Efest 26650 query

[theyettie]

Hallo you smart people

I hope I'm not talking crap, please bear with me...

So I've got an Encom 80W TNT mod (new on the market, so don't know if many will know it). I run an Efest 26650 3.7V 3500mAh (Lithium Manganese) battery in it. I know that Efest doesn't make, but only rewraps batteries, so I've peeled off the branding, but there's nothing on the battery. How the hell am I supposed to know what this battery can handle? If I work on the specs printed by Efest, ie:

3.7V
3500mAh
Discharge current: 32A/64A

This battery would be able to fire a 0.11 ohm coil (not that I would even consider building this low as I like my face and the fact that I've got two hands...)

Is my calculation correct and does anyone know the actual specs of this battery?

 

[SamuraiTheVapor]

Product Description
Efest IMR 32/64Amp 26650 3500mAh 3.7v Battery - Flat Top

The Efest IMR 26650 3500mah 32/64amp Flat Top High-Amp battery is the newest longest lasting battery Efest has made to date!

Enormous 3500 mAh Purple Single Efest IMR 26650 LiMn Flat Top Battery. These batteries have a lower internal resistance and therefore will deliver more current under a heavy load than most lithium when used in a high-drain e-cig, or vaporizer. Efest was able to dial these huge batteries to 32A continuous maximum discharge making them fantastic for unregulated / mechanical mods, however they will work just as fine in a VV/VW regulated mod as well.

To make sure the batteries are safe during transport, they are shipped with 40%(3.7V) - 50%(3.8V) power. Please charge the battery(s) before first use or you may damage them.

Specifications:

• Size: 26650
• Type: Li-Mn (High Drain)
• Rated Capacity: 3500mAh
• Nominal Voltage: 3.7V
• Peak Voltage: 4.2V
• Cut-off Voltage: 2.5V
• Dimensions: 18.2mmX65.11mm
• Rechargeable: Yes
• Chemistry: Lithium manganese Dioxide (Li-Mn02)
• Style: Flat Top
• Color: Purple
• Maximum Continuous Discharging Current: 32 A. Maximum Charge Voltage: 4.2±0.05 V

Attention : These IMR cells have much lower internal resistance than regular LiIon 3.7V cells and they may end up with a higher ending voltage when charged in certain chargers. Please check the voltage of them right out of the charger to see if they are above 4.20V when fully charged with your charger. Overcharging above 4.25V may shorten life/cycles. Above 4.50V may even pop them or making them leak. DO NOT use the charger if it seems to overcharge IMR cells.

 

[theyettie]

Thanks @SamuraiTheVapor !! So I'm safe as houses. My apologies if this was a stupid question, but I dug through the internet for about an hour and couldn't understand most of the info I got. I really do appreciate your reply, because I posted the same question yesterday and got only one reply, which didn't pertain to the battery. This saddened me a bit.

 

[SamuraiTheVapor]

Thanks @SamuraiTheVapor !! So I'm safe as houses. My apologies if this was a stupid question, but I dug through the internet for about an hour and couldn't understand most of the info I got. I really do appreciate your reply, because I posted the same question yesterday and got only one reply, which didn't pertain to the battery. This saddened me a bit.

You should be ok. But always be careful when using Efest batteries - They don't exactly have the best reputation.

All the best with your vaping venture bro

 

[Andre]

Thanks @SamuraiTheVapor !! So I'm safe as houses. My apologies if this was a stupid question, but I dug through the internet for about an hour and couldn't understand most of the info I got. I really do appreciate your reply, because I posted the same question yesterday and got only one reply, which didn't pertain to the battery. This saddened me a bit.

Probably because independent info on the 26650 size is scarce. I also tried, but could not find anything trustworthy. Thus, could not respond to that question of yours.

 

[theyettie]

@Andre Ja that was my concern, it's very much an unexplored/undocumented size/type. I yesterday went as far as emailing Efest directly. I'm not putting money on a reply, but if they do, I'll post it.

Ciao mate!

 

[Silver]

Hi @theyettie

Not saying those specs are 100% correct, but let us assume they are and that the battery can do 32 amps continuous.

Then, to work out the lowest resistance, use the equation V=I*R or said differently, R=V/I. So at 4.2 volts fresh, the resistance when the current (I) is 32A is 4.2/32=0.13 ohms.

In your original calculation (where you calculated 0.11 ohms) you used 3.7V. But remember that when its fresh, it is 4.2 volts. The voltage reduces as the battery gets drained. 3.7V is the nominal value but it starts at 4.2 and goes down usually to about 3.2 or thereabouts.

To be safe, build in a healthy margin - so assume that 20A draw is the max - then it would work out at 0.21 ohms.

If it were me, I would not go lower than 0.2 ohms.

 

[theyettie]

Thanx @Silver !! Makes sense,rather safe than make ur jaw disappear... Ciao!!