Much More Powerful Pie Now!!!

[Pwd]

Hello everyone, I came to this thread to ask a question...

I'd like some more torque on my bike and I was wondering if you'd recommend the shunt mod or dual pies. Onces the roads dry up, I will be commuting to work again on my bike until November-ish.
Here is what I've gathered so far..

Shunt mod:
Possible heat issues/larger power consumption
cheap (whats involved beside some solder?)

Dual pie:
better efficiency
very expensive ($495 CAD after tax/shipping)

What would you recommend and why? I've got a GM 48V/12ah battery.

[MonkeyMagic]

Hey pwd !

Good work with your research, you pretty much nailed it right on the head with your query

One member here I've seen has had no issues with his modded controller, but a few I've seen do put a bit of stress on the mosfets inside. I guess it really depended on how much you affected the shunt resistance to fool the controllers comparator.

Personally, I have dual drive - and own the GM12Ah battery same as yourself.

You are right about the current consumption, and I guess really it would be a gamble to mod the controller. So you could risk the health of the controller for more power, but less range - or you could have same if not better hill climbing and overall better efficiency running 2 motors. I also believe modding the controller will affect the regen, so again that could cause issues if that's a feature you would like to use. Anyone with a modded controller without regen issues?

That $495 would perhaps be spent one day on an extra battery anyway because you are chewing threw them with your hungry controller!

2 motors will distribute your bike weight more evenly, and picture one 'high power wheel' (with the modded controller) against 2 hub motors front and back. You could imagine the rear high power motor will want to mono/wheelie the bike opposed to dual drive evenly weighted - the front wheel possibly spinning a bit on take off. The stopping power of dual regen will also be an advantage.

Plus if one wheel fails for some reason you can use the other

Matching wheels You know what cars look like with mag wheels on rear and stock wheels on front... Doesn't look right hehe

I have to wonder about the BMS on the 48v12Ah battery as the cells are individually rated at 10A continous, I'm not actually sure of the peak output of these but I would say it would be near double at least.

Having said that, the 48v12Ah battery technically should put out 30A continous, so running dual drive is okay. The internal controllers peak around 25A so this I feel suits the battery well. The reason I wonder about the BMS is the description on the GM website says otherwise (20A cont. 35A peak).

So modding the controller could be something to consider if your battery could peak higher, remember you won't increase your top speed though.. And if you wanted more range you would buy more batteries and increase your bike weight anyway.

My 2c is go the dual drive, and have peace of mind you are running something you wont have to monitor and possibly die one day when you try and race a car lol

There ya go, a heap of reasons to go dual drive hehe

[Pwd]

Thanks for the insight MonkeyMagic. The dual-pie setup is the better option for sure as far as reliability and efficiency. Seeing as how it would be me daily commuter, I'd rather have the peace of mind. Assuming everything works great for years to come it will be worth it. I'd still like to here anyone's thought's on this.

[Andrew]

Did someone mention dual pies?

Hi PWD,  I've just converted my bike from one rear pie to dual pies and the difference is like night and day. I run it all off one GM 48v/12ah battery too.
look here, scroll down .... http://goldenmotor.com/SMF/index.php?topic=2810.15
Compared to single pie.....
Much much better torque
stronger pull/acceleration
Stronger take-off
Much stronger hill climbing
better top speed

The bike is more edgey, but still completely controllable with subtle throttle movement.The bike is much better balanced compared to having just  a rear set-up and makes for a betterride. in my opinion it sounds no louder, and connecting up the pie motors to battery and pie throttle wires/connectors to main throttle cable is very easy to do.  Joining together any other functions would be a piece of cake as well.

Andrew

P.s I have no experience or skills with modifying a controller, although I would suggest having couple of replacement controllers if you go down this route

[GM Canada]

My 2 cents..

I have seen a few do the shunt mod with sucess, but from what I have heard you just blow the fets eventually anyway. It would be wise to carry an extra controller with you if you go this way. As for the dual drive, I love it and the others here that have done it love it as well. The weight balancing on the bike is an added bonus too. I also added an extra battery to the front and it really does give it a motor cycle feel. I had seven motorcycles in my days of riding and am quite familiar with the way it feels. Then I also went to 2 Cycle Analysts, 2 headlights etc. I just wish the damn snow would go away so I can get back on it!!

Gary

[Andrew]

My 2 cents..

I have seen a few do the shunt mod with sucess, but from what I have heard you just blow the fets eventually anyway. It would be wise to carry an extra controller with you if you go this way. As for the dual drive, I love it and the others here that have done it love it as well. The weight balancing on the bike is an added bonus too. I also added an extra battery to the front and it really does give it a motor cycle feel. I had seven motorcycles in my days of riding and am quite familiar with the way it feels. Then I also went to 2 Cycle Analysts, 2 headlights etc. I just wish the damn snow would go away so I can get back on it!!

Gary

gary,  what about adding some stablizing ski's either side of your sled, all you need then are some spikey tyres

[DirtyGinge]

Gary....you know we love you here in pommieland .....

any chance on getting some inside scoop on the 15 amp limit once usb software is used ??, they must know something right ?...not that I need it, but im drawn towards a competitors controller, they must understand sales are involved

[GM Canada]

Gary....you know we love you here in pommieland .....

any chance on getting some inside scoop on the 15 amp limit once usb software is used ??, they must know something right ?...not that I need it, but im drawn towards a competitors controller, they must understand sales are involved

You mean send in an email and hope for a response? Hmm interesting.. Maybe I should try that. I think they are back on the 8th from Chinese new year. I'll see what I can find out.

Gary

[MonkeyMagic]

I wouldn't say it's the software that limits the current. It would be the comparator on the controller board the measures the resistance across the shunt and limits the switching current (PWM) on the mosfets. That's why changing the shunt or modifying the resistance by adding solder to the one already there doesn't "trick" the controller but puts the comparator out of calibration.

If anything the software could possibly be changed to send different strings to internal controller. I asked Tom for the RS232 strings a couple of times but he hasn't replied about that (if that's leaked then why would you buy a USB cable?? hehe)

Anyway I sat there for a day or 2 at one point with a serial TTL converter and connected it inline with the usb PI-200 cable. I can post some more info on what the USB cable uses for data if anyone is interested. I was wanting to make a small terminal to change wheel settings on the fly

So technically yes, you could add solder or change the shunt resistance to a point where the heat/current limits are OK. But that's touch and go... My guess is that progressively GM have changed the boards to suit a reliable current. There is actually room to make a custom heatsink to fit in there that would work an absolute treat if you did anything heat dispersal wise

That's why the external controller most definitely has higher power due casing the external controllers are enclosed in, plus the fact they are outside in one way or another. Also not sure if running 2 external GM controllers dual drive will be okay with the 48v12Ah battery I think the BMS will crap itself...

Has anyone opened the latest GM external controller? And know what the PCB model is? Not sure if that says anything.I say that as the MX-316 board I've had for a long time (internal) I felt peaked much higher than my newer pies but that controller died bigtime lol

My MX-316 board has the shunt mounted on the bottom of the board, and looks like the capacitors can be easily swapped to the other side (which would make it the external controller) Newer boards on recent pies are MX-319 to my knowledge and have the shunt on top like all other internal controllers I've seen.

Plus the heatsink plate the internal controllers are mounted on is only like 2mm thick if that, I haven't measured any room if you were to add a thicker one but the main cause would be heat building up in the small area surrounding the mosfets. If you look at the external case, it has like 5mm thick + surrounded in naturally cool aluminum cast anyway.

Generally if you want power you would go with external controllers as a rule of thumb. I know its a bit of a gimmick with the wattage readings on the website but at one stage the internal controllers may have peaked at 50A but not now... Maybe they are ashamed to change it lol

Still think its a good wheel though... My dual drive has served me day in day out now like a champ. And I'm also noticing much less "5 beeps" topics being posted from newer purchases that's good.

Okay so I will remember to have another stab at the serial strings going to the internal controller. That could be a safe method without having to mod the controller and you could step the current as you felt was safe.

Peace out
MM

[DirtyGinge]

Many thanks MM

I do love the pies, they serve me well..The angle I was coming from was that I have seen several reports of the controller pulling less amps after the usb cable has been used to save any settings.....i know the internal will always be a bit limited due to the heat dissapation but a nice informative post none the less.....

I guess the other angle is that if we could put more than 20 amps into a wheel with an external, we wouldnt need the duals ??

Thanks all

[MonkeyMagic]

Yo yeah I know your angle... Mine is the same lol unfortunately the wheels weren't available with external controller option when I bought them, even if they did I think I would have gone internal controllers anyways.

And you have a good point about the higher power wheel vs. dual drive I thought about it a bit but there are too many pros of having the extra wheel with internal controller lol (weight, matching wheels etc.)

I will say that when my rear wheel had issues, and just running 1 wheel I much preferred having just the front wheel running. I had the battery on the rear then so maybe if I had the battery on the front and running a single rear wheel it would have felt the same anyway haha

I really like the internal controllers, and my recent decision rather than modding both wheels to external, then getting controllers and higher power batteries etc. is running a cyclone brushless chain drive motor.

Tom says it's fine but I am still VERY sceptical of pushing my 20" wheels to say 80km/h and what goes on with the voltages spinning at that RPM..

I'm thinking I will have to switch off one or 2 of the phases on each wheel when I push it past say 60km/h. Any tips anyone

[Bikemad]

I'm thinking I will have to switch off one or 2 of the phases on each wheel when I push it past say 60km/h. Any tips anyone

Do you really think the cyclone will be able to overcome the drag from two pies and power you past 60km/h all by itself?

Alan
 

[MonkeyMagic]

Hmmm well I'm not 100% sure how well it will do it, but I do know it will go past 60km/h even with the drag.

What gave me the idea is, normally I reach what I feel is top speed on a flat which is around 40km/h. Downhill I go past 50km/h, as soon as I start descending the motors switch off (or reach the speed limit)

Then one day I had pretty big wind behind me and on a flat it topped out and the wheels were only kicking in out. You always have a thought of increasing the power... But I considered this idea with the room I had on my bike.

I guess my bonus with the cyclone kit is I can remove my pies and run 2 wheels - 20" to 26" size. So I can convert it for pretty heavy off road using normal wheels but I'm thinking I'll leave the pies on. I've also since changed my suspension spring to fix the pedal height difference along with a layback seatpost.

Anyway the motor I got was the geared 1200W (1600W peak) motor, although that's just the sticker I'm sure it's the max rated power. From all the info I've read the bigger (1500W 4000RPM) motor (the one you posted in the pic) is not only massive and loud (louder than this motor would not be nice) but has crap torque compared to the geared motor. Also I've read using the geared motor I have with a heavy thumb on the throttle taking off will eat the gears for lunch...

So I went back and forth with 'Paco' from Cyclone, he said he has customers who add cyclone kits to their hub setups for acceleration, and said it will work with higher top speed. Obviously I just lose a portion of torque with the gear ratio I've chosen.. He also warned me that the crankwheel minimum RPM will be 200+RPM so I cannot pedal at that speed. Lol I think I would look really funny attempting to pedal on my bike at 40km/h+ with my size wheels anyway haha

So here's my setup:
Geared brushless motor, 14T freewheel
34T, 44T, 32T freewheeling crank chainwheel (running single chain to rear)
Probably going with a 5 speed rear freewheel (14-28T)
20" wheels

There is some gearing choices to make, but I will probably try motor to 32T then 34T to rear (should equal around 45mph)

I really am unsure of how efficient this will be as in the end I want to switch off both pies and run the Cyclone. The controller I'm using is a 25A cont. 47A peak limited, hoping it will be safe with the cyclone as they draw upto and over 70A lol

Won't be running them all at once, depending on the current draw at speed, I will be switching off the pies. But I'm still not sure if that is necessary. I know switching phases from star to delta can spike a controller, so could a similar effect happen running wheels in excess of the rated voltage RPM? Tom says no, but I am still hesistant lol

I will say that I test rode a 'Hybrid' pedal scooter that has pedals, 33cc engine and 48v hub motor. The petrol motor can be switched on and off. Top speed electric was 32kph, 16" wheels. Top speed with petrol + electric was 68km/h. Its a new thing in China. The petrol motor also charges the battery and the running range with a few dollars petrol was something like 200km. Would hate if all your power ran out trying to pedal that boat around... yuck

The other day on Youtube I watched this big hippo of a guy riding a 36v cyclone upto 50mph and if it pulled his junk along with the SLA's it gave me some hope there..

So I wonder how that recumbent build is going with the petrol motor attached to the pie? We might have to give that topic a shake and see if there has been a test run

I'll look for the big guy video, but heres a few from people with cyclones if you are interested. Not to try and convert anyone, but they do have some torque and are a decent motor.

http://www.youtube.com/watch?v=WutMg1zlCJA
http://www.youtube.com/watch?v=zo9VND-69iw

Oh and this guy totally gives Aussies a bad name... He must have the IQ of a shoe lol
http://www.youtube.com/watch?v=Zn5cujWYfW4

If it doesn't work, well I'm not really fussed. The Cyclone motor kit without controller, but with the freewheel crank chainwheel + mounting hardware etc. was only $250 delivered. So if this bums out I'll remove it and use it for something else.

I want the extra top speed only for these 3 long flat stretches of road I use regularly, and also at night it would be good to get places faster without traffic on the road. Otherwise I'm happy sticking to around 40km/h it has already. And won't be using the cyclone uphill.

Looking around I haven't seen anyone else do it, so maybe it is a bad idea. lol. If I had bigger wheels I would never had considered it but I think this could work.

Have you or anyone seen a similar project somewhere that runs chain+hub drive?

Jesus I just wrote a novel... whoops sorry

[DirtyGinge]

a cyclone as well,.....monkey, you are truly nuts   

[DirtyGinge]

Is anyone riding around with full downhill MTB helmets or just normal cycling helmets

one thing im aware of, having had several real nasty crashes, is the potential energy of a 25 mph smash on the head...

any thoughts on this  ?

http://www.mtbr.com/cat/mtb-apparel-and-protection/full-face/met/parachute/PRD_413925_6705crx.aspx

bearing in mind if your front forks go, the face is going to take the first impact, should face protection be a consideration ??


just a thought ?