New Elev8 Build, Problem with Motors Not working
Hello everyone!
I'm new to the forum, new to Parallax gear and multi-rotor RC aircraft. I've flown small RC helis, run electric and nitro RC cars/truck, and have some time in full-scale airplanes (still a student pilot).
I'm reaching out for some help troubleshooting my freshly built Elev8 v2. I followed the detailed online directions from the Parallax learn site and used all of the kit parts (no substitituions). I'm using a Futaba 6J radio and receiver. I synced the ESCs multiple times and have been testing with the copter secured to my work table and in actual flight.
Initial testing seemed to indicate correct operation, with all motors running at proper speeds and proportional to control inputs. I moved to low level test flying with small hops and then low altitude hovers. During this test, after about 15 mins total running time, the motor speed on motor #1 would suddenly drop and the copter would dive (I ate through a few props in flight testing before I resigned to bench testing).
I switched back to bench testing and after repeated tests (duplicating flight test results) I've arrived at a slightly different issue. Motors 2 & 4 appear to respond correctly (still), but now motors 1 & 3 don't spin up at all and simply twitch/beep (previous behavior for #1 was normal operation then power down and some twitching/beeping, while #3 appeared to work fine). This new behavior is consistent and repeatable. I've run the ESC synch procedure repeatedly, verified that all of the throws and endpoints are appropriate and that the appropriate channels are reversed (since I'm running Futuaba radio gear). I've verified all of the connections multiple times. The worst crash I experienced was from about 6ft into fairly plush grass. The only apparent damage has been props. I have spares from crash kits. I'm using the Elev8 branded batteries (behavior is consistent between the 2 I have), and the Tenergy LiPO balance charger. The batteries appear to charge normally.
The flight controller arms/disarms as expected and the status lights on the receiver and Hoverfly board are solid green while flying/testing. Lacking any experience building/flying these things, I'm open to suggestions for troubleshooting/testing. I have an email into Parallax support, but it has gone unanswered for several days. I'm guessing they're swamped with end of year sales/service matters. I have a multi-meter and some basic electric/electronics experience, but nothing specific to micro controllers or ESCs.
Any thoughts or suggestions would be appreciated.
Thanks!
Shane
I'm new to the forum, new to Parallax gear and multi-rotor RC aircraft. I've flown small RC helis, run electric and nitro RC cars/truck, and have some time in full-scale airplanes (still a student pilot).
I'm reaching out for some help troubleshooting my freshly built Elev8 v2. I followed the detailed online directions from the Parallax learn site and used all of the kit parts (no substitituions). I'm using a Futaba 6J radio and receiver. I synced the ESCs multiple times and have been testing with the copter secured to my work table and in actual flight.
Initial testing seemed to indicate correct operation, with all motors running at proper speeds and proportional to control inputs. I moved to low level test flying with small hops and then low altitude hovers. During this test, after about 15 mins total running time, the motor speed on motor #1 would suddenly drop and the copter would dive (I ate through a few props in flight testing before I resigned to bench testing).
I switched back to bench testing and after repeated tests (duplicating flight test results) I've arrived at a slightly different issue. Motors 2 & 4 appear to respond correctly (still), but now motors 1 & 3 don't spin up at all and simply twitch/beep (previous behavior for #1 was normal operation then power down and some twitching/beeping, while #3 appeared to work fine). This new behavior is consistent and repeatable. I've run the ESC synch procedure repeatedly, verified that all of the throws and endpoints are appropriate and that the appropriate channels are reversed (since I'm running Futuaba radio gear). I've verified all of the connections multiple times. The worst crash I experienced was from about 6ft into fairly plush grass. The only apparent damage has been props. I have spares from crash kits. I'm using the Elev8 branded batteries (behavior is consistent between the 2 I have), and the Tenergy LiPO balance charger. The batteries appear to charge normally.
The flight controller arms/disarms as expected and the status lights on the receiver and Hoverfly board are solid green while flying/testing. Lacking any experience building/flying these things, I'm open to suggestions for troubleshooting/testing. I have an email into Parallax support, but it has gone unanswered for several days. I'm guessing they're swamped with end of year sales/service matters. I have a multi-meter and some basic electric/electronics experience, but nothing specific to micro controllers or ESCs.
Any thoughts or suggestions would be appreciated.
Thanks!
Shane
Comments
Chris and I have been looking at your message in a perplexed sort of way the last couple of days.
It's possible that you didn't set the throttle range on the ELEV-8 V2. Did you do this step properly?
Your point on the endpoints is important - good to know that's right.
The only "black box" kind of QA/QC issue that sometimes surfaces is with the ESCs. We could ship you four of them and see if that solves the problem. It's possible they're troublemakers.
Send me your address pronto and let's try that. All I ask is that you report back to the forums to close the ticket up, when you know. This may be our problem and I apologize for the inconvenience and extra build time required, too.
Ken Gracey
kgracey@parallax.com
Let Ken send you some new ones and see if that eradicates the problem. They were very responsive to my ECS problem. Had one in my mailbox in three days.
I believe Ken is working on new ESC's to include in the ELEV-8 package.
Is the throttle range set by the ESC Sync process? That's the impression I got. I have done this a few times during testing and it doesn't see to resolve the problem. If there's something else I need to do, I'll gladly do it.
I'll reach out with my shipping address.
SP
Yes the throttle range is set when you run through the setup with the throttle full and throttle down, and get the confirmation beep.
I tend to run each ESC throttle setup by itself for a first build, but the Hoverfly Open will do it with all ESC's connected.
Hmmm... OP says "after about 15 mins total running time" - that's a long time (depending on the battery). I get 13 minutes on my 5000mAh battery. So, sounds like a plausible problem to me.
-Russ
As to running time, 15 minutes would be a long time to run on a single charge, wouldn't it? When I said total running time, I meant total running time period, since I finished building it and began testing. I realize there was a window for ambiguity there. I've not run it for more than about 5-7 minutes per battery charge so far. So for about 15 minutes (split two different batteries) it seemed to run fine. About half that time it was strapped to a table and about half that time I was trying to fly it. It worked almost perfectly for a few minutes in the air (nice stable hover/proportional response) and then started to lose power on #1. Initially I chalked it up to pilot error. After a few more very brief attempts (and broken propellers), I decided bench testing was the way forward. Now motors 2 and 4 run as expected, while 1 and 3 just twitch/beep. Despite checking all the connections, recharging batteries and otherwise going over what I did in construction I decided to raise my hand and ask for help.
Ken from Parallax has suggested new ESCs, so I'm waiting on those. I have the copter partially disassembled on my workbench awaiting their arrival. Any other thoughts are certainly welcome. I'll gladly report back the results of further testing.
I think the ESC's may be suspect. As much as Parallax tries to get the best quality for the price, the ESC's have had a few failures. I had one smoke on a new build of a Version 2, and suspect a bad on on my Version 1, which exhibits the same as your "loosing power" to a certain motor.
First, I'd like to add that based on my experiences this summer, the ESCs are the most likely/common failure point. However, I second spraay's battery question. Could you please clarify what capacity and discharge rate battery you are using, as well as your charger. Was the 15 minute "flight" only on one battery? Do you have any sort of low voltage alarm? (If not, I highly recommend you purchase one, such as Parallax Part # 752-00014, which I use and selected for Parallax). I ask this because the behavior you described is characteristic of the ESC low-voltage cutoff (though I admit there are a plethora of other possible reasons). For your information, the stock ELEV-8 V2 Beta I flew this summer for my internship with Parallax had an average flight time of 8:05 at a density altitude of 2181 ft, and 85% discharge (which is a little high than ideal, you are supposed to leave 20% or so charge in the batteries) with a power consumption rate of appx 340 mAh/min.
Hey Kyle,
Could you elaborate on that figure. Can't be for the whole bird flying under power. Did you miss a zero?
It's based on a flight I have logged (on 7/21/14 at Parallax HQ) of the stock ELEV-8 v2 and 3300 mAh battery without any additional payload. The flight lasted 8:11 and used 2816 mAh of power (the charger I use tells me how much power it puts into the battery, so this number is based on the number it gave be when I recharged the pack after the flight). I divide the power consumed by flight time to get a power consumption rate of 344 mAh per minute. (I rounded in the appx calculation, hence the slightly different number). Some algebra turns that into an average current for the flight of 20.64 Amps. Note that I slightly over-discharged the pack (Ideally, I shouldn't use more than 80%, or 2640 mAh), but that doesn't effect the discharge rate.
I think I've got this working reasonably well. Held a pretty successful test flight this afternoon. It's kind of windy and cold, so I'm not spending a LOT of time outside, but my Elev8 hovered and handled as expected (given the conditions and my fledgling pilot skills).
The fix appears to have been a combination of things. I replaced two of the ESCs (thanks Ken!) and went through and re-soldered every connector and wire. I did get one glitch on the #3 motor during bench testing, but low altitude flight testing went without a hitch. I'll fly some more tomorrow and report back. Hopefully my adventures will be instructive to others.
For all who asked about my describing '15 minutes of total run time' in my initial post, that was cumulative time, using multiple battery packs. I don't think I've tried more than 5 minutes or so on a single charge.
SP
I'm sure myself and other ELEV-8 pilots would love to here how things progress.
Weather around here has me pretty much shut down. Another 3" of snow coming in tomorrow.
- the ESC accompanying that motor had the throttle range set upon power-up by having your throttle stick all the way up (then you hear a beep beep, then put it back down)?
- all screws around that motor mount are tight?
- the connection of the motor bullet connector to the wires in the boom isn't being touched by the screw that holds the landing gear?
Thanks,
Ken Gracey