Mosfet Noob..

[Bar1975]

I just fried the trigger contacts in my M4. I said once i fried them i would look into a Mosfet to deal with the 11.1V Lipo i like to run.

So... for $4 i can pick up a new set of trigger contacts that will last me another season or i can take the time now to do this Mosfet upgrade and be done with this voltage challenge. I really don't want to drop a lot of money into this and while decent enough at teching my own guns i have no real experience with Mofet installation/setup. (I've read enough articles to have a basic understanding of what a FET is)

If i get a mosfet will i still need to use trigger contacts? (If i have to replace the physical trigger contacts to use a FET then i might as well just pick up the replacement set and leave it at that for now)

I run a moderately high speed set up and like to lean on the trigger for a few seconds from time to time... :twisted:

Can solve this for around $50 or so? If so what are the options..

[K3vX]

Yes, you can for under 50$

A mosfet could be described as a electronic device that handle the power delivery instead of you trigger contacts. You still need the contacts, but the will only handle the signal, and not the current.

You can get fairly cheap (in price, not quality) from Stealth at AirsoftStore.ca. to install them, there are guides everywhere, and all you need is a solder base.

I installed mine from no experience and it works great. There's a link on my sig.

[Hectic]

You may be able to clean up the contacts to work but once you get a fet (id suggest the merf3.2) you can wire two signal wires to the two contacts on the trigger switch. Once its wired like that the battery attaches to the fet the fet to the motor then a seperate set of smaller wires runs from the fet to the trigger switch. Once this is done the trigger doesnt carry the current at all just a small ammount for signal the battery power runs directly to the motor from the bat to fet to motor no scorching of trigger.
Plus you can set up burst function rof controll and some other features. I also think once you tell it the voltage of the battery it also will monitor the voltage so you dont over discharge lipos.

[ccyg8774]

Originally Posted by Bar1975

If i get a mosfet will i still need to use trigger contacts?

Depends on the type of MOSFET, some will have a "sensor unit" to replace the trigger contacts, some will still need the trigger contacts but only pass very small current on the trigger contacts to control the MOSFET.

Originally Posted by Bar1975

Can solve this for around $50 or so? If so what are the options..

http://www.airsoftcanada.com/showthread.php?t=89097
Probably the cheapest opition... But you have to be careful.

[Hectic]

http://www.airsoftstore.ca/index.php...roducts_id=135
The merf is a lil more then you want. They offer another one without all the fancy features that will solve the trigger contact issue

[K3vX]

Originally Posted by Hectic

You can wire two signal wires to the two contacts on the trigger switch. Once its wired like that the battery attaches to the fet the fet to the motor then a seperate set of smaller wires runs from the fet to the trigger switch.

This would be the best way to do it if you get a GATE FET, yes.
For his need, I'd get the 20$ one, small as heck and a good one. But, I think, the wiring will differ from Hectic one, I'm not sure.

[Stealth]

We are bringing back some Gate GDS-4005 by popular demand. Some users have asked for them but honestly the new PicoSSR handles most of the builds out there. (I just gamed mine for a whole day on a setup that pulls 37 amps continuously and up to 70 amps burst). John runs the GDS-4005 and the MERF 3.2 and those setups pull similar amps. I suspect that 90% of ASC builds won't see anywhere close to those kinds of draws.

So you have a few options: Gate PicoSSR, GDS-4005 (in a few weeks), nanoAB, all for under $50. MERF is available later on if you want to step up to more features.
I'm not going to plug my wares any more than other users already have but here's the link:
http://www.airsoftstore.ca/index.php...ex&cPath=35_34

If you absolutely want to do away with the trigger contacts you COULD try to find a AWS Stealth (how ironic) or Raptor but they've long been discontinued. Black Talon Concepts is supposedly coming out with its new Spectre which is a spiritual successor to the AWS systems, but it just seems to be forever in development. Look for it in June probably. Their Chimera unit has been relatively well-received by techs but in my opinion the form factor isn't conducive to space-constrained systems. It is however a very reliable system if you have the space for it. I think it actually has much higher power tolerances and much lower failure (if any) compared to comparable units on the market.

[cetane]

new Spectre which is a spiritual successor to the AWS systems

It looks like a good design too. No cutoff lever with. Lobe on sector directly trips switch.

[m102404]

if you can fit one of Stealth's mosfets...it's the surest, simplest, bombproof way to go. The "trick" will be fitting it and the wiring.

The latter gen AWS mosfets have good solid reports in use...so they're an option if you can get one.

Trigger contacts burn from arc'ing...that happens at the start and stop of a trigger pull. It's aggravated by high voltage batteries. Run full auto only on a 7.4V battery and your trigger contacts will last a long time....run semi only on a 11.1v and they won't.

If you're the type who tends to fiddle with their gun a lot and find yourself into your mechbox often...it's not that hard to simply swap trigger contacts when they wear. They're not that expensive...it's not hard to do if you're in it already....etc.....

Good mosfets have come down in price...a very good option if you can rework the wiring to fit your setup.

....problem free AEG afterwards....probably not. It's airsoft...so as soon as your switch setup is "nuke proof" your piston or something else will go and you'll be tearing apart your mechbox. LOL. best of luck

[Chiba]

If you want the simpliest functional MOSFET, and you can solder, you can build one yourself.

[moz_boz]

I have a P90 running on LiPos, all I did was install the Gate Nano AB. Simple straight-forward mosfet without tons of bells and whistles. Depending on where you live, I can do the wiring for you.

[Stealth]

Okay I lied. the GDS-4005 is completely discontinued.

[canabubba]

I bought threee fets from extreme-fire.com this winter, installed them (I'm not an electronics guy, but installation was easy), and they work perfectly. I bought the simplest, cheapest model, the SW-S, for $20.

I had the same issue - was running 10.8's and cooking contacts pretty frequently. My primary is a G&G, so clone switches don't work, and switches from G&G aren't cheap.

I'm now running 11.1's.....the motors get hot, but run nice and smooth.