Blue series 12A ESC

From Hobbyking's website specifications:

Cont. Current: 12A
Burst Current: 16A/10sec
Battery: 2-4 Cell Lipo / 5-12 Cell Ni-XX
SBEC: 5V/ 1A Output
Size: 22*21*4mm
Weight: 10g
Fig 1:

Fig 1 shows the label of a Blue series 12A ESC (its clear shrink cover removed).

Note the conflict between the label and the Hobbyking web site specifications. The supplied printed manual also lists the ESC as 2-4S Lipo.

Fig 2:

Fig 2 shows the ESC. This uses a TFQP32 package Atmega8A, so connection using the Hobbyking chip adapter (332000007) is convenient.

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

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

Fig 3:
Atmel Atmega Socket Firmware Flashing Tool


Fig 3 from Hobbyking shows Hobbyking's Atmel Atmega Socket Firmware Flashing Tool (332000007).

Once a bootloader is installed, and fuses and lock bits set correctly, the ISP connection can be removed and future flash and EEPROM updates done via the servo connector using a Turnigy USB Linker.

Fig 4:
Turnigy USB Linker for AquaStar/Super Brain


Fig 4 from Hobbyking shows Hobbyking's USB Linker (T-USBLink).


The ESC contains a BEC rated at 1A in the manufacturers specifications. The BEC was tested alone at 12.6V input (equivalent to a fully charged 3S battery). The BEC uses a linear regulator which means that dissipation will be a function of load current and the voltage difference between input and 5V output.

Though it does deliver 1A for a brief period, it goes into thermal shutdown at continuous current above 0.43A at which the case temperature is a dangerous 100°. Temperature rise at 0.15A continuous was measured at 40° which would result in a case temperature of 70° (sufficient to burn skin on continuous contact) on a 30° day.

This ESC is variously rated for 3S and 4S. At 4S, continuous current rating is reduced by about 33% (to 0.1A), and at 2S the continuous current rating would increase by about 130% (to 0.35A).

Whilst the regulator goes into shutdown to protect itself from damage, the consequences of loss of power supply to critical model elements might be catastrophic, best to avoid thermal overload.

These ratings are for the BEC alone in still air. Heat dissipation of the ESC motor functions will reduce the BEC thermal capacity somewhat. The effect of forced air cooling in some scenarios may extend the current ratings of the ESC, it should be located with at least a good supply of cool air, even better some forced air cooling .

Stock vs tgy

The ESC was tested on a NTM 1312-2400 which has proved to have some starting difficulty.

The stock FW started the motor reliably, though sometimes creating quite a burst of speed before settling to a lower speed. tgy started the motor reliably and very smoothly, no sign of the speed burst apparent with the stock FW.

The motor was tested at about 33% load on 12.6V to evaluate the current drawn. Stock FW delivered 7500rpm @1A, tgy delivered 7500rpm @0.8A (a 20% reduction in input power)

Similar top speeds were achieved, at least as much power, though at about 10% less current with tgy. Evaluation of full load was difficult as the motor heats very quickly and internal R increases spoiling attempts to measure the performance accurately.

At all times, the ESC was barely warm.

tgy does not have some features of the stock firmware, eg card programmability, low voltage cutout, over temperature cutout.

By way of comparison, a Turnigy Plush (new series) on its stock FW delivered 7500rpm @0.85A, though at full power, speed and current were comparable with the Blue series. The Plush firmware was reliable and smooth in starting the motor, recovered from stalls well.


The Blue series 12A 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.

See ZTW A series 12A ESC for discussion of what appears to be OEM branding of the same hardware for discussion of wii-esc firmware.

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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