9C direct drives runs on 48V but not72V. HELP

[EZgo]

A FINAL PUZZEL FOR 2021!

Is it possible for a direct drive 2013 9C hub motor to run fine at 48 volts but not on 72 volts? (jerks/vibrates forward or backward) Please read below.

This bike has run better than perfect for me for 3 yrs. at 72 volts through a 100amp Lynn Extreme Controller & a V3 CA . Then a medical issue kept me from riding for 4 yrs. & the bike sat. Three months ago I installed a new 72V battery & started riding again. Once again it ran perfectly for 2 weeks. I put it away after a 5 mile run one night & got it out the next day. It would not run.

The bike itself was originally built using a 2015 48V kit from ebikekit.com. It's a 1000 Watt direct drive 9C hub motor. I soon thereafter modified it with a 72 volt Samsung battery from Luna Cycle a V3 Cycle Analyst & a 100 amp Lynn Controller setup for 72V. Lynn built the controller for me and installed the necessary plug ends so that I did not have to do anything other than plug it in to my 72 volt battery and my ebikekit.com wiring.

The bike ran perfectly for about 3 years until my medical issue knock me out of the game.

It sat for about 4 years until three months ago when I put it back into service with a brand new 72 volt Samsung battery. The new battery uses the Samsung 21700 4000mAh 30A Cells which is tiny bit hotter than the old samsung18650 cells. I have never run this bike hard save for a few top speed runs. Here are the symptoms & my troubleshooting methods:

With the rear wheel off the ground when I give it throttle it jerks (vibrates) forward and or backwards depending on its mood.

I trouble shot this issue by first ruling out the throttle, then any wiring connections and then the V3 Cycle Analyst unit.(I bypassed the V3 & plugged the throttle directly into the controller getting the same result) Grin in Vancouver helped me to rule out any other possible Cycle Analyst issues. I have also installed a new twist grip throttle even though the old throttle worked fine. (just to be sure)

That left me with the Lynn controller or a phase wire issue with the direct drive hub motor. I eliminated the hub motor by parking my wife's 48 volt ebike next to mine & connecting her ebikekit.com plug (same vintage) directly into my hub motor plug. I used her 48v battery, throttle, her wiring & her original 48 volt ebikekit.com controller. My motor ran fine even under load.

Lynn has tested his controller for me as of 12/29 & said it works fine although he did this using 48 volts. I have since emailed him back to see if he could test it at 72V.

I've been a mechanic for 30yrs, a DC floor machine tech for 10yrs & an ebikekit.com dealer since 2012. I'm not a ebike expert but I do know how to trouble shoot & isolate faulty components.
I would greatly appreciate and welcome any suggestions, Ideas, thoughts or comments as I am fresh out of ideas. THANKS & HAVE A GREAT 2022!

 

[E-HP]

Did you try running your wife's motor off of your controller?

I'm guessing poor/intermittent contact on the hall sensor connector.

 

[amberwolf]

Hall sensors are the most likely problem, not necessarily the sensors themselves (since it works at a lower voltage), but wiring / connections.

Does the system operate normally when offground at very low throttle, but not operate correctly at higher throttle or when under load? If so, it could be electrical noise from the phase wires induced into the hall sensors, causing them to read incorrectly. Higher voltages cause higher currents and create larger RF bursts, so it might work poorly at the higher voltages and be fine at lower ones.

A bad ground wire on the halls could cause problems with all of htem (as could bad 5v to them, but a bad ground could be almost fully complete, with just the barest connection so that if you were to do a continuity or static voltage test it would pass, but under load / operation it could show problems).

Possible causes include a bad crimp, corroded connection, spread pin/contact, stretched/damaged wire inside the insulation (where the insulation appears undamaged).

I'd try the test E-HP suggests first, of cross-connecting yoru controller to your wife's motor, since youv'e already eliminated everything else in the previous tests.

 

[EZgo]

Thanks for the reply. When my 72 V quit on me . (I had just ridden it the nite before) I gave it some throttle & it jerked/vibrated but went no where. I tipped it back on the rear mount kick stand & gave it a little throttle it would jerk a little bit forward. Id leave off & twist the throttle again & the same thing. I did this a number of time & sometimes it would jerk backwards. I thought of the phase wires write away. But I wanted to do the simple stuff first.

Throttle tested fine with a meter + I unplugged it from the V3 CA & plugged it directly into the Lynn controller.(I got the same jerking action) I unplugged all the electrical plugs sprayed them with contact cleaner & worked them back & forth. Throttle position is between 1/8 to maybe 3/8. Opening wider than that does move the wheel at all.

What both you guy are suggesting Is my next step, but I have to get my controller back from Lynn. I was thinking he was going to do more the just run 48 V through his controller into his test wheel which is a 9C same as mine. I have asked him to run this at 72V if he has that available. I also asked him to hook his laptop up to it to confirm that the setting have not changed. If he does not find something wrong with it a second time I will disconnect his controller wire from my wheel & plug it into the hub motor cable on my other bike.

This is Lynns YouTube testing my controller https://youtu.be/upspM8hjHLo

I was so sure that it was the controller that I never even thought to do that. I did pull lynns controller apart & tested the mofests & they did test fine. But that was the only thing I new how to trouble shoot in there

.

 

[amberwolf]

Thanks for the reply. When my 72 V quit on me . (I had just ridden it the nite before) I gave it some throttle & it jerked/vibrated but went no where. I tipped it back on the rear mount kick stand & gave it a little throttle it would jerk a little bit forward. Id leave off & twist the throttle again & the same thing. I did this a number of time & sometimes it would jerk backwards. I thought of the phase wires write away. But I wanted to do the simple stuff first.

The hall wires, connections, and sensors are the first simple stuff to check for the specific problem you describe.

If your Lyen controller is like the ones that I've had, it uses a 5-pin JST-SM for the hall connector, and this is not just an open connector that can get water in it (even tiny amounts of moisture can oxidize and corrode the contacts in these and cause poor or no connection).

It is also a connector that can have pins back out on their own when they arent' fully seated. This can happen for a number of reasons, but the most common is the tiny tab on the contact pin gets mashed down during crimping or insertion into the shell just enough to not fully catch on the shell and keep the pin from backing out when the mating connector is plugged in.

So you can get a plug that looks connected, but the contact pin is pushed back enough to eventually vibrate loose, or even just make poor connection enough that slight oxidation over time eventually prevents even that much connection, so it "works" up to that point.

You can often see this problem while it's connected because the open back of the JST will let you see that most of the pins are pushed farther in than the one(s) that aren't seated.

If you can't see it you can find it on the "male" pins by gently pushing on the tip of each contact from the "front" of the connector with something flat-faced on the end with a small crosssection (chopstick, etc), and any of them that slide backward aren't seated. You can also pull on the wires from behind, but that has the risk of damaging the wire at the crimp and creating a problem that didn't exist before. It's harder to test the "female" pins this way because they're enclosed inside the shell, but you can do it with a needle or straight pin or thumbtack with it's point against the edge of the metal of the contact.


Another problem with these is that during crimping it's possible to actually cut thru or crush the conductors, while leaving the insulation appearing intact--the insulation can hold the conductors against the contact for a long time, and eventually over time the insulation stretches / relaxes and the connection goes bad or is entirely broken. This can be tested for visually with good light and magnification, sometimes, but a continuity test from the tip of each pin at the "front" end to the other end of the wire (inside the motor and inside the controller) will reveal this problem, though you may have to gently move the wire aroudn relative to the back of the shell/contact while listening to the beep of the meter's continuity tester. (an ohmmeter reading only works on an analog meter because the response time of the digital ones is often too slow to react while moving the wire and you may read low ohms all the time on the display because the open reading was too short to show up).


It's unlikely to be an actual sensor problem, because the motor works on your other bike. But a connection problem could still exist, most likely on the controller's hall plug, but possibly on the motor's.

I unplugged all the electrical plugs sprayed them with contact cleaner & worked them back & forth.

That doesn't always fix connection problems, unfortunately.


It is possible for it to be a phase wire or winding problem at the motor as well, but these don't usually have the same symptoms. I did once have a motor winding falure where the winding insulation was compromised where it touched the stator laminations. It only showed up definitively under high voltages, with a tester that uses a couple hundred volts+ as pulses (isolation tester) but it also had certain wierd issues (controller shutdowns, etc) under high load and high throttle demand. Different from your symptoms, but the only voltage-related problem I've encountered directly.

If it is a winding problem, then your other bike's motor will work fine on your bike's system and higher voltage. There's no reliable tester hardware for this issue besides an isolation tester, that I know of.

 

[EZgo]

Crushed connectors is a great idea. I have discovered that problem before on DC floor equipment (usually on new equipment) If after getting my controller back from Lynn & finding it runs my other bike motor at 72V that will be by next step. Thanks

 

[EZgo]

Finding & fixing this problem has been a slow process since it's winter in PA but as it turns out everyone's suggestion was correct. So thank you.
It was not the controller as I was sure it was but the wiring inside the motor. The insulation on 3 of the 5 hall sensor wires was bad leaving sections of bare wire exposed. The red power wire just inside the axel had exposed wire as well. None of it was discolored from heat but I built this bike in 2014 & I guess 7 yrs is a long time in hub motor years. I decided to purchase a new wheel & motor & will eventually replace the wiring on my old motor & use it another bike.

I had first inspected & tested the Lyen Controller as per Lyen's instructions & could find nothing wrong but since the motor ran fine off of another controller at 48V it simply had to be controller. So I ended up taking a long detour in the troubleshooting but in the process learned a lot.

 

[99t4]

Might you be able to revive the motor by rewiring the damaged sections?