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Hello everyone, I currently have an Original Sondors Fat Tire bike from 2016 (I believe).  I purchased it from a friend who had performed some upgrades to it.

As the bike sits today:

  • Luna Storm 48v 20ah Battery
  • Controller Model KT36/48ZWSRMD-SLSLD02 Rated for DC 36v or 48v, Rated current 12A Maximum current 25+-1A (Assuming this is from Luna as well)
  • Original Motor Bafang RMG06 36v 350W(10) 26-1-1508195560-6
  • LCD Luna LCD Dashboard for Sondors KT-LCD3

Took the bike out for a ride the other day after it had been sitting in the garage for about a month and received a motor hall connection error on my LCD screen. Tried the usual unplugging the connection under the chainstay and making sure I had charged the battery. I'm wondering if I am able to replace the cable coming out of my motor (if that is the culprit) or if I need to replace the motor altogether. If that is the case, would anyone recommend I upgrade to a 48v motor? Would it make a difference/ work with my existing upgrades? I'm new to the forum and Ebike scene in general so I appreciate any help. Thanks!

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Well Lane, without any performance or anomaly information, from your last successful ride, (any unauthorized use possible?) I wouldn't pick the Motor or Motor Cable as my first guess at trouble shooting as the culprit. If you are sure there are no damaged pins in the motor cable Higo connector and that it is plugged together ALL THE WAY, controllers are much more likely to be suspect because motor failures are very rare (unless abused or a lot of water incursion, which raises the possibility),and controller failures are pretty common. What’s puzzeling, is why the problem suddenly surfaced if the bike was just sitting.  The motor cable is, for the most part, not replaceable. Sourcing a cable might be problematic and wiring/soldering all 9 connections would be beyond the skill level of most Sondors owners.  The stock replacment motors are realtivly inexpensive.

 You already have a 48v Motor serendipitously rated @ 350 Watts. Your original motor will run at 52V quite happily as long as you don’t try climbing the hill to Coit Tower repeadly without pedaling. Motor manufactures rate their motors at whatever value benefits sales. For instance, the Rad Rover 750watt Motor is actually zackly the same as our 500watt issuses. And your motor is the same motor that’s rated to 250watts for the European market. This is where I buy my Bafang Motors.They are the likeliest supplier to be able to have a motor cable. https://eunorauebike.aliexpress.com/store/904105?spm=a2g0s.9042647.0.0.32334c4dHUCxnp

Based on your assesment, just to check the motor for damage inside the case you’ll have to destroy the single speed freewheel to remove it to open up the motor case, so buying a spare/new freewheel, regardless it you find motor damage or not because if you do find damage you’ll need a new freewheel for the new motor.  The only worthwhile motor upgrade would be the 750watt Bafang but and you already have  a 48  battery to power it but  you’ll need to upgrade to the  35Amp controller because both the motor and controller have a larger Higo connector. 

Any aftermarket 25Amp hot rod controller, from the three US based Sondors suppliers will work. I’d contact Boltonbikes.com for a replacment. Luna is not presently stocking the 25Amp.  Tell Kyle Reddy Kilowatt sent you.




By the way, Ive flown my Cannondale H400 city bike to San Carlos airport in my Grumman Aircraft, from Texas, to visit friends in BelMateo and spent my days exploring all of the area by bike,E516CE09-176C-4DCF-9D35-4BEB140EFDE1.jpeg.8cff802b7747db9abfa52f8721b70a67.jpeg from riding over the hill behind San Mateo to Half Moon Bay,  Across the Golden Gate to Sausalito and the Marin Headlands and all over San Fran. 


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Thank you for your reply @Reddy Kilowatt! To answer a few of your comments, There has been no unauthorized use, everything prior to the month sitting was on the street.  Water damage is most likely not the cause unless it happened prior to my purchasing, which I find unlikely due to the fact that the bike was running fine for 7 months before it sat for 1 in the garage (controlled environment).

Correct me if I am wrong but these are the steps I will take to try and find a fix

  1. Doublecheck Higo connection.
  2. Purchase a new controller and test.
  3. If 2 doesn't work, take off single speed freewheel and check for motor damage.
  4. Purchase new single speed freewheel, and new motor if damage is found.

Thanks for the help! I really need to get up to Golden Gate and Sausalito once I get this thing fixed. I'm situated about 7 mins from the 92 to Half Moon bay. 

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Lane I’d say that’s the likeliest trouble shooting procedures. There is a slight possibility of a BAD LCD. Before you tear into the motor let me see if I can get another owner in your area test your bike with their LCD to eliminate it. I reread you first post and realize you already have a 48v battery. That makes purchasing a 750watt Bafang a more viable option, if you determine the 350watt is troubled, but still requires the 35anp Controler. That’s where my Dailey Driver is at and now over 11,300 miles. It’s realtivly Bullet Proof. 

I’m really disappointed my friends moved from San Mateo. That whole area is so cycling friendly and of course the bicycle cars on CalTran makes getting into the heart of the city a treat. I can access all the light rail in the DFW Metrostool for a day pass of 3 bucks making getting anywhere in the vast area a pleasure and there is the Denton Katy Trailway that makes riding from my house  into all my regular haunts, much safer than mingling with the unfriendly motorist on all the  city streets keeping them to only 30% of my regular routes. 




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@Reddy Kilowatt do you know if there is any solution to a partially bent wheel stud/ lug bolt that hold the rear wheel in place? When I purchased this bike there was no rubber cap on the motor cable side and the end of the bolt was bent ever so slightly outwards making removal of the lug nut virtually impossible without stripping the threads of both. I have attempted to remove the lug before, but when I felt it getting very tight to turn I stopped fearing I would damage the wheel stud.

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The Plot Thickens. I think the chances that a wire is damaged in the motor cable, now surfaces as the probable cause of your problem.  I’ve never seen a Bafang Motor axel/spindles replacment offered for sale. Regardless of any other problem that is causing your issue, you’ll need to replace the motor. I don’t see the exact replacement at either main Aliexpress supplier but it might be superseded. Try messaging the motor suppliers and asking about a direct replacment. 

Youve also got the option, at this point, in upgrading to a Sondors XS mechanically. 7 speed, Bafang 750 Watt and 35Amp controller. There are threads here outlining the whole procedure.  

I also looked here. https://www.aliexpress.com/store/group/Hub-Motor/3562004_512880449.html?spm=2114.12010615.0.0.1e0bd717rSfCtN

So with damage to the right side axel, most likely from falling on that side, you might try manipulating the cable, at the exit point and see if you can initiate any change in the hall sensor error. 





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@Reddy Kilowatt I'm ready to find out the surprise happy ending to this story haha. .  I've done some research and will move forward with the motor swap and controller after I've save up for it.  (I hope when your friends moved from this area they were able to buy a nice big house and some land ;) ) Debating between the 7 speed upgrade or sticking with the single speed. Can't decide. Also need to research if my Luna LCD will be compatible with the new controller and motor. Below I've attached the a picture with the bent axel and the punctured cable after I was able to crank the lug nut off.  



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Lane, The new motor will work with your Luna LCD or any other aftermarket LCD. Sondors’ LCDs have a proprietary communication protocol, so they could charge more $$ for the Sondors version. They only work with the Sondors Controller and are now model specific. There are at least three, 750watt Bafang 8 Fun geared hub replacment motor options that are on the Aliexpress Sites. One like mine is designed for a 7 speed Freewheel. Featured in the conversions featured on the forums upgrade threads. 


Using a single speed freewheel with this motor requires a special freewheel (not like the 350w Bafang freewheel) because the 750watt Bafangs were designed for 7 speed gear clusters. The threaded portion of the motor hub to accept the clusters is longer in the 750 Watt motors.  If you decide on this option I’ll find that Freewheel somewhere buried in a threads here.

There is a newer version motor designed and used in the Sondors XS for a 7 Speed Cassette that doesn’t have threads, rather a splined motor hub body to accept the cassettes design. I’m not sure what hardware would be required to use the cassette hub motor for single speed but I assume some Bike  Conversion Parts and Cog can be fitted that are used for Fixie Bike Conversions. To my knowledge, no one has aptempted that on the Forum. 


So when you get your funds together it’s important to have decided on what gearing option you’ll choose. Although requiring a few more components, a few more dollars and a couple of extra hours of installation time, I’d really suggest installing the gearing, especially where you live. Being able to start in a low gear and travel up thru gears as you accelerate to the small cog, high gear,  shift to a low gear for hills will make riding around San Francisco the ultimate  option. 

All the conversion information is contained on the Forum. Look here https://sondorsforum.com/topic/880-upgrade-750w-bafang-with-7-speed-upgrade/ 

Depiction of Freewheel and Cassette difference: https://www.bikeman.com/bicycle-repair-tech-info/bikeman-tech-info/1640-how-many-gears-can-i-put-on-this-thing






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I should have added that my friends had found homes all over the frigg’n place. First to some acerage in Lovettsville, VA, close to Harper’s Ferry. Then near Winchester VA  @ Holiday Lake. Are you old enough to remember Perfect Circle Piston Rings?


They bought the Original Owners Mansion in Hagerstown Indiana. The Dana Corp bought out Perfect Circle. They sold the house to a group of investors who made it into a Bed & Breakfast. Next they Bought a home on the Front Range of the Rockies, just North of the Airforce Academy @ Perry Park Ranch @ Larkspur Colorado. A lot less land but a hell of a view. 


Thru all these moves, Tad my friend’s office, is in Oakland and he’d commute, for a couple of days every week or two to meet with his staff, but work mostly out of his home office. You couldn’t carry the airline miles he accumulated in a backpack! 

Nice Work If You Can Get It.



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