ESC size

A little advice please.

I’m building an inspire clone so around 650 / 700mm frame equivalent. The motors will draw no more than 25A from a 6S battery at a burst, normally less than 20 A So 30amp 6S escs sgould be capable. Looking at 4 in ! ESCs some are recommended for smaller frames only. Why is this? I thought if amps and voltage requirements were met then an ESC is an ESC. Where does size of the aircraft come in?


I have little bee 30A 6s esc on my tarot 680 pro turning 400kv motors with 13" props. No problem with them.

Do you have a link to some of those esc’s?

It’s e-bay

@stevesb Thanks for the recommendation Steve, they are one of the ESCs on my eBay watch list / Banggood wishlist.

I’m finishing a 3D printed Inspire clone that I obtained part built. For a large UAV there is surprisingly little space in either the real thing or in the clone. The clone uses the battery space for a PDB - the raising mechanism servo draws a fair current I think. So I was thinking of a 4 in 1 ESC in the same space with long power leads going inside the tubes to the motors.

The Little Bee may fit in the tubes to keep things neat but I would worry about cooling.

@notveryprettyboy I looked at the Spedix IS40 40A 4in1 ESC (3-6S) (20mm) and the specs said:


The Joshua Bardwell 30A 4 in 1 doesn’t mention size other than ideal for freestyle or racing drones

This one seems a bit of overkill but it gives me the opportunity to up rate the motors if I find performance with 4 x 4114s too sluggish. The solder pads could also be placed in the tubes close to the motors with bullet connectors directly soldered although I think it safest to keep the number of joints, whether mechanical or solder, to a minimum.

All advice gratefully received as my only experience with ESCs is the full size things that cable-tie to the arms of hexacopters/

Ah yeah. It has 20mmx20mm hole spacing. So ideal for a small 3 or 5 inch racer maybe as they are short on space and have mounts suitable for 20x20 rather than 30.5x30.5. But absolutely fine for a bigger quad if it fits ok. BLHeli32 is better than BLHeli_S though if you have the option.

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Thanks for the info. I needed to be sure that I wasn’t buying something that wouldn’t cope with a larger aircraft. space is at a premium, I’m going to fit two batteries, one either side like saddle tanks and run them in parallel. That should leave enough space for controller (Naza or Wookong as I have them lying around), video TX and switcher for FPV and main camera and RX and satellite.

Will be a long term project :slight_smile:


As long as the amp rating is enough for the current drawn by the motors you will be fine. That being said you may need to adjust the motor timings if your swinging big ass props but that’s all done in blheli

Thanks, I’ve now got a couple of 32 bit 4 in 1 Escs on my wish list now. I’ll be using 14, possibly 15 x 5 or 5.5 props I think. Do I need to get involved in Windows anywhere along the line with Blheli? I’m not keen on Mickeysoft getting anywhere near my computers!

No idea mate. Macs are for hipsters lmao

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Apple products in general :slight_smile:

Open-source software for me.

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There’s an android app too. Only run windows myself though.

Thanks for that, app installed and, at first sight, looks fairly easy to use.

Word of warning blheli and blheli32 are different and you can break stuff on the esc’s by using the wrong one

Thanks for the warning. I ordered an ESC from the Banggood website as I have had good service from them and also got a good discount on top of the sale price. They had put a link to the correct Android 32 bit app in the listing,

Sounds like an easy mistake to make, presumably several people have done this?