Help Urgently Needed

[Macster58]

Hi everyone and a merry Christmas to all. Now I am new to forums as I have never needed them so please be patient with me.

Now I am hoping that someone may be able to answer some questions for me.

I was given a FreeGo hawk electric bike last week due to it having a fault. Now I have tested the battery pack which is 36v and after fully charging it and letting it settle for 48 hours the multimeter reads 41.54volts. Now I did find that the pedal assist sensor was pressed up to the magnet disk so once I moved it to 3-5mm from the magnet disk the sensor kind of worked but only for about 4 miles. Now it’s starting to stutter. I did follow a tutorial on YouTube for diagnosing faulty controllers And after testing the phase wire MOSFETs ( continuity buzzer test & ohms test) I found the result wasn’t encouraging as the YouTube tutorial person said that the Reading should be over 13 k ohms. The multimeter reading that I got for all six of my MOSFETs was around 9.5 k, ohms so does this mean they are possibly be on there way out?.

Also I am looking to replace the MOSFETs for new ones I’ve tried looking online but I’m stuck with the numbers on the MOSFETs. The main number is HY1707 but there is a second row of numbers. Are the second row of numbers important?.

I also heard online that each phase wire has a positive and a negative to it. is this correct? And if so how do I identify which one is + and which one is- ?.

I have provided in the picture what is wrote on each Component on each side of the blue yellow and wire phase wires. I hope this helps. If the mosfets are on there way out can you point me to an online retailer but not Ebay. Thank you. Merry Christmas and happy New Year.

 

[Nealh]

9.5k ohms is absolutely fine for mosfets, ignore a lot all of the utube crap. As long as the fets all read the same you have no worries and replacing them is futile.
All of my fets measure about much the same at 9.5k.

Stuttering can be PAS pick up alignment incorrect or a connection issue with phase or hall wire connection.

3 - 5mm is often to great for disc/sensor distance 1 - 1.5mm max on all mine.
Firstly check the Disc is firmly in place and can't be rotated by hand around the shaft also make sure the sensor is pinched tight and can't be moved. Check to see no magnets are missing.

Check the hub motor to controller connector, it is usually about 10 -12" from the hub follow the cable to the joint on the rear stay and make sure the connector is fully pushed home. The Julet connector usually has a raised etched line which the female side pushes up to. If the connector isn't checked and the hall pins are even 1 - 2mm short of being fully home then you can get the stuttering pick up via an intermittent contact.

Lastly locate the ali box controller and check the phase bullet connections and the hall wire connector for any looseness. If the phases wires are burnt/discoloured then the connection needs remaking/replacing.

 

[Macster58]

Hi thank you for taking the time to read my post. I am currently out with family however tomorrow I will go through what you have said and try it all. I must say I was wary of following advice from YouTube as I always seem to get conflicting results as one guy says one thing whereas another guy will say something else. But I don’t know anybody that knows how to repair electric bike to even anything about them so I had to turn to the online forums but thank you for your advice have a Merry Christmas and I’ll upload my results tomorrow

 

[Nealh]

In the end you have come to right place for good advice.

 

[vfr400]

Too much internet research on sites that just spout rubbish!

The pedal sensor gap should be 1mm. Mosfets are typically 3 at 7k and 3 at 14k, though anything from 6k to 25k is possible.

 

[Macster58]

Too much internet research on sites that just spout rubbish!

The pedal sensor gap should be 1mm. Mosfets are typically 3 at 7k and 3 at 14k, though anything from 6k to 25k is possible.

Too much internet research on sites that just spout rubbish!

The pedal sensor gap should be 1mm. Mosfets are typically 3 at 7k and 3 at 14k, though anything from 6k to 25k is possible.

Hi again just a quick update. I think it’s fixed as I just took it on a couple of mile cycle ride around Brighton and it seems to be fine. I went up and down hills with no problem. I didn’t feel a single glitch I’m very very chuffed indeed thank you again for your help it was much appreciated