*Improved* MOSFET mod...
Posted: Fri Apr 16, 2004 8:46 am
I have found some MOSFETS that are (on paper) better performers than the IRLML2502 mosfets we have all grown to love. These MOSFETS offer 20% more performance than the IRLML2502 fets that everyone is using. They are nths5404t1 and they are available from www.onsemi.com
Let's review some stats:
So the nths5404t1 have less resistance that the regular IRLML2502. This means more torque for the motor! This is higlighted in orange in the table above.
SNEAK PEAK!!! Also I have found some fets that when double stacked they outperform a triple stack of IRLML2502 fets(see the yellow records above), stay tuned for futher developments on this.....
The only bugger is that the package they come in (ChipFET) isn't compatible with the pin layout of the BitChar-G PCB. This means problems. So I made my own little external TURBO, lol, to accomodate these FETS.
Seems like a lot of wires but really it isn't. There are two wires(white & blue) that goto the battery terminals, - and +. There are two wires(yellow & orange) that go to the motor since the motor no longer connects to the BitChar-G PCB. The last two wires(brown & dark blue) goto the PCB and solder on to the locations for the Forwards/Reverse signals. For people(techos) in the know, these two wires go to the respective Base pin of the two NPN transistors in the motor H-Bridge.
Here's an idea on it's size:
Here's the finished product!
NOW, YOU'VE GOT TO SEE THIS VIDEO!!!!
http://users.tpg.com.au/ph2t/fet/fet_comparison.avi
DivX, 900KB.
The video shows a comparison between three identical cars starting from a stop. The surface the cars are running on is a rubber mat that is incredible for its grip. After approx 1.5m there is a steep incline for the car to travel up. The car's setups are as follows:
Car 1: Stock PCB with 3.0 TOMY Motor and 12:1 gears.
Car 2: Single Fet Stack PCB with 3.0 TOMY Motor and 12:1 gears.
Car 3: Triple Fet Stack PCB with 3.0 TOMY Motor and 3.95:1 gears.
The video shows some interesting results. First the obvious, the stock car doesn't even make it all the way up the hill, both mosfet modded cars do this easily. The stock car is the last to reach the foot of the incline, both the single stack fet and tri-stack fet cars reach the incline before the stock car.
Keep in mind that what's impressive about the 3rd car is that the gearing is set to 3.95:1, vs that of 12:1 for the other cars (stock and single fet). This clearly shows the INSANE about of torque that the tri-stack of fets delivers to the motor...
ph2t.
Let's review some stats:
So the nths5404t1 have less resistance that the regular IRLML2502. This means more torque for the motor! This is higlighted in orange in the table above.
SNEAK PEAK!!! Also I have found some fets that when double stacked they outperform a triple stack of IRLML2502 fets(see the yellow records above), stay tuned for futher developments on this.....
The only bugger is that the package they come in (ChipFET) isn't compatible with the pin layout of the BitChar-G PCB. This means problems. So I made my own little external TURBO, lol, to accomodate these FETS.
Seems like a lot of wires but really it isn't. There are two wires(white & blue) that goto the battery terminals, - and +. There are two wires(yellow & orange) that go to the motor since the motor no longer connects to the BitChar-G PCB. The last two wires(brown & dark blue) goto the PCB and solder on to the locations for the Forwards/Reverse signals. For people(techos) in the know, these two wires go to the respective Base pin of the two NPN transistors in the motor H-Bridge.
Here's an idea on it's size:
Here's the finished product!
NOW, YOU'VE GOT TO SEE THIS VIDEO!!!!
http://users.tpg.com.au/ph2t/fet/fet_comparison.avi
DivX, 900KB.
The video shows a comparison between three identical cars starting from a stop. The surface the cars are running on is a rubber mat that is incredible for its grip. After approx 1.5m there is a steep incline for the car to travel up. The car's setups are as follows:
Car 1: Stock PCB with 3.0 TOMY Motor and 12:1 gears.
Car 2: Single Fet Stack PCB with 3.0 TOMY Motor and 12:1 gears.
Car 3: Triple Fet Stack PCB with 3.0 TOMY Motor and 3.95:1 gears.
The video shows some interesting results. First the obvious, the stock car doesn't even make it all the way up the hill, both mosfet modded cars do this easily. The stock car is the last to reach the foot of the incline, both the single stack fet and tri-stack fet cars reach the incline before the stock car.
Keep in mind that what's impressive about the 3rd car is that the gearing is set to 3.95:1, vs that of 12:1 for the other cars (stock and single fet). This clearly shows the INSANE about of torque that the tri-stack of fets delivers to the motor...
ph2t.