Making my car a little less powerful?
07-21-2013, 02:06 AM
#16
Tech Initiate
iTrader: (7)
How do you slow the motor down while still giving the esc a break at full throttle? Does the phrase "If it ain't broke, don't fix it" still apply?
I've been using a Hobbywing 150a esc shoe gooed to the battery/esc tray, Tekin 1900 motor when has never been taken apart and been ran sensor less, Ecopower 4100 4S, and a limited throttle EPA of ~110 out of 150, and never had the slightest of problems since I got this combo well over a year ago. Yet there are many more people at my track who have their throttle EPA maxed out, velcro/2-sided tape to cushion the esc, and inspect the motor regularly have many issues. Yes, there are many more variables than that, but it still is ironic. Even with my frowned upon electronics setup, I am more competitive in E-Buggy than nitro buggy, and have no problem running with the pros.
On a side note, its amazing how much faster rookie and sportsman drivers especially can become just by changing endpoints. Someone will ask me to drive their car and check it, so I look it over a minute and see how steering end points are set, and ask if I can adjust their radio. On the track I adjust throttle and brake endpoint first, as 80% of the E-buggies around here have 1. an uncontrollable amount of power, and/or 2. excessive brake which ruins their corner speed. Then, based on how much steering they have and how far the servo traveled originally, increase or decrease their steering endpoint to get the desired steering feel. On cars with tons of steering to the point of being hard to drive, going down 5-15 points can make a huge difference in making the car easier to drive. This is probably the quickest and most effective way to change a car's handling/steering in your warm up laps. That being said, after everything is adjusted and the owner drives his car again, 99% of the time their response is how much better their car handles, and how much funner and confidence inspiring it is to drive. To clarify, I'm not saying changing endpoints will make a poorly handling car great, but wrong/off endpoints can make a good handling car bad. It's almost always better to adjust tires or other chassis settings to get the car to handle how you want, but the next best thing is adjusting end points.
I've been using a Hobbywing 150a esc shoe gooed to the battery/esc tray, Tekin 1900 motor when has never been taken apart and been ran sensor less, Ecopower 4100 4S, and a limited throttle EPA of ~110 out of 150, and never had the slightest of problems since I got this combo well over a year ago. Yet there are many more people at my track who have their throttle EPA maxed out, velcro/2-sided tape to cushion the esc, and inspect the motor regularly have many issues. Yes, there are many more variables than that, but it still is ironic. Even with my frowned upon electronics setup, I am more competitive in E-Buggy than nitro buggy, and have no problem running with the pros.
On a side note, its amazing how much faster rookie and sportsman drivers especially can become just by changing endpoints. Someone will ask me to drive their car and check it, so I look it over a minute and see how steering end points are set, and ask if I can adjust their radio. On the track I adjust throttle and brake endpoint first, as 80% of the E-buggies around here have 1. an uncontrollable amount of power, and/or 2. excessive brake which ruins their corner speed. Then, based on how much steering they have and how far the servo traveled originally, increase or decrease their steering endpoint to get the desired steering feel. On cars with tons of steering to the point of being hard to drive, going down 5-15 points can make a huge difference in making the car easier to drive. This is probably the quickest and most effective way to change a car's handling/steering in your warm up laps. That being said, after everything is adjusted and the owner drives his car again, 99% of the time their response is how much better their car handles, and how much funner and confidence inspiring it is to drive. To clarify, I'm not saying changing endpoints will make a poorly handling car great, but wrong/off endpoints can make a good handling car bad. It's almost always better to adjust tires or other chassis settings to get the car to handle how you want, but the next best thing is adjusting end points.
+1!!!
Here's how I see it. EPA, its there for a reason, to help. Its a tool, use it. Why try to use only a few millimeters of throw on the trigger when you can use it all. Do whatever is easier for you. Learn to crawl before you walk.
Also when are you ever at 100% throttle on the track, maybe at most 2 second blip down the straight. The rest of the time you are using less then 100% throttle. Guess what.... now think about it... the rest of the time are you at less then 100% duty cycle. Which is the same thing as limiting your throttle for say 95% of the time you are on the track. DC motor speed is controlled using pulse width modulation by adjusting the duty cycle. Full throttle is 100% any slower your esc will be pulsing the signal to the motor according to where your trigger is. You're gonna get noise all the time, its only an issue when the caps are out of spec, bad lot, bad quality control/screening, or bad design and if that is the case its going to fail anyways. Don't scare the guy about blowing up caps if he's not at anywhere other then full throttle...
.
07-21-2013, 03:51 AM
#17
When the esc is at anything but full throttle, the esc is being bombarded by ripple current. Take away full throttle (by limiting epa) and you get rid of the "break" the esc gets at full throttle. The capacitors on the board of the esc are the filters for the ripple current. Overwork them, and they will fail.
I am trying to teach you how to look up stuff for yourself. That way you don't have to rely on someone else's bad advice. If it seems a little off, you can look it up and see for yourself. Much better way to live.
I am trying to teach you how to look up stuff for yourself. That way you don't have to rely on someone else's bad advice. If it seems a little off, you can look it up and see for yourself. Much better way to live.
Last edited by madweazl; 07-21-2013 at 02:43 PM.
07-21-2013, 04:53 AM
#18
Suspended
iTrader: (7)
First, I'm fairly certain this guy is not on the track, in which case, he is probably spending much more time at full throttle. So way to go on everyone's forest from the trees perception.
Next, end point adjustments were created back when you needed to adjust the amount of travel on a servo. Tricking the speed control by limiting the amount of input it sees is not right, no matter how many people do it. It was less wrong back in the brushed days. Even then there were other settings much more effective (I really liked the little jumper blocks on the LRP V6). A brushless esc takes a DC voltage and turns it into a square sine wave (I think). In that process there is a lot of noise. The capacitors filter that noise. Think of ripple current like this. If you move your finger around in the flame of a lighter, and periodically move your finger away from the flame you are fine. If you move your finger around in the flame, but never pull it out of the flame, you will get burned.
Lastly, maybe it is just because I am who I am, but people never want to believe me. Can anyone point out an esc instruction manual that states to lower the epa? I'll have to see if I can get Randy or Charlie to weigh in on the subject here.
In all likelyhood lowering the epa will get the job done, and not cause an issue. There is still a chance that it could cause an issue.
Bonus points to anyone that knows what the noise filtering component from back in the brushed days was called.
Next, end point adjustments were created back when you needed to adjust the amount of travel on a servo. Tricking the speed control by limiting the amount of input it sees is not right, no matter how many people do it. It was less wrong back in the brushed days. Even then there were other settings much more effective (I really liked the little jumper blocks on the LRP V6). A brushless esc takes a DC voltage and turns it into a square sine wave (I think). In that process there is a lot of noise. The capacitors filter that noise. Think of ripple current like this. If you move your finger around in the flame of a lighter, and periodically move your finger away from the flame you are fine. If you move your finger around in the flame, but never pull it out of the flame, you will get burned.
Lastly, maybe it is just because I am who I am, but people never want to believe me. Can anyone point out an esc instruction manual that states to lower the epa? I'll have to see if I can get Randy or Charlie to weigh in on the subject here.
In all likelyhood lowering the epa will get the job done, and not cause an issue. There is still a chance that it could cause an issue.
Bonus points to anyone that knows what the noise filtering component from back in the brushed days was called.
07-21-2013, 07:00 AM
#19
A square sine wave lol.
Schottky diode.
Schottky diode.
07-21-2013, 07:47 AM
#20
Tech Adept
A throttle is not a light switch. Don't want to go so fast? Don't pull the trigger so hard...
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
