Review: Tekko32 F3 Slim ESC by Holybro

by Oscar

The Tekko32 F3 Slim ESC by Holybro is very light weight and compact, designed to be mounted on the slim arms of racing drone frames without creating extra air resistance. Check these out if you are looking to push the performance of your mini quad.

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New to ESC? Don’t forget to check out our ESC buyer’s guide.

Where to Buy?

Banggood: (use coupon “Tekko32F3” to get $5 off)

In the bag, you will find a 220uF 35V capacity (of unknown brand), 3x 24AWG silicone wires for signals, and 2x 16AWG wires for power. All wires are 10cm long.

Specs and Features of Tekko32 F3 Slim ESC

Supporting 3S, 4S, 5S and 6S LiPo, the Holybro Tekko32 F3 Slim ESC have a continuous current rating of 45A, 50A burst.

It’s has the fastest micro controller in all ESC’s at the time of posting, yet the F3 MCU doesn’t actually make any difference right now. Hopefully it’s more future-proofing when BLHeli_32 firmware takes advantage of the extra processing power.

I have to say, Holybro has gone a long way when it comes to ESC size and power. Take a look at the size comparison below, on the left we have the Tekko32 F3 Slim rated at 45A, and on the right is the previous Tekko32 ESC (F0) rated at 35A.

size comparison, Left: Tekko32 F3 Slim 45A; Right: Tekko32 F0 35A

Left: Tekko32 F3 Slim 45A; Right: Tekko32 F0 35A

The F3 Slim weighs at only 2.5g (without wires), which is less than half the weight of its older brother, the 35A ESC of 5.4g!

Racing frames are designed to be as light as possible, therefore the arms are made extremely slim with less than 10mm width. For this reason, most “slim ESC” on the markets have a minimum width of around 10mm. However the Tekko32 F3 Slim are slightly wider than that, at 12mm.

Closer Look at the Tekko32 F3 Slim

Here are some close up shots of the Tekko32 F3 Slim ESC.

Solder pads are well sized with decent separation, that should make soldering easy.

It has a similar design style to the Tekko32 F3 Metal ESC which we recently reviewed, both use  busbar for lower resistance and better cooling.

You can probably tell that the current sensor looks a bit different here. Holybro is using what they call “low resistance” shunt resistor here. Lower resistance is a good thing as it generates less heat and improves efficiency.

Notice on top of the MOSFET’s, there are little square metal plates. These act like heatsink to the transistors and enhance cooling ability. After checking with my multimeter, I found they are actually connected to one of the MOSFET’s terminals (drain). That means the metal plates might be connected to battery voltage when the motor is spinning. Therefore you should definitely put heatshrink tube or electrical tape over them to prevent electrical short.

The three small solder pads are, ESC signal, telemetry, and LED. There is no signal ground pad, which they replaced with LED signal here.

Most BLHeli_32 ESC these days have built-in LED’s, and it’s configurable in BLHeliSuite. But since the Tekko32 F3 Slim doesn’t have an built-in LED due to the lack of space, they let you connect external WS2812 type LED’s to the ESC via the solder pad.

Again, because of the compact form factor, there aren’t many filtering capacitors onboard either. You will likely need to run external low ESR capacitors, and therefore they’ve provided one with the ESC.

The Tekko32 F3 Slim ESC is a great option if you are looking for tiny ESC’s, especially for racing quads and endurance builds where weight plays a huge part. However there are better options out there if you are looking for low noise performance because of the lack of filtering capacitors onboard. For example the new Tekko32 F3 Metal, or even the older Tekko32 35A are some of the “cleanest” ESC.

Update (25 Mar 2019): You do have to use the capacitors they provide in the kit, otherwise you are going to get lines in your FPV. Or at least use one big 1000uF cap in the main power.

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Shurtugal 30th April 2019 - 5:52 am

Oscar thank you for your analysis. Start in the FPV world 3 months ago and your blog is a great help in all this time

Mark Pfeifer 28th February 2019 - 5:05 pm

Those look nice, but I don’t see any advantages to running individual ESCs (especially if you have to solder 4 capacitors on). I have a Tekko32 Metal 65A 4in1 on order right now, I think that’s the “state of the art” solution right now….

Steve 2nd March 2019 - 8:55 pm

advantage is that when one blows you can just replace one esc not all 4.

Rc_Edgy 28th February 2019 - 2:08 pm

Hi Osacr and thank you for this review :)
Do you think these esc’s will handle 6 with 2208 1800kv motors ?

Oscar 11th March 2019 - 3:56 pm

Don’t see why not as soon as they are not pushing too much amps through them :)
I am actually going to use these on my 7″ quad, 2407 1600KV motors