My First MOSFET ... need help

[Bar1975]

hey folks.. i have a lot of various airsoft guns and would like to start using a mosfet accross as many of them as possible... as i use them in games and what not.

I don't want to install one per gun as that will get rather expensive so what is the best multi purpose 'swap-able' Mosfet out there these days?

I know to get the best benifits of a mosfet you would wire it directly into the gearbox and i'll end up doing that with a few of my more pampered guns but for my first Mosfet i just need something i can add via Deans directly in the path of the battery and use with all my guns.

Only really looking to protect my trigger contacts and some snappier trigger response but i'll take all the additional bells and whistles as well..

i was considering the GATE MERF 3.2.. or something less expensive like the GATE NanoASR/AAB.. anyone have experience using either of these units?

[devbro]

Are you running 11.2V batteries? If not then use of mosfet will not be that beneficial to you. If you do and all you want is to protect your trigger then I suggest opening the gearbox and waxing your trigger contacts using teflon lube. It will protect your contacts against arching. Plus it will be much cheaper and less headache compared to new wiring.

If you still want mosfet, both of those mosfets are good. MERF GATE is the better of the two. This was what I was about to suggest anyway.

[lurkingknight]

inline units are not mosfets, they are fire controllers. They will not regulate battery current through the trigger contacts, they will not prevent arcing that burns them up. If you want burst fire or lipo monitoring, that is what they are good for.

To properly install a gate asr, merf or aab, you need to solder in the trigger wires so you have 3 or 4 wires depending on your configuration to plug into the mosfet. Plugging it inline will not give you any benefits of the mosfet itself.

[Zeroroaster]

If you do want to make a mosfet switchable between guns, then you need to prep your harnesses accordingly. Run one set of wires from your contacts with the desired connector to the battery compartment. Then run your motor and battery wires as required. If you prep your battery compartments you can plug and play, otherwise, it's one for each.

When I get around to putting in mosfets into my guns, I'll be running plug and play contacts for the mosfet not only from the prospect of interchangeability (even one type of mosfet to another), but in the event the mosfet cooks, I can have it replaced in no time. Nothing beats a direct, well soldered permanent connection, but in the interest of servicing the unit, it's not a bad idea.

[ThunderCactus]

What he said^
You can use the GATE nano across all guns, but you need to wire them all to do that. Which means you need those JS connectors or whatever they are, but more importantly you're probably gonna pay a tech $45 a gun to do it.
Then there's resale, is anyone gonna buy a gun without the mosfet it's meant for?
What's an extra $15-$20 for a simple mosfet?

If you're running an 11.1v battery, you need a mosfet.
If you're running a 9.6 mini or a 7.4 lipo, don't worry about it.
If you want the burst fire, learn how to fire bursts with full auto. Burst fire is useless and it's REALLY not worth the extra $45/gun plus the FET that it's gonna cost you.

[Bar1975]

some great feedback guys thanks.... looks like im breaking out the soldering iron after all. Didn't really research mosfets all that much until recently... that is tonight... that is after reading all your feedback and realizing how ignorant i really was!

I run 11.1's predominantly and preferrably.. ive tech'd my own guns and others for years so the complexity of installing any of the units won't be an issue... always enjoy an actual reason to open a gearbox besides for the fun of it.

My issue (not really an issue in reality) is that i have over 25 guns right now and from one weekend to the next i'm using them all in the course of a season.... i REALLY like airsoft

[ThunderCactus]

I would thin out the collection, thats a lot of upgrade parts lol

[Bar1975]

I picked up the GATE NanoHARD mosfet today. Anybody use this one?

Will install this puppy and see what this mosfet noise is all about

[lurkingknight]

all mosfets will perform the same basic function, there's really no 'noise' about them, either it does it's job well or it burns up because the spec on the fet itself wasn't high enough to handle the amperage spiking that occurs in airsoft guns. GATE fets are known to be on the lower end of amperage handling.

They should be reasonably ok for stock or close to stock systems or low draw motors like zci or shs high torques, or any higher TPA neo magnet motor. If you want top speed output like 40rps from 13:1 gears and a tienly 35000 though or a 45000, you're probably going to burn up the fet sooner rather than later.

Most stock guns draw about 16-18 amps of power. Slower motors will draw less. It wouldn't be out of the realm of possibility to triple if not quadruple that number to assume what the amperage spike is on motor startup. I think the nanohard might be higher, but the other gate fets (nanoasr sticks out in my mind) from memory were closer to 20-24 amps constant draw. A lonex A1 motor on 13:1s draws 22-24, so you can see how close that rides the line of the nominal performance spec. Add in repeated semi and your spikes could hit 66-88amps for milliseconds, over time this can burn up the fet. This is also why when building for high speed you need to understand burst rating on lipo packs, and why you need to plan for as much mah and C as you can stuff into your gun.

You can make quick change harnesses for home made 3034 fets which are common in higher performance guns, all you need are high amperage banana connectors and you can just move the fet from one gun to the next, provided you take the time to solder it all in.

Honestly I would just install fets in 2-3 of your favorites and call it done.

If you play with a variety of guns, I would install fets when trigger contacts burn out. There's no point in opening them all up to solder and run new wiring, you might as well just pay the extra 25 bucks for the whole fet with wiring.

Guns I would want to protect trigger contacts on would be prioritized: guns using microswitch triggers or have proprietary contacts that are hard to replace because of availability.

If everything is v2, I wouldn't bother doing all of them if they all aren't being used extensively.


As for using lesser batteries, I've seen vfc contacts burn up on 8.4 nimhs after only 1 year of use as a primary.