MOSFET on/off power switch - RC Groups
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Nov 06, 2017, 01:58 PM
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Mini-HowTo

MOSFET on/off power switch


No more sparks!

Here is a design for a very capable semiconductor on/off switch that can be built DYI and used with LiPos from 2s to 8s. Rated for 50 A continuous and 180 A peak.
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Nov 06, 2017, 03:43 PM
just look at it smokin'
z-matrix's Avatar
Quote:
Originally Posted by Robert Havener
No more sparks!

Here is a design for a very capable semiconductor on/off switch that can be built DYI and used with LiPos from 2s to 8s. Rated for 50 A continuous and 180 A peak.
Hi!

Almost the same as i drawn few days ago to a guy, but mine was better
Rearranged the resistors so they do not form a voltage divider, and dded a diode to catch inductive avalanche (safety and reliability)
Mosfet driver and schmitt triggered, debounced input signal conditioning is the next level.
Btw.: Maybe the proper forum would be https://www.rcgroups.com/diy-electronics-199 ?


Z
Nov 07, 2017, 04:31 PM
Registered User
A neat idea, but since I use my main power battery, via a BEC, to power my receiver and servos, I wouldn't want to risk the possibility of a switch (or its connections) failure shutting down the power supply. Or even the MOSFET failing, with the same result.
Nov 07, 2017, 06:59 PM
Registered User
pilotpete2's Avatar
MPI makes a no spark version of their heavy duty arming plugs for high cell count setups. You connect your battery with the arming plug removed, then when you want to arm the plane, you simply press a small momentary switch that charges the caps on the esc through a resistor, so no spark when you insert the arming plug.
A friend uses one on his 12S Factor 30cc. Works great!
Pete
Nov 10, 2017, 12:10 AM
Registered User
vollrathd's Avatar
Quote:
Originally Posted by Robert Havener
No more sparks!

Here is a design for a very capable semiconductor on/off switch that can be built DYI and used with LiPos from 2s to 8s. Rated for 50 A continuous and 180 A peak.
I've picked up a 200 Amp MosFet from Digikey a few weeks ago, and it will be used with my 4500 Watt electric Corvus. The maximum current pulled by the Rimfire 50 cc electric motor is 125 Amps. The Mosfet's maximum current capability is limited by its terminal screws. The silicon chip itself is rated at 350 Amps, with a 1000 Amp peak current rating. It cost $25 or so.

I'm going to put together a DIY in RCGroups in a week or so.

Right now, I'm dealing with losing our youngest son six months ago at age 45, and two days ago, my spouse of 55 years.
Nov 10, 2017, 09:02 AM
An itch?. Scratch build.
eflightray's Avatar
Here's a thread on anti-spark from 10 years ago =

https://www.rcgroups.com/forums/show...t=spark%20anti

and there are several other threads available, here's another --

https://www.rcgroups.com/forums/show...nti-Spark-lead

Also quite a few connector manufacturer do anti-spark connectors for RC, even Hobby King do them --

https://hobbyking.com/en_us/catalogs...=&q=anti-spark

.
Nov 14, 2017, 02:50 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
.
"The spark is your friend" ( CastleCreations).

No spark, then input caps are dead and rest of controller will soon follow. Preferably taking plane with it
Explanation
www.rcgroups.com/forums/showthread.php?952523-too-long-battery-wires-will-kill-ESC-over-time-precautions-solutions-workarounds


On the other hand, too big a spark is bad for connectors. Not to mention my nerves.
Solution: use a cheap extra sacrificial connector.
The extra/very thin wire will reduce current, no need for resistor. You'll still hear a (weaker) spark as an ok signal/indication.

from
www.mgm-compro.com



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