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No power. Lights don't come on

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I have the original Sondors  fat tire 3 speed thumb controller bike. No upgrades.

My charger failed and shorted out unknown to me. The charger plug wire shorted out when I plugged it in to charge without being plugged into the wall. It sparked at the plug  before it was fully inserted. When I turned the bike on the lights did not come on. No power anywhere. I do not have the LCD screen. I pulled the cap off the throttle and tried shorting the switch wires. No power No lights.

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I doubt your charger failed or has / did short out.  The charger will not charge when connected in the reverse order. Turn you battery rocker to off. Plug the charger into the battery, then connect it to your 110v outlet. Make sure your battery is fully seated and locked into the cradle. After charging and verifying full charge using the led’s on the canister battery top (one red the rest green) turn the rocker switch on and try and power on the bike.  Your Fat Sondors must have been bought used because none were produced with a 3 speed freewheel. That is considered the first upgrade that new owners did to their bikes to give them more utility.




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Thank you for the quick response. I will try to make it a bit more clear. I was a Navy ET 50 years ago.  I do know very basic electricity functions.

I bough this new. It is the basic  fat tire with the springer front as the only  factory add on.  It has a 3 speed throttle and no mechanical gearing.  It has the  bullet shaped  battery if that matters. I just looked at the sondors  parts page.  It could be the 2015 model.  the controller model:  SD36ZWSR-LD01 . I can not find the serial number  on the head. If it's there it is painted out and I would have to  scrape paint.

When I plugged the  charger cord into the battery there was a very large spark. I had forgotten to turn off the power switch.  The battery had a partial charge with only a couple of miles of riding on it.  The charger was not plugged into the wall. I don't see how it could have hurt the controller unless it was the inductive kick.

I was going to ride for a while, so I wanted to top it off.  The  charger cord had failed at the plug so I soldered a replacement plug as a repair. I charged it this way twice while I was looking for a new heavy duty cord.  I did not make a very good repair.  The tape I put on the wiring had failed and shorted together.  

 I checked battery voltage and it is 33.9 volts.  The switch on the handlebar works. I tested it with a  multimeter.   

Should I get a new controller?  And a throttle switch maybe?

Sondors Controller wiring.jpg

Sondors Controller.jpg

Edited by Ray Cornelius
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If you bought this bike new you’ve changed the battery. Your battery connectors are not Sondors. Make sure you turn the battery switch off with the charger unplugged from any power source. Connect the charger to the battery. Then plug the charger into the surge protector. Then connect the surge protector to the wall outlet. The charger light will go green momentarily, then to red signifying it’s charging. When the battery has finished a full charge, the charger will again turn green. Disconnect in the reverse order. 
The lights on the paddle thumb  throttle are to indicate battery reserve, not 3 speeds. There is a battery fuse in the base of the battery under a screw cap.  I’d check it before I’d consider replacing the controller. You also have to make sure the battery is securely attached to its cradle as it produces a loudness click when locked in place. The throttle could be inop. I’m pretty sure it’s a low voltage signal device and I have switched to a new aftermarket ver on my Original.  Your White (Alabaster actually) is a second generation Kickstarter Campaign Custom, as designated when that campaign was offered. This was the day I assembled this one. I order this Sondors with 26 X 4.0 tires, Aluminum Frame and Suspension Fork, and that made it a Custom Narrow. 



As you can see from the 36V battery percentage chart 33.9 volts is about 33% of full charge and well ABOVE the Batteries & Controllers BMS, battery cut off voltage (around 31V) but well BELOW your perceived battery level. Your Sondors battery charger is set to charge your canister battery to 42V @ Full 100% charge. But 33/34V should power the bike just fine, just not a fast as a fully charged battery. 
I can’t tell you the value of that fuse, since I was not using the 36V canister battery, I sent my fuse to a stranded Sondors owner in Florida after a hurricane. 
If you have made sure that power is not getting to the throttle (my custom narrow still uses the original 3 light; green, yellow, red, lcd’s and the power button below the paddle lever, and only the yellow and red led’s still light. .... but on the other bike’s, original throttle, no led’s would  light but that’s not why I replaced it.  And if you know power is getting to the Controller by using your multimeter, and the pins in the battery cradle base and the detents that receive them in the battery base are both secure with no melted plastic around their mounting hardware (one, not uncommon problem with the canister batteries is that if the battery is not securely snapped into the cradle with an audible snap of the locking system, a poor connection might be in effect and resulting in high amperage drain that has been known to melt power wires in the battery or cradle bases. This is usually evident if plastic, melting down there, is visible. 



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  • 1 year later...

My c hargers light will not come on, nor is the fan startimg on the charger. Is this a common problem that the charger shorts out or something?  I live in chicago and need my bike to get to work as I am so broke I cannot afford public transportation at the moment. Is there any way to check to see what is wrong with the charger, ot is there a way to fix the charger? I really need help here, as I cannot afford  the seventy something dollars the charger costs. Any ideas are welcome.. I have the fold x and the x as well.


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No, not common nor completely unheard of. 
Sure, with a multimeter you can check the output voltage but that sounds like it will be 0 if there is no lights or fan. You can also check the wall outlet to make sure current is getting to the charger.
The exact chargers are available online at pretty low prices. Try a google search by control name and output voltage as listed on the Charger, and using the search function, here on the Forum. Another member has posted a link, pretty recently. But be careful with the probes on the multimeter not to short anything,



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You don't need a high end multi-meter for this troubleshooting.  Amazon or Walmart have them for around $12:



If you are going to own an ebike and troubleshoot it yourself, it's a good investment.

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