Brushless Maxx hesitates - Page 3 - RC-Monster Forums

neweuser · 06.05.2006, 10:16 AM

This is exactly how i have my truck too, but my controller sits on a plastic plate up front, my receiver sits in the back with foam underneath with adhesive, then the ubec on top sitting on a mount plate as well. I have the same exact problem steve080773, I have tried everything...redoing my batts, new receiver, rx pack, putting in a swith, everything. let me know what happens. I'm gonna try a new chassis and redo my whole truck again! but thinking maybe my controller to motor wires are not good? hmmm, not sure, but would like to test all my connections somehow. Sorry to hijack the thread, but we are having exact probs. When did you get your controller?

steve050773 · 06.05.2006, 10:27 AM

Serum - maybe it is the solder joins. The problem really is evident when the truck is rolling (maybe 1/8-1/4th throttle) and I try to make a stab at the throttle. It also seems to be worse when there is more rolling resistance, ie dense summer grass vs pavement or dirt.

Any thoughts?

Newe - my controller is probably only a few months old bought from Mike. Very odd that we are having similar problems...

neweuser · 06.05.2006, 10:32 AM

Mine is just as old, of couple of months maybe. allso from Mike. Although, i had less of a problem when i ran the plastic stock chassis. what chassis are you using?

steve050773 · 06.05.2006, 10:47 AM

I have a UE lightning chassis (aluminum). I haven't thought about trying a plastic chassis - makes me ill to think about running plastic with this much power.

steve050773 · 06.05.2006, 11:01 PM

Here are some closer pics of the layout.

I'm really beginning to think its the controller to motor wiring. Spent a lot of time just tooling around in the drive way and the hesitation really only occurs when I ask for more than 1/8th or so of throttle. Consistently, and the hesitation is worse if I try to go full throttle. I find it hard to believe that its interference because it was so predictable. I did reprogram the controller and no change occurred; I also tried a different radio/receiver and no change.

Here's what the motor and controller wires originally looked like:

Do you think I should try and direct wire them or use some 4mm plugs instead of 3.5mm? Or do you think I'm just on the wrong path all together?

squeeforever · 06.05.2006, 11:35 PM

It could possible be a motor, esc, or even battery connection. Check em all and maybe consider 5.5mm plugs if you have problems soldering the wires into the small connectors. For temperary I would just direct solder.

Serum · 06.06.2006, 01:18 AM

It's hard to tell what your problem is. Did you tried another receiver/transmiter? Or another set of batteries?

This must be frustrating for you.

BrianG · 06.06.2006, 01:25 AM

I didn't catch if you were running it fine for a while and it just starting doing this, or if it was doing it from the start?

I don't know what a 7 turn high-amp motor will pull for current, but maybe the 9920 just isn't up to the task? I know I've seen over 100A bursts from my BK Wanderer 8XL when I punch it from a standstill. Or if it's not that, maybe the ESC was overheated quite a bit burning out a few FETs and now is running on fewer FETs? I don't know of any type of current limiting capability in these ESC, but that's exactly what it sounds like.

One way to tell a bad connection would be heat. A bad connection creates a voltage drop, which in turn dissipates power as heat when high current flows. Wire and connectors should not be warm at all to the touch, or VERY little.

As far as direct soldering goes; it will be a better connection providing it is done correctly (no cold solder joints), but less convenient than connectors if you need to replace something. Just make sure the connectors are soldered well and they fit snugly together. The 5.5mm ones Mike has are quite beefy.

Serum · 06.06.2006, 01:30 AM

They are beefy, untill you crash them once. then you need to reposition the pins on the male plugs. you need to feel a rather firm resistance when plugging/unplugging them.

steve050773 · 06.06.2006, 07:34 AM

Brian - its been doing this from the start, and it does it irregardless of the battery pack I use.

I'm hoping for now that its not the battery wiring from the esc as I have little excess wire to mess with. I don't have a switch, so I have to unplug that batteries to shut the truck off and I have never noticed any warmth to the plugs/wires.

I am going to try the esc to motor connections next - probably over the next few days. I always felt a little uncomfortable with that connection because the 3.5mm plugs didn't fit all that well with those large wires (especially the copper windings coming from the motor). If the 4mm doesn't look like it will improve things, I will direct solder.

Unfortunately, I don't have another ESC to experiment with. I bought the 7 turn hi amp and 9920 from Mike after much collaboration with him, so I would hope its not the problem. I will add that to the list though, and if redoing the motor connections doesn't help, I will look into buying a 12020 or perhaps the new quark.

Thanks for the feedback guys! I'll update later this week.

Steve

BrianG · 06.06.2006, 09:48 AM

Well, if you are local to one of the other forum members here, maybe someone will meet up with you and let you try one out? I'd get those connections straightened out first.

Does it hesitate under a light load? Like if you were to put the truck on a stand or something where the tires aren't touching anything? No load will pull much less current, and would at least eliminate interference...

BrianG · 06.06.2006, 09:53 AM

Quote:

Originally Posted by Serum

They are beefy, untill you crash them once. then you need to reposition the pins on the male plugs. you need to feel a rather firm resistance when plugging/unplugging them.

I've crashed mine numerous times and those 5.5mm plugs are still tight. As a matter of fact, I tried to pull them apart once and ended up yanking the heatshrink off instead. If they ever get a little loose, I'd just use a tiny screwdriver to gently and slightly spread the prongs on the male plug.

steve050773 · 06.06.2006, 09:58 AM

Brian - good point. I forgot to mention that I have tested the motor and controller where I have disengaged the pinion from the spur and the motor runs smoothly. I didn't give it full throttle for fear of exceeding the motor's rpms, but I did go over half and it turned without hesitation.

The truck will roll smoothly under 1/8th throttle on concrete and pavement, but any additional throttle and I get the hesitiation. Its less of an issue on pavement, but if I roll into grass its a mess. It also happens in reverse on almost any surface.

Definitely think its a connection issue the more I talk through it.

Serum · 06.06.2006, 10:14 AM

Well Brian, my idea was to put a small nylon pin inside the male to prevent this. that would make it a good plug.

Daniel and I ran it a few times and they got loose. so apparently you are lucky! I just don't like them too much anymore. I swapped all the plugs to deans..

You have got a weird problem. if you have got another receiver (non PWM) try that one.

coolhandcountry · 06.06.2006, 10:55 AM

It is very strange indeed. I personally am thinking it may be the esc. I hope to be wrong. If you lived close to me I would gladly help you out. I don't have many rc people near me.