Replace of relays with lighter mosfets for drone application

Other Hardware General Electronics
1

I am putting together a tilit rotor drone for my studies.

Its 2 props are powered by 2x 81A ESCs powered from 2 separate 11.4v Batteries.

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I am currently using a 5V latched relay for each ESC, switching on and off manually. (J1-Sw)
This works fine but the relays are heavy. My intention was to carry the switching using Mosfets but was dissuaded as the ESC can apply reverse voltage and damage the Mosfet.

Can anyone provide some guidance how to tackle this? The weight of the relays and their counter balast weight has rendered the craft too heavy and I would have to remove them. However I am uncomfortable not having a kill switch on an aircraft with 2x 10 inch blades spinning at 15000 rpm.

Michael

2

But only if you tell it to reverse. Do you intend to do that?

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3

Why would a reverse voltage damage a mosfet.
Mosfets are a switch one way, and a diode the other way.
Leo..

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4

Generally it will not. There are parameters you must stay withing. Vgs is normally specified as + or - in the 15V to 30V range Drain to source has a voltage limit, if you reverse the connection the substrate diode will conduct. Its RDSon will be in the range of 2X the enhanced MOSFET so current can be a factor.

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5

No. Can the ESC generate a back emf or harmonics back into the mosfet? Or become a generator somehow?

6

I was looking into SiSF06DN, however open to sujjestions

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