GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: Spacey on August 21, 2010, 02:07:31 PM
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So I've just put together my new Magic Pie with the external controller and no matter what setting I put into it using the Usb cable the maximum amps I can get the controller to pull is 15 amps or 700 to 800 watts on my turnigy meter.
I am a bit angry as the software (and advert specs stated), that I could chose between 1 and 50 amps peak with 1 to 30 amps continuous.
Now before anyone asks what battery I have....... I bought the best I could get which are the Headway 12ah 48volt pack (which hold 55volts for ages), these are capable of 100 amps continuos and 160 amps peak. So I am not happy with only getting 700 watts from an advertised 1,000w continuos motor and 15 amps out of a supposedly available 50 amps!
I live in a very hilly area and need the extra amps to get me actually up the hills faster than I could walk backwards lol. So GM how do I release the extra amps, even 30 would be nice?
Or do I have to buy an external controller to get the advertised specs as 15 amps does not do it for me personally. Any ideas people?
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Hey spaceman
Hmm I've sorta discovered the same thing. Not sure if its the internal controller current limitation or the fact that they have been designed for future or optional dual drive use.
The GM 48v battery max continuous discharge is ~35A so I figure thats why.
I'm too scared to even try to run suitable guage phase wire through the axle haha
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I think it's the controller getting extremely hot even at 15 amps that is the problem or why they restricted it. Not happy though as I bought batteries that were capable of delivering constant 100 amps let alone he 30 to 50 amps that I would need for getting up hills.
Am also a little worried about the thickness of the main feed wire coming out of the axle, how many amps can it take?
Will have to do the mod to the controller to allow for higher amps as it's just not strong enough in it's current restricted form. I don't need the speed, it's the torque....measured 680 watts coming home today.....not quite the 1,000 watts that were advertised.
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Well I opened up the external controller and did the mod that bypasses the 15amp limit.
Damn this thing goes like a rocket now, only problem is that I saw 84amps on the meter lol and over 4,000 watts lol :D
So I'm hoping the amp limiter in the software still works sort of and will scale down so that I can use 50 amps. Cooling is going to be the main problem here so I will have to make sure the heatsink gets airflow.
I think it's time to get an external controller that can do 50 amps with a large enough heat sink to cope with the heat.
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I think it's time to get an external controller that can do 50 amps with a large enough heat sink to cope with the heat.
I suggest you organise one very soon, because your external controller is unlikely to last very long at 4,000 Watts!
(http://www.arhservices.co.uk/GoldenMotor/emoticons/everyday_wink_230608.GIF)
Alan
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The light that burns very brightly does not burn for very long ;D
I've connected it to the usb software and set a limit of 40 amps so hopefully that will take the amps down a bit. The 85 amps was going up a huge hill though.
Making a box so that the cooling fins on the controller see some air.
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Making a box so that the cooling fins on the controller see some air.
If you can take some pictures as you go, it would be nice for others to see exactly what's involved.
This was my initial suggestion for fitting the controller outside, but keeping the wires and connectors inside:
(http://goldenmotor.com/SMF/index.php?action=dlattach;topic=2409.0;attach=3092;image) (http://goldenmotor.com/SMF/index.php?topic=2409.msg13522#msg13522)
But it might be possible to open up and reassemble the controller with the box actually sandwiched between the top and bottom casings.
(http://www.arhservices.co.uk/GoldenMotor/emoticons/everyday_think_230608.GIF)
"Thinking outside the box" can sometimes help!
(http://www.arhservices.co.uk/GoldenMotor/emoticons/everyday_shy_230608.GIF)
Alan
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Hi!
I am wondering if the 15A limit is new as indicated in post. Was older versions of the pie less limited / protected?
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Hi Guys,
Maybe you would like to check out my thread on the pie in the mods section.
http://goldenmotor.com/SMF/index.php?topic=2286.0
Spacey I know how you feel, But I managed to get 20 amps out of the external magic controller before the mod. I sent you a P.M of the controller and website I got it from!
Your mod will not work long term so you will need to get a new one and fast as the external magic controller will NOT take more than 20-25 amps for long. You will get stranded somewhere like me, and peddling the pie home without assistance is a real PAIN!
GM are taking the P**S now. They advertise the controller as 30 amps continuous and 50 peak? no way! ;D but for god sake make sure you have 2 torque arms, and strong ones at that or you could be hurt!
The Magic controller is a nice little controller for 20 amps MAX, changing the amps is nice and the regen. But until they offer something that is capable of driving this pie motor I would seriously suggest people look elsewhere for an external controller.
Spacey, isn't it fun at that kind of current though? lol I nearly got thrown several times. Like being on a wild horse! ;D
Spacey just so I'm right, Did you initially purchase the pie with internal or external controller?
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Cheers for the PM with the controller info, will get one as soon as.
Bikemad, funny thing is last night I built exactly the same design as you've posted. I have given it a 30 mile test ride pushing mostly 30 to 35 amps up hills settling to 15 amps as it approaches the rather slow speed limit.
The controller just did not get wRk with the wind flowing over it. I did add some heat paste used for computer CPU coolers inside the case. I think adding some better heatsinks would work better but works nice at the moment. Makes the bike useable and very torquey.
I will put up some photo's when I get back from work.
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Yes, I'm afraid it's true - I set the PIE to max everything with my excellent 48V setup, and couldn't get more than 15.71 amps out of it (max ever).
Having the pie advertised as 1000 watt and having the program look like it works for 30 continous amps of power is really very upsetting. False advertising anyone? >:(
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Yes, I'm afraid it's true - I set the PIE to max everything with my excellent 48V setup, and couldn't get more than 15.71 amps out of it (max ever).
Having the pie advertised as 1000 watt and having the program look like it works for 30 continous amps of power is really very upsetting. False advertising anyone? >:(
Hi Magneto,
Yes indeed, upsetting!
I know they may have had problems with over heating, but then they should advertise it as a 750 watt motor!
The same for the magic controller!
I'm glad in a way that I wasn't the only one to discover the problem. Did GM honestly think they could get away with it forever?
Now that the word is out, I hope they do something about it. Either sell the (Internal controller pie) as a 750 watt motor, or improve the cooling!
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Just done another 25 miles with the nodded GM 15amp controller which now chucks out 70 amp peak but mainly 35 amps up hills. Still going strong but am waiting for it to fail. Bike is a little faster as I had the programmer set to 24 volts.
I think you can only change one parameter at a time with the software, then save....disconnect....get config....change another parameter etc....
Controller's heat sink is in the wind flow of the open air and just doesn't get warm. A bit of heat paste on the fet's is probably helping as well. Will still get the controller that Scorpion has recommended though.
Scorpion, is the Magic Pie any faster with the new controller?
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hi Spacey,
where are you from?
No the pie is not any faster with the new controller. :'( But that's because of the way it's wound. You could have it wound for more speed, but at the expense of some torque.
My friend pat's motor will go around 30-32 max on level ground. Wind in back. He would win a race on the straight, But I leave him standing on hills. So, where I live, with some steep hills I think the high torque pie is faster in the long run, because when Pat hits a strong head wind he will slow to around 25-27 sometimes less, and 10-14 on some steep hills where I can climb @ 18-22mph. Even he said he would prefer my motor.
I think this is the only 1 real disadvantage of direct drive motors. The geared motors like the BMC V2, V3 have internal gears and are smaller, lighter and can go a good bit faster on 48V and still have good torque, Though I have no experience with geared motors to compare to the pie! Geared motors have no regen and gears can fail, though that's mainly because people run them @over twice the recommended power!
I would Like to compare the BMC V2 speed, and V3 version to the pie @ the same voltages and watts!
Spacey, I really think your controller will die, it's just a matter of time! It's running well above what it was designed to do, Getting hot or not!
I have noticed there is not the same kick of acceleration with the new controller, It takes off fast, but not as aggressive as with the modded magic controller. Maybe that's because there is not the same level of high peaks going through it? Either way it's still a beast!
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I think what has happened was a huge order needed to get filled and took a lot of controller away, so the Magic controller that were made up for the mini motors are now being thrown into the kits.
I cant say for certain, but the indications seem to be related to this. 15 amps is the GM suggested limit for the mini motors and the magic controller is used for the minimotor kits.
GM shouldn't sell mini motor with a controllers set at 30 amps out of the box and what of those who don't purchase the usb setting cable?
This reason makes sense to me. 'The 10 watt resistor wire maybe too much I tested it on a cheap DMM and an old 12ah SLA I got just over 15 amps. maybe move down to the 5 watt resistor wire and make it longer.
One guy used a paper clip and reported the shunt was too big, another person used single strands of copper and kept adding them over the sunt until he got the current exactly.
I think copper is wrong for the job.
cheers.
.
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Another suggestion is to shorten the existing shunt by a little at a time.
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This seems the right stuff but I cant find any to buy on retail..
RW 45 NICKEL 45% COPPER 55%
A copper-nickel alloy used mainly for its medium range electrical resisitivity and very low temperature-coefficient of resistance.
A Nickel-Copper alloy wire used mainly for its medium range electrical resistivity and very low temperature-coefficient of resistance.Applications include power resistors, shunts, thermocouples and wire-wound precision resistors having operating temperatures up to 400°C.
You need something that doesn't change resistance much when it gets hot, look for high temp co efficiency,
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Hello,
It's been a while since I run my mini motor at 444W/666W (10S 37V Lipo battery and magic controller at 12A continuous and 18A peak).
This provides me 20mph on a 20'' wheel but I need more. I want the Magic Pie.
I have some questions about the pie:
1) Why do you use the magic controller (external) with the pie? Isn't the internal controller good enough?
2) If I should use the external controller like you guys do, how can I change it to give me more than 15A?
3) Do you know something more about the Magic Pie II? When will it be available?
Thanks a lot guys!
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Hello,
It's been a while since I run my mini motor at 444W/666W (10S 37V Lipo battery and magic controller at 12A continuous and 18A peak).
This provides me 20mph on a 20'' wheel but I need more. I want the Magic Pie.
I have some questions about the pie:
1) Why do you use the magic controller (external) with the pie? Isn't the internal controller good enough?
2) If I should use the external controller like you guys do, how can I change it to give me more than 15A?
3) Do you know something more about the Magic Pie II? When will it be available?
Thanks a lot guys!
Hi luisgouveia
The Magic Pie external controller is offered by GM because of customer demand, ( you don't have to use GM's external magic controller) for people who want more power for climbing hills or acceleration. Or top speed, by using a higher battery voltage, 60 volts or 72 volts the Higher voltage will give you a higher top speed. Current gives you torque. @48-52 volts you will get a max speed of 25mph from the pie!
I would not recommend modifying the controller in any way as I have fried 2 of them by doing so. If you want more power ( more than 700-800 watts) and the ability to use more than 52 volts, then you need a different controller from a different manufacturer.
To the best of my knowledge, the pie II will be available sometime in 2012!
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1) Why do you use the magic controller (external) with the pie? Isn't the internal controller good enough?
The magic controller came out before the Magic Pie.
Before the pie, the motor did not have a built in controller.
They had an old version of the controller that seemed to have
been problematic. On the plus side, the older controllers did
have the wires coming out of the end instead of out of the face
(WTF G.M.?) so it fit in the frame a little better.
I upgraded my controller to the magic controller and am still
using it on my 500W wheel.
The 1KW Magic Pie bike is together except for the batteries.
I just requested an invoice from Echo
for two 24V15AH packs to hook in series for my Magic Pie.
I want to mount one on each side along the rear frame to balance
the bike and keep the center of gravity (CG) as low as possible.
I am still trying to find out about balancing both packs,
tho I suppose two 24V chargers will not kill me instead of a 48V
charger.