p75nf75

[perdigon]

I buy
http://cgi.ebay.com/10-pcs-STP75NF75-P75NF75-New-Original-ST-/180563501981?pt=LH_DefaultDomain_0&hash=item2a0a6c639d
thx

[Bikemad]

have they down graded the fets the original one's were stp140nf75 and new they are stp75nf75 so have gone down from 120amp to 80amp does any body know anything about fets?

The one FET that died during my unsuccessful dual controller mod was on the newer mx-318 pcb and it was a P140NF75.

I won't know what FETs are on my original mx-315 pcb until they finally admit defeat, they've managed a quick burst of 56.41 Amps and are still alive!



Even the P75NF75s lower rated 70Amp continuous at 100°C is still three and a half times more current than my standard controller would draw (just over 20Amp max).

I'm guessing they are cheaper to use, but still capable of handling the restricted power of the GM controllers.

Alan
 

[o00scorpion00o]

That's not another burned GM controller I smell is it? 

Sorry I couldn't help it!   

[gf3]

have they down graded the fets the original one's were stp140nf75 and new they are stp75nf75 so have gone down from 120amp to 80amp does any body know anything about fets?

The one FET that died during my unsuccessful dual controller mod was on the newer mx-318 pcb and it was a P140NF75.

I won't know what FETs are on my original mx-315 pcb until they finally admit defeat, they've managed a quick burst of 56.41 Amps and are still alive!



Even the P75NF75s lower rated 70Amp continuous at 100°C is still three and a half times more current than my standard controller would draw (just over 20Amp max).

I'm guessing they are cheaper to use, but still capable of handling the restricted power of the GM controllers.

Alan
 

Are you going to have a go at doubling up on the number of fets on a controller as you said in you two controller thread?

 I am temped to have a go. Is there any reason you didn't try this yourself?

[Bikemad]

Are you going to have a go at doubling up on the number of fets on a controller as you said in you two controller thread?
I am temped to have a go. Is there any reason you didn't try this yourself?

I thought the second controller with additional capacitors and its own shunt would have been a simpler solution, but it proved not to be the case.

Doubling up the controller FETs was the other alternative I had considered, but it's perhaps not quite as easy as I first hoped.
The additional FETs will need some form of circuit board and will also need to have their own shunt, ideally the same value as the host controller.

I could probably replace the blown FET on the dead controller and chop the tracks on the board to isolate the FET assembly from the rest of the controller electronics and refit it back onto the heatsink which is still inside the wheel, but I'm not sure that I want to spend more time and money on a controller which is not renowned for either it's power or it's reliability.

I'm pretty sure that something else on the controller will probably fail eventually, necessitating a replacement controller anyway.

As much as I love the cleanliness and simplicity of the internal controller, I still think that I may end up opting for an external Infineon controller conversion if (more likely when) my current controller gives up the fight for life.

I want high current capability and reliability, and the Infineon appears to have this as standard, plus it can handle a much higher voltage (with minor modifications) for those who are after a higher top speed.

Alan
 

[GM Canada]

Does anyone understand what the question is?

Gary, in case you still haven't realised, he's looking for some MOSFETs for a gm controller, presumably he's got some that have failed.

Let's hope that replacing the FETs is all that is necessary to get it going again!



Alan
 

Thanks for that, I could not figure out what he was talking about

Gary

[DirtyGinge]

Hi alan

I got a minimotor controller 6 FET fron Lyen recently, small unit etc etc...dang thing puts out 25 amps continuous !!!!!!!!  I think landed cost was about 65....

Still got alphawire, converted another internal to external for a friend today.....

P.s. I ordered an external pie for spares.....had a look at the wiring for the external versus the alphawire....nearly pi$£"$%d myself laughing, its the same loom as on the minimotors  :O, not putting an infineon anywhere near that ....

get large guage in there my man......!!!

[Bikemad]

I've just been out in the garden testing (messing around with) my bike and I still can't believe the difference in power.
I managed to flip it over backwards half a dozen times so far, because the front end simply defies gravity every time I twist the throttle.

I've been trying to compare the differences between 25.9 and 51.8V, and here are the readings from my watt meter:

Minimum Voltage 26.98 Volts
Max Power 1536.4 Watts
Max Current 56.59 Amps

Minimum Voltage 50.91 Volts
Max Power 3039.9 Watts
Max Current 58.63 Amps

I found that using the lower voltage, the bike still has loads of power, but the front wheel stays in contact with the ground unless you pedal slightly. On the higher voltage, the bike is just unreal and tries to throw you off the back when you accelerate hard on inclines. I can't ride up my drive on full throttle any more because it just wheelies.

I am surprised that the shunt modification does not seem to have had any effect whatsoever on the regen, which seems to work just as it did before.

After 15-20 minutes of intense testing (playing) the controller decided to cut out on me. I disconnected the power and then plugged it back in again and it started working again straight away, and this continued to happen a few more times over the next 10 minutes.

I now wish I had the hall sensors working, as the throttle is not very predictable at very low speed in sensorless mode (not ideal for controlled wheelies) and it can sometimes catch you out when accelerating and turning tightly.

I was planning on replacing the hall sensors when the controller dies, but it looks like I may have to replace them on their own, as my internal GM controller just keeps on going!

Alan
 

[MonkeyMagic]

That's it.... I'm going to drop some solder on either side of my shunt.

Hey Alan, did you put that diode leg/shunt wire in addition to the original GM one?

Can you tell me a bit more of how you came to choose/fit this piece? Thanks pal

[Bikemad]

Hey Alan, did you put that diode leg/shunt wire in addition to the original GM one?

Can you tell me a bit more of how you came to choose/fit this piece? Thanks pal

Monkey, I put the additional loop directly across the existing shunt on one controller, as you can see in this photo:



The other controller had the shunt hidden underneath the circuit board, so I simply scraped clean a small area of copper on the circuit board and soldered the additional shunt there instead. (see attachments)
I was aiming for a total of around 50Amps from both controllers, so I figured that as the thick shunt was allowing 20Amps, an additional thin wire (the leg of an LED just seemed to be a good choice) would hopefully produce an extra 5Amps or so on each controller.

My highest wattage before any modifications was 1073Watts, and with the shunts fitted I managed 1340Watts, pretty much the 25% increase I was hoping for (I'm now convinced that I was only getting power from one controller and not both).

When I removed the failed controller (see attachment), I also removed the additional shunt and soldered this onto the working controller in addition to the extra shunt I had already fitted. These two thin shunts were spaced approx 1mm apart and I decided to fill the gap between them with solder to greatly increase their cross sectional area and lower their resistance for more power!
(Sorry Monkey, I didn't take a photo of the fattened up shunt)

This is why I'm now getting such a large increase in the maximum current draw, 58.6Amps compared to my previously highest recorded figure of 20.66Amps before the shunt mod.

I'm wondering whether the current draw would be different if the hall sensors were working. If my controller can survive long enough, I may eventually find out.

Alan
 

[o00scorpion00o]

P.s. I ordered an external pie for spares.....had a look at the wiring for the external versus the alphawire....nearly pi$£"$%d myself laughing, its the same loom as on the minimotors  :O, not putting an infineon anywhere near that ....

get large guage in there my man......!!!

You are joking? WTF 

Though to be fair I  imagine GM just install the guage wire suitable for their own controllers. That's a pity really as you will have to pull the motor apart to rewire it for any decent controller!

Does GM not listen to the fact people who come here and probably many people who buy their products want the option of a higher power setup?

They really should start offering high power controllers and wiring from the pie as that pie can take some crazy power!

There are so many people that if they read this forum won't touch their magic controllers with a barge pole and will shop elsewhere!


Mark

[DirtyGinge]

Hi Alan

Altough I am happy for you with the new current draw, and yes the front wheel jump is great, I think that you really need to look into cooling those mosfets down, either by much additional copper blocks, or external means......

The heat will eventually get to them...maybe a lot of thermal paste between the fets and panel, and the panel and the stator arms...the fact that your motor is cutting out shows that heat is reaching critical levels..........

p.s. the infineons don't cut out at such a low ampage as 50 amps 

[MonkeyMagic]

I'm thinking of putting a peltier plate or 2 in mine, and temp switch the hot side. This is a pretty neat solution and can work with the wheels power too

I'd be keen to know anyone who has 'cooled' their GM motor but have yet to see it done

I'll buy some plates this weekend and see what I come up with

[DirtyGinge]

Just some info for you guys on fet numbers

I tested a hill for a customer today on my setup, 1500 Watts continuous for 2.5 minutes, controller not even warm, Magic Pie, not hot, just warmer.....

Now today im testing a minimonster infineon ( 6 fet, 3 inch x 2 inch), on a gm minimotor, running at 500 watts, peak 750, and after 3 miles of flats, was about as warm as my infineon gets on 25 miles of full throttle....

Cooling comes down to 3 things I guess

Metal surface area
Component redundancy
Air Velocity on aforementioned surface area....

Ive done lots of watercooling on pcs, custom copper welds, so no biggie technically, using 8mm copper should get you in the axle, its just getting the time , and willl the copper be close enough to the windings to make a difference on peak amps..