Installing thicker Phase wires.

[spdas]

Aloha, I have the Leaf 14" rim with 48v 1000w low torque/hi speed motor running at 16s 5000mah 66v to 60v.

I noticed when running WOT for a few minutes the phase wires understandably get a bit warm. WOT is 38mph and I use it on a couple of scary car sections of the road, but use mostly 25mph on the flat --------SO-------

1) is there any point trying to fit larger phase wires or are the current size wires "a reflection" of the size of wires on the winding? ie larger phase wires will allow more amperage, but the winding wires will be the first to "let go" rather than the phase wires.
2) Phase wires are SS....any point to going to copper?
3) Any real world advantage to using larger wires from controller down to the hub and going with standard phase wires to inside the hub? (normally there would be an advantage)
4) Is there one phase wire that carries more current than the other two?

I don't think there is an actual overheating problem, but I like to tinker and improve things!

francis

 

[spinningmagnets]

In a three-phase motor, each the three phase wires are energized 2/3rds of the time. If we label them 1, 2, and 3, then...1+2 will energize one phase-group. Then 2+3 will energize another phase group. then, 3+1 will energize the last phase group. After that, the sequence repeats over and over.

There is a benefit to squeezing-in the fattest wires that can fit from the inside of the motor to the outside. Then, there is a benefit to making the three phase wires fatter as soon as they exit the motor, all the way up to the controller.

Use teflon-insulated wire to travel from inside the motor to the outside, because the teflon insulation is much thinner than the common high-temp silicon, and also more heat-resistant than the common PVC. For a given "pass through" hole size, less insulation thickness means more copper mass in the wire strands.

Outside the motor, you can go to a fatter wire of any type, like the affordable hobby king silicone-insulation wire.

"DIY 10awg phase leads through axle in 9C hubmotor" (Luke, LFP...5 pages with pics)
https://endless-sphere.com/forums/viewtopic.php?f=2&t=14580

"Doubling the phase wire thickness on Bafang BPM"
https://endless-sphere.com/forums/viewtopic.php?f=16&t=51237#p758156

 

[spdas]

Thanks, a lot of great tips on your recommended threads.

1) Hard to believe the 2x16 gauge is smaller than 1x12 gauge. Looking at the pix the insulation on 12 gauge seems to be much thicker and 16Ga very tight around the strands though.

2) My controller outside insulation diameter of wire is 3 mm You think this is 12 Ga?
and hub motor is 2.2 mm 16 Ga?

Francis

 

[spinningmagnets]

The gauge of wire only refers to the copper strands, the insulation can be thick or thin on the same gauge of wire.

 

[wesnewell]

Check voltage drop chart at bottom of page to see if you think it's worth the trouble.
http://www.powerstream.com/Wire_Size.htm

 

[izeman]

if you phase wires gets warm, then it's a good idea to upgrade them.
but on the other hand: if your bike reaches almost 40mph you feed it probably something around 3kw.
so if you open the motor anyway you may install a temp probe to the windings if this hasn't been done before to check motor health.
good luck!

 

[macribs]

If wires get hot the resistance will increase, and that is not desirable.
Thicker wires will solve this and will give you "more power" - most likely not noticeable at all but if you do the math you will see how lower resistance will be positive.

What you could do is to start off with the simpler mod. Fat wires from the controller to the outside of the motor. Because the length of the original and thin wire has now been greatly reduced it could be that this will fix it for you. That way you will not have to go trough the pain of fitting fat wires in to the motor.

If you still think more modifications are in place do fat wires all the way into the motor. Remember you don't need "garden hose" sized wires all the way. You can use that fattest wires from controller to outside motor, then a little beefier wires from outside and in that replaces the final stretch of the original wires. Just choose a wire that will fit, yet still be thicker then the original wiring.

Or you could go insane and have a custom axle made with larger OD bearings to allow for fatter wires to exit the motor. But that is last resort and requires much work.

 

[spinningmagnets]

The individual wire strands are likely "tinned" and so they have a silver "look" to them. Trust me, they are copper.

 

[spdas]

There is a benefit to squeezing-in the fattest wires that can fit from the inside of the motor to the outside. Then, there is a benefit to making the three phase wires fatter as soon as they exit the motor, all the way up to the controller.

Outside the motor, you can go to a fatter wire of any type, like the affordable hobby king silicone-insulation wire.

I put fatter COPPER (yup u r rite, tinned copper) wires down to the axel and re-did connections.

Question is.....do the learning wires "fine tune' or just get the motor direction and 60-120 phase sorted? ----- Because my motor seems to running a wee bit noisy and tweaky after I re-did the wires. The motor after redoing the phase wires at first jerked backwards but now seems to be ok, with the complaints above. Will using the learning wires help the above symptom?

thanks
francis

 

[spdas]

Aloha, how are RC 3.5mm Male/Female Gold-plated Bullet Banana Plug Connector connected? Solder or can they be crimped. I know, I know, just google or search here, but could not find a quick answer.

(I am going from a 4s pack to a 2s pack as I am getting a few cells going south in my hard case 4s 5ah batteries, so cheaper to buy and swap out a 2s @$20.00 than a 4s @ $40.00). --- but they come with Deans connectors, and harder to "Series".

thanks
Francis

 

[izeman]

Aloha, how are RC 3.5mm Male/Female Gold-plated Bullet Banana Plug Connector connected? Solder or can they be crimped.

solder. what current do you plan to run them with? xt60 has 3.5mm bullet imho. so they should be good for up to 60A.

 

[levleon13]

If wires get hot the resistance will increase, and that is not desirable.
Thicker wires will solve this and will give you "more power" - most likely not noticeable at all but if you do the math you will see how lower resistance will be positive.

What you could do is to start off with the simpler mod. Fat wires from the controller to the outside of the motor. Because the length of the original and thin wire has now been greatly reduced it could be that this will fix it for you. That way you will not have to go trough the pain of fitting fat wires in to the motor.

If you still think more modifications are in place do fat wires all the way into the motor. Remember you don't need "garden hose" sized wires all the way. You can use that fattest wires from controller to outside motor, then a little beefier wires from outside and in that replaces the final stretch of the original wires. Just choose a wire that will fit, yet still be thicker then the original wiring.

Or you could go insane and have a custom axle made with larger OD bearings to allow for fatter wires to exit the motor. But that is last resort and requires much work.

guys can you please explain what would these be exactly ? i mean how can i know im pushing in phases fatter than the original but not for nothing , knowing it will eventually get trough ?

 

[Voltron]

No way to tell for sure until you're 95% done and realize they don't fit

There's such a range of wire guage to insulation thickness that is hard to get a solid "this will fit" answer.

 

[markz]

Buy Teflon PTFE wire, and if necessary use a rotary tool to give you extra space for the phase wires.

 

[fechter]

If you do the math, unless your phase wires are really long, the percentage of your power lost there is going to be very small. What may be more important is not having the insulation melt. It's pretty easy to use heavier wire outside the motor. You can make a connection and go to fatter wire fairly close to where they go into the axle and run that up to the controller.

Depending on the motor, it may be easy or incredibly difficult to stuff new wires through the axle. Most of my experiences have been more toward the difficult side. Using wire with higher temp insulation may be a worthwhile upgrade if the wires are really getting hot. I have seen melted phase wires. There may be a trade off between insulation temp rating and durability. Silicone and Teflon are good for high temps but more easily damaged than standard PVC or Nylon.

 

[dogman dan]

Re do the learning, if your motor is running rough. If that does not fix it, you have done something, like you have a short, or a bad halls connection.

For others reading,, one sweet trick is to just put huge phase wires on the motor, but leave the original wire in the axle itself. The big fat wires will act as a heat sink, and help cool hot wire in the axle. I ran 40 amps of 110v through the original wires with no problem for some time. The fat wires stayed cool, which helped them pull heat out of the remaining stock wire.

A very easy modification.

 

[macribs]

If wires get hot the resistance will increase, and that is not desirable.
Thicker wires will solve this and will give you "more power" - most likely not noticeable at all but if you do the math you will see how lower resistance will be positive.

What you could do is to start off with the simpler mod. Fat wires from the controller to the outside of the motor. Because the length of the original and thin wire has now been greatly reduced it could be that this will fix it for you. That way you will not have to go trough the pain of fitting fat wires in to the motor.

If you still think more modifications are in place do fat wires all the way into the motor. Remember you don't need "garden hose" sized wires all the way. You can use that fattest wires from controller to outside motor, then a little beefier wires from outside and in that replaces the final stretch of the original wires. Just choose a wire that will fit, yet still be thicker then the original wiring.

Or you could go insane and have a custom axle made with larger OD bearings to allow for fatter wires to exit the motor. But that is last resort and requires much work.

guys can you please explain what would these be exactly ? i mean how can i know im pushing in phases fatter than the original but not for nothing , knowing it will eventually get trough ?

Well the sad part is you don't know before you try. If you look at one of the wire thickness/length diagrams you will more easily visualize how the resistance work to heat up the wiring, more heat build up even more resistance. If you replace all the phase wires from the controller with phat gauge wires, you can still get most of the benefits of thick wires mod. If you leave just enough original wire to make a secure connection between original wires exiting the motor/axle and the new phat phase wires from the controller because the total length of thin original wire now is so short compared to original length your wires should not heat up to increase resistance even more. If you feeling up for the task, do change the wires all the way. And while you have the motor open consider to paint the inside of the side covers and motor mat flat black to help the heat exit the motor faster.

 

[markz]

Its been said, the easiest way is to snip the stock wires at the axle then install 8awg or bigger wire (low guage), many people do it that way. Icecube57 did it that way on one of his bikes. I tend to do things the harder way, so I went with 10awg phase and computer ribbon cable for the halls/sensor/gnd/pos. Now I've read some people using ultra thin wires instead of what I did, ribbon cable. I would stay away from solid wire, and go stranded.

 

[dogman dan]

For me the bottom line is this,, if the power you are pushing can't go through 8" of the original wire without melting down,, you just need a much bigger motor in the first place.

Pushing 3000w,, that is 72v 40 amps through the last few inches of stock wire on most 500w rated DD motors is no sweat. But you will see a cooler wire on the entire length if you upgrade to 12 or even 10g.

Put the controller within 12" of the motor is another way to solve it.

 

[amberwolf]

One other consideration about wires and heat is that if they get hot when bundled up inside stuff...don't do that.

Even a teensy bit of airflow over otherwise insufficient-seeming wires or connections can make all the difference between usable and disastrous meltdown. The wires in my SB Cruiser's right wheel get pretty hot under acceleration or active braking, from controller to x5304, with just a 30-35A 12FET generic controller. But since they are mostly not in a jacket, and have individual phase wires exposed to the air, most of the way from controller to the wheel (inches away), I don't have any melting issues, even though the actual wires are kinda long (so I can pull the wheel off and work on it if needed, since all my wires are soldered).

If I had them all heatshrunk and jacketed, and buried inside a harness or otherwise out of airflow, I expect I'd see damaged or even melted-thru insulation by now.

(they are 10g house-wire AC type, see here: https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1092854&hilit=x5304+upgrad%2A#p1092854 )