Modern BEC rethink
#46
Yeah, on the bench it's largely a DC system so it might not appear too bad. I'd be concerned under higher load conditions that there might be significant voltage differences on the ground.
But sounds like you are aware and checking, good stuff. Please update us if anything interesting comes of it.
But sounds like you are aware and checking, good stuff. Please update us if anything interesting comes of it.
Has anyone experienced an external bec failure where the bec did not damage other electronics? If so, what bec was it? It may be a better idea to change out the castle bec to one that does not run as high of a risk to other electronics.
#47
My experiences with my son's car(s) and my own car(s) is that the savox/spektrum brownouts are indeed caused by the receiver. My son and I both run SPektrum DX3C radios. He runs a savox 1268 servo, I run a 1258 servo. Originally we started out both running SR300 receivers...both of us had brown out issues. I used glitch busters on both cars...and that worked well for a while. Then I noticed that whenever flysky radio's were on at the track, we would have to re-bind our radios (that may be an entirely different issue alltogether...but I'm not convinced) that worked most of the time.
Well then I started reading online that it was an issue with the SR300 receiver, So I bought us some SR200 receivers. I initially installed them with no glitch buster on both cars, and all was well. The weird thing though...after a couple months of running that way, my car, developed a glitch. re-binding would cure it for the night, but it would come back the next day, the next race, 2-3 races later....it was really random...so I put the glitch buster back on my car (my son's car still not running one with the SR200)
So then I start reading about people running DSM2 receivers and reporting that the glitch issues were completely eliminated...So I run off and buy a couple knock-off SR3100's to test this. I'm blown away! Not only is the glitching 100% gone, but I notice a faster response, and I also notice that the LED on the reciever is MUCH brighter on the SR3100 (even side by side with an SR200)...
So In short...I'm not sure WHY i got the results that I did....but it is FOR SURE the receiver that is causing or producing the glitch/brownout.
Now, I'm not saying the servo doesn't influence things...because when I was glitching with my car, and my sons car didnt....I swapped our receivers (both were SR200's at that time) and the glitch stayed with my car.....I swapped receivers back....and swapped my 1258 servo for my son's 1268 servo....the glitch FOLLOWED my 1258 servo.
So I would say the servo for sure contributes to the problem....but the SOLUTION was to replace the SR200/SR300 DSM receiver for the SR3100 DSM2 receiver.
Take my info for what its worth....just trying to help people understand whats going on.
Well then I started reading online that it was an issue with the SR300 receiver, So I bought us some SR200 receivers. I initially installed them with no glitch buster on both cars, and all was well. The weird thing though...after a couple months of running that way, my car, developed a glitch. re-binding would cure it for the night, but it would come back the next day, the next race, 2-3 races later....it was really random...so I put the glitch buster back on my car (my son's car still not running one with the SR200)
So then I start reading about people running DSM2 receivers and reporting that the glitch issues were completely eliminated...So I run off and buy a couple knock-off SR3100's to test this. I'm blown away! Not only is the glitching 100% gone, but I notice a faster response, and I also notice that the LED on the reciever is MUCH brighter on the SR3100 (even side by side with an SR200)...
So In short...I'm not sure WHY i got the results that I did....but it is FOR SURE the receiver that is causing or producing the glitch/brownout.
Now, I'm not saying the servo doesn't influence things...because when I was glitching with my car, and my sons car didnt....I swapped our receivers (both were SR200's at that time) and the glitch stayed with my car.....I swapped receivers back....and swapped my 1258 servo for my son's 1268 servo....the glitch FOLLOWED my 1258 servo.
So I would say the servo for sure contributes to the problem....but the SOLUTION was to replace the SR200/SR300 DSM receiver for the SR3100 DSM2 receiver.
Take my info for what its worth....just trying to help people understand whats going on.
#48
Tech Master
iTrader: (39)
+ YouTube Video | |
Last edited by ufoDziner; 05-25-2013 at 09:20 PM. Reason: Added video
#49
Tech Champion
It took a while to get her truck on the track, but here are the results from my wife's 22T with a Savox SC-1258TG powered by a Novak Havoc Pro SC X-Drive. The big gap is when I was taken out by another driver such that it popped out one of the power connectors to the ESC. After the graph is a vertically shot vid (she forgot that she can rotate her phone cam and have the video be correct) of me driving my wife's Mid-Motor 22T today.
Can you export the data? I have data analysis software I use for full scale acquisition, nCode GyphWorks. If you were able to acquire comparable data with say a Futaba BLS servo it might be interesting to find out if I can see anything, say with a frequency spectrum check (or do you have that capability?)
In any event many thanks for your efforts in taking and sharing the data.
#50
Tech Master
iTrader: (39)
Very interesting, if not somewhat perplexing. While there is a significant difference, it doesn't appear to match up with some of the other reported (but not as clearly documented) measurements. Wonder if there is any chance Savox has updated the servos, or have you had the servo in question for a while?
Can you export the data? I have data analysis software I use for full scale acquisition, nCode GyphWorks. If you were able to acquire comparable data with say a Futaba BLS servo it might be interesting to find out if I can see anything, say with a frequency spectrum check (or do you have that capability?)
In any event many thanks for your efforts in taking and sharing the data.
In any event many thanks for your efforts in taking and sharing the data.
#51
Tech Elite
iTrader: (6)
In my Serpent 1/8th e buggy I had a Savox 1256 servo and Spektrum radio, powered through a RX8. This set up would cause the receiver to brown out just by moving the steering from full lock to full lock, I replaced the servo with a Futaba and the brown outs were gone. I have since changed to a Sanwa/Airtronics MT4 and never had a problem since.
So it would seem that a Savox servo can draw more than 5A to cause the BEC in the RX8 to struggle.
I actually think part of the problem here is the current carrying capability of the receiver, and hence my thinking that maybe it would be better to remove the receiver from this role and power the servo direct from the ESC. Having high fluctating currents in the same area as sensitive electronics that involve radio frequencies is surely asking for trouble. I suppose this shows how good modern receivers and radios are.
So it would seem that a Savox servo can draw more than 5A to cause the BEC in the RX8 to struggle.
I actually think part of the problem here is the current carrying capability of the receiver, and hence my thinking that maybe it would be better to remove the receiver from this role and power the servo direct from the ESC. Having high fluctating currents in the same area as sensitive electronics that involve radio frequencies is surely asking for trouble. I suppose this shows how good modern receivers and radios are.