750 Watt Motor Teardown & Repair - Polarna M6

[@KaDude2010]

Why not replace the nylon planetary with high carbon gears?

[@danielwhiteman9120]

Hello, found your video searching for a help video. I have a polarna m4 and after many attempts I can't reach customer support...... turned my ebike on after charging and an error code popped up code 21 over current protection ??? Any help would be appreciated or how to reset thanks in advance,Dan

[@ericrandall9286]

Sad to say, but Polarna just wants to sell e-bikes, and customer support is not high on their priority list. I had the same error and opened up the controller access panel and found the insulation tape on the three wires from the controller to the motor had melted from high current and were occasionally shorting. I separated the three power wires, removed melted insulation tape and installed a power plug, which Polarna should have done in the first place. Alternative solution would be to remove melted tape and retape but make sure power wires aren’t right next to each other. Hope this helps!

[@danielwhiteman9120]

Thank you very much I will be on it this evening

[@danielwhiteman9120]

Good morning,I opened the controller panel inspected all the wires and no melting. Two wires had cracked insulation so I taped them. Powered it on while apart and code is still there. Put everything back together and powered it on and same code. I did the factory reset and still there. Can I buy a new controller?

[@ericrandall9286]

The error indicates there is too much current being drawn, which typically would indicate a short circuit-- could be a nicked wire, melted insulation, etc. If nothing is visible, from the controller access panel disconnect the plugs one at a time, and after disconnecting each plug, power on and see if the error still exists. label each plug set for ease of troubleshooting. if after disconnecting one of the circuits, the error goes away, you then need to follow the cable and see what is going on... Obviously don't disconnect the display panel plug... If you still have the problem after going through these steps, you may have a defective battery or BMS (battery management system) card in the battery. Do you know anyone else with a Polarna? If so, try swapping batteries and see if the problem persists with a different battery. If you are still in warranty, ask for a replacement battery. I personally would not buy a new controller or battery until I was positive that was the problem (you could be throwing good money after bad). Oh, one other thing. In the display settings you can change the maximum current draw -- try reducing that number.@@danielwhiteman9120

[@ericrandall9286]

Another possibility is that the power wires going to the motor have shorted where they enter the axle. Examine to see if they got crushed, broken insulation, etc. Is your bike still in warranty?

[@Therockny1]

I will not buy this bike. Recently, I had a problem with the controller, which showed an error on my screen. Despite having a one-year warranty, when I contacted Polarna Ebike, they initially replied but did not offer to replace the controller under warranty. I gave up on this and purchased the controller from the Polarna website in July last year. However, I never received the controller and my attempts to contact them went unanswered. I then bought the controller again, thinking that maybe the first one was sent to the wrong address due to a discount offer email I received. I purchased the second controller in September, but I still have not heard back from the company despite sending multiple emails.

[@nycbullriders2435]

Hey me too. What did you do to fix it? Or just junk the bike?