Need help with diagnosis of dead Riding Times Z8!

[drobins9]

Hello- I bought my son a Riding Times Z8 electric bike for Christmas. It lasted 100 or so miles before it went dead and, shockingly, the support has been virtually nonexistent. I have been trying to make my way through resources to understand what is going on and what I need to do. I would greatly appreciate any help or guidance.

The bike does not power up. It is completely dead.

Batteries: The two 48V batteries are fully charged, the electronic gauges work on them, and they output about 50V.

Battery Equalizer: Both batteries are wired into a unit that merges the power. The output on the unit is also about 50V, so power is making it to the system.

Controller: The controller is labelled KCHQ RD-Z8, and seems to be a pretty standard one.

• When I connect a negative multi-meter terminal to the negative battery input, the positive multi-meter terminal reads 8.58-8.59 kOhms of resistance on each of the 3 motor phase wires.
• When I connect a negative multi-meter terminal to the positive battery input, the positive multi-meter terminal reads no resistance/continuity on each of the 3 motor phase wires.
• When I connect a positive multi-meter terminal to the positive battery input, the negative multi-meter terminal shows overload resistance on each of the 3 motor phase wires.
• When I connect a positive multi-meter terminal to the negative battery input, the negative multi-meter terminal reads 8.58-8.59 kOhms of resistance on each of the 3 motor phases.

I've searched around a lot, and I am not clear why the order of the multi-meter terminals matters (it seems to be continuity is continuity, regardless of the order of the terminals), or whether this suggests have a problem.

Motor: There is complete continuity / 0.00 resistance across any combination of the 3 motor terminals. The bicycle moves smoothly. If I connect two of the unpowered motor terminals, it gets more difficult to move.

I contacted the company, and after a few weeks, they sent me a new controller. I hooked it up and when I turned it on, there was a "pop" where the controller connects to the battery equalizer. There is some noticeable black marking on the negative input cable of the controller. With everything connected (after that), the bike was completely dead.

I have tried connecting only power to the controller and the 5-wire connector to the digital display to see if it would power on (thinking if there are issues or shorts in other places, at least the display might turn on if it is the only thing connected), and it does not.

At this point, I am unsure if my controller was "blown" from whatever problem might be in the bike and made have made it pop when I connected the new one. I am unsure what to check next. The company (Riding Times) has not responded to my inquiries for the last few weeks. I have been looking through online resources, but am confused on where to go next.

Could anyone possible provide a little guidance?

Thank you so much!

 

[Annieolnie]

I'm afraid you may have shorted out your new controller. If I had to venture a guess, I would blame the battery blender. People do have trouble with those. If there is a way you can get them to send you another controller and you can set it up without the blender and just run one battery at a time, that would be my best thought. You could test the rest of the bike for continuity, but it sounds like the blender is putting you in an over voltage situation.There are a number of YouTube videos on testing controllers and you obviously have some skills, so you could start there, but it sounds like the voltage blew out a number of your brand new mosfets.