Help, A2B Metro just stopped working

[robbiesd]

A while back I bought a Metro w/no battery. I bought a used "B" battery and rode it for a couple of months. I wanted to get more speed and range so I bought a 48v 20 AH "Okoman" battery off eBay, mounted it on the book rack and wired it the "A" position of the switch thinking I would get more speed and distance. Since doing this I've ridden the bike about 15-20 times with no issues however the speed and range was no greater than with the 36v 13AH factory battery which I've since sold. First time ridding it in three days, it was fine that last time I used it. Yesterday I started off, all seemed perfectly normal and then in about 15' of movement it just stopped. I released and twisted the throttle again, the motor acted like it wanted to turn but there was a stick thru the spokes so to speak, the motor made a bit of a clunk sound, I could feel the torque of it wanting to spin but it didn't. I turned it on and off, pulled and released the brakes but nothing changed. Checking things over for a loose connections or something else wrong and after a couple more tries the battery lights failed to come on and twisting the throttle no longer did anything. Today I've used a MM, the brake switches are working fine. The battery reads 54v. I moved the battery connector to the "B" position on the switch module, nothing changed, the fuse on the switch module is good. I measured voltage at the chain stay motor connector, its also 54v there.
Anyone have any ideas what could have happened? Did I burn up the motor or the controller? How would I test for this?

 

[HK12K]

Sadly you purchased a junk pack.

Nothing legit about Okoman.

May or may not be related to the failure at hand, but it wouldn't surprise me.

 

[amberwolf]

48v 20 AH "Okoman" battery
<snip>
36v 13AH factory battery

First question: Was this particular version of the system designed also to operate with a 48v battery? If not, it is possible that at some point a component not rated for that voltage has failed. That's usually inside the controller, and could be it's low voltage power supply or could be it's FETs.

If the motor is hard to turn by hand when off ground, or feels "coggy", like it clicks from postion to position, it could be blown FETs.



FWIW, another potential issue when changing voltage of a system is that it will have more watts for the same current limit (which is typically the only limiting a controller can do, it doesn't "know" how many watts there are). So the motor may heat up more, and if this is one of the UltraMotors with the ocntrolelr built into it, the controller will also then heat up more. Over time, heat affects components, and is also a potential cause of failures.

 

[robbiesd]

Thanks amberwolf,
Yes, with the wheel off the ground and the power off, the wheel does feel coggy when rotated by hand, although not hard to turn but not free spinning either. The bike is designed for 36v so it seems you are likely correct.

 

[amberwolf]

The good news is you can replace the controller with a generic external one, but it's a PITA if it's like the typical Ultramotor, because you have to unlace half the wheel to get inside it to take the old one out and then run phase and hall wires thru the axle, in place of all the existing axle wiring (whcih comes out with the dead controller).

You can see this thread, or several others on the Ultramotor and various A2B's, for how to do that.


The built in display/etc wont' work anymore, and you'll have to figure out which wires in the cable to the motor are your 5v, ground, and throttle, and if you have PAS that wont' work unless your new controller has the ability to work with that specific PAS sensor (or you change it to one that it can handle), or you add something like the Cycle Analyst v3 that can take various kinds of input and generate a throttle signal based on that.

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