Speed Passion V3 motor plugs unsoldering themselves

[Big G]

My 6.5 was the biggest culprit of this. During the race it would just unsolder terminal A leaving the car stranded with steering, but no gas. The plugs are covered in solder so the connection is good. no dry joints!

re-soldered back on and sometimes it would do it again next race or sometimes it would go for weeks no problem. This happened indoors and outdoors where gearing was varied and the motor was never too hot to touch.

I don't remember this ever happening in my B44, just in the Cat and I think once or twice in the B4.

On disassembly of my 6.5 I noticed the A terminal was wobbly on the PCB and had burn marks around it. I figured this must be generating extra heat melting my solder. So the 6.5 was condemned. In went the 7.5. A few meetings later same thing happening. The A terminal again had a slight wobble to it. nothing at bad as the 6.5 though. then the 7.5 stopped working all together and won't run without wiggling the A plug. I don't swap the motors twice a week only every now and then so I wouldn't say there was excessive force on the terminals

In went my last V3 motor the 5.5. Again this happens! It's really starting to annoy me now having £150 of dead motors which I can only related to this problem not to mention the races I've had to retire from

Something that did cross my mind is I run the larger power cap of 4 capacitors on this LPF of mine. Could this possibly be related? I didn't buy it, it came with a 2nd hand SP LPF speedo I bought on ebay...

Until Taly this weekend it's always been terminal A, but on Sunday it was plug B

Any ideas?
I'm going to reinstall the standard power cap that comes with the speedo and see if that makes any difference.

[GRIFF55]

check all your plugs going to the motor are a tight fit and dont wiggle on the motor connections and also the ones to the lipo are a secure fit.
let us know your findings mate

[Big G]

I've used brand new plugs on the motor as well as ovaling a old plug to make the fit tight to try and stop the wobble.

can't be the motor as it's doing it on all 3 of mine. I can only think it's the speedo or the power cap.

I've used new wire aswell. and my lipos are 3 weeks old.

[DCM]

Agree with Andy, check the 'fit' of the plugs into the motor, if they are a little loose, change them, the little 'play' will cause it to overheat and melt the solder, also, look at your wiring layout, so it isn't pulling on the connector!

[RogerM]

G ... interesting this. I have been running my Speed Passion stuff for around a year now with no issues at all. I only have 2 motors that I use (8.5 and 6.5) and they sometimes get swapped between the cars regularly but sometimes are left in for months at a time too. My cars are always commented on as "being a bit hot" as I have found the Speed Passion stuff likes to be geared a touch higher than most so if it was heat then I would have had a failure by now I am sure!

Only thing I could think of that is different between our two situations is that you run a cat with it's 'alternative' motor mounting method and that could be putting different vibration signitures into the connectors.

Do you have the wires tied down or free to wiggle about? I always keep my wires tethered so there is no relative movement at the connector, originally I was concerned about a connector falling out but they have always been rock solid ... actually sometimes VERY stiff to remove.

Hope you find the root cause.

[markwilliamson2001]

Have to say Gareth, I have no problems with this at all. I did notice that your wires were very very short in your Cat last time out, so any flexing will be exaggerated. In my b44, I have never had a problem like this at all, or in my B4, so I would invest in some new plugs, and get someone else to solder them for ya!

Let me know how it goes.

[Big G]

My wires are free to move if they desire (not a lot though). Granted my wires in the cat are reasonably short, they are longer than my original install where they ran down the side of the chassis. they now run the width of the speedo then round to the motor. I think slightly longer than the original install. I wouldn't of thought pulling on them should do this. they would have to get hot enough for the solder to let go wouldn't they? I think durango installs have shorter wires than mine... come to think of it I wouldn't have said they were much shorter than in the B44. When I 1st got the cat I just lifted the speedo out of the B44 and straight in without touching the wires.

Last night I installed the original power cap and ran the 10.5 all night without any problems at all. fantastic motor for ludlow!

I will continue to monitor the issue now running the 10.5. This was geared on 23/81 and temp gunned at 136 after a race with 2-4 warm up laps.

If it's the speedo at fault I'll treat myself to a new Pro version

[mbrayf]

Try changing your solder as you may have been sold some lmp (low melting point) solder by mistake, this melts at a much lower temp than regular solder... and this is somthing that may only cost a few pounds to try which is much cheaper than a esc. I recoment the brand 'Multicore' as it is very consistent and high quality.

Mark

[mof]

I haven't had this issue on my 7.5T in a 4wd buggy or in a 2wd SC truck.

[Big G]

the solder I use is from Maplin and I've had it for probably 4 years. Some silver stuff. I'm almost out anyway so I'll replace it with that stuff.

weird that it's only been plug A until sunday that had unsoldered itself. all 3 plugs were soldered at the same time with new wires only a few weeks ago

[ApexSpeed]

I doubt it's the solder, itself. Even a low MP solder will only melt at DOUBLE of what your motors should be temping out at if geared even optimistically. Considering you have been using the same stuff for 4 years, it's likely that you would have had issues before.

Cold solders are more likely. Dirty connectors, bad soldering practices, no flux, non R/C ESC wire and wires too short could all be problems.

I wouldn't even mess with anything in this case. Replace ALL of the ESC wire to the motor with good quality 12g silicone wire sold for R/C racing, use brand new SP motor plugs/connectors, tin the wires before soldering together, use a good quality flux on your connection, and use the proper capacitor for the ESC.


I would also open up a cooling vent in the body for the motor, and use a temp gauge to monitor the temps of the motor on your longer runs—just to make sure. Solder melts usually over 200° C and motors shouldn't be geared to be above about 80° C, so you're well out of the range for heat issues. Bad, dirty or cold solder joint on the plugs is likely your culprit, but you should try to monitor and limit the heat to your motor anyway, if possible.

[Big G]

my 10.5 came off at around the 135oF/57oC degree mark indoors on polished floor on tuesday. Geared on 23/81 (2.6) in the cat. I've been tipped off to bend the ends of the plugs inslightly to enclose the end of the wire. I also installed the supplied power cap not a larger one I've had on for a while. Surely your speedo should thermal out before the melting.

I replaced all the wires on the motor and battery only a few weeks ago. I'll install brand new plugs over the weekend.

Back to my 7.5 which wouldn't run unless I wiggled the A plug. Tonight I stripped it down and had a better look. Turns out the braided wire that attached to the plug was no longer attached. because the plug wiggled it made contact. I had to cut the fibreglass ring that the plugs mount to to remove the A terminal. resoldered it all together and it works again just need to be careful removing the A plug now since it's not as secure as before inside.

On a side note my speedo refuses to say stuck to the chassis. my dad suggested perhaps it was getting hot and loosing it's stick. Even indoors with no jumps or bumps I will put my finger underneath it after the next race to prove that one. If this is all down to the speedo I feel a treat in the form of the GT2.0 Pro might be arriving in the post

[Northy]

I vote for your connectors being worn or damaged in some way, what Apexspeed says is right. You are getting localised heating at the connector hot enough to melt solder, if the whole motor got that hot it would be scrap!

A bad connection and the associated current high power brushless motors use will warm up the connector enough for it to unsolder. I guess the 10.5 was ok as it is lower power, and/or the male part of the connector on that motor is in better condition.

G

[Big G]

I ran a 5.5 the week before lol. could just be down to the motor. the 6.5 that died 1st was 2nd hand when I bought it. dunno about the 7.5.

new plugs. bend the ends slightly and go from there now

[DaveG28]

Originally Posted by DCM

Agree with Andy, check the 'fit' of the plugs into the motor, if they are a little loose, change them, the little 'play' will cause it to overheat and melt the solder, also, look at your wiring layout, so it isn't pulling on the connector!

Hmm, I have a problem on this. My C connector on the motor side is not wide enough, so I now have to crimp the plug on the esc wire, which I'm worried will overheat???

So, can you get replacements for the part attached to the motor itself?

[Big G]

Dave, do you mean the male part of the plug?

[DaveG28]

Originally Posted by Big G

Dave, do you mean the male part of the plug?

Yep, it's tightish now I crimped the female, fingers crossed it works! Don't want to have to get a whole new motor!?

[Big G]

that's the part I just removed and replaced. it's messy, but works.

[DaveG28]

Is there a part number?