one more try at sorting out this flaky motor issue ...

okay, scrap the above about it not running. i rewired everything and the motor runs as before. but that still leaves the problem that led to the phase wires flaming out. see pic for what i found. sure don't want that to happen again. think it's because the controller is 17a and the battery is much less?

okay, to answer my own question: perhaps i overloaded the connection from controller to motor and that's what caused the melting biz. got this idea from: What happens when you overload phase wires?. will resolder everything using xt60 connectors or similar.

woofnbike said:

think it's because the controller is 17a and the battery is much less?

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Here is my overview as I see things...

A motor is designed with a set of components to handle, at the minimum, a specific wattage. But can often be pushed to higher amounts with certain considerations taken into account.

In your case the motor was built with the goal of 360 watts to be handled on a continuous basis. That means the windings, the wiring size and insulation, connections, ECT, should be able to handle 10 amps at 36 volts. (Watts= Volts X Amps)
And your previous controller was matched with this motor to provide this amount of current, with a little overhead for possible short periods of time. Note: When looking at specs, look and understand the differences between "continuous" and "maximum", or temporary, current draws.

So, the original concern was if your battery could handle the increased current demand of your new controller, that can supply a current of 17 amps to your motor. This seems to be a moot point, as it looks like it can provide enough power to toast your phase wires.
Also, it was recommended that you keep as close to the 10-amp current draw limit as possible.

In conclusion I would say it's not so much the matching of battery to controller. But the failure of the phase wiring, that was possibly running at twice it's designed current.
Feel fortunate that the wiring sacrificed itself and acted as a type of "fuse". Hopefully saving the motor's windings from terminal meltdown or damage.

What can you do to make sure this can't happen again? A few possibilities...

Purchase a controller that matches your original system specs.
Purchase a controller with as minimal over current specs as possible but has a display that can limit current output.
Purchase a programmable controller.
Install a fuse or circuit breaker in your battery supply wire that would trip when exceeding desired limit.
Keep your current 3 speed switch in low position.
Limit your throttle output by mechanical or electrical means to maintain a maximum current limit at WOT. This would NOT be fool proof as in an uphill scenario the controller would still want to satisfy the throttles speed position to the best of its abilities. Drawing as much current as possible...

Along the lines of "hardening" your motor for excessive power.

Increase the phase wire size.
Install a temperature sensor and display.
Add stator fluid for water cooling.

Just my thoughts, don't know how much would hold up in court. Example. I believe that phase amperage will run up past 2 times the battery current draw. But would expect the motor design to take this into account...

As to your last post... A poor or defective connector will certainly melt and toast. But typically, right on, or close to the bad/undersized connection.

oh lordy it's enuf to make a grown man weep, all these complications. one thing i forgot that your post managed to lift from the dim recesses of my brain is that the motor is not the original one. the OG died and was replaced with a so-called Jump motor from uber's failed scooter venture. remembering this, i did a search here and found this thread about the motor: 350W Jump Bafang front hub motor+wheel+tire+brake $45@BCH. from what i can tell, a prolific poster by the name of momotech was using his with a 17a controller and wanted to go even higher, to 20a.

the implications of this, if any, are beyond me. can you help?

p.s. the only thing original to the scooter at this point is the battery, for better or worse.

woofnbike said:

p.s. the only thing original to the scooter at this point is the battery, for better or worse.

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I agree with TommyCat.

A few things to note.
For phase wires, the pic only shows one side. What do the wires on the other side of the connectors look like. Ideally the conductors from the controller to the motor should be sized sufficiently for the full run.
Most phase wire failures I’ve seen on the forum start at cheap connectors that first heat up, then the heat transfers to the conductors, so use good connectors.
Phase wires need to handle more current than battery wires, since under higher loads (accelerating, going up hill, etc.), phase current can be 2 or 3 times the controller’s current rating, so both the conductors and connectors need to be sized with that in mind.

woofnbike said:

the motor is not the original one

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Any chance that the phase wires had been replaced with an incorrect size or type?

woofnbike said:

a prolific poster by the name of momotech was using his with a 17a controller and wanted to go even higher, to 20a.

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I’d try sending him a private message and ask what custom modifications he made to allow such an increase.
And to verify the controller type amperage output. (Continuous, peak, or phase…)

I couldn’t find the link to his controller that worked.

e-hp: here's a pic of the new and improved phase wire connection set up. i mostly used xt60 connectors removed from the cases so i could switch the wires around if necessary. no real damage done to the wires beyond the mess in that earlier photo.

TC: not sure about the phase wire. i will drop mm a note but he hasn't been here since last may. here's a link to the controller that the jump-motor's seller once recommended: https://www.aliexpress.us/item/2251...c00PAT423&mp=1&gatewayAdapt=glo2usa4itemAdapt.

Looks good on the controller end. The adapter cable wires look less beefy, so not sure what the ones going to the motor look like. Xt60’s look great for this application though.

yes, the controller wires are beefy compared to the ones going to both adapter wires and the wires going directly to the motor, which are both the same. nothing i can do about that, near as i can see, so i'll just have to keep my speed down, avoid hills, and not lend the scooter to any of my weightier pals. thanks again for your help.

fyi info:

here's mototech's recommended controller, link fixed: 24V/36V 250W 36V/48V 500W 36V/48V 1000W~1500W Brushless DC Torque Simulation Square ebike Electric Bicycle Hub Motor Controller

someone else wrote: "Mated with an old 20A KT square wave controller and LCD1. It's good enough for the usual 20 mph on 36V."

another recommendation: 48V 36V 22A Controller For 250W 350W Brushless Motor Ebike Electric Bicycle | eBay 48V 36V 22A Controller For 250W 350W Brushless Motor Ebike Electric Bicycle

back to mototech and what likely happened to my wires when a big fella on my scooter attempted to go up a big hill:

"Follow the First Rule of climbing hills w/ a hub motor (or any electric motor I suspect), which states;
Never allow the motor rpm to fall below 1/2 max. rpm. ... Never try and maintain the climb when the climbing speed to falls to below 1/2 the bike's top speed. It's at this 1/2 level when the system starts to make more heat than forward motion.
If you have to, jump off and push, it's starting and stopping on hills that melts stuff, but in my experience, it's the phase wires that will melt before motor damage occurs. Hopefully your kit came with at least a 20 Amp controller and for that motor, I would use one in the 20 Amp to 25 Amp range. As others have stated, the more momentum that can be maintained, the further you can make it up the hill before the rpm's drop into the danger zone.
As counter-intuitive as it sounds, the more Amps the better (up to a point) to maintain momentum. But one has to know when it's time to jump off and push, To "lug down" a mini is an invitation to start melting stuff, in this order;
1) the phase wire connections
2) the phase wires
3)Something in the controller
4)The windings in the motor"

super interesting stuff and good to know.

one other factor: these jump motors were used on front wheels, while i necessarily put mine on the back wheel.

also from mototech, re motor winds: 10 turn - 27 MPH (I would consider this a high/mid range motor). This what was used in the frt. drive Jump bikes.

anyway ... onward.

woofnbike said:

, but in my experience, it's the phase wires that will melt before motor damage occurs.

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You were fortunate to had crappy connectors that caused your phase wires to melt before your motor got cooked. But I wouldn’t assume that is a way to protect your motor. Adding a temp sensor will take out the guesswork and provide actual data. With the right controller, or with a cycle analyst, current can automatically roll back when the motor temp exceeds a set threshold.

woofnbike said:

super interesting stuff and good to know.

Click to expand...

I found this post by Electric Scooter Parts Support very helpful in understanding the ratings/usage of controllers.

"The Watts rating is continuous, and Amps rating is intermittent - that is why they do not relate to each other mathematically. A controller's maximum current rating indicates its intermittent duty rating (for accelerating from a standstill and going up short inclines), while its Watts rating indicates its continuous output rating capability. They build controllers that way, so they have enough power for intermittently heavy loads such as getting up steep driveways and ramps. If you continuously run a controller at its maximum current rating it will probably burn out before the motor does. The amount of current that a controller outputs depends on both the load that the motor is placing on the controller and the position of the throttle.

For a 36 Volt 450 Watt motor a controller with a maximum current rating of 25 Amps will be a good match for it. As long as the motor is not running too hot then it should last a long time. If the bike is being used for going up long hills then you might want to stop after a while and check if the motor or controller is getting too hot and throttle down a little if either one of them are to keep them from burning out."

You can use a controller that is rated for significantly more Watts than the motor is rated for as long as the motor is not getting too hot while it is in use, the extra power could be used intermittently for climbing ramps and short grades, but not continuously, otherwise it would most likely overheat the motor. The safest thing to do is use a controller that is rated for the same or slightly more Watts as the motor is, and to take it easy when going up long or steep hills.

As seen in this thread...
eBike Modification - Controller and Amperage questions



I would encourage you to at least make the phase wires the same size and type as the controller has out of it. From inside the motor, to the connector at the controller. Eliminating the multiple/redundant connectors if you haven't already done so.
And as a bonus, while you're inside the motor, to install an inline temperature cutout for automatic motor over-temperature protection if desired. Nestled nicely amongst the coils. Sounds like a good winter project to me.


Glad to have you up and running!

Cheers,
T.C.

thanks much, t.c. i'll consider changing the phase wires going into the motor, although what what i can tell, the size that's on there now is pretty universal, although (pt 2) with that said, maybe my case is a special needs one.

btw / this kooky scooter has a weirdo feature where you can make the front wheel roll elliptically -- bouncy bouncy. why that was added, i haven't a clue, but i tried it yesterday for the first time, at the lowest setting, and it nearly threw me off like it was a bucking bronco. don't believe i'll do that again. go to 1 minute in to see what i mean.