Announcement: Beta85X ESC Failures

Dear customers and dealers,

As you may have known, or just have occurred on your drone, the ESC on Beta85X may burn up or catch fire. Please accept our profound apologies for this accident of Beta85X, which could not have happened to you.

Our team pay a high attention on it and launch a full investigation. For every each unnormal accident, we check out all the information(including emails, feedback and reviews), analyze the potential reasons in meetings, take steps to remedy this problem and make sure such accident won't happen again.

Here is an overview of this accident.

The defective Beta85X drones are all from the first mass bulk-production. The quantity of the first batch is 2000 pieces, but there are about 100 ESC fire accidents at present under statistic analysis. It was February 1st that we received the first vital feedback from Jai Cho on FB TBS Group. During the Chinese New Year, our teammates paid more attention on it and took steps once we were back to office on February 17th. Our marketing department gathered the first information by doing surveys, analyzing the pilots' feedback, while our R&D department tested the parts in different extreme condition, and restored the flight scenes as what you described.

Surveys on Facebook Page and Group

Until now, we have a primary conclusion.

1. A defective BLHeli_32 ESC is the cause of the fire. The percentage is about 1%. In details, the components are not soldered properly to the ESC. The problem doesn't occur in the situation when motors spin slowly or the drone hovers in the testing. But in real flying condition, the defective ESC could not stand the continue current and would burn up.

Why did these defective ESC boards use in the first batch?

Mostly, the lack of BLHeli_32 ESC testing experience is the cause of these 1% defective ESC boards in the bulk production.

2. The BLHeli_32 ESC and 1105 motors could not stand the 4S power continuely. In the testing, when we try to fly 85X in the aggressive condition (with many dives, powerloops and split actions), the 85X burns up in the air. This mostly happens in the percentage of 50%.

Here is a table showing the testing procedure and result.

Drones and batteries we use in the testing are Beta85X HD drones and Tattu 4S/3S 450mAh batteries (fully charged).

Flying Condition
Group A
Tattu 4S
Normal, with some dive/powerloop actions
2 pieces catch fire when throttle up after dive, 1 piece crash and no smoke.
Group B
Tattu 4S
Aggressive, almost full throttle all the time, with many dive/powerloop actions
3 pieces catch fire in the air, 2 pieces crash and no smoke
Group C
Tattu 3S
Aggressive, almost full throttle all the time, with many dive/powerloop actions
No one catches fire or crashes
When we inspect the crashed drones (the ones that didn't catch fire after a crash), we find that some components fell down after the solder melted as the picture shown below.

Based on the result above, we test the ESC and motors seperately with tools. The result is as follows: The ESC and motors will catch fire after 15 seconds when we fly in full throttle with 4S battery.
Voltage Full throttle Current Continue time
11V(3S-3.7V) YES 6.5A Always
15V(4S-3.7V) YES 8.5A Blow after 20 seconds

Why did this issue exist in the design of Beta85X?

The original testing method is limited and imcomplete. Firstly, we didn't use the motor meter tool to test the power system seperately. Secondly, we used to fly the 85X HD drones in slow speed most of the time. As a result, we didn't find out the esc failure problem on the 50 pieces prototype drones.

Explanation about some pilot's doubt.

1. The motor has not spinned yet, while the drone burnt up when it was armed and throttled up.

Reply: The ESC or motor may be damaged in your last flying loop with 4S battery. Also, as shown in conclusion 2 above, some parts might have already been missing when you flew 4S battery.

2. Why did my 85X still catch fire in the air with 3S battery? 

Reply: As the conclusion 1 shown above, it is possible that the defective ESC was assembled. Further on, we noticed that a crash and damage on the motors could cause the ESC burnt up.

How to solve the problem.

1. To prevent this from happening again in advance, please do not use 4S battery when next fly.

2. Based on BETAFPV warranty policy, we will take 100% responsibility for all the burnt drones, so that we could better support all our customers. Belows are 2 solutions for dealers and customers which are from web shop directly.

#1 For dealers Please contact your sals representative directly, who will be always ready for your after-sales services.

#2 For customers which are from web shop Please go to this blog in which we have listed several solutions for you to solve the problem.

As a Chinese proverb goes, a fall into the pit, a gain in your wit. This accident reminds our team that we should always be humble, modest and prudent. In the area of whoop drones, we still need more people to participate, communicate and progress together. Howewer, we will not stop by this accident or cease to advance. What doesn't beat us will only make us stronger. On the other hand, this accident has alerted our company to develop or update series of new procedure for manufacture and test standard for new products, which could ensure more great performance and high quality FPV products to the pilots in near future

Last but not the least, much thanks for Albert Kim's survey on Youtube and Andy RC's feedback in the video. Thanks for Nate and Cato yuen's continue testing after this accident occured. Thanks for every pilot's feedback and advice.


                                                                                                      ------ BETAFPV Founder Frankie


  • i just receive this beta85x 3days ago.just fly it 2times the third time one of the motor didnt spin well..maybe esc or motor or fc problem..i just use 3s 450mah that i bought from u guys..what should i do? can u guys respond to my problem..

    halimi hamdan
  • How can I know if I have the second batch ESC? And where they also tested?

  • All the esc from 65x forward have been having this issue… The larger the motor and or battery the sooner it happens..

    Richard Mohns
  • I buy a BETAFPV 85x still not me to come, not if as soon as it arrives deveria prove it or not, that I recommend you, because and bought many lipos of 4s tatto 450mah, was bought on 6 of Frebero 2019 I want to use it to 4s if or if , because then Huviera bought another one,

    aitor rodroguez bea
  • Thank you for the information and honesty! I only run mine on 3S and I bought my ESC separately as a part (since I built my own 85X with parts I had). I took a precaution and reflowed my ESC, and so far, it is performing well. Would you like more people to do testing for you? I’m happy to help. I love your products!

    Rob Harrison

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