Fed up with brown outs
 

Hoping for some "fix-ya" advice.
I bought a used Ko Propo EX-10 Helios which came with a Spektrum SR3001 Pro receiver and SM1001 Pro transmitter module. It browns out at the worst times! On the straight away, out of turns, prior to a jump, during a jump when flight attitude needs adjustment.... pretty much all the effen time!
Sometimes, the problem does not show itself at all, for short periods of time.
I'm using a Savox 1267 servo, and I have a Castle BEC properly installed to prevent glitching. I'm also using Castle MMP with 3800kv motor. I use the Castle Link to program the esc.
Is this particular Spektrum equipment unreliable? Is there a fix for it? The antenna has been relocated (by the previous owner) from the side of the Tx module to the top of the controller.
I'll be willing to refit the controller with Ko Propo equipment, but that'll cost $200.
What other Rx/Tx modules are compatible that may not cost as much as Ko Propo?
Any comments and feedback are greatly appreciated!

Get a better radio or get rid of the Savox. Problem solved. Savox are one of the most power hungry servos you can get. That and their QC sucks, so sometimes you get one that works great and doesn't draw a huge amount of power and other times you get a crappy one. Its a roll of the dice, and the price reflects that. Also my understanding is the older 2.4 modules compound the problem.

Something to also check to help reduce the amount of power the servo needs is your endpoints. If the servo hits the limit the wheels can go but the servo wants to go further it increases the power drawn. This doesn't seem to be the issue though since its doing it on straightaways as well. A higher C rated battery may help if you are running a lower C rated battery. What it comes down to is something is drawing more power than the rx can supply. Whether it is because of a general lack of power supplied or too much power being drawn. Better Tx and Rx can handle more power supplied to them. Better servos draw less power. Its not always just one thing. Sometimes its a package deal that's the problem.

There is a known problem running Spektrum receivers and Savox servos. There shouldn't be a problem since you have the external bec. Most of the time a glitch buster or bec will fix the problem. You could just get a different servo instead of the Ko Propo stuff. Might fix your problem. My LHS stop carrying Savox servos cause they are such a problem.

Old Spektrum = junk... sorry to break the news.

Thanks for the replies! What combos do any of you recommend?

airtronics mx-v for under $80 on ebay is a great radio w/o the brownouts.

If your using the CC BEC(10amps) and still having issues. You have other problems...

Are you sure it's hooked up right?

I have a fair amount of experience with the MMP (albeit the 1-cell version) with 3800 4-pole Trinity motors. My data logs show that they can draw enough amperage to max out the MMP. With that being said, it's possible that a contributing factor to your brown-outs is that the battery voltage is sagging enough to cause the receiver issues. This seems likely as in your description you state that the brown-outs happen at all times, which means that the servo isn't necessarily the issue. What do you have the BEC voltage set to?


Do you have any data to support this? All of mine shows that they don't draw much. Another forum member showed, using an oscilloscope, that they do draw aggressively at the start. For reference I have attached logs for a 1258 and 2271.


http://i514.photobucket.com/albums/t...ps544866fc.png

http://i514.photobucket.com/albums/t...rrent_Draw.png

Thank you, checking that out. That is cheap alternative for sure!

BEC is spliced/soldered into the ESC battery connections, and is plugged into the BATT terminal in the receiver (even tried it in the AUX terminal, same crap), ESC is plugged in with its' red power wire unplugged. Can't imagine it's any less simple. But I do agree, I have a problem elsewhere. I suppose, in the meantime, I'll peel off the heat shrink and have a look at my BEC-to-ESC battery connection. It might be possible I have a cold solder there. I'm better at soldering now than I was then, so that could be it.
BTW, I am running SMC 6500 70C batteries. Shouldn't be a problem with power delivery. And, I'm feeding the Savox all the power it can handle.
I'll look at anything you guys suggest.
That is why I'm getting so upset about it. I've heard and read enough remarks about older Spektrum equipment and Savox. Heck, A-Main even includes a footnote about Savox servos in their description: *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.
I bought my servo from a hobby shop on impluse because my stocker fried. I wouldn't have bought one if I had read that or been told about it.

BEC is set to 7.0V. It is a Savox 1267SG, Speed(@7.4V sec/60): .09
Torque(@7.4V oz-in): 277.7
Do I need to custom set that voltage? Should I give it less?
Thank you for your input!

Funny thing is, I recall that I didn't have this problem when I installed the servo in my Slash 4x4, which has the stock VXL-3S esc.

Can the servo run at 6volts? Try setting the bec to 6v and see what happens.

On Using 3 cells the voltage never gets low enough to cause an issue. I suggest setting the BEC to 6v as well. There will be less fluctuation.

I seem to recall that using less volts to feed the servo can help the mmp esc. I think I will try less volts, per the recommendations.
Could the mmp 's lower amp limit be the problem with using power hungry servos? Thanks again, for responses.

You're not using the MMP's BEC, so the MMP BEC issue doesn't matter. Also, per your description, it's the motor that is what is consuming the power in this case.