RC4WD excavator turret problem

[Jeremy]

G'day Gents,

I've had my RC4WD Excavator for about a week now and am having a little difficulty with it.

The problem is with the turret. I connect the battery, switch on the r/c, turn on the hydraulic pump and everything seems ok, though after about 5 mins of operation the turret slows down and eventually stops.

The tracks still work, the hydraulic pump and all related functions still work though no more turret swing action.

I turn everything off for a couple of minutes, repeat the start up process and eventually get back to the problem.

Please help :)

and go easy on me.. I'm as green as they come.

Cheers,

Jeremy

[YoungGunz]

I don't have one of these and I don't know if they come with a speed control installed already or if you have to install it for the rotating function. Anyways you might check to see if the ESC is overheating? If it is you might try geting a new or bigger one. If you have an extra one sitting around you might try swapping it and see how it performs.

That's what I would check first, since after that might come replacing a motor and that could be scary for a new guy.

Hope this helps,
J.D.

[fhhhstix]

If you are using a Li Po battery and the escs have Li Po cut offs in them, the esc for the swing may have the cut off set higher than the others. What kind of battery are you using? Is the battery fully charged? If it is a Li Po battery is the battery balanced.


Travis

[Jeremy]

Hi Guys,

It doesn't seem to be over-heating J.D and I'm not sure if they have a speed controller.. I did try doing a running test without turning the hydraulics on.. It was going strong for ~10 mins without showing signs of giving up.. I then turned the pump on and within 5 mins was at a stand still again..

Yep, it's a LIPO travis. Yep the battery is fully charged. How can I check if the battery is balanced?

Cheers

[ihbuilder]

"How can I check if the battery is balanced? "

with 1 of these :) or similar

http://www.astroflight.com/index.php?main_page=index&cPath=34

[fhhhstix]

Hi Guys,

It doesn't seem to be over-heating J.D and I'm not sure if they have a speed controller.. I did try doing a running test without turning the hydraulics on.. It was going strong for ~10 mins without showing signs of giving up.. I then turned the pump on and within 5 mins was at a stand still again..

Yep, it's a LIPO travis. Yep the battery is fully charged. How can I check if the battery is balanced?

Cheers

If you don't know if it is balanced then you can't know it is fully charged. What kind of charger are you using and does it have the ability to balance while it is charging?

If you can not answer some of these questions please take the time to go through the links I am providing and it should answer a lot of the questions you may or should have. This will also make your experience with this hobby a pleasant one.

Li Po maintenance (http://aedownloads.com/pdf/care_lipo_batteries.pdf)

acronyms, abbreviations, and technical terms used in RC (http://radiocontrol.wikia.com/wiki/Terms_and_acronyms)

When you go to the 2nd link you can click on the highlighted words for more in depth definitions.

If you have more questions don't hesitate to ask we are here to help and asking is a good way of learning.

Travis

[Jeremy]

Hahahha :) I interpreted 'ESC' in your responses as short for 'ESCAVATOR' :) and my stupid brain never bothered to tell me that it already knew the correct spelling is 'EXCAVATOR' LOL! Well I feel a bit silly :) Thanks for that list Travis.

As for 'fully charged' It was inferred based upon a charge time of 73mins and being told (by the seller) it should take about an hour.

The charger is an IMAX B6, I'm gonna play around with the charger and see about making sure the battery is balanced before I continue..

Though just one more quick question.. In the last post I said that the electronic functions operate normally when the hydraulic motor is off.. Is that any type of clue?

I appreciate your time guys! I would be bugging the guy I brought the excavator from, though he's out working on a rig and won't be back for some time (weeks).

Thanks again :)

[fhhhstix]

Though just one more quick question.. In the last post I said that the electronic functions operate normally when the hydraulic motor is off.. Is that any type of clue?



Yes it is. From what you are describing the esc for the swing may be bad or set up wrong.

Travis

[Jeremy]

Ok, so the battery is now fully charged (it read 'FULL' on the display) and the other screen read;

4.19 4.19V 4.19V
0:00 0:00V 0:00V

I'm no expert or mathematician but I'm guessing thats a balance? :)

I'm going in for another test..

[fhhhstix]

Looks good. How many mAh is the battery you are using?

Travis

[Jeremy]

6500 mAh

I just did another test, this time running the electrics for 6 minutes (just swinging the turret round in circles) and all good. Then I turned the hydraulic motor on for 10 mins and did nothing. I then tested the turret again. All good. I started using the hydraulics and again the problem presents.

There's a black box where the servos are hiding in.. should I try and open it up to investigate? I'm just a little worried cause all the hydraulic lines are connected into that part..

I just did another test where I worked the hydraulic servos whilst swinging the turret and it does not stop..

Does that rule out a bad setup for the ESC??

[fhhhstix]

Without having it to look at it is going to be hard to determine the problem. It sounds like a voltage drop problem like you would have with a servo but with it being an esc quitting the pump should shut off as well if it is a voltage drop problem. Since you are using a Li Po if it was voltage drop the whole machine should shut down if it has the proper battery protection.

Travis

[Jeremy]

If it were a voltage drop problem.. How would you go about fixing it?

[Lil Giants]

One or all the valve servos are crap on mine, they would overload the BEC from the pump esc & shutdown the entire model.. I even tried to use a 10A Castle Creations BEC to run the rx and the CC BEC got very warm and eventually timed out inside of five mins. That was a couple weeks ago I was tinkering with it and haven't got back to it. I'll likely change all the servos & try again.

[Jeremy]

Ok, after a week or so of pacing up and down racking my brain to figure out the problem I'm no any closer.

I spoke to the guys down at Big Rigs WA this morning and the consensus is faulty servos.
Thank you all, and Lorrey in particular for his great help :)


I thought about it more on the drive home and did some more tests this afternoon to try and understand the problem.

if I swapped servo plugs and channels, and the problem was still there.. does that not rule out faulty servos?

Here's a 30 second clip (cut from 5 mins) of the machine running with the hydraulic motor on. Notice the engine noise get weaker and weaker..

http://www.facebook.com/photo.php?v=3775260663515

Anybody have any ideas before I take her into a hobby shop tomorrow?

P.s. sorry to lure you onto facebook... it was the easist way for me to upload the clip.

[titandigs]

Hi Jeremy,
Lorry changed the speed controller from the slew to the tracks and then the tracks went slow. So this would /could be the speed controller for that function is faulty not the servo.
If you take it to a shop your best bet is to see Scott at Ace models in Midland.
Good luck Paul

[Jeremy]

I see, my bad.. I must have heard wrong, and am still coming to terms with the terminology.

Thanks Paul

[Jeremy]

Problem solved!

Thanks for all the help guys!

I took the unit to a bloke who works in the r/c industry yesterday. The good news is the problem didn't show up - though the ESCs were still over heating! What he figured out was that there were some switches leading from the ESC units that were switched to the on position.. apparently they should be off! I think I might have switched them on the first time I opened her up trying to get the remote to connect to the servos, which was another newb error I encountered [all switches on the remote should be switched away from the operator incase anybody else encounters this non-problem]..


I'm gonna give her some time in the sand pit today and fingers crossed the problem doesn't come back.

[jetdog]

Hey bud how did you go did you sort out the issue??? also what are you thoughts on these diggers as im really looking at buying one but cant seem to find much info..