Efest Purple 30A 2100mAh 18650 Bench Test Results...only a 20A battery

[Mooch]

Tested at 10A-30A constant current. This cell was purchased from IMRBatteries by me and used only for testing. To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18650, 26650, etc.


Disclaimer
The conclusions and recommendations I make based on these tests are only my personal opinion. Carefully research any battery you are considering using before purchasing.

Testing batteries at their limits is dangerous and should never, ever, be attempted by anyone who has not thoroughly studied the dangers involved and how to minimize them. My safety precautions are the ones I have elected to take and you should not assume they will protect you if you attempt to do any testing. Do the research and create your own testing methods and safety precautions.




Bottom Line
In my opinion, this is a 20A continuous discharge current (CDR) cell with average capacity for its rating.


Test Results



Comments

• At 10A it reached about 1900mAh. This is average performance for a 2100mAh-rated cell.
• At 15A the maximum temperature reached 65°C. This is too low for a cell operating at its CDR.
• At 20A the maximum temperature reached 76°C. This is just below the 78°C average temperature for a cell operating at its CDR.
• At 25A the temperature rose to 85°C. This is too high for a cell at its CDR.
• At 30A the cell reached 94-97°C. This is much too hot to set the CDR at 30A.
• Five additional cycles at 30A started showing some voltage sag but it's not really indicative of damage being done. The temperature was way too high to set a CDR of 30A. This is clearly not a 30A cell.
• The temperature at 20A is very close to the average for a cell operating at its CDR. I am setting a CDR of 20A for this cell.
• To see how other cells have tested and how hard you can safely push them, check out the links in my signature.

 

[Baditude]

Disappointed with this finding, yet the results are not that surprising being that they are Efests.

Purple Efest Batteries: Not As Advertised​

I don't typically buy Efest anything, but in a pinch I had purchased a couple of these 2100mah "30 amp" purple Efests believing that they were re-wrapped Sony VTC4's. I couldn't find any genuine Sony VTC's locally and I really wanted some 30 amp batteries. The B&M had the Efests so I bought them.

I never push my batteries over 50% of their advertised amp limit, regardless. I've since parted with these quite a while ago.

With Efest, you never really know what you are getting inside under the wrapper. It could be that they have switched from using Sony VTC4's to a lesser battery. They never have admitted to re-wrapping batteries in the first place.

Thanks for the heads up, Mooch.

 

[Mooch]

Disappointed with this finding, yet the results are not that surprising being that they are Efests.

Purple Efest Batteries: Not As Advertised​

I don't typically buy Efest anything, but in a pinch I had purchased a couple of these 2100mah "30 amp" purple Efests believing that they were re-wrapped Sony VTC4's. I couldn't find any genuine Sony VTC's locally and I really wanted some 30 amp batteries. The B&M had the Efests so I bought them.

I never push my batteries over 50% of their advertised amp limit, regardless. I've since parted with these quite a while ago.

With Efest, you never really know what you are getting inside under the wrapper. It could be that they have switched from using Sony VTC4's to a lesser battery. They never have admitted to re-wrapping batteries in the first place.

Thanks for the heads up, Mooch.

My pleasure.

The cynical side of me says the use of VTC4's was quite calculated. Start with them to get the glowing reviews and test results, then switch to a lower rated/quality cell but still enjoy all the benefits of everyone thinking it's a VTC4. By the time everyone figures it out they've released new cells.

All completely conjecture though...

 

[State O' Flux]

This may have been mentioned somewhere in ECF before... but it's new to me.

As we're chatting about Efest... I picked up a few Efest "purple" 18650/2500mAh for dirt cheap (yes, they're "genuine") and it appears they've adjusting their labeling.
No longer is there a prominent amp rate... as seen in the first image in the link Bad' posted... just the nominal voltage and mAh rate in large, white type.
The amp rate, still in white but much smaller (and impossible for me to read without glasses) type, states "Discharge current 20A/30A".

It will be interesting to see if, in the future, we see a shift towards "truth in advertising" from battery "sellers"... or at least a reduction in weasel words.
Much like Bad'... I'll retain a healthy level of distrust and cynicism for most of the purveyors of "too good to be true" batteries.

 

[Mooch]

This may have been mentioned somewhere in ECF before... but it's new to me.

As we're chatting about Efest... I picked up a few Efest "purple" 18650/2500mAh for dirt cheap (yes, they're "genuine") and it appears they've adjusting their labeling.
No longer is there a prominent amp rate... as seen in the first image in the link Bad' posted... just the nominal voltage and mAh rate in large, white type.
The amp rate, still in white but much smaller (and impossible for me to read without glasses) type, states "Discharge current 20A/30A".

It will be interesting to see if, in the future, we see a shift towards "truth in advertising" from battery "sellers"... or at least a reduction in weasel words.
Much like Bad'... I'll retain a healthy level of distrust and cynicism for most of the purveyors of "too good to be true" batteries.

I've seen "dual rating" wraps for Basen's too. And Aspire has labeled their new 2500mAh as "20A/40A". I hope you're right and that this is the beginning of a new trend that sticks around.

 

[State O' Flux]

I've seen "dual rating" wraps for Basen's too. And Adpire has labeled their new 2500mAh as "20A/40A". I hope you're right and that this is the beginning of a new trend that sticks around.

Not to give you a big head or anything

... but I believe that your published testing has had a dramatic effect.
Not just on knowledgeable ECF members... but well beyond that, to vendors, wholesalers and vape market "re-labelers" as well. I doubt you would admit your contributions, or even take a moment to consider their substantive impact... but your work may very well have been the flash point for that "new trend" we look forward to.

And now... back to our regular programming.

 

[hypocritelecteur]

Battery companies are definitely watching the vape community. Its a huge emerging market. A single voice preaching accountability and exposing false advertising can have an amplified effect--especially one as studied and meticulous as our Mooch.
Mooch you're doing God's work here.

 

[Baditude]

Battery companies are definitely watching the vape community. Its a huge emerging market. A single voice preaching accountability and exposing false advertising can have an amplified effect--especially one as studied and meticulous as our Mooch.
Mooch you're doing God's work here.

I would agree, and I continue to propose that a Go Fund Me be organized for Mooch so that he is able to continue to finance his projects. He shouldn't be expected to pay for his own batteries for his research when we all benefit from his efforts.

 

[hypocritelecteur]

Definitely. I'd toss a few dollars his way.