upgraded FETs - Page 26

moebrown20 · #**376** 01-07-2005, 02:43 PM

Quote:

Originally posted by aaron
You can now do better than IRF7389 by using IRF7317 which give an internal resistance slightly button than SI4562DY..

'Bout USD20 delivered for 10 of them!

A.

whats the stats on the irf7317?
do you have a photo of your setup?

aaron · #**377** 01-09-2005, 10:05 PM

I've actually avoided X-Mods as I'm not keen on payign the prices people are asking on ebay.

But specs on the IRF7317... RDSon is about 0.062ohms compared to the 0.065of the SI4562DY (so essentialyl the same).. They're good for about 6A which makes them more durable than stockers and if you keep the plate above them to assist with cooling they'd be a very tough option.

I pimp the things through ebay and the online store with ausmciro.com but really you can get them anywhere - Digikey etc have them.

moebrown20 · #**378** 01-10-2005, 08:28 AM

Quote:

Originally posted by aaron
I've actually avoided X-Mods as I'm not keen on payign the prices people are asking on ebay.

But specs on the IRF7317... RDSon is about 0.062ohms compared to the 0.065of the SI4562DY (so essentialyl the same).. They're good for about 6A which makes them more durable than stockers and if you keep the plate above them to assist with cooling they'd be a very tough option.

I pimp the things through ebay and the online store with ausmciro.com but really you can get them anywhere - Digikey etc have them.

I know what you mean about ebay, but they are not the only place that has Xmods. 6 amps you say, that sounds like a nice conversion.

aaron · #**379** 01-12-2005, 03:57 AM

Other ways to score a Xmods when you're not in the states? Do tell more my good man? I made be in a cash position to consider splashing out in March

A.

ninja828 · #**380** 01-26-2005, 10:48 AM

i did this fet mod a loooooong time ago when it was new but due to having no one to race i sold my fetted xmod but after a while i missed messin w/ xmods so i bought a new one...now, on to the point:
im doing neuro's fet mod again and everything was fine up until i hooked up he fets to the li-ions. thats when my fets heat up like crazy enough to melt the solder off...yet i followed the schematics ...so can anyone help me w/ this?

moebrown20 · #**381** 01-26-2005, 12:21 PM

Quote:

Originally posted by ninja828
i did this fet mod a loooooong time ago when it was new but due to having no one to race i sold my fetted xmod but after a while i missed messin w/ xmods so i bought a new one...now, on to the point:
im doing neuro's fet mod again and everything was fine up until i hooked up he fets to the li-ions. thats when my fets heat up like crazy enough to melt the solder off...yet i followed the schematics ...so can anyone help me w/ this?

I have the same problem.
Maybe we have one set mixed up?

ninja828 · #**382** 01-26-2005, 08:22 PM

could be....but im lookin at all the schematics that people have made and posted here and my setup at the moment and everything is correct....im really confused as to what could be the problem...it worked before....im really tempted to connect the drains back to IC5 an IC6 and just run everythin back to the main board

RacinSkillZ101 · #**383** 01-26-2005, 08:31 PM

hey guys i had the same prob... at first i thought it was cause i didnt heat shrink, but then it still happened so i thought the fets were bad, until i whiped out my good old multimeter, and discoverd that 2 fets are grounded - and 2 are grounded + so if u got the heat sinks touching together (as i did) u get a nasty short and also fry the fets u r using... i ordered 2 sets form digikey and if i get it wrking ill sell it off to who ever wants it.

to avoid this only the fets with a source + may touch each other same goes for the source -. however to avoid any sort of mihap i will insulate my fets entirely with heat shrink.. good luck ill b on the forums if u need further help

ninja828 · #**384** 01-26-2005, 09:09 PM

huh...interestin....but i thought that the heatsinks were connected to the drain and not the gate? plus lookin back to page 6 an 7 of this topic, LithiumXmod did the same thing and it worked for him (im not tryin to start anything but im just statin what i see)

RacinSkillZ101 · #**385** 01-26-2005, 10:38 PM

hugh i dunno, all i know is 1 set of fets is positive and the other is negative... i looked over that sheet relgiously and this is all i can come up with, my order will b in on friday so ill get to solder on sat and ill update u guys by then.. if u want try wut im saying, have all the fets seperate.. its worth a try right?

also i read over ur post, the heat sinks are through the drains, if they were through the gates ud have issues with the fets opening/ closing... i also know its the drian cause i didnt have this issue b4, then i ran my motor and whamo it heated up, i now know my fets are fried cause they are always open, i.e. the short occurs as soon as i apply power

if u dont understand the concept of a fet its simple.. power goes to source, the gate (a low power source) opens and allows the electricity to flow through the drain.. its basicly a switch controlled by electricity and allows a small power to controll a large power

hope this helped..

ninja828 · #**386** 01-26-2005, 10:49 PM

hm...ok, i'll try it w/ the fets separated. thanks but what i was tryin to get at and what i understood before was that since the drain of both the 3705 and the 4905 fets were tied to their heat sink then i could just solder them together back-to-back to save some space...but i guess that wasnt such a good idea...oh well...back to tha work bench

moebrown20 · #**387** 01-27-2005, 08:25 AM

Quote:

Originally posted by ninja828
hm...ok, i'll try it w/ the fets separated. thanks but what i was tryin to get at and what i understood before was that since the drain of both the 3705 and the 4905 fets were tied to their heat sink then i could just solder them together back-to-back to save some space...but i guess that wasnt such a good idea...oh well...back to tha work bench

Ok Ninja, I haven't had time to get in to it(soo much snow to move) let us know how it turns out. Take a photo if possible(that would be a big help).
OK RacinSkillZ101, could you do a drawing? A cheap one will do.
The S08 type fet's have both N and P channels. So even tho we see 2 there is really 4. how is it that they donot over heat like the AB220?

ninja828 · #**388** 01-27-2005, 07:51 PM

well it seems that i wont be upgrading my fets for a while because after checking i found out that i fried both sets of fets that i had for this mod...

......hey racinskillz, i dunno if you got that email but i think ill take you up on that offer of the set of fets if you're still up fer it....CODs are expensive w/ digikey...and it doesnt help that i dont have a credit card

moebrown20 · #**389** 01-27-2005, 08:01 PM

Well, I have 4 left...... I will give it one more shot. I think I got it now. I think there was a error in the drawing. I will let you know the out come. If it works I will let you know!

RacinSkillZ101 · #**390** 01-27-2005, 09:04 PM

hey ninja828 id love to make a set for u, it can even b regulated, but it wouldnt b soon, i still gotta make mine wrk b4 i can sell it to ppl... hopefully this weekend ill sink my teeth into the project

hey moebrown20 ill get a drawing up tomm, itll b nice with colors and such and ill show how the connections goe and stuff