upgraded FETs - Page 19

Jshwaa · #**271** 05-25-2004, 06:36 PM

Quote:

What do you mean by "ground"?

In this circuit, "ground" is a common point of zero potential. It's the point where all of your voltages would be in referrence to. Ground doesn't always mean "surface of the earth". There are different types of "grounds". In xmods it would be the point where the negative most terminal of the power supply(batteries) are.

charliebrown · #**272** 05-25-2004, 07:21 PM

Quote:

Originally posted by Jshwaa
In this circuit, "ground" is a common point of zero potential. It's the point where all of your voltages would be in referrence to. Ground doesn't always mean "surface of the earth". There are different types of "grounds". In xmods it would be the point where the negative most terminal of the power supply(batteries) are.

Ok ok...."Ground" meaning, to the main source of power? Or, to the source where power comes from? And as for your regulator mod, the explanation is kind of confusing....Basically, you have a chip that takes the power in one leg, chokes it down to smaller power to another leg to be drained from, and gives full power to the drain of the motor...? I'm confused...

I'm sorry to be a P.I.T.A. to teach this stuff to....

Chuckster...

Jshwaa · #**273** 05-25-2004, 08:40 PM

Quote:

I'm sorry to be a P.I.T.A. to teach this stuff to....

Not at all. I'm glad you asked.

Quote:

And as for your regulator mod, the explanation is kind of confusing....Basically, you have a chip that takes the power in one leg, chokes it down to smaller power to another leg to be drained from, and gives full power to the drain of the motor...? I'm confused...

That is correct, but the grounds of both the regulator and the xmod are connected. The regulator has 3 terminals, input, ground, and output. You are using a common ground with the regulator because you connect the ground of the batteries to both the ground of the 5V source(regulator) and the ground of the xmod. The part that's confusing you is how I let 5V go to the sensitive electronics and not the FET/motor circuit as well as allowing full battery power to the FET/motor circuit and not the sensitive electronics. That, my friend, is where the genius of this modification lies, and it's been the single-most improving mod that I've ever encountered.

If it wasn't for lithium, however, there wouldn't be much of a point because to put enough Ni-MH cells to create 16.8V would necessitate a trailer. So hats off to lithium too.

Get your regulator and the know-how on installing it....Jshwaa@insightbb.com

Jshwaa · #**274** 05-25-2004, 08:45 PM

Oh, and I almost forgot to let yall know....

I built an external H-bridge with some choice FET's. Here's the car.

Here's what happens when you can't respond before you go out of range with a hot rod like this. Check the vid out below.

JSHWAA CAN'T DRIVE

ph2t · #**275** 05-25-2004, 08:59 PM

lol, loved that vid mate. I take it you got your opto coupler circuit working well? I see a (14pin?)DIP pkg to the right of your fets in that pic above.

cheers,

ph2t.

Jshwaa · #**276** 05-25-2004, 09:27 PM

Indeed.

charliebrown · #**277** 05-26-2004, 05:23 PM

I'm still having a hard time understanding what "ground" is....Should I just label "ground" as the main power source on which everything functions? HELP!!!

Chuckster...

jon.jon · #**278** 05-26-2004, 06:50 PM

Quote:

Originally posted by charliebrown
I'm still having a hard time understanding what "ground" is....Should I just label "ground" as the main power source on which everything functions? HELP!!!

Chuckster...

to make it short and simple its where all your used energy goes. I hope this can help you understand it a little bit more if any

charliebrown · #**279** 05-26-2004, 06:55 PM

Quote:

Originally posted by jon.jon
to make it short and simple its where all your used energy goes. I hope this can help you understand it a little bit more if any

So, it's where power that is used up goes to? In this case, it would be the negative battery terminal because that's where used power goes...???

Chuckster...

jon.jon · #**280** 05-26-2004, 07:19 PM

Quote:

Originally posted by charliebrown
So, it's where power that is used up goes to? In this case, it would be the negative battery terminal because that's where used power goes...???

Chuckster...

"Either method will work in giving tremendous speed. And there's one thing that's common with both methods as far as the wiring goes......the power sources to the motor and the elecs. have to share the same ground. You can't have one battery for the elecs. and the other for the motor. That won't work."

if it goes by the same DC laws as a real car electrical systems I would believe so. and also it seem like you would be able to have multiple energy sources share the same ground.Im in class today and Im ready to learn so If Im wrong somebody kick me some knowledge.

Jshwaa · #**281** 05-27-2004, 08:58 PM

Quote:

I'm not "trying not to understand", it's just that I'm not a electronics god when it comes to these things.

Hehe, ok, and I'm sorry I flaired up a little there.

Ok, think of it this way. The regulator/electronics are in parallel with the FET/motor and a (up to)25V source. The regulator is preventing (up to)25V of pressure to be imposed on the elecs, while the FET/motor circuit in parallel is not restricted. So in essence, both circuits are sharing the same ground which would be the negative-most point of your power supply(minus sign of rear-most battery, or point of power supply the black wire is connected to). The regulator is a three terminal device, input, output and ground. So the regulator also shares that same ground.

And this ground is merely a referrence point, not to be mistaken with earth ground.

charliebrown · #**282** 06-03-2004, 11:21 AM

Quote:

Originally posted by Jshwaa
Hehe, ok, and I'm sorry I flaired up a little there.

Ok, think of it this way. The regulator/electronics are in parallel with the FET/motor and a (up to)25V source. The regulator is preventing (up to)25V of pressure to be imposed on the elecs, while the FET/motor circuit in parallel is not restricted. So in essence, both circuits are sharing the same ground which would be the negative-most point of your power supply(minus sign of rear-most battery, or point of power supply the black wire is connected to). The regulator is a three terminal device, input, output and ground. So the regulator also shares that same ground.

And this ground is merely a referrence point, not to be mistaken with earth ground.

lol, ok, so let me guess-timate some of the facts:

What you've done is basically install the high power batteries, then choke it down for the PCB, while the FETs that send power to the motor are grounded....correct?

Jshwaa · #**283** 06-03-2004, 07:41 PM

Quote:

What you've done is basically install the high power batteries, then choke it down for the PCB, while the FETs that send power to the motor are grounded....correct?

everything is grounded(meaning connected to the negative terminal of the rear-most battery) yes

charliebrown · #**284** 06-04-2004, 08:23 PM

Quote:

Originally posted by Jshwaa
everything is grounded(meaning connected to the negative terminal of the rear-most battery) yes

Why just the negative, why not BOTH positive and negative? And what do you mean by "rear-most"?

I warned you, I'm a PITA to teach electronic stuff to..

BTW, for those of you who want to stick with SO-8 packaged type FETs, here's a quick link:

http://ec.irf.com/v6/en/US/adirect/i...e&punchInID=71

Chuckster...

Jshwaa · #**285** 06-04-2004, 08:34 PM

Quote:

I warned you, I'm a PITA to teach electronic stuff to..

At this point, we're really not even dealing with the electronics of it. Think of a row of batteries connected in series. The rear-most would be the one that is in the BACK of all of the other ones in that series combination. SO, THAT BEING SAID AGAIN........the negative terminal of the REAR-MOST battery in WHATEVER AMOUNT OF BATTERIES IN A SERIES COMBINATION....is going to be your ground(or in this case, the point of referrence that all voltages are taken from)