Brown-Out Issues?
 

Having problems w/my TLR SCTE 2.0

I was having what I thought were brown-outs. Anywhere from 2-4 minutes into a 5 or 6 minute race, I would start having issues. The truck would just basically stop. No go, no steering. Usually after heavy braking into a corner and then attempting to accelerate out of a corner. After a second or two it would start again w/o intervention.

I was using a cheaper Savox servo (SC0251MG). Added a glitch buster cap, no help. Went to a better servo (Savox SC1258TG), no difference.

Just for kicks, I removed the fan that was on my motor (Novak 4.5t 550). No difference.

Thought maybe my ESC (Novak Havok Pro) was having issues, went to my spare, no difference.

Thought maybe my receiver (Spektrum SR301) was having issues, went to my spare, no difference.

I'm back to thinking it's the ESC. I check the temps on it after having issues, but it's always in the middle of the 'acceptable operating range'. I'm kinda at a loss now. I don't have a spare motor to try, nor do I have another battery to try (using a new SPC 6500 mAh, 65c).

Anyone got any ideas?

It's your spektrum receiver, I had the same problem with my old scte 2.0, hobbywing xerun combo with savox 1258 sr3300t rx

I do have an Orange Rx I could try.

To double check if it's your receiver, prop up the truck on a stand and give full throttle, fast steering etc. and watch the rx light to see if it blinks, it could be barely browning out as well where you could barely see the light blink on/off, the orange rx might work as well, I would usually brown out at the end of the straight into the sweeper full throttle to brake and turning sending into the wall a few times, I use my savox in my t4.2 with mt4 tx/rx with no cap/glitchbuster and no glitching

I've tried to get it to do it on the bench with no luck. I was holding the rear tires stationary, alternating throttle/brake and steering. It never stuttered, but I was not looking at the light on the Rx.

yea check the light the rx while on a stand or someone holding it and do what you would do while driving/racing, what radio do you use

Spektrum DX3C

I was using the dx2s and both are dsm not dsm2, not only was I getting brownout issues with the rx but when racing or a lot of people on the driver stand I would get interference when other trucks would be close to me so it's possible you could be getting brownouts on the rx along with some interference, just check your rx to see if the light goes on off etc., it might be time for a new radio system

It might be the battery, I noticed that one of the batts I have had a cell that is a lil lower than the other, and if I run that batt the esc glitches and the thing acts crazy!! Just an idea:)

That's interesting... the worst spot for my issues is the farthest parts of the track from the drivers' stand. They just happen to be hard brake/acceleration zones, too.

Just make sure u have a good bind with the rx/tx and see if it does it in that point again!!

A good BEC, and good batteries.
/Thread

Spektrum and Savox are not friends, they are enemies :)

Every time somebody asks me about radio problems and I ask what radio and what servo they answer Savox and Spektrum

I can't figure out why with the tons of Savox issues threads people still buy them, 'cheap' is not an answer if you want to race

4WD SC is THE most demanding power wise of any class

So... Why does it work perfectly for 3 minutes? If they "don't get along", wouldn't they not get along from the second the switches go on?

Because the esc has only so many amps to send the receiver and servo at the same time, usually 5amps at 6v. When the pack is fresh it's easily doable, but after a few minutes when the voltage has dropped a little the savox servos are known to pull high amps basically using what is available not leaving much for the receiver.

If your at full steering and powering out of a turn, the voltage drop from the motor digging deep and the servo pulling higher then normal amps(savox is known for this) then the receiver "browns out"

Castle BEC, again is the answer. Its really simple, using a bec you will never pull more amps or voltage from 1 savox servo that a good quality BEC can supply. As an added bonus you can run it at 6v getting faster movement and more torque.

Bolded because its the correct answer I highly doubt any thing else could cause what your having problems with. Dont add a cap or any other bandied setup, just run what will for sure fix the problem.

savox may be cheap compared to other servos but it doesn't mean they're bad, I had "savox" issues and when I changed my radio system no more glitching, didn't use a cap either so the savox wasn't the problem, just like other rc electronics some things don't work as well together as others do, even the "best" most expensive brands can have issues

Wow, talk about leading people up the garden path.

I run Savox in all my cars, never had a glitching issue. But I use a decent radio (Airtronics) and decent ESC's (ie NOT A CASTLE) and I test the amp draw of the servo before I install it to make sure it's appropriate for the job.

Spektrum DSM is 7 or 8 yr old tech, Castle ESC's are well known for internal BEC issues (strange that the solution is a BEC they sell for an extra $20-$30)

Well, I'm getting desperate. If my LHS has an external BEC, I'm buying it. What I don't understand is why this problem is cropping up in the last 3 weeks or so. Why not the 6 weeks before that?

Just for kicks, adjust your steering end points. I had a similiar problem my SCTE (savox servo, rx8, futaba tx/rx) and it was a 2 part problem. Item 1: at full lock (like diving into a corner) the steering linkage was binding a bit, making the servo work harder and pulling more amps leading to a mild brown out. Item 2: the bec in my RX8 was starting to fail, repaired by Tekin.

After each step it got better but didnt always go away until both issues were addressed.

Couldn't tell ya, but the point is i have seen this over and over again, atleast a handful of times at the track and countless threads on the forums about it and every time some describes the exact same issue your having its the same thing, a savox servo paired to a spektrum receiver.

Also recheck your end points for your steering on the radio, make sure the servo isn't trying to travel further then necessary to achieve full steering, if you turn the wheel all the way and the servo is buzzing real bad it could be causing an extra high amp load aswell.

I think the end points are ok, just reset them w/the new servo. At least I have a couple of things to try: 1. Orange Rx, 2. External BEC

Better than when I posted this stuff yesterday.

The havok pro has a 3 amp bec

The max amps at locked according to the specs of both of these servos are above 3.2 amps
Normal amp draw is under 1 amp, but at full steering & full throttle they will approach or go above the max amps of the internal bec.

A Main Hobbys advises for both of these servos.

*NOTE: Certain combinations of receiver and ESC have been found to cause "Brown Out" issues when combined with Savox servos. An external BEC, or BEC stabilizing receiver capacitor may be needed for efficient, glitch free operation in low voltage electric applications.


Normal usage with any brushed will increase the amp draw as the brushes break in.

I use a castle bec, I prefer it to a capacitor as the valve of my truck is around $600 & to me the $20 bec that produces 10 amps makes me feel better.

I have many friends that use either with no problem.

And yes I have an amp meter I have put inline to check this.

Hope this helps
TM

Your novak's bec puts out 3a @ 6v.
Your savox can pull up to 5a running 6v at stall.
Your servo may be pulling 4 or so amps under a heavy load, if your end points are set too far it will pull 5a (or very close to it).

Either scenario is a problem.

Savox servos are a little less $$ than other good servos but not a good value IMO. Spend the extra $25 bucks next time. They are ok for buggies or other light 1/10 scale that do not run high amp draw power systems.
Or 1/8 high voltage, low amp power systems.

High amp draw SCT, fail. That and spectrum radio... fail of the year.

On reception, my friend showed up to the track with a lower end spectrum radio and could not drive as everyone was over powering his radio. He bought a low end Airtronics radio (MX-V) and problem solved.

Edit:
Ha ha... didn't see the second page. Will leave text as is though.

Wow... Fail of the year... That's harsh.

I know right. Like it should be on YouTube :D

At least it's an easy fix.

True, I've had much more expensive problems before. Good luck with it :tire:

I have a similar problem but not quite as bad and it's also not repeatable. It seems to happen randomly during the mains on a full drivers stand with my Tamiya M-05. On some race days it's fine and on others I get lots of problems. I get a combination of power loss and glitching where the steering just won't work like they way I want it to and I end up crashing all over the place. When my car stops moving with loss of power it will usually get going all by itself again after 5-10 seconds.

I'm using an Airtronics M11 radio with the Spektrum module so I tried replacing the receiver and still had the same problem from time to time. I tried using a Futaba, Hitec and finally a Savox steering servo and still had the same problem. The only conclusion i can come to is that the problem is with the ESC on my Orca Spark brushless system. I never had this problem when I was racing with a silver can motor. The weird thing is I use the same Savox servo and Spektrum receiver on my touring car and I never get these issues.

The orca spark system bec is only rated at 2 amps, not near enough for todays servos. The bec circuit is likely getting warm & losing efficiency. I would try a cap or bec.:tire:

the manuals

http://www.orcarc.com/en/supports.asp

Just go with a BEC, 2a from the esc is nothing and i don't think even a receiver cap can help

Well, I was trying another receiver, caught a rock in the gears, burned up the ESC. :(

But, on the bright side, it didn't glitch or brown-out.

lol at all the bickering, you had your answer 2 pages ago. Sorry to hear about your loss, now you can move onto better ESC's like a MMP with BEC.

Mmp? Good luck with that!!

I like to make blanket statements, herp derp.
/sarcasm

You have some hatred for castle care to say why? In that other thread you did some silly things and tried to link Google about castle problems and then you ignored the fact that I linked Google searches for other popular ESC failures.

Kinda what I thought. CC doesn't have a good rep. I'll probably just send it in to Novak, exchange it for an Activ8. (Not that Novak hasn't had their problems.)

I think I will try adding a bec to see if that helps. The Orca Spark is what every racer at my club uses and none of them have any issues so maybe it's just mine that's a bit defective.

The saga continues...

I installed a 10 amp BEC and my back-up ESC. Put it on the track and could only run about 10% throttle w/o a significant shutter. Shutter continued between 10 and 20% throttle. 20% and up it went dead.

Hall effect sensor test checked out ok. Did notice some burnt insulation on my sensor cable, undoubtedly from the last ESC burning up.

So... Is it just the sensor cable being damaged having issues at higher power levels or did my last ESC take my motor with it?

Check the sensor wire, see if there is any resistance across each wire. Try running it with out the sensor connected. Then if nothing else switch in a known good motor. If that still fails you need to look at radio problems.