question about torque and speed

boho · #1 07-02-2003, 09:36 AM

So I got a question. I've been made to understand that volts=speed and current=torque. Is this correct so far? Well, if it is, then will putting two batts in parrallel increase the torque? I wonder if somebody could give me more information about the differences between MAH and MA, and the effects on the motor.

Sorry, I know this is kind of a newbie question, but I'm not afraid to admit I'm still a bit of a newbie.

Namuna · #2 07-02-2003, 11:06 AM

No, it's not a noob question. It's about electronics and it's easily confusing.

Increasing the voltage is the easiest upgrade because the PCB doesn't regulate the voltage from the Battery to the Motor/Steering...therefore yes, voltage directly relates to speed.

Now, torque and current is a different animal. The PCB does regulate this and therefore setting up multiple batteries in parallel won't do much but increase your runtime. If you want to increase torque you've got to adjust how the PCB regulates it, you can do a search on 'mosfet' to learn more about that.

mAH = MilliAmp hours. This is a general capacity rating. Kind of like a regular cars' mileage rating. Like an SUV has like 15 miles per gallon rating. Exactly what the numbers mean is hard to explain, but simply put; the higher the MAh number, the longer it should provide power when properly charged.

mA = MilliAmp. This is the power demand or output of something. If you buy an AC Adapter that is 500mA, that means it will put out a constant rate of 500mA. Or if a Motor is rate for 230mA, that means it demands 230mA to run properly.

vtheo · #3 07-02-2003, 08:03 PM

Namuna, i think you a tiny bit wrong in your description

Quote:

mAH = MilliAmp hours. This is a general capacity rating. Kind of like a regular cars' mileage rating. Like an SUV has like 15 miles per gallon rating. Exactly what the numbers mean is hard to explain, but simply put; the higher the MAh number, the longer it should provide power when properly charged.

mA = MilliAmp. This is the power demand or output of something. If you buy an AC Adapter that is 500mA, that means it will put out a constant rate of 500mA. Or if a Motor is rate for 230mA, that means it demands 230mA to run properly.

mAH rating on your batt is like how big your gas tank is. a fully charged 150mAH battery will last longer than a fully charged 100mAH battery in the same car, just like a 20 gallon tank will last longer than a ten gallon tank in the same car.

the mA is more like the mpg of
of a car. it is how much the motor, pcb, steering, and such require from the batt.

Sorry if i am just mudding the waters.

boho · #4 07-02-2003, 09:24 PM

Wow, thanks. Now I get the picture. I had no idea that the current was being regulated. Now the mosfet mod makes more sense. Will more torque increase the chance of spinning out?

I just did a dual cell with a dremel. I dremelled out part of the back so the batts would sit closer to the motor. This makes the car less front heavy. So far it's turned out to be the best controlling car I have. But I don't want to screw it up if the mosfet mod puts too much torque on it and makes it spin out.

vtheo · #5 07-02-2003, 09:55 PM

Maybe, depending on your tires. It will peel out if the tires are slick enough, just like if you put plastic wheels on a stock bit... exept you just need stickeir tires, i dont have a mosfet mod car so i dont know just how sticky your tires need to be, stock ones could be fine.

moshbmxa · #6 07-02-2003, 09:57 PM

too much torque and not enough traction will definitely make you spin out. you can try new tires and slow down a bit b4 corners to avoid rollin it over or sliding out and doing donuts. also you can learn to drift with the right setup, browse the drifting section if you are interested. i haven't done the mosfet mod myself, but i have heard from several ppl that it does make a huge difference in torque but not top speed. a single cell car with mosfet mod will smoke a dual cell off the line and until the dual cells top end overcomes the topend of a single cell. there are many positives to having a mosfet single cell over a dual cell car. browse those forums as well. hope this all helps i know i talk alot.

boho · #7 07-03-2003, 08:13 PM

Hey, it helped alot. Thanks.
Also some of those ergonomic pen grips are super sticky.
I'll probably try a mosfet mod with a single cell first, then a dual cell. Boost cars are also great for drifting, because you can hit the boost just before conering. It takes a little practice, but it's worth it. I bet a dual cell booster with mosfet would drift great if you had the right tires.

GT Racer · #8 07-04-2003, 08:59 AM

Yo Namuna can you do that electronic thingy reply in english?Please it would greatly help,e-mailme your reply to Dranzerflame929@hotmail.com

strongshock · #9 04-18-2004, 04:16 AM

electronics don't need to be confusing. more gas/electric car analogies:

Quote:

This is the power demand or output of something.

electrical power is measured in W. e-power is basically the product of current and voltage (power = current * voltage). the W is analogous to a gas engine horsepower rating.

Quote:

the mA is more like the mpg of a car.

the mA is analogous to fuel consumption rate (gph). gas mileage (mpg) translated to electric r/c would be miles per mAh.

launching off the line, or any other heavy acceleration at low speed, produces a very large current (mA) draw compared to running full speed. a single cell mosfet cars launches harder than a dual cell transistor car, because at high currents a regular transistor's high resistance absorbs significantly more voltage while the mosfet allows the motor to use all of the battery's voltage regardless of the current. however at top speeds, the extra voltage from the second cell overcomes the voltage difference and the dual cell transistor car pull away.