Motor brakes or mechanical?

[SidewaysLS4]

I looked over some of my Eagletree graphs and dont see any regen-like voltage or current on braking. But my Eagletree is set not to log unless there is 1A current or it only sees things going battery -> esc and not the other way so....?

[BrianG]

Does the ET even log "negative" current? Even with a simple meter, I've seen voltage spikes higher than the battery voltage happen, and when there is a difference of potential, there is current, guaranteed.

[SidewaysLS4]

Yeah, I wonder if - current is read also. I wonder if the regen current gets past the esc to the battery?

[Mozzy]

I know & understand what's been mentioned here, but, in the past I've heard from a few electric brushed & bl racers that the ESC's aren't designed to feed eletricity backwards & are only designed to draw it from the battery.

Can this be confirmed by an actual ESC designer & not by someone that assumes?

Perhaps someone from Castle, Losi, Novak or LRP R&D?

I think only one of these people would be able to give a definite answer.

I don't care if you're an electronics wizz or have a degree in the field. I want to hear from an actual designer as they'd only know what's truly going on with their product & could tell you exactly what's happening.

[BrianG]

Originally Posted by SidewaysLS4

Yeah, I wonder if - current is read also. I wonder if the regen current gets past the esc to the battery?

The ET device most probably reads the voltage drop across a very small (like 0.001 ohm) precision resistor shunt. If current is going the other way into the battery, the voltage read would be negative. Not sure if it can read that.

Originally Posted by Mozzy

...Can this be confirmed by an actual ESC designer & not by someone that assumes?

Patrick (Pdelcast) from CC has indeed stated they are regenerative.

[Mozzy]

I still don't get it Brian.

Why did I gain runtime using the same packs & motor with the same ESC set up (less motor brakes) when I changed from motor to mechanical braking?

I know it wasn't alot, but, 4mins is 4mins. :-)

[BrianG]

Did you drive the exact same way on the exact terrain? Granted, motor braking won't put in as much energy braking than it did to accelerate it by far.

[Mozzy]

Yep, same track, same surface, same ambiant & battery temps, but, the motor temps were slightly higher when using motor brakes.
I'm guessing with the motor braking it creates more heat to make the motor brake. Could that be the reason?

[Ryu James]

Originally Posted by Mozzy

Yep, same track, same surface, same ambiant & battery temps, but, the motor temps were slightly higher when using motor brakes.
I'm guessing with the motor braking it creates more heat to make the motor brake. Could that be the reason?

that is exactly the reason. this is advertised in all of Teknos conversion ads; that mech. brakes result in lower temps. your motor has to work a lot harder to stop a 9lb truck by spinning in reverse than it does when you let a servo do the work.

btw, the proof is in the pudding. 4mins is mins. more than i have heard from anyone seeing increase the other way around. granted you would get a more accurate depiction if you recorded say...10 run times of each setup with the exact same setup.

Mozzy, do you always track your runtime? if so, when you had motor brakes did your runtimes ever vary by more than 4mins? if so, then it is simply just that much variation exists in your runtime regardless of brake setup. let us know more about how you did your test? more than once? just one time?

Monster Mike has just joined this discussion without knowing. This is a quote from the store (1/8th conversion kits):

*Direct drive - like electric should be. Stay connected to your drive train - this is the most efficient drive scenario for electric power. Power delivery can be tuned on your radio and esc. Motor braking is consistent, tunable and puts energy back into the battery pack. No extra rotating weight, extra components or complexity of mechancial brakes. Less parts to fail or tune. Low weight, optimum acceleration and control. Motor is coupled to the center diff, allowing the chassis to flex as intended without affecting gear mesh or accelerating gear wear.

[Ryu James]

Originally Posted by drkdgglr

Monster Mike has just joined this discussion without knowing. This is a quote from the store (1/8th conversion kits):

imo, that is mostly marketing and aimed at the "other" kits to try to get sales. despite some of it being truth (and some of it opinion) it is not the "gospel" just because it came from this site or from Mike. (as much as we all love both!)

read this from the Tekno site.

*Mechanical brakes with front/rear brake bias provides world class handling while lowering operating temps and easing the stress on your motor, ESC, and drivetrain
*Patent pending Elektri-Clutch system to tune the power delivery of the hottest brushless motors. Our hardened steel clutchbells will last and last because the motor is disengaged from the drivetrain off power. For those that prefer direct drive, our kits are compatible with long shank 5mm bore mod1 pinions as well. More options and flexibility than any other kit on the market.



oh hell, who are we kidding? this debate will never end will it?

[George16]

You sound like one of those infomercial pitchman .

I'm using mechanical brakes on my Tekno revo and motor brakes on my ST RR. I like the feel of the motor brakes better than the mechanical brakes. I think it's just a matter of getting used to. I never really cared much about my runtimes but I do use the same batteries between the two trucks.

Now as for TeknoRC's elektri-crap, I took it off due to temp problems. After I was able to lower the temps (by running it without springs), I never liked it because it seems to be more unpredictable compared to using a pinion.

Bottom line, use whatever works best for your application. What might work for you might not for another. Opinions and facts are all part of a dicussion and marketing but in the end, it's still up to the end-user to make the final decision.

By the way, I used to run nitro trucks only until I started converting my trucks to brushless 10 months ago. Based on this, I can only speak about my personal experience using mechanical and motor brakes.

[Mozzy]

Originally Posted by Ryu James

that is exactly the reason. this is advertised in all of Teknos conversion ads; that mech. brakes result in lower temps. your motor has to work a lot harder to stop a 9lb truck by spinning in reverse than it does when you let a servo do the work.

btw, the proof is in the pudding. 4mins is mins. more than i have heard from anyone seeing increase the other way around. granted you would get a more accurate depiction if you recorded say...10 run times of each setup with the exact same setup.

Mozzy, do you always track your runtime? if so, when you had motor brakes did your runtimes ever vary by more than 4mins? if so, then it is simply just that much variation exists in your runtime regardless of brake setup. let us know more about how you did your test? more than once? just one time?

I have timed my runs from the start (which isn't that long ago) to see the difference between the gearing/motor & battery chosen.

I'm using Zippy 5S packs both 4000 & 5000 with a 2.5d in my CRT on a 15t pinion.

The difference between the two packs is 5mins.

I have a timer on my 3PKS & as soon as I hit the track or accelerating I hit the start button. If I roll I stop it untill I begin accellerating again. As soon as the pack shows signs of dumping, I stop the timer.

[_paralyzed_]

Mozzy seems to have the real world answer. Of course, theoretically regenerative motor braking would be more efficient. But with an r/c, on a track, how often do we brake and coast to a stop? Never. We're either stabbing the brakes or locking up the wheels, which of course wouldn't regain any power. More a/b comparisons like Mozzy did will confirm that mech brakes are the more efficient setup. Very interesting. One more reason to always keep an open mind and always keep learning. Thanks Mozzy!

[Ryu James]

i totally agree with you paralyzed. the proof is in the pudding and Mozzy is the one who has brought some to the table.

@George
i agree with you about the elektri-clutch setup. I dont like it. i definitely prefer direct-drive. i dont know, i was going to pull out a clutch again this week and try it again since i am a better driver now. the Tekno guys still religously use the clutch setup. but Danny recently told me that one of their biggest sellers recently are the long shank pinions. that would be a good user name - Longshanks. lol. anyway, when i switched from cluthc to direct drive i was expecting some huge difference but i didnt notice much. other than the pinion is sooooo much quieter. i can still control at low speeds. not quite like a clutch i guess but i have never felt i need to switch.

mozzy, thanks for sharing more info. so it sounds like on motor breaks your run times were always roughly the same amount of run time. so the mech brakes 4 extra mins was after several times with motor breaks, right?