The trials and trbulations of a failed ebike build

[dazium]

It seems that I am suffering from Murphy's law. I started my first ebike build in December and have had nothing but failures with it so far. For some reason unannounced to me there seems to be a higher power that refuses to let me enjoy the bike. in 6 months and 3 actual rides. The darn thing keeps breaking somehow, somewhere consistently. first my controller blows. i send it to stevo for repair. I order a Lyen controller 18 fet. here i think to myself, ok if one goes ill use the other. in the ebike lab i used the default settings. take it for a spin and my spokes break. ok replace rim for a stronger one, and get custom spokes made. installed new stuff. next day i take it for a 15km ride about 10 k into the ride the controller clicks off. oh great. i check the wires all is warm but still connected, the small power wire for the controller slipped out of its home. I put it back to the power, get on the bike and get moving and hit the throttle,. The motor is cogging it lasts for about a second and the controller shuts power off to the motor.
(I should point out that this is the most recent problem i've had.) so cogging is a hall sensor thing or one of the fets. i check the easy stuff first to see all is well. Great i think its the controller. i opened up the controller to see nothing burnt or otherwise. I realize that with the 5303 can draw lots of power and run hot for some people so maybe it was a fet that went. but then it hits me, this controller is rated for 100v. I'm running 80 on a full charge. (SLA) what i dont understand is why i keep blowing fets. a very similar thing happened with my clyte controller but i wasn't riding it when it happened. i was moving it in the garage pushed the throttle just enough to move it and click. nothing. Stevo fixes my controller and sends it back. i haven't tested it yet but i did see the youtube vid of it working. good enough for me. Now before I put the old controller back on and potentially blow a gasket when the fets pop sell the motor and controller and convert it back to my beloved mountain bike.

does anyone have an idea as to why I keep blowing fets. I just dont understand why it keeps happening.

I have been very patient with this ebike so far but it is wearing thin my wallet and temper. will somebody please tell me that this happens to all of us

 

[Red_Liner740]

it happens to all of us...

bought a Magic Pie, put everything together, bikes sitting upside down, i test the throttle, wheel spins i'm happy....i flip the bike right side up, zip tie some loose wires to go for a test ride...nothing...cant get it to run...

Gary from GM Canada was extremely helpful and immediately replaced the wheel/controller combo.

2 weeks later (bikes sitting around waiting), build my Lipo pack, in a rush to go for a test run i accidentally swap terminal leads on my anderson....plug the battery into internal controller and release magic smoke....FUUUU just cant get a break...blew both caps on the controller...so much for reverse polarity protection.

12 fet Lyen controller gets installed and Magic Pie gets rewired for external controller....finally a proper test run...couple km around the block i come back park the bike and notice loose spokes....10 or so spokes are loose...5 of these i can actually finger tighten the nipples back on...and one nipple totally spun out...i knew i had to watch and retighten the spokes, but not after 10 min of riding!!! Take apart the wheel, find the nipple, reinsert it and true the wheel....

i'm sure there will be TONS more of these moments...

 

[Tincan]

I hear you.

My mongoose build has been nothing but dissapointment (mainly from myself being a tight ass when it came to motors)

From my old scooter I had some good gear, 18 4115 fet lyen controller, 10ah 132v lipo pack and a ca.

Being in aus motors are rare as rocking horse shit here, so i took my chances on an ebay bike and purchased it with the intent of using it only for the motor.

Mounted it up, and it lasted 5 mins? before the wiring from the lyen to the motor heated and shorted out. My fault, i had some spare wire that i used, later to find out it was just 240v general house wire. no good.

Replaced that and then i melted the phase wires inside the motor the first time i loaded it up a hill. No issues i thought, stock wires, upgraded them and moved on.

another ride later and again, melted the phase wires.

I have just put it down to the motor (of what appears to be a 5x11 or something with 190w stamped on it) cant take the juice of the lyen. A shame considering i used to dump 3 - 4kw into the "200w" scooter 16" wheel.

Now have a 9c motor coming from Hyena so with any luck, i might be actually able to have some fun.

 

[Jason27]

kiss

keep it simple stupid.

find a new mtn bike. Get a golden motor or amped bikes kit. Follow the instructions online. Keep it at 36 or 48v using hobby king lipo and that is all you need.

oh and dont forget a torque arm.

 

[FMB42]

We're sorry to hear about your troubles dazium.

I'm running 80 (volts) on a full charge (SLA)

I'm wondering what your "all up" weight is (bike, power system, rider, and batteries). You must have ~ 60-75 lbs. in batts alone. This, coupled with everything else, might be causing you to draw to much amperage (especially under acceleration and while climbing hills).

I'd really like to see you follow Jason's "KISS" advice by using a LifePo4 or Lipo battery of 36-48 volts. This alone would probably shave 40-55 lbs. off of your machine.

Most of us can relate to having "problems" with our e-bike builds. I, in fact, have had to "temporarily" halt my rear DD FS MTB build due to "unforeseen" (i.e. I'm a dumb-dumb) problems (never mind that I'm ~ $700 USD into it with no "end in sight"). BTW, my wife has found great pleasure in mentioning this build whenever it suits her fancy.

Hang in there, you'll get it.

 

[dazium]

im 220lbs, batteries 50, motor 25, battery brackets 3 lbs

total weight 300

 

[FMB42]

im 220lbs, batteries 50, motor 25, battery brackets 3 lbs

total weight 300

Sorry, I forgot to ask you to add the weight of the bike to the total. Let's see, a ball park figure of 30 lbs. for you bike would, of course, equal 330 lbs.

Either way, that is no "light weight" ride you've got there dazium. But hey, the "all up" weight of me (210) and my geared 400w 36v LifePo e-bike is ~270 lbs. and, it tends to get pretty darn hot during the summer under "light to medium" riding conditions (i.e. relatively level and smooth paths and trails w/ somewhat "cautious" throttle application).

You might consider a "Cycle Annalist" and/or the use of a cheap IR or "non-contact" thermometer (~$15 USD from a discount tool supply) as a means of monitoring your actual amperage draw and/or heat build up.

 

[edcastrovalley]

...next day i take it for a 15km ride about 10 k into the ride the controller clicks off. oh great. i check the wires all is warm but still connected, the small power wire for the controller slipped out of its home. I put it back to the power, get on the bike and get moving and hit the throttle,. The motor is cogging it lasts for about a second and the controller shuts power off to the motor.
(I should point out that this is the most recent problem i've had.) so cogging is a hall sensor thing or one of the fets. i check the easy stuff first to see all is well. Great i think its the controller. i opened up the controller to see nothing burnt or otherwise...

does anyone have an idea as to why I keep blowing fets. I just dont understand why it keeps happening.

I have been very patient with this ebike so far but it is wearing thin my wallet and temper. will somebody please tell me that this happens to all of us

Carefully check the clear vinyl bullet connector insulators on the motor phase wires near where they connect into the controller. The clear vinyl tubing they use melts super easy and when the motor wires get warm, and it doesn't take much, a sharp edge of the metal connector can melt through very neatly and make contact with another motor phase wire having the same problem. It can be hard to find but if you spread your motor wires apart you may notice the vinyl tubing barely sticking to each other. That is a sure sign. The symptoms are the same, you get cogging from the motor. Don't open the throttle if this happens. That could take out some fets in your controller. Turn everything off and check your wires and get some separation on your connectors. Better yet, wrap a couple turns of electrical tape around the vinyl tubing part to begin with.

This happened to me a few times with my 80 volt bike and twin Lyen 12 fet controllers until I figured out what was going on.