Question about dual 18650 box mods

[charliehall72]

I am in the market for a new mod and have been thinking about going with a dual 18650 box mod (wooden preferably). There are two I am looking at right now which are the AXIS and the P.A.P.S Inc v3 unregulated box. My biggest question right now is if I have two vtc5's in the unregulated box, does that put my constant amperage limit up to 60? makes sense in my head but I dont know much about these kinds of things.

Also feel free to post any reviews you have of these two box mods or suggestions for others I should take a look at

 

[KurrptSenate]

in an unregulated box mod, yes as the batteries are in parallel

in a series box mod, like the AXIS, no. Those batteries are in series

 

[VapingTurtle]

... if I have two vtc5's in the unregulated box, does that put my constant amperage limit up to 60? ...

No!

In parallel, the capacity (mAh) is increased. In series, the voltage is increased. In neither case does the Constant Amperage Limit increase.

Your vtc5's wired together either way are still 30A limit.

 

[charliehall72]

awesome thank you for the info. I might have to switch back over to looking at the slug in that case

 

[Yotdawglife]

No!

In parallel, the capacity (mAh) is increased. In series, the voltage is increased. In neither case does the Constant Amperage Limit increase.

Your vtc5's wired together either way are still 30A limit.

I believe you are incorrect about amperage. The limit IS increase because the amperage is shared between the two batteries thus putting the amp draw equally from both batteries.
for parallel.

The other type of connection is Parallel. Parallel connections will increase your current rating, but the voltage will stay the same. In the diagram to the left, we're back to 6 Volts, but the Amps increase to 20. It's important to note that because the amperage of the batteries increased, you may need a heavier duty cable to avoid the cables burning out.

BatteryStuff Articles | Understanding Series and Parallel Battery Configurations

 

[VapingTurtle]

I believe you are incorrect about amperage. ...

Thanks for the correction.

 

[Yotdawglife]

But that is true for series, amperage DOES NOT increase but voltage doubles.

 

[Mike_S]

In a perfect world parallel cells would share the load equally, but there's probably a difference in internal resistance between the two meaning one cell will carry more of the load than the other. The difference in contact resistance in the battery holder(s) can make the problem worse. Typically what happens is that the cell with the lower resistance will discharge faster causing its voltage to drop. The cell with the higher resistance was carrying less of the load and has a higher voltage which causes the two cells to then share the current more equally.

We've done these unregulated parallel builds quite a bit on the flashlight forums, but we rarely (basically never) run the cells anywhere close to their max continuous discharge rating. One cell will almost certainly exceed its rating until its voltage drops and the current sharing starts to even out. If the resistance is much lower for one of the cells the current might never be shared equally and when you remove the cells from the device, you'll find that one is at 3.0V while the other is at something like 3.5V.