Author Topic: Golden motor performance issues  (Read 5095 times)

Offline magicaffair

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Golden motor performance issues
« on: August 29, 2012, 10:31:13 PM »
Hi all,
I've just bought a bike with a 1000w Magic Pie kit built on, and a 48v 12ah golden motor battery pack. It has had a golden motor external controller fitted after the internal one stopped working after a harsh winter. Upon riding it, the battery lost power quickly and the bike juddered terribly when going up hills. I presumed it didn't have much charge. I have placed on charge now to see two red lights on the charger (even though it says red/yellow means charging?? the fan is kicking in on charger, and everyone on here seems to think this is what should be happening (2 red lights) so I will leave it for a bit, is this normal?) 

The new external controller is set to factory spec and not very fast (18mph unassisted) where can I get a cable to programme the controller? Is it easy? Sorry to ask so much I'm a newbie with Magic Pie and it's a minefield of info out there... this site seems to have straight talkers :-)

Offline atcspaul

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Re: Golden motor performance issues
« Reply #1 on: August 30, 2012, 12:07:33 AM »
i thought mine was messed up to. however 2 red lights is what it does, if battery really low it will take about 4.5 hours to charge and the fan will turn off and you will have one red light and one green light saying charged and ready to go

Offline magicaffair

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Re: Golden motor performance issues
« Reply #2 on: August 30, 2012, 05:45:12 PM »
thanks, and yes got it charged. But now I have a new problem ??? Motor is very juddery at low speeds and makes a groaning sound until I get going fully... and when I do I can only achieve 15-18mph full throttle... it feels gutless... the internal controller crapped out so the chap I got it from wired an external GM controller under the seatpost... I've checked all the wires and they seem correct according to the config sheet I found online for the controller. I'm wondering if there's a problem with a hall sensor as I can't throttle from standstill (bike needs to be rolling before motor kicks in) V frustrating I have a Magic Pie 2 with 48v 12ah GM battery... the battery has charged in 4.5 hours and still pulling after 5 mile run around block.. just bloody slowly?!?!

Can anyone help or had this problem... juddery and noisey til i'm going, then low top speed. I'm wondering if the controller came programmed to limited speed or something? I don't have a usb cable and can't seem to find one in uk anywhere, if this is the problem?? You guys here seem to know your stuff, so I'm hoping there's a saviour out there... I used to have a 500w 15ah kit which kicked arse (27mph) but bike was stolen  :( always wanted Magic Pie now i'm gutted!

Offline truly_bent

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Re: Golden motor performance issues
« Reply #3 on: August 31, 2012, 12:34:08 AM »
Can't offer much as I don't run GM controllers but, some things are common to most controllers.

If you're referring to the BAC-281 external controller, it falls back to sensorless mode in the event of a faulty hall effect input sequence. Nice feature. I didn't see anything in the manual which tells us how long it takes to switch back into hall effect mode if the proper input sequence resumes. This might account for acceleration jitters if there was an intermittent signal break. That might be an indication of faulty wiring. Check pinch and flex points.

I don't have much faith in that solution actually, but it wouldn't hurt to check continuity in whichever wires you can access at both ends. Of course, if it's an intermittent fault, you pretty much have 50:50 odds of not seeing the break.

I'm stuck on the idea of a misfire though. Just sounds that way from your description. If one of your phases wasn't firing or firing intermittently, it would be running at 2/3 power (= lower top end speed) and would certainly feel more jittery in the lower rpm range. The assumption then is, that the hall effect wires are fine and the controller isn't using back EMF (sensorless mode) to time the sequence. Presumably, if the controller were expecting a back EMF pulse and it missed one, it would be smart enough to call a fault right away.

There could be several reasons for the loss of a phase, a fried FET or two perhaps, but all of them will have to be chased down to the board level. You might get lucky and spot something obvious, but without the electrical schematic (proprietary), the job might be best left to an authorized pro (okay, probably cheaper to buy a new one).
 
Personally, I don't have the time or the inclination to reverse engineer one of GM's boards, but you may.

I don't use 'em anyway. ;)
Jeff
Burley Canto recumbent w/ MP II, Lyen 18FET controller, 48V 20AH LiFeP04, Cycle Analyst, and 4 pounds of zip-ties

Offline Kirk

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Re: Golden motor performance issues
« Reply #4 on: September 10, 2012, 01:34:41 PM »
I don't have much faith in GM controllers anymore. Love the motors though. It sounds like a Hall sensor or sensor wire might be faulty causing low performance and cogging at low RPM. The controller might not be catching it and not going into sensorless (sic) mode. Ed Lyen has a really nice controller/throttle/motor tester, that can find the fault. Contact him thru his website http://lyen.com/ there is a video on YouTube showing how it works also.
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