infected Posted August 24, 2011 Report Share Posted August 24, 2011 I can't figure out any reason as to why it wouldn't work. Link to post Share on other sites
badwillhunter Posted September 9, 2011 Report Share Posted September 9, 2011 Hi all I want to fit a mosfet, read up on them I can't seem to find one with the reverse brake on it could some one point me in the right direction please. Cheers Jay ! Link to post Share on other sites
Tommygunn Posted September 10, 2011 Report Share Posted September 10, 2011 I think I'm going to build a basic, non AB, Mosfet circuit but could someone give me some advice on the componentry I've chosen. There are two Mosfets that I'm considering, and I'm unsure about the resistors. Here are the specs: Mosfet Hexfet IRL2203N: http://www.irf.com/product-info/datasheets/data/irl2203n.pdf Vds = 30V Id = 116A(25C) / 82A(100C) Pd = 180W(25C) Rds(on) = 7.0mΩ Mosfet Hexfet IRF3205N: http://www.irf.com/product-info/datasheets/data/irf3205z.pdf Vds = 55V Id = 110A(25C) Silicone Limited / 78A(100C) / 75A(25C) Package Limited Pd = 170W(25C) Rds(on) = 6.5mΩ Resistors: 30K Ohm 0.25W Carbon 100 Ohm 0.25W Carbon or the same in 1W, 2W or 5W Metal. So, which Mosfet would I be better off with, I presume the the first one with the highest Pd? Also, could someone clarify that extra info for the Id of the second Mosfet i.e. 3x ratings and descriptions? I'm guessing that I can go with the low wattage carbon resistors, correct? Cheers, Tom. Link to post Share on other sites
Tommygunn Posted September 12, 2011 Report Share Posted September 12, 2011 No one willing to advise me? Tom. Link to post Share on other sites
SteevoLS Posted September 12, 2011 Report Share Posted September 12, 2011 Either one should perform fine, given that it's just a basic "dumb" FET. This is why we use MOSFETs! I finally opened up my SPR to add a MOSFET and new shell + trigger. Link to post Share on other sites
Tommygunn Posted September 12, 2011 Report Share Posted September 12, 2011 Thanks. Am I ok with the low wattage carbon resistors? I read somewhere that it is not recommended to use a mosfet with anything less than 8.4V or 9.6V, I can't recall exactly. Is this true, as I want to use it in conjunction with a 7.4V Lipo? Tom. Link to post Share on other sites
SteevoLS Posted September 12, 2011 Report Share Posted September 12, 2011 I'd recommend a MOSFET for any gun. They can only improve the performance, assuming they're assembled and installed correctly. I use MOSFETs in everything from 7.2v NiCDs all the way up to 14.8v lipos. Those resistors should be fine. Link to post Share on other sites
Tommygunn Posted September 13, 2011 Report Share Posted September 13, 2011 I am looking to place the Mosfet circuit up front, inside of the RAS, while my battery will be in the buffer tube. Have I drawn my circuit correctly? I presume it does not matter where the Mosfet sits in the circuit just as long as the positive connects to the Drain and the negative to the Source? Tom. Link to post Share on other sites
sneaky rat Posted September 23, 2011 Report Share Posted September 23, 2011 Hello i have a extreme fire mosfet in my m4 but i really don't like it the trigger response isent as good as i would have liked so is it just a case of cutting it out and soldering the wires back together or is there something special i have to do. Link to post Share on other sites
infected Posted September 23, 2011 Report Share Posted September 23, 2011 Your trigger response isn't going to get any faster by removing it. What battery, spring and motor are you using? If you pull the unit out you will need to rewire at the trigger switch. Link to post Share on other sites
LordElpus Posted September 23, 2011 Report Share Posted September 23, 2011 your battery or motor may well be holding it all back. Link to post Share on other sites
sneaky rat Posted September 23, 2011 Report Share Posted September 23, 2011 im using 9.6v its a g&p m120 and i dont know what spring it is Link to post Share on other sites
infected Posted September 23, 2011 Report Share Posted September 23, 2011 What brand and capacity (mAh) is the battery? Link to post Share on other sites
sneaky rat Posted September 24, 2011 Report Share Posted September 24, 2011 dont know the name but its those red ones you get everywhere and its 2200 mah Link to post Share on other sites
Powerslave Posted September 28, 2011 Report Share Posted September 28, 2011 Hi guys I'm having a big issue. I have made an AB mosfet system using Doubletaps guide here: http://www.cerberusairsoft.co.uk/Mosfet/ I built the mosfet a while ago but never got it running and assumed I had some knackered batteries. I finally received my new battery (a flightpower evo-pro 30c (30c continuous, 60c burst) 4200mah 7.4v) the other day, charged it (with an Eclipse LX61b) and connected it up only for nothing to happen. The only thing I could think to try was to swap the thin wires I was using to connect to the trigger switch around (although I couldn't see how that could make a difference what with it just being a mechanical switch). I wired up my battery to the open gearbox (V2) via the mosfet system with the motor (golden eagle super high power) electrical taped to the table. I pulled the trigger and the motor activated. However upon rebuilding the gearbox and pistol grip assembly with the motor inside I reconnected the battery, selected full auto and pulled the trigger. The motor felt like it was trying to move but was jamming on something and so I removed the bottom of the grip and pushed on the bottom of the motor until it was in the gearbox and pulled the trigger again. This time the same thing happened but I could see some smoke coming from the motor. I thought I may have wired the motor backwards as the terminals are not clearly marked (both sides have some red paint on them so I assume the one with more red paint than the other is positive), so I tried the other way round and nothing happened at all. I am beginning to think I imagined it working yesterday as I am sat here now just looking at it and poking it with no real idea how to troubleshoot. If you understood any of the above (I certainly don't) then whatever suggestions you have will be appreciated! Cheers, Mike EDIT: Update: I just had the same thing happen again. I had the gearbox open and all the wiring connected up. Pulled the trigger and the motor spins. Put it back together (pistol grip back on with motor in it), selected full auto and pulled the trigger. There was a click noise as if the motor was trying to spin and I felt a jerk which would indicate the same. After this I let go of the trigger for a second or two before pulling it and holding it on (I believe stress is getting the better of me). This time nothing in terms of movement however the mosfet began to smoke and sizzle. I immediately disconnected the battery. Again this problem is well beyond my expertise. Could it be the mosfet itself is a bad design/badly made? This doesn't seem so due to the fact that the motor spins very well when the gearbox is apart. Could the gearbox itself be jammed causing the circuitry to overload? I simply don't know. Link to post Share on other sites
Road_Dancer Posted September 28, 2011 Report Share Posted September 28, 2011 Does it work without the mosfet? Link to post Share on other sites
Tommygunn Posted September 28, 2011 Report Share Posted September 28, 2011 Got my Mosfet today and immediately went to work on it. Not the usual installation as I have the battery in the buffer tube and the mosfet up front. It worked out very nicely without any bother or fitment issues. Plenty of heat shrink and then superglue to hold all the components together. Lastly, one large piece of tubing will cover the whole ensemble. Still yet to test the circuit under load but without a load it works a treat. Tom. Link to post Share on other sites
Simo_Hayha Posted December 28, 2011 Report Share Posted December 28, 2011 I was referred to this thread by Hedganian, p'raps you gents can help. I'm looking for a one or two-wire MOSFET diagram of a finished AUG with CLEAR pictures. It seems the rest of the internet is terminally retarded when it comes to taking any kinds of pictures of a finished product. Hed said that it's not too different than any other mosfet installation, but the pictures I've seen online seem to have the mosfet wires attached to the full auto circuit contacts on the outside of the gearbox. I'd really prefer to do this the right way the first time, and a clear picture of a wiring diagram (not something someone drew on MS Paint) would be immensely helpful. Thanks in advance. Link to post Share on other sites
paranoiddroid Posted December 29, 2011 Report Share Posted December 29, 2011 ok I have a p90 I want t put a mosfet in with AB for reliability and just protection, want to go lipo eventually and also ideal wnt to change auto to a 3 round burst what are my options? been reading up and getting hopefully lost and confused. Link to post Share on other sites
Tommygunn Posted January 2, 2012 Report Share Posted January 2, 2012 Currently I have the IRL2203N fitted to my 1J M4 and I'm looking to buy some more Mosfets for other similarly rated guns. From looking at the specs below will I get any perceivable advantages from paying extra for the alternative mosfet. Current Mosfet (IRL2203N). Vds: 30V Id: 116A Pd: 180W Rds(on): 7.0mOhm Prospective Mosfet (IRL1404ZPBF). Vds: 40V Id: 75A Pd: 230W Rds(on): 3.1mOhm So, will there be any great advantage to getting 50Watts more and a lower resistance rating? Will the Id Amperage be a negative or since an AEG never tops 40Amps then the value of 75A is a perfectly acceptable headroom? Should I stick with my current mosfet type or pay the extra? Cheers, Tom. Link to post Share on other sites
Tommygunn Posted January 6, 2012 Report Share Posted January 6, 2012 Nevermind, I went with an alternate mosfet, the IRF3808. Specs: Vds: 75V Id: 140A Pd: 330W Rds(on): 7.0 mOhm Tom. Link to post Share on other sites
point_7 Posted January 11, 2012 Report Share Posted January 11, 2012 hi. I have a AWS raptor v2 fet, today i instald it in my gun, but i have a problem with it. i will not work like i should be. here is a video that i uploaded so you can see my problem. i hope some one can help me out ? http://www.youtube.com/watch?v=LabsRQCs5mI&feature=youtu.be Link to post Share on other sites
adrian_geot Posted January 11, 2012 Report Share Posted January 11, 2012 Check the height of the motor, too much friction for me. Link to post Share on other sites
point_7 Posted January 11, 2012 Report Share Posted January 11, 2012 i allready played with the height but it did not work. Link to post Share on other sites
Amenthea Posted January 18, 2012 Report Share Posted January 18, 2012 You could also check the shim job, it looks like the gears are perhaps not always connecting solidly with each other. Link to post Share on other sites
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