Yolintech Reviews 

I reached out to Yolintech via email about compatibility concerns with a failing display and controller. Prior to ordering, Yolintech assured me that I could order the new display with "zero risk" money back guarantee. They never stated that this was a "custom-manufactured" item. On the contrary, they provided a purchase link as an "OEM Replacement".

Well, I just received the following response that should serve as a WARNING to any potential customers to STAY far AWAY from Yolintech:

"Our Compatibility Guarantee covers situations where a correctly purchased display does not work with a healthy, functioning e-bike system. However, based on the diagnostics and the videos you provided, the root cause of the issue is a faulty controller on your end, not a defect or incompatibility in our custom-built display.

Because this item was custom-manufactured specifically for your serial number, it is a unique product that cannot be restocked or sold to anyone else. Therefore, as per our policy for custom-made items, we cannot accept a return or issue a refund".

I am writing this review to warn other consumers about my experience with YolinTech's order fulfillment and customer support. If you are purchasing an aftermarket display, be aware that their quality assurance is highly unreliable, and they will abandon you if their hardware causes system damage.
The Purchase & Compatibility Trap
In May 2026, I purchased a Yolin YL-81F display directly from the YolinTech store (Order #YL410208 / #YL410198) for my Veefa X2 e-bike. I made this purchase based on a direct claim on their website's FAQ section , which states:
"How do I know if this display will work with my e-bike? The easiest way to check is to look at your original display. If you see the 'Yolin' on the back, it is guaranteed to be a perfect fit. As the original manufacturer, we have the database to verify the exact protocol. If you no longer have the old display, just send us your e-bike model or controller model, and we’ll check compatibility for you."
Before shipping the item, a representative named Jack even reached out to ask for the serial number of my original working display (Yolin YL-81C, Serial: 81C487C295Y0305) to seemingly ensure this "guaranteed" exact compatibility with my bike's setup. My e-bike uses a JYTcon (Yuecheng Electromechanical) brushless motor controller (Model YCKH172-179-487).
The Failure
The moment I connected the new YL-81F display, the bike powered up, but as soon as I applied load by pressing the throttle, the entire system instantly shut down. Following this, the bike became completely non-functional, intermittently displaying an "Error 02" communication error and shutting off whenever any function or PAS level was changed. Even worse, when I reconnected my original, perfectly working YL-81C display, it also threw Error 02, confirming the communication circuit on the controller had been damaged.
The Technical Evidence
I systematically isolated the problem using a digital multimeter:
Battery voltage was healthy at 54.4V DC.
Voltage at the display connector plug was stable at 53.6V DC.
I contacted the controller manufacturer (JYTcon), and their engineering team officially confirmed from their system logs that my controller runs strictly on the lidian2hao (锂电2号) protocol.
Despite their website's promises of verifying the exact protocol through their database, Yolin shipped a display hardcoded with an incompatible factory protocol variation rather than the standard S1/S2 data frame. I later proved this conclusively by swapping in a brand-new replacement JYTcon controller and plugging my original YL-81C back in—the bike instantly worked perfectly again, confirming the wrong display version permanently fried the original controller's communication lane.
Abysmal Customer Service
When I brought these diagnostic results to Yolin support, Jack completely dismissed the issue and outright refused to acknowledge the damage their hardware caused, stating that a display cannot cause a controller to burn out. He simply sent me a generic, copy-pasted Shopify support link meant for troubleshooting an unrelated Error 30 code. Once I provided the final technical proof and demanded accountability for shipping the incorrect protocol variant, Yolin support completely ghosted me and ignored multiple follow-up deadlines. As a result of their mistake and refusal to take responsibility, I was forced to buy a brand-new replacement controller out of my own pocket just to get my bike running again.
If you own a bike with a JYTcon lidian2hao controller, do not buy standalone parts from YolinTech, regardless of the "guarantees" on their website. They are prone to shipping the wrong protocol versions, and their customer service is entirely non-existent when their mistakes break your equipment. Save your money and time.
Date of experience: June 2026

Great service with fast and correct advice. Thanks Jonas