Bench Test Results: AM04 - 45A 4000mAh 21700

[CamLight]

THIS REPORT IS BASED ON MY TEST RESULTS, RESEARCH, AND DISCUSSIONS WITH PEOPLE IN THE BATTERY INDUSTRY. ALL STATEMENTS HERE ARE JUST MY PERSONAL OPINIONS AND ARE SHARED ONLY FOR INFORMATIONAL PURPOSES.

The full AM04 test report (two documents) is done and posted to my Patreon wall so I can easily keep them updated in one place if anything changes. You can access it here: https://www.patreon.com/posts/bench-test-am04-122489376

The report is huge so here’s a quick overview…

• The AM04 is a rewrap of the Ampace JP40.
• The AM04 performs a touch worse than the other JP40’s but you probably won’t notice the difference.
• There are serious AM04 performance inconsistency issues at high power levels.
• There are multiple AM04 datasheet errors and ratings that can cause rapid cell degradation and even cell failure. This affects user safety.
• An uncalibrated prototype testing system and inconsistent, slow, and inaccurate temperature sensors were used to set some of the AM04’s ratings.
• A video on Austin’s web site falsely claims that it shows AM04 cells being made.
• The AM04 has none of the required safety testing and regulatory documents. Pack assemblers, make sure your insurance still covers you if using this cell!
• Austin was given a chance to preview the test report and respond with a statement that I would include in the report. I have never offered this to anyone before. Unfortunately, his statement was just an appalling mix of bad science and a sales brochure. Such a wasted opportunity to address all the issues I found.

For more information, please read both documents as the second one has a lot of additional test results. I’m happy to answer questions here too.

 

[BlueSwordM]

Oof, 18650-21700.com and Austin will be absolutely cooked after this.
Also, lmao for 160A/2s pulses. These are obscene pulse ratings if you don't attach big asterisks to them.

The usual rule for pulsing is that with careful parameter, you can use calculated 2x max current pulses to perform some interesting shenanigans during <1s periods (>1Hz). That would be 20C <1s, not the monstrosity of 40C/2s.

I'm also scared from the fact that these cells might be third shift cells, and that the seller is pocketing the extra money for dubious rewrapped cells.

Finally, why was he using thermistors instead of thermocouples? Thermocouples aren't very expensive at all...

 

[CamLight]

Finally, why was he using thermistors instead of thermocouples? Thermocouples aren't very expensive at all...

I think only thermistors are supported by the VESC controller-based test rig he has.

 

[BlueSwordM]

Oooh, I know understand why they sold the AM04 at the same price as the JP40: they wanted to make it seem as legitimate as the latter cell, which both increases their profit margin and their sales volume.

Super scummy behavior.