Peak died (short in controller?)

adcockj

Member
I have a Magnum Peak, several years old with 3000 miles on it, that just died. I rode it yesterday and everything was fine. Today, nothing. When I plug in a battery, it trips the BMS, which will reset itself after leaving it for 10 minutes or so. The voltage on the battery is fine (54.6v), and I've tried a different battery (same manufacturer). I measured the contacts at the battery input connector, and it reads a dead short. If I unplug the display and read at the battery input connector, it still reads a short. If I unplug the connector from battery input cable to the controller, then the battery input connector reads open, which it should. I suspect a bad controller, but I don't know for sure it that's the problem.

I also have a Magnum Metro, and measuring across the battery input connector reads about 20 M-ohms, which sounds about right.

Is there anything else I should check before just replacing the controller? I like the bike overall, so would prefer getting it back into operation...though I might be open to replacing the controller/display/etc with aftermarket stuff assuming I can figure out parts compatible with the DAS-Kit 48v 500w hub motor.
 

jkvt

Member
Out of curiosity, did you get this straightened out? I have an NCM Moscow Plus, which is really similar and I'm just wondering what this ended up being and what you did in case I run into this down the road. The controller down near the bottom of the bike has always made me nervous.
 

adcockj

Member
Out of curiosity, did you get this straightened out? I have an NCM Moscow Plus, which is really similar and I'm just wondering what this ended up being and what you did in case I run into this down the road. The controller down near the bottom of the bike has always made me nervous.
I wasn't excited about taking the Peak to the bike shop, since I figured it would be expensive for diagnosis, labor, and parts...and I'd end up with a bike that still had "proprietary" parts on it. So I decided to just pull out the DAS-KIT stuff and do my own with parts I could work on (and program).
The motor itself tested OK on a little ebike tester. But the cadence sensor and throttle tested bad, and I didn't know about the controller. The brake motor cut-outs were also OK.

The motor is just a basic Bafang motor. So I ordered the other parts from ebikes.ca (Grin Tech). These included a new 20a controller, cadence sensor, programmable display, and throttle. It did take a little rewiring/adapting, but nothing particularly difficult/technical. If you haven't looked at Grin's website, it's worth your time -- these guys really know their stuff, and there's LOTS of information on their site.

I couldn't be more pleased! It runs great, and I can program it with as many assist levels as I want based on specific speed %, or a kind of "soft cruise" which increases/decreases assist smoothly around speed levels -- feels REALLY good. In fact, I could also buy a torque-sensing bottom bracket from them (I didn't) and program the Peak as either torque-sensing or cadence-sensing bike whenever I want.

In the end, I figure that I haven't spent any more than it would have ended up costing me to have it fixed by a shop and I now have a system that I understand better and can repair myself.
 
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jkvt

Member
This is a great summary! Thanks very much! So you're saying the Das Kit motor you have is really Bafang, so you were able to save the motor and change out the remaining electronics? Can't stress enough how helpful what you wrote here is. I hope I won't have to do any significant work to the bike anytime soon but it's great to hear how you did this.
 

adcockj

Member
That is correct. Unless your motor is different somehow (and I doubt it), it's a standard Bafang motor. I got the 20a Grinfineon controller from ebikes.ca and it can come with the Z910 plug...the pinouts for the phase and hall effect wires are Bafang-standard. You'd also need their CA3-WP programmable display to go with it. I used the existing brake cut-outs and a throttle I had in a bin, but bought their cadence sensor. I also bought (on Amazon) some JST-SM plugs for signals (throttle & brake cut-out connections) and some XT-60s for power, which made wiring mods easy.

If you ever decide to swap the DAS-KIT stuff out for Grin stuff, you'll be amazed at much smoother the bike rides (and a little more powerful as well, since the Grinfineon is 20a as opposed to the DAS-KIT contoller's 18a).

It did take me awhile to get the settings right, including some help from amberwolf over on another forum. If you take the plunge, let me know and I can send you the setting I use.
 
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jkvt

Member
For sure! This is great info. I'm thinking maybe a project for next winter maybe, so if I end up with down time it doesn't cut into my riding time too much. I have a friend with a Juiced bike and it has a Bafang setup and it's a lot smoother like you say you found with yours now. It would be good to have all those nice speed control settings. Thinking about it more, maybe I'll jump on it sooner than next winter. I'll let you know if I head down this route. Thanks again!