I tried Hunan Huahui New Energy Co and see the result

[Oaristys]

Hi folks ! Here is a buyer beware about Hunan Huahui New Energy Co.

I know that many of you keep an eye on the evolution of the promising lithium titanate (LTO) cells. I just take this moment to remind you to carefull and aware of the fake products. I've let my guard down in my engineering process. Here is my my story with Hunan Huahui New Energy Co.

I'm a product engineer and I work on the developpement of high reliability and highly customized solar roducts. I've seen these solderable capacitor shaped LTO cells offered on Alibaba, Aliexpress and some well known online suppliers like GWL, AA Portable Power Corps and other. I've ordered one hundread of two parellel cells 2.4 V 2,600 mAh LTO packs with an built-in BMS. What we've got, really late, was horrible.

Hunan Huahui New Energy Co. ship us pack made with these yellow 2.4V 18650 1300 mAh cells (See the attached logo). At first, they were looking good. They arrived charged at 2.5 V. But when tested, they behaved just like regular Lithium cells and charge normally over 4 V. On top of that, that said "BMS" was in fact just an array of shunt resistors that makes the BMS dissipate power as heat over a voltage threshold. There were NO min or max voltage cut off.

I had to solve that issue. When I've tried to get a feedback to Hunan Huahui New Energy Co., they first act as if they didn't understand the issue. Then they tried to put it on my fault and finally, faced to all the evidences, they admit the problem. But instead of solving it, they bought time by acting like they were working on it. Month of excuses later, they still didn't solve or ship anything.

There are few good manufacturers like Yinlong for LTO products, but Hunan Huahui New Energy Co. is NOT one of them. Don't embarassed yourself and avoid touching this supplier even with a 10 foot pole, unless you want to be your coworker's runing joke for a while !

Cheers !

 

[MarcoWasRight]

Have you tried opening one of those cells up? The fact that it charges up to 4V like a lithium ion cell (and I'm assuming displays the same charge/discharge graph as NMC/NCA/etc lithium ion) would make me believe that it is quite dangerous to cut open one of them....real LTO would be relatively safe if done outside with proper PPE just to be careful.

I have a funny feeling that under that wrap is an 18650 or slightly smaller cell that is an NMC 1300mAh cell hidden to look like an LTO cell. Perhaps even a 14500? It looks like 1300mAh is a bit outside of the max energy density a 14500 could contain so perhaps something between a 14500 or 18650? If the cell size you have is slightly larger than 18mmX65mm then I'd bet my last dollar that there is a low grade 1300mAh 18650 cell in there....

Which is kind of a strange scam since there will be NO capacity in the LTO range of 1.5V to 2.8V. I think LTO's range is mostly around 2.2V to 2.5V so an NMC cell would have already started dropping off rapidly and it would collapse under any kind of current and then would be damaged by taking it below 2V...like...wouldn't last more than a couple dozen cycles at most.

Edit: wait your thermal image seems to imply that there is just ONE cell inside those packs and they are using a 3.6V lithium ion cell to mimic a 2S LTO pack....wouldn't this be extremely dangerous since one would normally charge the pack up to 5.6V to 5.8V? Maybe that is the purpose for the....bleeder board? Prevent customers from learning of the scam by (hopefully) stopping the cell from exploding?

 

[zanydroid]

Replied to an ancient post

Also I do wonder if a nemesis competitor of this company was astroturfing against them