel and in a series setup.

parallel: The 20A are split between the 2 cells. So 10A each cell
series: ?? As I have double the voltage available, is it only 10A too or 20A per cell?

I tried to argue that in a parallel setup, the Amps are split in half (not exactly, but whatever) and in a series setup the Amps are also split in half per cell as I have double the voltage available. No one could give me an anwer. All the answer were "marry your batteries" hehe.

Thanks!

 

[Froth]

I can do simple, if that's what you're after. When batteries are wired in series it does not matter how many batteries you have, the amperage limit is still that of only one battery cell, you are simply increasing the available voltage. Ohms law is rock solid, 95W at 0.15 ohms is 25.16A.

 

[Daisychainvaper]

roger that, that was what I was looking for

 

[Spirometry]

I have some dual battery mods, some are parallel (istick 100) most are in series (ipv3li, ipv4s).

I think I know that the capacity doubles and the amps halve in a parallel mod (not exactly but roundabout). So drawing 25A of a dual 18650 in parallel with 2x 15A battery should be safe.

What about batteries in series? Still halve the Amps and double the capacity?

Thanks!

Story behind: I have a couple of Samsung 25R (20A) and also some 30Q (15A) now. Is it safe to use 2x 30Q in an IPV4S when drawing 25A out? (95W, 0.15Ohms)

In series the max continuous amps and capacity will be the same as a single cell, But your amp draw from the batteries will be half as much.

Working with a regulated mod, you need to work in watts because the board is a dc-dc converter and the amps will be different on the atomizer side and battery side. Also the amp draw will increase as the batteries get weaker.

95W in series and fully charged batteries.
95/8.4=11.3 amps

With weak batteries
95/6.2 =15.32 amps

Need to add in a little bit because the board isn't 100% efficient.
100/6.2=16.12 amps

 

[Daisychainvaper]

Parallel: A*2, mAh*2 at 3.7V
Series: A*1, mAh*1 at 7.2V

So it is different, but you only use half the A and half the mAh if you vape at the same Watts.
right? Like it is with the 3s LiPos. We need to calculate in Wh here to compare.