A possible contributor to the poor performance of the iJoy 20350’s I tested?

[Mooch]

I took apart both and found that the metal tabs from the positive and negative electrodes in the rolled up layers of the battery were poorly spot welded to the inside of the battery’s metal can.

These photos show the underside of the positive (top) contact of both batteries and, for comparison, a Sony VTC5A. I chose the VTC5A because it has the same 25A rating that iJoy claimed for these 20350’s. The differences in the spot welds is striking.



Both of the iJoy’s appear to have this spot welding done by hand. The poorer performing iJoy 20350 had one positive tab “burned” through by the spot welder and it was barely connected. The other cell, while not spot welded as badly, only had two spot welds for one of the tabs.

Both of the iJoy 20350’s had only a single spot weld connecting the two negative electrode tabs to the bottom inside of the metal can (no photos). The VTC5A had six welds, but of a smaller size. Both of the iJoy’s had one of the tabs burned almost completely through, barely connected to the metal can.

A single spot weld is inadequate for handling 25A in my opinion and, with one tab barely being connected in each cell, would contribute to the very high internal resistance of these iJoy cells (about 44mOhms, over twice that of the VTC5A).

This high internal resistance causes a huge amount of voltage sag making the cells I tested perform no better than a 10A rated 18350 and one a lot worse.

I am receiving another five iJoy 20350 cells for testing this week and next and will post the results of this testing as soon as it’s done.

 

[Heartsdelight]

I hope further testing of the 5 incoming batteries will provide better results. Thanks Mooch!

 

[Rossum]

I hope further testing of the 5 incoming batteries will provide better results. Thanks Mooch!

Even if new samples do provide better results, it would seem that iJoy doesn't do appropriate QC, and anyone who wants to use these cells at more than a fraction of their rating will have to do their own QC.

 

[spencercpu1983]

IJOY's re-wrapping cells with BS AMP ratings batteries are complete BS. First thank god i read your blog which im sure has prevented injury or even deaths from trusting the amp rating on the wrap. Because i was reading Blog when ijoy started switching cells using same wrap when we received some captain pd270 mods with the 4-leg cells i was able to give my customers the correct CDR and also called our wholesaler who was uninformed on the deceptive ijoy 20700 switching of cells. i get so upset when a company who is called out promises to change wrap in a statement sent to you (was not on their website, if they cared it would be on their front page) and over a year later same bull.... wrap and 3rd version with 5 legs to further deceive their customers. we no longer buy their mods or batteries. BTW their QC on mods started going down hill with their ....ty capo 100w and now the worst tack welds i have ever seen on a cell . Switched to Golisi S35 21700 and will be with 20700 as soon as we are out of their 1st version Panasonic version will switch to S32 or Sanyo NCR2070C. SHAME ON IJOY ONE OF THE MOST DISHONEST COMPANIES IN THE ECIG INDUSTRY!!

 

[mimöschen]

Doesn't everyone want to get his/her hands on the Sanyo 2070C?
It's a shame that this cell isn't available anywhere on the official retail market some very few occasional Vapcell rewraps aside.
The Molicel 20700A, which is rewrapped by Efest and EnerCig for example, is much better than the Golisi S32 though.

 

[Mooch]

Doesn't everyone want to get his/her hands on the Sanyo 2070C?
It's a shame that this cell isn't available anywhere on the official retail market some very few occasional Vapcell rewraps aside.
The Molicel 20700A, which is rewrapped by Efest and EnerCig for example, is much better than the Golisi S32 though.

Regarding the NCR2070C...good news soon, I hope.

 

[mimöschen]

The possibility of getting our hands on the 2070C would be great news indeed.
Hopefully not only as rewraps.

 

[NLVaper69]

I almost bought the 20350's a while ago, hoping I could find a 20350 tube which I didn't. Also thought It'd be cool to stack them in a 20700 mech for a series built. Reading this post now, I'm so glad I didn't buy these.

As alway great work @Mooch. You took the reviewing and testing to a next level with this way of dismantling a battery.