Hobbyking F-20A 20A ESC

From Hobbyking's website specifications:

Constant Current: 20A
Burst Current: 25A
Battery: 2-4S Lipoly / 5-12s NiXX
BEC: 5v / 3A
Motor Type: Sensorless Brushless
Size: 54 x 26 11mm
Weight: 30g
Fig 1:

Fig 1 shows the label of a F-20A ESC (its shrink cover removed).

Fig 2:

Fig 2 shows the ESC. This uses a TFQP32 package Atmega8A, so connection using the Hobbyking chip adapter (332000007) is convenient. There are a set of ISP pads on the top right of the board which could be used.

The three capacitors nearest the top right corner are the 1000pF BEMF filter caps.

The heavy conductors are nominal #12 (2mm dia) and don't easily fit into 2mm connectors. If you want to use 2mm connectors, you will need to replace the wires with #14.

Fig 2a:

Fig 2 shows the lower side of the ESC. It has a quite substantial heat spreader to assist in cooling of the six N FETs.

tgy bs_nfet.hex 2013-04-24 was installed and tested.


The ESC contains a BEC rated at 3A in the manufacturers specifications. It has two 7805 regulators in D packages, and it appears there is a separate regulator for the MCU.


The F-20A ESC is a sound basic ESC with integral BEC. The BEC ratings are overstated for continuous use. The stock firmware worked acceptably and has the advantage of some protection features and convenience of card programmability.

The ESC uses common Atmega8 TQFP32 hardware that is readily flashed with third party firmware. The tgy (SimonK) firmware delivered smoother low speed operation and lower current drawn for same motor output power.

No warranty

Advice (or a warning) to those who might try to replace the firmware on an ESC. Most FW comes with no warranty, and typically the OEM firmware is read protected so you cannot save and restore it. In most cases, changing the firmware may terminate any seller's warranty.

In making hardware or firmware modifications, you may damage the ESC, or the model may fail and cause consequential damage.

The author gives no warranty and makes no representations about the suitability of this technique or any particular products for the end user, or the accuracy of the article content, they must inform themselves and make their own judgment aware that there are risks. If you are not competent to do these things, don't do them!


The article should not be seen as a recommendation or endorsement of any products.

The products shown in this article are from Hobbyking who manufacture products under a range of brand names, possibly creating an illusion of competition. Their products tend to be low in cost and low in quality, products are not good value when you have to throw a proportion of them in the rubbish because the cost of returning them exceeds the value of the replacement which is only available after excessive delay, many follow ups and haggling. If you see the claim [o]ther stores will force you to ship the product back to China in full retail packaging every time! Hobbyking's warranty service is professional, fair and fast, don't believe it, it doesn't work that way in my experience... I get better service from most eBay sellers!




Version Date Description
1.01 25/05/2013 Initial.

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