Help with Ananda MC5-B0 24V controller

[Johan84]

Hello every1. This sweden calling for help!

I’m trying to fix my sons e-bike that hasn’t been working properly for a while(battery discharged fast after fully charged, sometimes the bike just loses power etc)
To make life easy for me, i just bought a new battery to see if this would help but unfortunately this made it worse.

See pics for old and new battery



I don’t know if the thin wires causes my problem, but when im trying to start the bike via the controlpanel the 2nd lamps blinks continuously. From the maual i dug up, this is an error code for ”over current”? If i put in the old battery again the problem remains.

I’ve made som continuty mesaurements on the controller to see if i could find any shortages, but everything looks fine. I’ve checked that i have 5V on the Hall sensor, checked the brake connectors, cleaned all connectors and now i’m out of ideas

Could it be the controller the has given up? Do you know an alternative controller i can buy and replace?

 

[saneagle]

Sounds like a dodgy MOSFET. With the controller disconnected, measure the resistance between the battery positive wire and each of the phase wires, then repeat for the negative. Each group of three should be identical and in the range somewhere around 7K to 14k. If your meter gives a constant rising or falling result, short the two battery wies and test again with the probes the other way round. you're only looking for the results to be the same, so that's not strictly necessary. You should see the next measurement starting from where the last left off when it's climbing or falling.

The thin wires will be for lights, accessories or something like that. The new wiring just doubles up the connectors for more reliability. If the thin wires were connected to lights, you can solder them onto the new one if you want.

The problem can also be caused by a damaged motor cable so check that too. You can use more or less any controller you want. they all work the same. Some have different features. some have better control systems, so you get a chance to improve the bike. Test the MOSFETs and motor cable first, then worry about which controller.

 

[Johan84]

All MOSFETS gets the same value 14,7k.
I measured the motor cables and there is o,oo ohms between all if them cant be good right?

btw, i unplugged the motorcables and the error code persists when i start..

 

[saneagle]

All MOSFETS gets the same value 14,7k.
I measured the motor cables and there is o,oo ohms between all if them cant be good right?

btw, i unplugged the motorcables and the error code persists when i start..

Not very likely that all three are shorted. It's got to be ten years since I've seen a burn out ebike motor.

The resistance of the phases is around 0.3 Ohm, so a normal cheap multi-meter won't show it. There is a way to measure the resistance by passing current through each pair in turn using a a supply that has current limiting, like a lab bench supply or lipo charger, then measure the voltage drop through the phase and calculate with resistance in Ohms = voltage drop divided by current in amps.

You can get over-current when the motor cable isn't connected properly at the motor. The connector must be right in, then some more, also when the bullet connectors at the controller end aren't tight enough. If one phase loses continuity, the motor jams and the remaining phase draws massive current.

 

[legitjamie10]

Not very likely that all three are shorted. It's got to be ten years since I've seen a burn out ebike motor.

The resistance of the phases is around 0.3 Ohm, so a normal cheap multi-meter won't show it. There is a way to measure the resistance by passing current through each pair in turn using a a supply that has current limiting, like a lab bench supply or lipo charger, then measure the voltage drop through the phase and calculate with resistance in Ohms = voltage drop divided by current in amps.

You can get over-current when the motor cable isn't connected properly at the motor. The connector must be right in, then some more, also when the bullet connectors at the controller end aren't tight enough. If one phase loses continuity, the motor jams and the remaining phase draws massive current.

Well, it has gone through 3 winters that has been all the way down to -10 celcius. And several times it have been so cold that the battery froze down in to the cords and it got stuck and didn’t start!and one time the battery has driven almost 10 kilometres on the blinking battery screen level and I had to “force it” on. So basically it just died when the battery on the display was blinking and I turned it on and off and then it worked, and I did that like 15 times for almost 10 kilometres. The bike has driven through water, forest, snow, dirt, rocks and extreme weather fishing adventures. Im surprised it lasted this long (bike owner) / (son)