Test/Review of Efest IMR18650 3500mAh (Purple) 2016

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HKJ
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Test/Review of Efest IMR18650 3500mAh (Purple) 2016

Efest IMR18650 3500mAh (Purple) 2016
DSC_3259
Official specifications:


  • Rated capacity: 3500mAh
  • Nominal voltage: 3.7V
  • Voltage at end of discharge: 2.5V
  • Max. charging current: 4A
  • Standard charge: 2A
  • Discharge current: 10A
  • Pulse discharge current: 20A
  • Charging temperature range: 0° ~ 45°C
  • Discharge temperature range: -20°C ~ 75°C

Efest%20IMR18650%203500mAh%20(Purple)%202016-info
This is a high capacity and fairly high current cell.
DSC_3258
DSC_3260 DSC_3261
DSC_3262
DSC_3263
DSC_3264
Efest%20IMR18650%203500mAh%20(Purple)%202016-Capacity
These cells handles up to 10A fine, but I wonder why they have a difference in capacity.
Efest%20IMR18650%203500mAh%20(Purple)%202016-Temp-10.0
At 10A the surface temperature of the batteries raises about 50°C, this means they are very close to 80°C.
Efest%20IMR18650%203500mAh%20(Purple)%202016-Temp-15.0
Efest%20IMR18650%203500mAh%20(Purple)%202016-Temp-20.0
At 20A the temperature raises to above 85°C fairly fast and I terminated the test. Notice the dark red curve, it do not jump up, but down, this means the battery terminated that discharge, not me (i.e. the battery blew an internal fuse and is dead).
Efest%20IMR18650%203500mAh%20(Purple)%202016-CapacityTimeHours
Efest%20IMR18650%203500mAh%20(Purple)%202016-CapacityTime
Efest%20IMR18650%203500mAh%20(Purple)%202016-Energy
Efest%20IMR18650%203500mAh%20(Purple)%202016-PowerLoadTime
Efest%20IMR18650%203500mAh%20(Purple)%202016-TripCurrent
Efest%20IMR18650%203500mAh%20(Purple)%202016-Charge
Conclusion
The cells are supposed to be fairly good cells, but I do not like the difference between them and they are not 20A cells.
Notes and links
The batteries was supplied by Efest for a review.
How is the test done and how to read the charts
How is a protected LiIon battery constructed
More about button top and flat top batteries
Compare to 18650 and other batteries

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

1dash1
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HKJ wrote:
At 20A the temperature raises to above 85°C fairly fast and I terminated the test. Notice the dark red curve, it do not jump up, but down, this means the battery terminated that discharge, not me (i.e. the battery blew an internal fuse and is dead).

Disappointing.

I’m confused about the internal fuse. I thought this was an unprotected cell (like most IMR cells) and contained no circuits nor fuses. Question

Rule 1-1 as it applies to life, take it as it comes.

HKJ
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1dash1 wrote:
I’m confused about the internal fuse. I thought this was an unprotected cell (like most IMR cells) and contained no circuits nor fuses. Question

Forget about the IMR moniker, it does not really have much meaning any more.
The cell is a high capacity cell and it has an internal fuse like many unprotected cells (high current cells do usual not), this is usual build together with the high pressure vent, but it cannot see any sign the cell vented (It might have, it is not always visible).
This has nothing with the PCB protection to do, but it build into the cell.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

1dash1
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Thanks for the explanation. I thought it was all-or-nothing (protection board or nothing at all).

And thanks for the review!

Rule 1-1 as it applies to life, take it as it comes.

lionheart_2281
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1dash1 wrote:
Thanks for the explanation. I thought it was all-or-nothing (protection board or nothing at all).

And thanks for the review!

Yes, so did I.

I can’t believe this battery doesn’t compete with the 30Q

will34
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If efest keep naming these mid drain cells as high drain it won’t be long until someone gets hurt with their vaping mod. Some are drawing 40A+…

I wonder what cell is really inside?

shadockan
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Without being absolutely certain, rather it is the LG INR18650 MJ1.
But drain, looks and with the Samsung INR 18650 35E.
The positive pole but it is like the LG MJ1

flashination
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HKJ wrote:
1dash1 wrote:
I’m confused about the internal fuse. I thought this was an unprotected cell (like most IMR cells) and contained no circuits nor fuses. Question

Forget about the IMR moniker, it does not really have much meaning any more.
The cell is a high capacity cell and it has an internal fuse like many unprotected cells (high current cells do usual not), this is usual build together with the high pressure vent, but it cannot see any sign the cell vented (It might have, it is not always visible).
This has nothing with the PCB protection to do, but it build into the cell.

I think this is worthy of further explanation. >internal fuse <

 

 

 

 

 
 
'I pledge not to get drawn into cpf/blf arguments, & just understand that both places have their own merits'.

HKJ
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flashination wrote:
I think this is worthy of further explanation. >internal fuse <

It is usual part of the pressure valve, when the cell vents the connections is broken. The more common name is CID.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

MAD777
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Remarkably bad result considering the stellar performance of its 3000mAh stable mate.

Mike

HarleyQuin
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Thanks for testing HKJ

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KutKhemist
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shadockan wrote:
Without being absolutely certain, rather it is the LG INR18650 MJ1. But drain, looks and with the Samsung INR 18650 35E. The positive pole but it is like the LG MJ1

I thought so too. Can anybody confirm this?

SpaceCowboy
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If you are “lucky” enough to get these Efest rewraps.
This is LG MH1 3200mAh cell, and another is completely different cell.
Even Efest do not know what they are rewrapping anymore.
I was about to say:
“One is LG MJ1 and another is Panasonic NCR18650GA”, but test results and picture of the top side showing different cell.
Efest is playing very dangerous game with safety.
Rewrapping anything they could find for cheap Wink

Hoop
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With the wide availability of bare cells there’s really no point in buying re-wrapped 18650’s anymore if not for protection circuits, which this cell doesn’t have.

SpaceCowboy
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Agree,
The only problem is: After so many incidents with vapers, big manufacturers are watching more closely how and where their cells are used-misused.

Sony is the first company that will prohibit sales of bare 18650 Sony VTC series.

LG Chem will be the second to do the same with their unprotected 18650.

shadockan
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I personally think it is wrong to give my money to companies in the past have given samples of bad behavior as the Efest

Why not buy an LG – Sony – Samsung – Panasonic and even if I can not find batteries of those companies , why not buy from AW – KeepPower – Enerdan …….., that so many years have given correct battery .
And most important of all , is that not ashamed to mention what batteries are under their label .

shadockan
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SpaceCowboy wrote:
If you are “lucky” enough to get these Efest rewraps. This is LG MH1 3200mAh cell, and another is completely different cell. Even Efest do not know what they are rewrapping anymore. I was about to say: “One is LG MJ1 and another is Panasonic NCR18650GA”, but test results and picture of the top side showing different cell. Efest is playing very dangerous game with safety. Rewrapping anything they could find for cheap Wink

I believe not …………
The LG MH1 has three endings to the positive pole .
Here if you are lucky , you will buy the MJ1 and if you’re still lucky , it will be good battery .
Unless they changed the positive pole , putting everything else can be found in the warehouse ……
You never know with this company ………….

SpaceCowboy
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I think you did not read my post.
There is a picture of only one battery.
I cannot see the other battery (If HKJ post picture showing both batteries (battery top) I might be able to identify the other one).
For 100 % accuracy picture of both bare cells would be much better.

My point is batteries tested are definitely not the same batteries.
Simply because I do not think that same MJ1 will provide such a different performance.

So in simple words::
Efest Imren Mxjo are dangerous rewrappers.
Why?
If you buy set of four (or 2) batteries you might end up with 4 completely different batteries under the same label (wrap).

Now that is some serious danger, and should be addressed properly.
If HKJ can confirm that these 2 cells are actually both MJ1 then 2 thumbs down for LG.

shadockan
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I read what you wrote and I do not disagree .
I wrote only that the batteries of HKJ photo is MJ1.
Certainly not insist, because I have old monitor .
It may be difficult to see differences that need better screen

I have just seen that the Efest in 3500 puts MJ1.

I know for MH1 – 32E – PF etc . , But if I’m not wrong , this puts the supposedly IMR 2800 – 2900 – 3000mAh.

Conclusion:

We buy from the same manufacturing companies and all the rest ( except a some cases, of course ) , just to overtake .