Replacement controller?
 

Hi all,

I have a good friend who's had an E-bike for a couple of years and has been having intermittent on/off problems. He's been told that it's the 48V controller. However, it could be something else. The bike powers normally whether pedaling or not, but then the boost or power cuts out after a minute or so. This happens after every on - off cycle. I have pictures of the components, I can post later, but first, I would like to hear from someone who has experienced a similar problem and how it was resolved. Our attempts to find a replacement controller have not gone well. However, I'm thinking this may not be the problems based upon my previous life as an electronics technician. There are a lot of sensors that need to work in unison with the controller. Looking to find a schematic as well.

Thanks

A couple of ideas:

What is the battery state of charge? Can you monitor the battery voltage when the failure occurs? This could be just a battery issue.

Most battery maintenance systems have a low-voltage cutoff to protect the battery from deep discharge. I have encountered this when the battery is low near the end of a long ride (or if I forgot to charge it!). It will power the bike, but under heavier load - hills, etc. - the voltage drops, the cutoff shuts down the pack and the bike goes dead. After power-cycling the battery the BMS resets because the voltage has recovered back to above cut-off and the bike will operate again until another heavy load. This is similar to what you describe as happening after each on-off cycle

This could also be a thermal protection system in the controller or motor, but I doubt that it would heat up sufficiently in only a couple minutes, and then quickly cool to immediately reset after a power cycle.

Since the system resets after a power cycle it unlikely to be an intermittent connection or wiring failure.

Controllers will vary depending on the displays and motor types, so more info is needed to help find a replacement controller. Do a google search for ebike controllers and /or wiring - it will produce various schematics that might match the system.

I have found eBikeling.com to be a good source for "generic" ebike components, and their service is good.

Like said above batteries have a computer in them and will disable the battery on low voltage. Sometimes batteries get a dead cell or two causing this to happen.

Also check all the connectors to make sure all the fittings are solid, not corroded and that nothing is shorting out.

Not much to go on, as far as info. As a tech, you know more info is needed. Make and model of bike? DOes it have throttle or pedal assist only.

What's the failure? Bike shuts off. Display goes dead? Does the bike retstart after a minute? When it fails, can you lift the wheel and run it on throttle? What's the voltage on the battery after it's charged?