Scorpion XXL

[Anttazz]

Tried the XXL I got to replace the horrible mess of speedos I was using in Cicatrix over the past few days and had a few wee glitches. Ive been called out to work so havent fully messed about with it and might manage to get it done myself but if anyone can suggest common problems that would be great.

Ive got it connected to 4 drills on 19.2v. Firstly, the BEC wasnt playing, took me a long time to get that to behave itself to the point were I may run a reciever pack instead, this had been suggested as a good idea anyway be a few people so I was eventually going to give that a go. After thia was working, the motors only seem to want to work in small bursts, turning on and off once every second or so. Does that sound like a current limiter is kicking in or maybe calebration problems? Might even be the BEC loosing power although it didnt look like it to me. I will post videos if I ever get enough time off, just seeing what peoples thoughts on it might be.

[craig_colliass]

Re: Scorpion XXL

With Tron (old) I had all kinds of problems like this, in the end I just used a sidewinder I had. But that went into Seraph so now I use the Wotty 100 speed controller this seems to work fine.

Now the Scorpion is in the walker (Pilgrim) running two 250w motors and has never missed a beat!

I think the speedo just doesn't like running 2 motors off one channel. I think there is enough power to run the drill motors but the software or what ever these things have just thinks the load is somehow wrong,

I am no electronics expert, but perhaps if you fitted a capacitor across the motors this may reduce the spike or noise or what ever the problem is and the speedo might play ball.
you can run the motors in series then the speedo would only see one load. but you would mess up the electrics and have to adjust the battery voltage.
I am sure you will get better advice than the above but that's my take on it.

[Anttazz]

Re: Scorpion XXL

Cheers Craig, I hope it is something simpler than you have suggested but i'm glad to know i'm not the only one having this problem. I was hoping for a simple plugin and go part, but I suppose that isn't quite the case . Hopefully there is someone out there who has successfully run 4 motors from an XXL and can let me know, I may even work it out after a few more hours messing about with it.

[typhoon_driver]

Re: Scorpion XXL

drop the guys that make it an email and see what they say

[Anttazz]

Re: Scorpion XXL

Is that just the robot power guys Gary yeah? I'm not sure if its an original XXL or a mod, David did tell me but it has slipped my mind at the moment, but I suppose that shouldn't matter too much. I have emailed them before, they're pretty helpful. I will give it another bash later or tomorrow morning and if its still misbehaving then i'll drop them an email.

[Anttazz]

Re: Scorpion XXL



Thats a video of how it is running at the moment, seems to work at the start of the video then it starts with the stopping and starting I was talking about. The second section of the video is when I turned the receiver off and it didn't seem to failsafe, it just continued to drive and when I tried to show the receiver on camera it accelerated forwards. Very strange indeed....

[maddox10]

Re: Scorpion XXL

I think the XXL goes into current limiting. I guess overvolted motors?
We had that in Kashei, on 6S 2P with 2 speed 900's on the MSR 12-54 drivetrain.

2 options.
Lower the voltage.
Or run the motors in series.

For Kashei, we now use a Sidewinder.

[woody]

Re: Scorpion XXL

Thats a video of how it is running at the moment, seems to work at the start of the video then it starts with the stopping and starting I was talking about. The second section of the video is when I turned the receiver off and it didn't seem to failsafe, it just continued to drive and when I tried to show the receiver on camera it accelerated forwards. Very strange indeed......

Odd ..yes.

However the last part ...transmitter OFF rather than reciever? ...indicates that it's probably NOT current limiting as it happily accelerates to flat out with no motor hunting.

Questions
Did you bind the BR6000 at the drive OFF failsafe position?
How have you got the XXL Jumpers set...are you using a voltage above 16v .. and if you are have you clipped the HV jumper wire?

Things to fiddle/play with.

Disconnect 2 drive motors ...one each side....see if it helps by reducing the load.
Try with a reciever battery ..remembering to clip the BEC jumper wire.

I have recently had an issue with the Spektrum recievers output signal being unable to drive a homebrew R/C steering servo ... the hunting was some what similar to your XXL symptoms.... this was solved by buying a signal line booster. http://www.spektrumrc.com/Products/Defa ... odID=SPMCP

EDIT I see from further up this thread that your running 19.2 v...you might be getting voltage sag after running for a few seconds and thus dropping under the 16v jumper limit. I remember reading that there is asolution to this ..but can't for the life of me think what it was.

[woody]

Re: Scorpion XXL

Been dredging my memory ... the 16v jumper ..as I recall is to do with the voltage supply to the BEC chip.

[Anttazz]

Re: Scorpion XXL

You're right Woody, the transmitter was off and receiver on in the last section of the video.

The BR6000 should be bound in failsafe mode yes, as it was failsafing properly when I was running with the old setup and I haven't redone it since then. The BEC wire is still connected and the HV wire has been cut.

I was told by a few people that the BEC can be problematic on the scorpions, I will get hold of a receiver battery and see if that solves the problem.

I will give those experiments a go and get back to you when I have.

[Anttazz]

Re: Scorpion XXL

I found an old receiver battery that I thought was busted in a mixture of HW electrics waiting to be reassembled and it seems to be a vast improvement. I still have to nurse the throttle up to full whack but it does get there after a few seconds, but that might be something to do with the battery not being charged for the last 10 years. I did also try the 2 motor thing and it worked better, but not properly before I added the receiver battery, it would go faster than with the 4 motors before it began to stutter but still stuttered before getting to full throttle.

Will probably look at getting a better receiver battery and getting it tried out with that as it seems to have fixed the problem. Is there anything specific I should be looking for in a receiver battery? I have never really had to use one before.

The failsafing is still not playing though, I may have to rebind the transmitter and receiver and see if that is the problem. Also only getting forward and reverse drive at the moment, but i'm sure thats a problem thats easy to fix once its all working.

[woody]

Re: Scorpion XXL

I'd also check your main batteries ... stick a meter on them whilst they're underload ...see what the voltage sag is.... I've a feeling that one pack is fudged.

[Anttazz]

Re: Scorpion XXL

They seem ok Woody, 11.something v when under no load and between 9.2v and 9.6v when running full tilt.

[razerdave]

Re: Scorpion XXL

You said the BEC wasn't working, generally speaking the XXL's BEC is utter testicles when used with Spektrum, thats why I used a seperate one (and why the BEC loop was cut on the XXL when I sent it to you).

As for current limiting, it may well be because it was with my Speed 900's, but that was due more to my motors than the controller.

[Anttazz]

Re: Scorpion XXL

The BEC was working to a point, but not well at all so I agree with you there. I charged that battery a bit and it seems like its getting better the more charged it is, but it is still very jumpy. The one I found has a max charge of rate of 900mA so takes ages to charge. Think I will have to get a battery ordered along with my new batteries for Daiske. Should I just get any reciever battery or am I better with a specific rating or anything like that? Also, is 4.8v NiCad the way to go on that front?