Low ohms on the Silver Bullet?

[CCIFA]

Hey guys. I have a AGA-T2 that i've been tinkering with, and trying out different ohms to my liking. I've come up with a .5 ohms resistance. It vapes perfectly.

My question is, should I be worried about vaping on such low ohms with my silver bullet? Nothing seems to get hot except for the AGA-T2 itself. Could I potentially be holding a bomb in my hand? I do run protected 18650 batteries and I would expect the hot spring to collapse or the wire to just snap way before something catastrophic happens, correct?

I would like to hear from other folks using SB's and RBAs running very low ohms.

Thanks.

 

[StevesCVO]

I don't have a silver bullet but I've run as low as .8 on Zens with no problems.

 

[ljxkevinljx]

I think the Max you should use is 8W-9W. Anything above that would be dangerous....

 

[CCIFA]

I think the Max you should use is 8W-9W. Anything above that would be dangerous....

Hmm. I was reading that the switch can handle up to 96 watts, and the spring should collapse at 7 amps.

Now, when I put it in an online calculator this is what I get.

Voltage 4.2 (fresh charged battery)
Amps 8.4
Resistance 0.5
Watts 35.28

I'm not sure if I should trust this math. According to what I've read, the spring should have collapsed by now.

 

[Ryedan]

Your math looks good to me CCIFA and I read the same thing about 96 watts. I agree the spring should have collapsed. I also think the protection circuit in your battery should have kicked out. I would run IMR batts in this application, because they will tolerate much higher heat before becoming unstable, which I think is safer.

Something is not adding up for me. Are you sure of the 0.5 ohm number?

 

[CCIFA]

Your math looks good to me CCIFA and I read the same thing about 96 watts. I agree the spring should have collapsed. I also think the protection circuit in your battery should have kicked out. I would run IMR batts in this application, because they will tolerate much higher heat before becoming unstable, which I think is safer.

Something is not adding up for me. Are you sure of the 0.5 ohm number?

Thanks for the replies everyone.

Ryedan, this is becoming odd. I run Efest 2000 mAh IMR batteries, and I've checked the resistance twice on a multimeter and my vamo and it always comes up as 0.5. I don't get it.

Maybe I should just start wrapping .7 - 1.0 resistance. Better safe than sorry. Plus I really don't feel like destroying batteries and springs and letting my mods be out of commission.

Thanks again for the replies everyone.

 

[tj99959]

I do run protected 18650 batteries

What normally happens is that you are not getting the watts that you think you are because the battery simply can't do it. That's why we use high drain batteries (IMR) instead of Li Ion batteries. If you were to put a volt meter under that AGA I doubt that you would see much over 3.4v.

 

[Ryedan]

Ryedan, this is becoming odd. I run Efest 2000 mAh IMR batteries, and I've checked the resistance twice on a multimeter and my vamo and it always comes up as 0.5. I don't get it.

Maybe I should just start wrapping .7 - 1.0 resistance. Better safe than sorry. Plus I really don't feel like destroying batteries and springs and letting my mods be out of commission.

I'm waiting on a mechanical mod right now and the plan is to explore sub 1 ohm coils, so this is quite interesting for me so I did a bit more research. Maybe this post from Manu on another forum will help explain it: Voltage drop under load explained well.

The main point of that post is comparing IMR to non-IMR batteries, but the issue of simple voltage drop under load is covered nicely at the same time. Here is an excerpt:

'MANU, 06/02/2013, 1:27 PM:
A lower atomizer resistance translates into higher current = more power = more vapour. However, the higher the current, the higher the voltage drop on the internal battery resistance and mod resistance.

Remember that voltage drops at high currents cannot be completely eliminated. The presence of voltage drop only means that the efficiency is decreased. With lower resistance coils, the power on the atomizer increases, but a higher percentage of it is lost on the way.

So, if your battery at 4.2 unloaded lost 10% under load= 3.78 V.
Voltage 3.78
Amps 7.56
Resistance 0.5
Watts 28.58

I have no idea what is normal for this kind of loss, but at 7.56 amps coupled with the spring on one side of its collapse tolerance, you might be right on the verge of collapsing the spring. Or the loss could be higher and you have much less to worry about.

In any case, I think the only thing you risk is a collapsed spring or a poped coil.