62LikesLet's talk modified 1/12
09-01-2016, 06:58 AM
#331
What about LiFe 2s? :-P
09-01-2016, 11:49 AM
#333
Your correct though, if your water pressure (volts) increases, then the amount of water flowed (amps)increases. Assuming the hose nozzle (resistance) doesn't change.
BUT, in electrical reality. If you lower the voltage, your load will draw more amps. So dropping from a 1s Lipo to a lower voltage 1s Life pack, should put more load on the ESC, if the motor can still pull it.
And generally in most cases, if my load only draws 2500 watts. And I can choose different motors or resistors to meet that wattage requirement (true work). Higher voltage will offer lower amp draws.
09-01-2016, 11:56 AM
#334
If you're still running a 3.5 with a higher voltage, it will draw a higher amperage. But a 3.5 drawing more amperage on a higher voltage, is going to dyno much more wattage than it would on less voltage.
So naturally you'd drop down to a 6.5 motor that could produce the same power/wattage at the higher voltage. And much lower amp draw for the same amount of true power output.
It's easier to figure with pure resistive loads. A 2500w 480v heater draws less amps than a 2500w 208v heater.
So naturally you'd drop down to a 6.5 motor that could produce the same power/wattage at the higher voltage. And much lower amp draw for the same amount of true power output.
It's easier to figure with pure resistive loads. A 2500w 480v heater draws less amps than a 2500w 208v heater.
09-01-2016, 01:10 PM
#336
Exactly, we're stuck with 1s.
09-01-2016, 01:14 PM
#337
The point is long gone or we wouldn't be talk about saving 1/12th 
RANT
If 99% of the racing community feels 1/12th MOD is too fast it's not on straight speed, if it was a minimum rollout would all but eliminate that.
See bellow what I see as the culprits of decline:
-In almost every other electric class one battery is enough for a race day, not 1/12th when you are close to dumping all the time and the turnouts are what they are;
-price of electronics, availability of 1s batteries and other classes they could be run;
-current pace of chassis design development is too fast and too many options. Aluminium chassis, longitudinal or transversal battery placement, flex, no flex, wide, narrow... It's a pan car! It's supposed to be simple, if it is not simple then accept that only a handful of drivers worldwide can run them. Required know-how is inversely proportional to people driving the mentioned class, it happened with 1/8th on road, happens with 1/10th TC MOD and the others. Off road is stable because the requirements are lower.
The whole formula for 1/12th is wrong from the beginning, who thought about decreasing voltage when capacity increased? Were we supposed to run 1.0v when the capacity reached 10A?
/RANT
RANT
If 99% of the racing community feels 1/12th MOD is too fast it's not on straight speed, if it was a minimum rollout would all but eliminate that.
See bellow what I see as the culprits of decline:
-In almost every other electric class one battery is enough for a race day, not 1/12th when you are close to dumping all the time and the turnouts are what they are;
-price of electronics, availability of 1s batteries and other classes they could be run;
-current pace of chassis design development is too fast and too many options. Aluminium chassis, longitudinal or transversal battery placement, flex, no flex, wide, narrow... It's a pan car! It's supposed to be simple, if it is not simple then accept that only a handful of drivers worldwide can run them. Required know-how is inversely proportional to people driving the mentioned class, it happened with 1/8th on road, happens with 1/10th TC MOD and the others. Off road is stable because the requirements are lower.
The whole formula for 1/12th is wrong from the beginning, who thought about decreasing voltage when capacity increased? Were we supposed to run 1.0v when the capacity reached 10A?
/RANT
09-02-2016, 05:14 PM
#338
http://www.electricaltechnology.org/...creases_4.html
Your correct though, if your water pressure (volts) increases, then the amount of water flowed (amps)increases. Assuming the hose nozzle (resistance) doesn't change.
BUT, in electrical reality. If you lower the voltage, your load will draw more amps. So dropping from a 1s Lipo to a lower voltage 1s Life pack, should put more load on the ESC, if the motor can still pull it.
And generally in most cases, if my load only draws 2500 watts. And I can choose different motors or resistors to meet that wattage requirement (true work). Higher voltage will offer lower amp draws.
Your correct though, if your water pressure (volts) increases, then the amount of water flowed (amps)increases. Assuming the hose nozzle (resistance) doesn't change.
BUT, in electrical reality. If you lower the voltage, your load will draw more amps. So dropping from a 1s Lipo to a lower voltage 1s Life pack, should put more load on the ESC, if the motor can still pull it.
And generally in most cases, if my load only draws 2500 watts. And I can choose different motors or resistors to meet that wattage requirement (true work). Higher voltage will offer lower amp draws.
If you're still running a 3.5 with a higher voltage, it will draw a higher amperage. But a 3.5 drawing more amperage on a higher voltage, is going to dyno much more wattage than it would on less voltage.
So naturally you'd drop down to a 6.5 motor that could produce the same power/wattage at the higher voltage. And much lower amp draw for the same amount of true power output.
It's easier to figure with pure resistive loads. A 2500w 480v heater draws less amps than a 2500w 208v heater.
So naturally you'd drop down to a 6.5 motor that could produce the same power/wattage at the higher voltage. And much lower amp draw for the same amount of true power output.
It's easier to figure with pure resistive loads. A 2500w 480v heater draws less amps than a 2500w 208v heater.
But brushless DC motors don't seem to work like that.
If you lower the voltage the motor wants to pull more current to compensate.
09-03-2016, 04:26 PM
#340
09-03-2016, 05:59 PM
#341
Long version:
There is no such thing as a DC brushless motor. Our brushless motors are three phase, permanent magnet motors, or permanent-magnet AC (PMAC) motors. The reason we use these for RC racing is that they can provide power very smoothly, unlike an AC induction motor which is the workhorse AC motor for everything from your clothes washing machine to a streetcar.
Even though it may be difficult to explain the inner workings entirely, what we call a "Brushless Motor ESC" would more accurately be called a "variable-frequency, hall-effect sensor-triggered, DC to 3-phase PMAC motor power supply."
In spite of these being, at least at a glance, more complex than non-induction brushed motors, the operating principles and forces are exactly the same. Zero-RPM peak torque (and peak amp draw at 0 RPM) can be calculated from internal resistance, ideal zero-load free-spin RPM calculated from resistance and strength of the internal permanent magnet rotor, and amp draw at any RPM is ideally a perfect linear correlation between your peak amp draw at zero RPM and your max free-spin RPM. With locked timing we can slightly "trick" the motor into upping the power output at the expensive of efficiency, but the power curve will still follow these rules.
Power = Volts * Amps.
Amps = Volts / Internal Resistance.
Therefore Power = ((Voltage)^2) / Internal Resistance
The only way to make a motor (in operation) increase its amp draw following a drop in input voltage is to hold the motor much closer to its stall speed.
09-03-2016, 10:02 PM
#342
Yes, exactly.
09-08-2016, 09:39 PM
#343
Vegas 6.5
Hearing Vegas will be 6.5 .... Any thoughts
