Electrical connection overheat (Mobility Scooter)

why not just solder it? Saves a lot of time wasting

'Just solder it' what?

'Soldering' was my suggestion in the form of soldering some suitable wires in where the spades were and remoting a better connection, so that I can still disconnect the controller / motor if required?

And I don't call 'doing a good job' 'time wasting'? ;-)

Cheers, T i m

Using soldered wires on any item subject to vibration is not ideal.

There are some PCB mounted crimp connectors where you can dispense with a troublesome spade connector.

Just an idea:

Agreed, if rigid and unsupported.

That is an idea but I'm not sure what actual advantages it would give over soldering and supporting a short flying lead / 45A Powerpole plug?

I mean, I get this is 'a vehicle' as such but it's not a rally car, has inflatable tyres and suspension (of sorts) so as long as any cables are supported and not allowed to flap about, I can't see anything failing?

I'm going to de-solder the spades in a while and then I can measure the holes to see how I might proceed.

I could either solder 3 thinner wires (conductors filling the holes on the PCB) and joining them together into one flying connector, into 3 individual connectors (powerpoles can interlock into one plug but each individual can still be passed though the metal case if required) or using a larger conductor split into three with each soldered though a different PCB hole (of the original spade pins) and intro one plug pole of some sort?

I can 3d print a frame to represent the outside of the original plug (with some slack) and then fill it with hot-melt glue or silicone once complete and tested. Or 3D print a 3 part 'guide' that goes in and supports the wires. That way the wires would be supported but I could still get the ally case off (also the heatsink) if I needed to get to any other connectors in the future?

Cheers, T i m

I'd have fixed it ages ago.

NT

On 19/08/2020 10:59, Fredxx wrote: .

Does rather depend on how well it is done, though. I'm sure that many of those here assembled will, in their youth, bought ex-WD stuff in the local market to disassemble for the useful bits and pieces.

You get very used to the "wrapped round three times before soldering" spec that WD/MOD had for tag strips, valve bases, etc.

I still keep one set of spanners in a box that used to be labelled "First Aid Kit, Large, for Armoured Fighting Vehicles".

Oh I'm sure you would, then when some poor bastard tries to disconnect the controller in the future ...

And since when was it 1) 'a race' or 2) have you seen the weather out there recently (so neither I nor Mum would want to be out in it).

Anyway, I've ordered some AWG16 silicone flex cable and will solder 3 lengths into where each of the spade connectors went for the each of the motor cables and another pair for the electric brake coil. A bit of sleeving over the cables and boots on the plugs / sockets and it should be a flexible, safe, upgraded job I'd be proud to have my signature on.

Not a 'who the f bodged this up and soldered the plug in ...' ;-)

Cheers, T i m

p.s. When I had the desoldering tool out earlier to do the scooter controller I also replaced the switch on an Aldi/Lidl charger for a mate and powered up the 'dead' scooter charger with a strand of copper wire across the blown fuse to see if it was just the fuse (it wasn't).

Solder is not recommended for high current connections. A good crimped or other mechanical connection beats solder, more so if the solder joint isn?t well made and/or there is vibration.

I?d clean the spades, a fibre glass brush is good. If replacing terminals, use decent ones and a proper crimp tool. (The simple flat plate type don?t count.) While I can?t be sure, the photo suggests moisture has got on the terminals. If there are other signs, find out where that is coming from.

As for Powerpoles, excellent connectors but again, use the right tool.

Solder joints go ?dry? if stressed by temperature cycles and especially if vibration is added. The temperatures don?t need to be anywhere near high enough to melt solder just hot to touch. You see it in old power supplies.

Whilst you are probably right (as in 'good advice'), I have been soldering and running fairly high current (for the size of the conductor / connector) devices for many many years and I can't think I've ever had an issue with a soldered only connection failing or breaking?

Ah, well I guess like all things there are things that become problems because of poor workmanship and / or design / implementation.

How would you consider the vibration of an RC 4WD electric car that flattens 7.2V / 3Ah NiMh cells in 5 minutes or so?

If I could find replacement PCB mounted spades and the correct inserts for the plug and a new plug body, I might consider returning it to stock ... on the grounds that once they are burned there isn't much chance of ever getting them back as they were new.

What I tend to do is crimp the strands within the connector, then solder then crimp and sheath support / retaining 'legs' round. If going into an extreme environment I might also apply some heatshrink around the conductor and connector to 'support' the joint.

Whilst not impossible, the speed controller is mounted very high in the rear of the scooter with a plastic cover that goes down over all 4 sides and all that is under the rear 'boot' of the scooter.

I think the 'cause' of the discolouration of the spade connector and matching burning of the plastic plug body is the faulty parking brake [1] dragging over many miles and causing long term high currents and so overheating.

I do, a soldering iron [2]. ;-)

I can appreciate they can, not something I've ever experienced of my own soldering. [3]

It looks like at least one of the PCB spade terminals got hot enough to soften the solder as the burned one was showing it's pins on the back of the PCB. By remoting the plug / socket connection and using a good high current (and gold plated), should it get warm (and I doubt they would) they can do so away from the controller PCB. All the Model car / plane / boat speed controllers I have come across are used this way, with the (very heavy) conductors soldered directly to the speed controller (and often the motor) and an inline plug / socket on the battery connections.

Cheers, T i m

What is the peak current of the motor if the unit gets stuck? Does it have an over current cut out? Those can be pesky. I remember a tricicle design a friend had was doing this until the cut out module was replaced. Brian

I see you didn't want to complete that sentence.

it's usually not, but even a snail gets the job done in 1 day.

ditto, we still have things to do though

no-one recommended soldering plugs in.

NT

You saw nothing ... it really didn't need finished did it?

And isn't now?

Dump those old clockwork clocks and get new ones.

This is the 'left brainer' you you mean, not the right brainer me doing all sorts of others things in the background anyway?

So what did you recommend then?

"> >> [1] The bottom of the controller isn't sealed, only protected by a

Cummon, fast answer, no time wasting trying to make one up whilst back peddling ... ;-)

Cheers, T i m

Why do idiots like you want to waste so much time with so much bs? Clearly you have failed to find anywhere I suggested soldering a plug: maybe just maybe because I did not suggest that. Good bye.

And yet I ran around 200 amps through flexible cables with soldered on lugs in a shore to ship power supply (to drive compressors for pneumatic transfer of starch from ship to shore silos.)

Talking to a mate on this yesterday and he has also solder all such connections all his life a never had a problem either.

In fact, after suffering an intermittent problem on his car for years, he was doing some volt tests on a multi-plug connector and a wire just fell out of it's *crimped* connector.

Even if a connector was crimpable, he like me would crimp it first and then solder and never had it then fracture / fail.

Now, I'm not suggesting there aren't environments where crimping might be better, just that I can't think of one in my day to day usage.

Cheers, T i m

Likewise? Finished wasting peoples time here with yer obsolete old novelty clockwork clocks after admitting you were getting someone who has a clue in?

I haven't looked, I've asked you to state what you were suggesting I should 'just solder it', given we were talking of the cables and connectors between the loom(s) and the speed controller at the time?

You can squirm all you like you will only go deeper. That's what happens when you jump in with both feet and think you could do better / faster when you couldn't ... and speed wasn't the issue.

So what is there left to solder that would leave the controller tied to the main loom or motor? Cummon, you know all the answers so this should be easy for you?

Aww, he has shot himself in the foot again and is now hopping away. ;-)

Cheers, T i m

p.s. I really think a minority here have some sort of bi-polar disorder, fine one minute and then fly off the handle then next. ;-(

As a student, I worked with various parts of the SESEB. All underground joints were soldered.

Interesting, ta. ;-)

Cheers, T i m

So you're making up yet more bs.

Your inability to solve such a simple connection in minutes is too pathetic for me.