Dannn Posted July 14, 2015 Posted July 14, 2015 I've just got lots of components to make one of the double tap mosfets anyone made and used one ?
Supporters Sitting Duck Posted July 14, 2015 Supporters Posted July 14, 2015 You got a link to this "double tap" MOSFET ??? Tbh it looks like a normal 3034 one without a TVS diode Which many use even though a 3034 has some basic protection. By the way you should use the tab for negative motor wire Keeps voltage well away from 2 outside wires plus the tabe handles much more current Think it's Rusty's guide or something I based my stuff on But same meat different gravy £2 to £2.50 per fet cost if you buy say 10 or more Just make sure you get GENUINE ones The snides from fleabay just melt
Supporters Sitting Duck Posted July 14, 2015 Supporters Posted July 14, 2015 What is underneath basic fet ??? And F U C K ME them 2 neg wires are close hence tab Middle n right legs jeez lots of shrink on them Curious as to the underneath bit thingy Coz looks thick something or a flat TVS diode?? Soz for commenting, my soldering ain't perfect I use chunky TVS coz in stubby stocks I got plenty room Stock tube might be different
Supporters ImTriggerHappy Posted July 14, 2015 Supporters Posted July 14, 2015 £19 Gate nano asr mosfet at firesupport. Will replace for free if it ever fails. No hassle better made doesn't break the bank. But 10/10 for having a go yourself. Lozart 1
Supporters Sitting Duck Posted July 14, 2015 Supporters Posted July 14, 2015 Firestorm fet £10 with thermal fuse delivered Baby mofo fet if you don't wanna make your own 99.9% fet's blow from bad fitting The decent ones I mean Cheap snides fail no matter who fits them
Supporters Lozart Posted July 14, 2015 Supporters Posted July 14, 2015 And F U C K ME them 2 neg wires are close hence tab Middle n right legs jeez lots of shrink on them My thoughts exactly. Although to be fair I also thought "nice soldering" the joints themselves are actually quite tidy!
straffham Posted July 14, 2015 Posted July 14, 2015 Nice job Dannn, interested to know how it performs.
Dannn Posted July 14, 2015 Author Posted July 14, 2015 It took literally 10 mins to make, I put heat shrink over each joint then heat shrink over the whole thing. Seems to work as the gun works ! It cost about £4 and av half hour in total to do. All the parts were from RS components so all decent bits.
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 RS are cheap for 3034's if you buy 10 they are like £1:52 or something... http://uk.rs-online.com/web/p/mosfet-transistors/6887204/?searchTerm=IRLB3034PBF&relevancy-data=636F3D3226696E3D4931384E4B6E6F776E41734D504E266C753D656E266D6D3D6D61746368616C6C7061727469616C26706D3D5E5B5C707B4C7D5C707B4E647D2D2C2F255C2E5D2B2426706F3D313326736E3D592673743D4D414E5F504152545F4E554D4245522677633D424F5448267573743D49524C423330333450424626&sra=pIs where I bought mine fromCheaper than farnell and free ship on £30 or something like thatGet some wire n some other bits, maybe get a m8 to go halves with ya etc....People think it's a lot of messing about, best thing is make a few at a time once you got iron up to temp.Not much effort really, besides you gotta do same amount of soldering n care when fitting a pre-made mosfet
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 linky for the way I do it: http://ncairsoft.org/forum/showthread.php?7516-Rusty65-s-MOSFET-building-guide and also same stuff here: http://unconventional-airsoft.com/2009/08/26/how-to-make-a-basic-mosfet-switch/ diode is a pain but they use one - so who am I to argue if you are making one - make a few.... for what it is worth - the #6 bolts equate to our M3.5 bolts yes M3.5 - M4 is a bit too big to go through fet eyelet and M3 is a bit thin M3.5 is the bolts used is electric socket/switches in ya house but you need a m3.5 nut spring washer That is the usual basic fet gospel, some use other mosfet's but the 3034 is said to be one of the best ones available well that is the way I do it.... only minor difference toi Rusty65 is that I wrap the resistor across fet - leave resistor wire excess for now... position the diode leg the right leg where it goes - then wrap the excess around diode leg to hold in place & solder same for signal wire resistor - fitted by wrapping the excess around it & solder just a bit extra help holding it all together when soldering them to fet legs get the bits ready & shaped - wrapped together - ttsszz ttsszz - fet done repeat for other 2 or 3 fets - sorted
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 it is to prevent any back surge of current or something so the fet bible says..... I got an alternative spec tvs diode coz could not locate exact model but similar spec bollox - makes it a bit bulky but like I say I often use stubby fixed stocks for good size cheap block batteries in M4's v2 will need box opening to install wiring for fet v3 can be fitted without needing to open up gearbox like in V2's major decision is how thick the wire you can use and where to locate the fet itself on its own the fet does jack $hit except protect the contacts on heavier juice it is an additional device to switch on so in reality I guess it adds a few nano seconds in a normal stock gun it does not imho give you faster trigger response or make you more attractive to women etc..... it is when you rewire with thicker wire + deans that the fet comes into its own and it is the other bits that give the faster response not the mosfet - the fet just allows us to safely switch higher juice for heavier loads on juicy motors etc.... That is where the trigger response comes from - not the fet itself the fet just manages the bigger juice safely keeping your contacts looking good rather than deep fried
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 I'm no expert - far from it well even further from it when you see how the real techy pro's can fit these basic 3034's inside their gearboxes: yes I am but a humble trainee apprentice noob actually still think fitting inside a box is not a very wise option if I wanna change out a basic to AB fet or even a prgrammable one at least I don't have to open gearbox up but maybe for some compact guns - even AEP's people have managed to squeeze in a fet in the tighest of places clever mofo's out there - G&G fet dept should take note
Dannn Posted July 15, 2015 Author Posted July 15, 2015 All this info is great! I'm gonna girder a few capacitors too, I think I'll be able to fit them in somewhere !
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 Capacitors ???? nah that is old skool way of boosting ya charge on crappy nimah's really don't think anybody still does that - they just fit bigger and higher burst lipo's (some yanks go nutz on 14.8v - jjeeeezzz how fast ya need to go chaps) if ya got lipo you got plenty of mojo a lot of these guides are old but the fet malarky is still in use often many still use 3034 as best airsoft fet the capacitors - like for holding charge is obselete with lipo's now being the norm they can unleash juice quicker tha you can rip open a carton of Del Monte or Ocean Spray
Dannn Posted July 15, 2015 Author Posted July 15, 2015 Ahhhhh I've got 50c 11.1 lipos.. No capacitor needed then haha
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 me thinks not - go for 60c instead - jeeeez I'm content with 25 to 35c performance atm plus sticking to 7.4v and squeeze out every last drop (without the pips or pulp)
Supporters ImTriggerHappy Posted July 15, 2015 Supporters Posted July 15, 2015 Ahhhhh I've got 50c 11.1 lipos.. No capacitor needed then hahaNo but plenty of spare parts for your gearbox is probably a necessity.
Dannn Posted July 15, 2015 Author Posted July 15, 2015 I've set it all up.... Angle of what's it has been set, had a shim tastic time on it on it, new piston with teeth made from supermans shit, big fat wire all over the place and I've got a new one to drop in as soon as this one goes bang haha
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 word of strong advice.... test on 7.4v first - especially if a neodym motor is in there (or high speed gears - if using both neo and 13:1 then I advise ordering up new parts anyway - even on 7.4v coz that could hit 30) whatever she is firing at - BPS app or record sound and count spikes on pc etc....... then get a rough idea what rof is on 7.4v first 11.1v will be 50% more..... if hitting 20rps on 7.4v you will expect to hit aprox 30rps on 11.1v Warning 25+ very slight risk but 30 good chance of PE (depends on spring strength returning piston faster/slower and also weight of piston - lighter is faster return/ swiss cheese crap etc..) if you used a plastic toothed piston it will just strip but all metal rack - no weak point to shred and it will really go bang due to all metal teeth gears etc..... you could smash your piston to f*ck AND YOUR GEARS AND YOUR MOTOR PINION GEAR IF ALL METAL ON 11.1v no $hit - it can happen if you go too nutz without homework on stock m100 or m105 springs luckily I learnt the hard way but with plastic teeth shredding, now I have a rough-ish idea what to expect so I got a reasonable idea of when I can and when I can't use all steel piston rack (built up a collection of boned pistons to attain this knowledge of what NOT to do) faster n faster stuff at 30+ has to have shortstroking and M110 - m120 is safer with 2 teeth removed I got a rough maths table I think that works out about right - will know more as I build n bone more
Supporters Lozart Posted July 15, 2015 Supporters Posted July 15, 2015 it is when you rewire with thicker wire + deans that the fet comes into its own and it is the other bits that give the faster response not the mosfet - the fet just allows us to safely switch higher juice for heavier loads on juicy motors etc.... That is where the trigger response comes from - not the fet itself the fet just manages the bigger juice safely keeping your contacts looking good rather than deep fried That's....not entirely true. The capacity to switch larger currents is part of what makes the FET useful as it prevents all the current going through the trigger contacts which can then arc and lead to poor switching and conduction but it's also the ramp rate of the FET that makes the trigger response better. You could JUST fit a hardwired FET using all the original wiring and get a much improved trigger response because the FET can go from 0 to full current far quicker than a mechanical switch. Granted if you combine this with better wiring, Deans connectors etc then the trigger response will be better still but don't make the mistake of thinking that's where the greatest benefit in switching speed comes from.
Dannn Posted July 15, 2015 Author Posted July 15, 2015 With 11.1 im getting around 40 odd per second , but that's testing it with a crappy iPhone app..I'm going to short stroke it with an m120 I think Do you think plastic teeth are the way to go on really high speed stuff so only that goes bang ?
Supporters Sitting Duck Posted July 15, 2015 Supporters Posted July 15, 2015 Not gonna get into a debate on it but fet is an additional device with additional wiring often sited further backwards.... then the current would flow from the fet to the motor after the fet's own delay or switch on time even in nano/milliseconds it prevents trigger arcing/carbon which would cause resistance etc in switching but like for like as you wouldn't fit a mosfet when the trigger contacts were shot you would replace switch - but on clean good contacts under stock conditions at least the fet does not in my mind improve trigger response.... as stated above additional device, additional wiring and has its own delay or switch on time burnt out contacts are different - the point I am making is that many people assume the mosfet is improving trigger response it on its own is not - it is safely allowing the use of higher juice to the motor using thicker wire/connectors take two exact brand new guns and a soldering iron........ fit just a mosfet to one gun and to the other fit deans instead of small tamiya to other gun & battery Then dean's gun will show trigger response than the mosfet only gun maybe in time as carbon builds up on deans gun this may get so bad in terms of resistance the mosfet gun triggers faster but like for like new clean contacts the mosfet will not show any improvement in my mind like I stated above trouble is even if it did provide a smidge more, then often people would take it that most of the response must be down to the fet it is not it is when all the items are upgraded and the fet operates to prevent additional resistance building up at switch that trigger response is improved and maintained through the larger wire/connectors with little resistance The mosfet is there as I said to prevent resistance taking place - on its own it does not in my book when fitted improve response over time it helps maintain trigger response - I will admit that but I can't see how on its own with new contacts the response will be improved in the fet Vs deans gun scenario
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