Need recommendation for Wiring Harness/new CPU/Display

[54Goldtop]

Hello to all: I have a Mao Special handcrafted in one of the finest lamp and microwave factories in China. It is sold as an EKx 2000 watt ebike on Ebay. The bike is crude, powerful, and a delight to operate when functional. At this moment in time I have about $950 in the bike, and I have have ridden it just over 1k miles--therefore, cost has been a little over $1 per mile. Bummer. I received great help on this forum when, at about 250 miles, the controller burnt itself up. There was evidence at the time that the bike had been left on a charger for 3-4 days, and it does not have a battery cutoff. Bought new controller, and the bike ran beautifully for about 750 miles. It has now torched itself again. I need, if possible, someone to walk me through replacing the controller, the display and the wiring harness --I THINK--because I do have a good frame, good drivetrain, and the battery is very good (35 AH and lasts forever). It is my goal to buy an oversized controller, replace the harness with an upgraded, hotter wiring system, and bring in the new Display matched to the new controller. At this point I would also consider a full new system with new rear hub and everything related, except I do want to keep this battery operational if possible. See below for photos of the nuclear accident.
Here is the offending controller. Claimed 48v.

 

[54Goldtop]

 

[54Goldtop]

 

[54Goldtop]

 

[54Goldtop]

 

[54Goldtop]

I included a photo of the battery pedestal just to show that if I buy a new motor, harness, etc., I need to figure out how to wire that up, which might be easy. I think I understand I need to buy a controller that is at least 20% higher capacity than the one that we have here, which has now smoked itself twice. I think I need to replace the wiring harness because this time the damage went past the connectors to the actual wiring of the attachments (for example, the headlight wiring is damaged on both the controller connection side and the headlight side). So I think I should start over on that. Last, I included the photo of the mainline coming into the hub; I think that is either a link or a fusable link; I need to confirm that that connection can simply be pulled apart if I buy a new harness. Does anyone have any recommendations on where to start on this?

 

[54Goldtop]

I am more musing out loud than asking, but that engine is a weird one (SKUK). I wonder what it would look like disassembled? Same heat issues? When I take this thing apart, would it be worthwhile to take the hub apart and inspect? I realize that is easier to say than do...

 

[E-HP]

I believe in your previous thread, amberwolf provided some guidance on using the correct nomenclature so people can help you.
BMS, controller, MCU, etc. Perhaps you could update/edit your post to use the correct terms, which would be helpful. You may be talking about your battery's BMS, but only you can confirm that's what you are referring to when you say CPU, but in your first post I would have guessed controller.

 

[54Goldtop]

Thanks for the generous remarks. The controller is burnt--and I want to upgrade the controller as well as matching display, with a new wiring harness commensurate with the upgraded controller. I want to keep the present battery... Are my goals realistic?

 

[Chalo]

Your "2000W" e-bike would be called a 500W e-bike by most mfrs and sellers. It's about 1kW peak electrical power, which is usually cut in half when characterizing most commercial e-bikes' nominal power.

Your problems aren't the controllers, but the crappy plugs on them. Replacing controllers over and over isn't going to fix that. You need to use legitimately functional power connectors (R/B battery wires and Y/G/B motor wires).

The thing already showed you what was the matter when it failed the first time. Not fixing the real problem is on you. Nothing happening inside the box will result in plugs overheating outside the box.

 

[E-HP]

Thanks for the generous remarks. The controller is burnt--and I want to upgrade the controller as well as matching display, with a new wiring harness commensurate with the upgraded controller. I want to keep the present battery... Are my goals realistic?

Yes, they are realistic, since you didn't mention lights or horns or any extra crap.

You need to select a controller with the features you want, and buy the controller and display as a paired set. Do you have a multimeter and soldering iron? Since the display and any associated buttons are paired to the controller and the cable between them is usually a generous length, you'd just need to fish the cable between the handlebar and where the controller is located. Since the motor cable is already at that location, as are the PAS, throttle, and brake disconnect connectors, you won't need to do anything else but match up/swap out connectors if they don't match. You will likely need help with configuring the phase and hall conductors to the motor, when the time comes, unless you buy a controller with a self learning function.

 

[54Goldtop]

Thanks for reply: " Do you have a multimeter and soldering iron?" YES. And I don't need to keep any of the existing controls . I don't need a PAS. I do like the headlight but I have several from other bikes that are add-ons. Don't care either way. The one thing I do want is a twist throttle. I ride forest roads in the mountains and I like to get a workout, so I put the power right under pedalling torque, usually. Because I often ride with a dog, I also want to go slower at times than the PAS will allow. So don't really want it.

"Since the display and any associated buttons are paired to the controller and the cable between them is usually a generous length, you'd just need to fish the cable between the handlebar and where the controller is located." GOT IT.

"Since the motor cable is already at that location, as are the PAS, throttle, and brake disconnect connectors, you won't need to do anything else but match up/swap out connectors if they don't match." CHALO points out something obvious to him but not to me--this is not my area of expertise, or i wouldn't be asking. Won't a matched wiring harness and controller/display have the appropriate plugs? Is that a common alteration when putting these together from stock?

"You will likely need help with configuring the phase and hall conductors to the motor, when the time comes, unless you buy a controller with a self learning function." Is this because I am considering keeping the existing motor? Maybe I should buy the whole kit with new rim and engine...

 

[E-HP]

"Since the motor cable is already at that location, as are the PAS, throttle, and brake disconnect connectors, you won't need to do anything else but match up/swap out connectors if they don't match." CHALO points out something obvious to him but not to me--this is not my area of expertise, or i wouldn't be asking. Won't a matched wiring harness and controller/display have the appropriate plugs? Is that a common alteration when putting these together from stock?

"You will likely need help with configuring the phase and hall conductors to the motor, when the time comes, unless you buy a controller with a self learning function." Is this because I am considering keeping the existing motor? Maybe I should buy the whole kit with new rim and engine...

For a cheap, or even decent controller, having decent phase wire connectors is less than common. I like XT 150’s, but that’s my preference since they make good contact and don’t get hot. Other folks like Andersons. In any case, cheap bullet and spade connectors seem to be problematic and it’s common to see fried connectors and conductors posted on ES.

It’s not difficult to match the controller to the motor, so not a reason to swap out the motor unless you’re trying to upgrade it.

 

[99t4]

I have a Mao Special handcrafted in one of the finest lamp and microwave factories in China.

Well that may be true but they obviously cheaped out on the wiring connectors (and likely other components as well).

Your two photos of the burnt connectors and adjacent wiring show the main problems. They are easily repairable using simple well-proven wiring best practices methods. Splice in new good quality wiring sections as necessary, and replace the burnt connectors with better quality. E-HP suggested XT150 connectors above in post #13, that would be a good choice.

Are you experienced with wire soldering, crimping, heatshrinking, insulating? That's the basic skillset needed for these repairs.

 

[54Goldtop]

Soldering crimping, heatshrinking, insulating, yes. Lamp/microwave factory remark meant to be funny. So controller might still be usable with splice-in? Time is my problem. I would rather buy a new set for plug and play. If my battery is sufficient (claim is 35ah) I was thinking something like this: https://e-rideworld.com/product/3000w-rear-wheel-electric-fat-bike-conversion-kit-72v-80a-sabvoton-programmable-controller-7-speed-flywheel-torque-arm-20-4-0-rear/

 

[54Goldtop]

It would be ideal if I could buy the same kit above without the engine--but having a new, more powerful engine would be nice. I am willing to upgrade if it means the wiring for that bike is commensurate with the heat production.

 

[99t4]

So controller might still be usable with splice-in? Time is my problem. I would rather buy a new set for plug and play.

It's worth a try, but also a good plan to have spares on hand for the more high-failure items (for many this means throttle, display, controller).

If my battery is sufficient (claim is 35ah) I was thinking something like this: https://e-rideworld.com/product/3000w-rear-wheel-electric-fat-bike-conversion-kit-72v-80a-sabvoton-programmable-controller-7-speed-flywheel-torque-arm-20-4-0-rear/

Are you sure it will work for you? Do you have a 72V battery? Is your bike compatible with 4" rear wheel (fatbike)?

PS: looking at that kit, WHY do they continue to include that PROVEN UNSATISFACTORY unreliable TA design? (Pet peeve of mine.)

 

[lnanek]

PS: looking at that kit, WHY do they continue to include that PROVEN UNSATISFACTORY unreliable TA design? (Pet peeve of mine.)

Probably cheaper to make than Grin's newer designs with the adjustable angle insert. Less material, fewer cuts.

As someone who owns both, it is kind of annoying having to use a vice to get that insert into the arm too. Hammering wouldn't do it for me. So old design probably gets fewer returns even though it's worse in almost every way.

 

[54Goldtop]

Guys, does TA mean throttle assembly?

 

[E-HP]

Guys, does TA mean throttle assembly?

Torque Arm(s)

 

[54Goldtop]

 

[54Goldtop]

 

[54Goldtop]

Here's the battery and plug in configuration for the power transfer. If I understand (this is not my area of expertise) a 3000 watt engine will draw too much power and will either damage or not operate correctly with the above. Is that correct? Or is it simply that the above battery would not have the capacity to send full power to the engine? The bike is a 4x20" wheel rear hub, as mentioned. My vision is I have a good frame, adequate running gear, and I can make the choice between ne controller/display/throttle and wiring kit, or same plus new rim and engine, utilizing existing battery. Will the above battery work with a 3000 volt kit or should I look for 48v 2000?

 

[E-HP]

30A x 48V = 1440W. Upgrade the battery before doing anything.

 

[Superb_Raccoon]

30A x 48V = 1440W. Upgrade the battery before doing anything.

Yeah, the original will get pounded faster than case of PBR at a frat party.