ebike down. Died going uphill.

[mrpulldown]

HI All, I need some help. I bought my son an amazon "V8" e-moped 2 years ago. 48v 500w. Put about 1200 miles on. It has been great, and takes everything we have thrown at it till about a month ago. Son 1 and 2 together (250lbs of the 300 capacity) were riding up hill and it starts to get really slow. Then just shuts down and then nothing. This hill was steeper than the hill we ride daily, 2 up with even more weight. The display gives a E07 error and a little motor icon.

The battery showed full charge when they took off. Less than half a mile and was dead on return. A couple of minutes on the charger and it was back to full. Assumed we cooked a cell and the battery pack is now unbalanced. But even un balanced I thought it should still spin the motor. Our does nothing. Make a little hum and the wheels might move a couple of degrees. Probing the output terminals of the battery yields 50v.

The 9 pin connector (to the motor) had a burnt out looking pin (blue wire). The plastic around the pin was melted some. Cut the harness back and the pin joint still has continuity so probably just over heated. Next we took the hub apart. At least one of the wires seems like it has some cracked insulation but nothing shorted. Not sure it is the problem. We did not take the other side cover off as it was really pressed on tight.

Next we looked at the controller. The board seems to be pressed/glue into the case so I could not take it apart further without destroying the board. It does look like the battery wires are cooked.

At this point I am a little lost on how to proceed. I would rather further troubleshoot than throw new parts at it. I see that there is an ebike testing device but do not know how to use it. I am pretty handy, but have no experience in e bike repair, at least the "E" part of it. Right now I am leaning towards the controller needing to be replaced. I have drawn out the wiring diagram and think I have found a suitable replacement.

I am seeking help from the collective in trying to learn and get input. Thank you in advance.

 

[mrpulldown]

Here is a picture of the bike in question.

 

[m@Robertson]

It looks like a Bafang motor, and those are very nearly indestructible. So maybe the good news is the motor is still ok. The not so good news is an E07 is an overvoltage error. Have you tested your battery leads to see what the voltage is? If not, thats your first step. Get out a voltmeter.

I would not bother with one of those arcane tester doohickies.

You might want to get a look at the copper windings. If they are black the motor is cooked and done for. If they are black-ish, its maybe done for. Sounds like your wires and connections are stressed but workable.

This is generally fixed by replacing one component after another until the thing starts working. Starting with the cheapest item first. In your case, there are only three. the battery, controller and motor core. all three are big ticket items unfortunately. If its not the battery you might be looking at a new motor core.

 

[m@Robertson]

Maybe you will get lucky and you only effed up the battery connection.

 

[mrpulldown]

It looks like a Bafang motor, and those are very nearly indestructible. So maybe the good news is the motor is still ok. The not so good news is an E07 is an overvoltage error. Have you tested your battery leads to see what the voltage is? If not, thats your first step. Get out a voltmeter.

I would not bother with one of those arcane tester doohickies.

You might want to get a look at the copper windings. If they are black the motor is cooked and done for. If they are black-ish, its maybe done for. Sounds like your wires and connections are stressed but workable.

This is generally fixed by replacing one component after another until the thing starts working. Starting with the cheapest item first. In your case, there are only three. the battery, controller and motor core. all three are big ticket items unfortunately. If its not the battery you might be looking at a new motor core.

Battery reads 50v. Terminals are clean. If I install a good battery (from another 48v ebike) and it is a fried motor or controller, could it possibly damage the tester battery. Battery mount and terminals are not the same, so i'd have to direct plug it into the controller.

 

[m@Robertson]

I don't see how it would damage the battery. 50v charge on a 48v pack is 70% so overvoltage isn't the root problem. You know... if you have a different bike that works, testing the battery on the working bike is a better idea, assuming that working bike is also 48v. Testing on a good bike would tell you the battery is truly working.

 

[Hozer]

I had the same problem. I live in the mountains here in Oregon. I had bought a trailer for my 75lb German Shepard. Works great. So I decided to go to Wally World and do some major shopping. BAD MOVE!!, I had put in the trailer, 4 gallons of milk, 2 cases of coke and bunch more groceries. Well as I was going to up the steep mountain to get home my bike the bike was going very slow and finally stopped just before I got home. I had to wait for about 10 mins for the controller cooled down. Then I turned the bike back on and as I was driving home I got a 02 error. I got home and took a look at my controllers and 1 saw one of the wires were fired on the main controller. I was pulling way to much weight going up the hill and I fried my main controller ( I have dual motors ) 1 controller for each motor. So lucky for me my ebike was still under warranty. So the MFG. sent me 2 new controllers for free.

So it looks like you may have fried your controller. See if you can get another controller for the Manufacture. I know it's not much help but it will give you some idea it maybe your controller.

 

[Annieolnie]

This is the 25 amp version of your controller, from the same manufacturer.

This would give you a little bit more leeway, although you would need to double check your plug arrangement. Just to note, when they tell you the capacity of your bike it includes the weight of the bike itself. So, I'm guessing you were maxing it out a bit.

 

[mrpulldown]

Thanks all for your help. Here is an update.

Hub Motor. Learned up on some testing methods. There is continuity between the 3 motor phases: GOOD. Could not get a good resistant reading. Probably because I have a cheap little meter that couldn't put out enough juice, though enough for continuity. Tried to test the hall sensors but had an equally difficult time.

We put the bike back together and of course still get the error message. Would think that I should be able to give it throttle and be able to test voltage at the connector, but couldn't figure that out. Further fussing with the display caused it to flash and not turn back on. Hope that it is something in the controller and I didn't fry the display.

Narrowed it down to 2 different controllers. This one seems the most ideal as it already has a 9 pin motor connector. But it isn't amazon prime so no free returns if it doesn't work. I know there are some ethics questions regarding returning electronic used for testing. It did sport a higher amp rating which was good.

https://www.amazon.com/dp/B09LYF5WZ...FNX0XM2W&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
We ending up getting this controller and a 9 pin pigtail.

https://www.amazon.com/dp/B0C82XF56Q?ref=ppx_yo2ov_dt_b_fed_asin_title
Everything should get here by the end of the week. I'll let you know how things work out.

 

[Annieolnie]

The upper controller is a KT. You would need their display to run it. I never heard of the other controller. Your current display is most likely a Dongguan Jing, which would be matching your old controller. For the most part, controllers and displays don't play well with strangers. Let us know what happens.

 

[biknut]

Based on your description of the failure I'm guessing either a hall sensor fried, or the controller failed.

 

[mrpulldown]

Based on your description of the failure I'm guessing either a hall sensor fried, or the controller failed.

Bike is running again.

I think the finial diagnose is a failed motor hall sensor. Testing the motor coils showed good continuity, but I couldn't get readings for the hall sensor. Made my voltmeter jump all over the place, but I assumed it was due to my slow to update auto ranging voltmeter. I wish I could figure out if the controller was sending power to the plug. Figured it would have been something like checking the voltage between the phase wires. But I don't think it is that simple. Anyone know?

Anyways here is the rest of the story. I bought the cheap controller and a 9 pin adaptor wire. Plugged everything in and the display does not power. After the motor died, the display would still turn on, and when the throttle was engaged the motor would a sound and move a few degrees then stop. Kept fussing with it, but one of the times messing with the display, it flashed and never turned on again. I think we killed the display, and it would have worked with the controller. I go and buy another of the same controller but with a display this time. Wired everything up and got the same "motor" error icon, and the E07 message. Should have given this error more weight initially. But with the new controller I was fairly confident that the motor hall sensor had failed.

Now the search was on for a 20x4 hub motor with controller. As these e-mopeds are very popular, finding a replacement was difficult. I had only found 1 or 2 sources that sold motor cores. Though mine looked like a Bafang, I don't think it was. They were also very expensive, about the same as a new wheel kit. I ended up getting this unit (no battery). I bought it off of Amazon with the product protection plan. I could have bought it directly from powallon for cheaper, but I did not know till after I received the unit.
https://powallon.net/products/bafan...r-for-20-fat-snow-bike?variant=45854876074141

Plugged it in and everything fires (after sorting out the brake cut off, it was engaged). It is a 750 vs the old 500. Came out to be about $300 before tax. Son contributed $100. The wheel also comes with a modern cassette instead of the old school spin on freewheel, which I think will fit any new 9-12 speed. His is set up for 7, and not wanting to mess with shifter and derailer, I find an old 11-32 seven speed and spaced it out. The 11 is quite an upgrade to the 14 he was running. The low end of the range is never really used anyways.

The last thing to figure out are the lights. His old bike had a headlight/horn, combo tail/brake/turn, and a turn/horn switch. The wiring was ungodly complicated, with in/out puts from the controller.