Consensus on EPA

[pullinteef]

So what's the final word on lowering the throttle EPA on the MMM? I keep hearing mixed answers, some saying it will blow the ESC, some say it's ok. Sometimes I like to go to about 90% and it seems more controllable without underloading the motor. I have an RC8 with 1512/2D, and have tried 13-16T pinions with a 46T spur. The 13 and 14 seem to get the motor too hot (175-180) after a 10 minute qualifier. The 15 seems pretty good and the 16 is just insane but I think it draws too many amps and heats up the battery a bit more (Flightmax 5000 25C). So I settled on the 15T but the motor still gets to 170 but If I lower the EPA just a little it seems to keep the motor a bit cooler. Will this blow the speedo? It's a V3 thats been great since November (just breaks fans)

[BrianG]

It won't "blow" the ESC, after all, setting a lower value is simply like driving with the trigger not open all the way. However, ESCs do run less efficiently at less than WOT.

If you want to slow it down, gear down, use lower voltage, or use a lower kv motor.

[pullinteef]

Yeah, I'd like to get a Tekin 2050kv, but trying to see what can be done with the 2D I've had for a while. It seems like when I gear down the motor gets hotter and it tops out too early on the straightaway. I already have timing and start power at lowest, don't like to turn up the punch control too much or I lose the ability to correct mid-air. Also, a buddy of mine smoked an RX-8, and he was told by tekin that part of the reason could've been that he was using the EPA at 80%.

[brushlessboy16]

Originally Posted by pullinteef

Yeah, I'd like to get a Tekin 2050kv, but trying to see what can be done with the 2D I've had for a while. It seems like when I gear down the motor gets hotter and it tops out too early on the straightaway. I already have timing and start power at lowest, don't like to turn up the punch control too much or I lose the ability to correct mid-air. Also, a buddy of mine smoked an RX-8, and he was told by tekin that part of the reason could've been that he was using the EPA at 80%.

thats total bull. changing you epa is equivelant to putting a foam block behind the trigger on your radio. All epa does is limit the max throttle percentage. if you set it to 50% its like holding the trigger half way from neutral to WOT


the signal the esc sees is that of the percentage of throttle.... I dont thhink the speed controller died because it didnt go full throttle....


on another note. i race with a guy who runs 3 rx8 systems, they run amazing, just as much power as the castle system- but the same guy blew the rotor in 2 of the 3 systems all in one day :(

[hobbimaster]

I've been running my SC8E at 80% EPA, seems to be more controllable. I'd like to hear from Castle on their take on lowering the EPA, I know an ESC is more efficient at WOT, but who out there can honestly say they run at WOT on a track with jumps.

[_paralyzed_]

It is no different than holding your finger at %50 percent. But you simply wouldn't drive like that for an extended period of time. People do however constantly change throttle position or hold it wide open for extended periods.

Changing the epa makes holding it wide open for extended periods less efficient than if it were actually wide open.

IMO this has worked for people running cool and proper setups, and the failures were probably in systems that lacked in certain areas.

Changing the epa makes the esc act as if it were not in normal driving conditions (again, holding a set partial throttle for an extended period) and I will limit my speed with voltage, not epa.

[Finnster]

I lower my EPA all the time, such as if I let someone else drive the cars (ie son, brother, friends, fiends, etc) No adverse effects. I would only do it once the system is properly set tho, not to compensate for a poorly designed system.

i also lower my epa all the time, ill run it around 90% in my truggy on 4s, then on 5s i keep the same gearing and turn it down to around 70-75% no problems running it like that, its not like your 100% full throttle very long on any track anyway

[pullinteef]

I agree with pretty much everyone, I don't see how it could damage the ESC. However I don't think I'm the only one who's read that it is strongly advised against. Not sure why though. Like others said, how often are you at full throttle, maybe 3-5 seconds per lap?

[Joe Ford]

It can damage the ESC if you're using it to try and reduce current in a system that is over the max the system will handle. Other than that it's because of a little more heat that is being generated from switching losses. That's about it. As long as you have a proper setup that you know is well within the limits of the system you shouldn't have any issue. I personally do not limit it...I just use the right kv motor, gear it correctly for the top speed I want, and put the right cell count battery in it.

[Jarvis]

Joe, this would also be the case if you had a 6S on the 2200kv in a buggy with 30-40% epa?

Is it better to make these type of power limiting adjustments in the MMM or through the radio?

This is a good post because a LOT of people have the castle system around here with the epa set low to limit throttle. I think it is just being lazy when you can gear down or swap motors for the track.

i dont think its being lazy at all, but more of a "fine tuning" also when theres no need to gear down on a slightly smaller track, you just move the epa a couple clicks, alot of time i adjust my epa to slightly over jump the biggest jump at full tilt, its more consistent that way, downside it everytime!

[fastbaja5b]

I use the EPA on my Savage Flux (bog stock) mainly when letting my nephew have a go, I tone it down to 50% so he can handle it.

I would be shocked if this was putting the ESC at risk.

This is an important post for us parents that let our young children drive competalevy. My daughter drives with the epa set at 50% I haven't had much of a heat issue. I have been wondering if changing the dual rate on the transmitter would be better, that way you would still have full trottle but less power in the mid section reducing spin out when getting through corners. Any thoughts

[SpEEdyBL]

In some cases, what I would do is set your voltage cut-off to around 3.5 volts per cell. It will shorten your runtime, but it will act as an amp limiter, reducing the current to keep the cells above 3.5 volts. You will lose initial punch, but you will keep most of the midrange punch and the same top speed.