Unregulated mod batteries - Molicel P26A vs Samsung 30q

[AngeNZ]

Just ordered some Molicel p26a 18650 batteries. Usually use Samsung 30q batteries.

My question is, based on watt-hours, will the p26a last roughly as long as the 30q, despite the 400mah difference, if I pull them at 3.4v or 3.5v.

I'm normally running a 0.7ish 0.6-0.7ohm coil, so pulling a max of 7A. Occasionally run a 0.45ohm coil. So I'm pulling a max of 10a

Bench Retest Results: Molicel P26A 2600mAh 18650...beats VTC5A, best all-around 18650

Bench Retest Results: Samsung 30Q 3000mAh 18650…a great 15A/20 battery!

 

[susieqz]

as far as i know, for your vaping 30qs are still best.
i doubt you'll get as much run time from your new batteries.
they seem to be good batteries tho.

 

[Mordacai]

I noticed something interesting in the specs @AngeNZ, check the performance specs and pay close attention to DC ir and energy to 3.2V.

At 10A the Molicel has more runtime than the Samsung, is this because of lower internal resistance and therefore power lost.

@Mooch, when you're available could you please help explain this? As I'd like to learn more about this, thank you.

 

[sonicbomb]

because of lower internal resistance and therefore power lost

Yes

 

[Mordacai]

Thanks @sonicbomb, at least I'm learning something useful.

 

[mimöschen]

7amps on a .7ohm coil? On a mech?
No way.
4.2V / 0.7ohm = 6A max.

But you're getting an even lower voltage at the coil due to battery sag and voltage drop of the mod.

So the equations look more like this:
3.5V / 0.7ohm = 5A
and
3.5V / 0.45ohm = 7,7A

In this case the 30Q might still be the better choice compared to the P26A.

 

[sonicbomb]

A larger watt hour value in the case of the P26 only really gives you more comparative runtime at the higher end of user amp draw scale.
That's my understanding.

 

[Punk In Drublic]

Not all unregulated devices are actually "unregulated". Some may employ a microprocessor that reads the coil resistance and applies a set voltage as per the design of the device. In other words, if battery voltage was at 3.7 volts, the circuit may deliver something such as 3.4 volts to the coil depending on resistance. I believe the Asmodus Pumper operates in such fashion. The circuits efficiency also needs to be taken into account. So if 3.4 volts is applied at a 0.7 ohm coil, this would result in 16.5 watts. 16.5 watts with a 90% efficient circuit at a battery voltage of 3.7volts equates to roughly a 5 amp draw - just as a simple example.

With that said, it is difficult to determine the actual current draw at the battery strictly based on coil resistance.

DC Internal resistance is an important value that can be used to determine run time. But it is not the only defying factor. A Samsung 20S has a much lower DC resistance than the P26, but due to it's much lower capacity, it also has a much lower WattHours down to 3.2 volts at 10 amps.

Comparing the P26 to the 30Q, it is easy to conclude the P26 slightly betters the 30Q with a 10amp draw down to 3.2 volts. But if we are not working with a 10 amp draw and a terminating voltage of 3.2 volts, then that conclusion is subjective. Closer analysis is needed using the actual current draw of the device and the terminating voltage the user wishes. IMO, at <10amps, these 2 cells will be very closely matched and the differences will be minimal and perhaps not even noticeable. with a ~10amp draw, you can't go wrong with either cell.

 

[CMD-Ky]

I noticed something interesting in the specs @AngeNZ, check the performance specs and pay close attention to DC ir and energy to 3.2V.

At 10A the Molicel has more runtime than the Samsung, is this because of lower internal resistance and therefore power lost.

@Mooch, when you're available could you please help explain this? As I'd like to learn more about this, thank you.

@Mooch I second this request or a reference to an article. I have seen this claim before but have never begun to understand it. I am always at 1.1 Ohms and, if I understand the Law, I would be safe using either of the two batteries mentioned. That being so, I would like to buy the longest lasting. But I would also like to understand why I am making a choice.

 

[Mooch]

@Mooch I second this request or a reference to an article. I have seen this claim before but have never begun to understand it. I am always at 1.1 Ohms and, if I understand the Law, I would be safe using either of the two batteries mentioned. That being so, I would like to buy the longest lasting. But I would also like to understand why I am making a choice.

I haven’t read the thread but if you are using a regulated device the coil resistance doesn’t affect the amount of current drawn from the battery. Only the power setting affects it since the battery isn’t connected to the coil. The battery is connected to the regulator circuit board.

There is no “safe” use of any round li-ion battery since they were never meant to be used outside of a protected battery pack and we use them at our own risk. We can try to keep the risks going up even more by not going over the continuous current rating though. Multiply the current rating by three to get a rough idea of the wattage each battery can handle before hitting its rating.

The Wh (watt-hour) or Puff Count (recently added) specs tell you how long a battery might run at different power levels. It gives you a good idea of the battery’s efficiency. No need to check the DC IR spec if you have the Wh/Puff Count specs since the Wh/Puff Count specs are actual run times and, by default, take the DC IR into account.

Just directly compare the Wh or Puff Count Numbers (higher = better) at the same current level. A few percent difference will probably not matter in actual use, choose either battery or try both and see which might fit your particular style of vaping a bit better.

 

[CMD-Ky]

Thank you for your response, it is helpful. I was really surprised by the recomenation to calculate risk multiplying the contiuous current by three. I have been looking at two times but I will revise this.
Thanks

 

[AngeNZ]

7amps on a .7ohm coil? On a mech?
No way.
4.2V / 0.7ohm = 6A max.

But you're getting an even lower voltage at the coil due to battery sag and voltage drop of the mod.

So the equations look more like this:
3.5V / 0.7ohm = 5A
and
3.5V / 0.45ohm = 7,7A

In this case the 30Q might still be the better choice compared to the P26A.

Thank you. And yeah, I should've said I was pulling a max of 7a/10a with the 0.6-0.7/0.45ish ohm builds. It was more to show that I'm in the teeny tiny wattage field

 

[AngeNZ]

I've had a few days of playing with the p26a and comparing it to the 30q. My 30q's are a few months old, so that may play a part

This is all been tested at 6a.

Anyway, I'm definitely getting no less runtime using the p26a. If anything I'm getting slightly more runtime with the p26a over the 30q.