Fat Tire Electric Bike Has No Power. Trouble Shooting and Diagnostics

Fat Tire Electric Bike Has No Power. Trouble Shooting and Diagnostics

June 26, 2022

Here at Fat Tire Bikes, we have never not been able to fix an e-bike, knock on wood… And there's no reason why you shouldn't either. The worst-case scenario is you just replace the core parts.

There are mainly three core parts to a bike that can go wrong with your Fat Tire eBike. 

  • battery
  • controller
  • motor 

You have 3 secondary items that come off of the three main parts that can have have issues.

  • throttle
  • display
  • wiring/cabling

So essentially, there are six things that could go wrong. But if you just go one by one and rule each one out, you'll figure out what's going on with your e-bike. 

The first thing we are going to check is the power going to the bike. The first thing we check for this is your battery. Is your Battery working? Are you able to turn it on and off? So take the battery off. Are you able to turn it on or off? Okay. If it turns on, okay, let's go to the next thing.

Trouble Shooting Components

Check all your wire connections. Check every single connection and see if it's tight. Unplug it. Take a look at all the pins. See if any of the pins are broken, bent, or missing. It happens. After you know that all connections are good, go back to the battery. Just because it turns on, maybe it's not making a good connection to your cradle. Check your cradle. Are all the pins there working good? Do they all look good? Do they look burnt? Sometimes these pins, every time you take this on and off, it could create a spark. And if you do enough sparks, you'll ruin your connection. You have to file it down or put a new connector on there. So take a look at those. Do they all look good? And every battery may look different, but it's the same idea.

If everything you did above looks good lets, take a volt meter to the battery. Make sure it's putting out the proper voltage. 48 volt batteries should be putting out between 41 volts, that's the very lowest. I would say if it's fully charged, it should be putting out at least 53 volts minimum. 54 volts and a little bit over if it's fully charged. 52 volt battery should be putting out about 58 volts. 58.8 if it's fully charged and it's brand new cells. 36 volt battery should be putting out about 42 volts. So if it's putting out that voltage, then you know the battery's good.

Check all your connectors there. We've seen this so many times, one of those tabs will be broken or bent or just corroded. It's been sparked too many times and it just needs to be cleaned or replaced.

If your bike has a display check the display. Are you getting any warning lights? Are all the lights lighting up correctly?

Replacing Parts

If you are still not able to find the issue we can start replacing parts, start with the cheapest replacements first. I would replace the display first. Find a cheap display, maybe borrow one from somebody and try that one. It could be your controller's fried. You could replace your controller. And finally, you could take apart your motor. If it smells like maple syrup and it just looks dark, you've probably got a burnt-out motor core.

Common Issues

Check every connection. See if there's anything that's been severed. See if there's anything that's been disconnected. See if there are any pins that it's causing an interruption in that connection. I'd say that is probably 80% of all power problems and operation errors. It's just a bad connection or a cable that got severed, or something that's just not making a connection anymore. Whether it's a sensor or anything else.

A common problem is brake sensors are cutting off. And if you have hydraulic disc brakes, there's a good chance that's the culprit right there. Your magnet has probably got misaligned or the magnet fell off, or any number of things. Start by disconnecting your brake cutoffs. If your bike has brake cutoffs, disconnect them. Now, try it. See if your bike works. Doing this will take care of 70% of your problems.

Check your speedometer, make sure that the little magnet is making contact with your speed pickup. Another thing we have seen a lot of is, your little battery cable that comes off of here, where it meets up with the controller on here, that could come disconnected.