2kW SmartPie

[Lollandster]

Hi, I did some modifications to my SmartPie and I thought someone else might be interested in the results.

Due to some problems with my internal controller (it stopped working) I ordered a new one, a Lyen 9 Fet. The new controller can do 85v at 30amps and I didn't see a reason why I wouldn't try to max it.

I bought four 5s lipos and connected them to make 20s with a "off the charger" voltage of 84 volts. You can see the test run here: http://youtu.be/n-EuvWoCess

I had a maximum of 22amps and 1750watts showing on my CycleAnalyst. I don't have an accurate shunt measurement for my current shunt and I believe the real wattage is higher than my reading. I'll connect my accurate 1mohm shunt later and get a real reading.

I used GPS to get a accurate speed reading on my test drive and I clocked 45km/h on the straights and 55km/h down hill. I did a run together with a pal of mine that has the MagicPie 3 unmodified (controller set to 30amps) with 16s LiFePO4 (~58v off the charger) and I had no problems accelerating away from him and hitting higher top speeds. Both where running on studded tires. I expect slightly higher top speeds on slicker tires.

I have installed a temperature probe right next to one of the coils and I got a temperature reading of 80C after gunning full throttle for about 5 minutes. The temperature sensor is connected to the Cycle Analyst and the throttle will automatically back off if I reach 99C. It was -8C outside so getting the coils that hot that fast is evidence that this isn't power levels the SmartPie is happy with. I won't recommend anyone to use close to 2kW on the SmartPie without a temperature probe.

I have written a lot about the modification on my blog. Feel free to read more there:
http://lollandster.wordpress.com/2012/12/25/modifying-the-smartpie/

[atcspaul]

something dosn't sound right. I have a Smart Pie and Magic Pie III. my Magic Pie III with the internal controller I get 45kmh on the flats and down hill I have hit 65kmh.
(actually more like down mountain then hill lol) I know others in the states that get the same results with the mp3.  I would think the higher voltage and better controller would give a lot better results. my smart at 48volts I get 37 to 38 kmh.
in the video it looks like it has amazing torgue. I mean it darn near yanks out of your hand. very impresive

[Lollandster]

something dosn't sound right. I have a Smart Pie and Magic Pie III. my Magic Pie III with the internal controller I get 45kmh on the flats and down hill I have hit 65kmh.
(actually more like down mountain then hill lol) I know others in the states that get the same results with the mp3.  I would think the higher voltage and better controller would give a lot better results. my smart at 48volts I get 37 to 38 kmh

I forgot to mention that both of us where running on very knobby studded tires (winter time here). I have included that vital info in the OP now.

[atcspaul]

by the looks of the video it will stand on end if you start out with full throttle. good fun for sure

[Lollandster]

by the looks of the video it will stand on end if you start out with full throttle. good fun for sure

No chance to get the bike up on one wheel. The torque is probably lower than on the MP3, but the acceleration is better. With the wheel off the ground the wheel accelerates up to 75kph almost instantly so it looks very impressive, but in the real world you can't feel the power until you hit about 10kph, below that it is not impressive, I can't even do burnouts on gravel.

I tried the bike off-road today since off-roading is the reason I want more power. Even with my studded tires with low air pressure the forest roads where way too slippery, it was actually safer to stay on the bike than try walking. I did however get to try some anyway and there was a big difference. At very low speed the extra watts does make a difference compared to 15a original, but it wasn't much better than setting the internal controller to 30 amps, I'm guessing exactly the same. But as soon as I gather a little speed this thing flies. I found some fields without too much ice and it feels like the acceleration never stops (at least my nerves stops before the acceleration does).

After a little playing around I got back to the street and test the power usage on sustained max speed on close to level ground and it shows 1100 to 1200 watts. I'm not sure how much my tires play a role here, but it looks like it is very ineffective and power draining. Can anyone quote the power usage to maintain ~50kph with a MagicPie? After finishing the short ride I had used 1.1 Ah (about 80wh) and the coil temperature was 109'C (ambient was -8'C) The motor was quite warm to the touch.

I think I'll use 10s2p in the future and not 20s1p. The motor gets too warm and uses way too much power at high speed. I might end up buying a slow wind BPM for off-raoding. Top speed isn't important to me, fuel economy is.

[atcspaul]

i used my Smart Pie just for an off road bike. I am using a 36v 8ah water bottle battery with it. top speed on flat is only 18mph however I found that more then fast enough for me off road. I like to play in the woods. jumping. bunny hopping, high speed turns ect. when I had the 48v rear rack motor on it wasn't possible. to much weight and rear weight was to much. the set up I did with the water bottle battery is only 47 lbs or 21kgs. its a blast I can do everything I could do with an regular mountain bike and more. take off power not a a lot top end not a lot. more then enough to get me up the hills and a lot of fun which is why I made it.

[Lollandster]

As I told you in another thread I love your battery, but I decided to build my own and that is the reason I bought 4000mAh batteries instead of the more normal 5000mAh lipos. From my calculations they will fit inside the bottle from greenbikekit.com ($25 intended for 18650 batteries) with room to spare for the cables. The bottle will arrive Thursday according to FedEx. If this is successful I'll share the build process.

I just realized a moment ago that I had block time (effectively the time spent in burst power) set to 0.1s. I change that to 5s and that made my peak power go up to 2800watts!  (I very sure the shunt value is wrong and that the real number is even higher) Boy that made a difference. I still can't to wheelies, but I can do gravel burnouts and acceleration is awesome. Later I'll try the woods again, I bet it makes a difference there too. I just hope I don't blow the small motor (I'm betting its life on the CAs temperature shutoff)

[atcspaul]

look forward to hearing about the bottle battery after you get it built. I really like them. solid mount which I did not expect. it does not move at all no matter how rough I am in the woods.

[Lollandster]

look forward to hearing about the bottle battery after you get it built. I really like them. solid mount which I did not expect. it does not move at all no matter how rough I am in the woods.

I got the battery case today and it was a total bust. The bottle don't fit inside my small triangle. I was betting a lot of money on this. I'm wondering how hard it would be to sell LiPo batteries of this size. The lipos fit nicely inside the bottle though.

It looks like your GM battery is smaller so maybe that would fit. Would you mind sharing some more measurements like the diameter and length from bottom screw to bottom of the bottle, it looks like it barely fits without drilling new holes on yours. If you do this for me then post it in your review so others, not interesting in 3kw, can see it too. Thanks.

EDIT: I turns out selling those LiPos was very easy. They sold 50min after I put them up for sale. No more high power biking for me.

[atcspaul]

. aproximitly 120mm from bottom screw to bottom of bottle. 93mm diameter. actually fit exactly where I wanted it. as far down as possible without the end touching on the frame. didn't have to drill any holes.
awesome on selling the lipo's nice and fast. high power intrigues me but I must say both the Smart Pie and Magic Pie do what I want them to and very happy. any mods I do to the bikes themself

[Lollandster]

Thanks, Thats is almost exactly the size of the bottle I've got, only slightly shorter and fatter. It won't fit my frame then. I guess I have a strange frame.

It was very fun to try 80v at 30amps, but the amount of juice that motor consumes at slightly higher speed was extreme and a deal breaker for me. Back to 36v for me.

[atcspaul]

have you tried a regular 48v battery. if I was using for transportation the 48v cruised around 24 mph which was plenty fast. I use the 36v because I do not need to go that fast in the woods plus I need the exercise

[Lollandster]

have you tried a regular 48v battery. if I was using for transportation the 48v cruised around 24 mph which was plenty fast. I use the 36v because I do not need to go that fast in the woods plus I need the exercise

No I haven't. I started out trying to keep things within the European legislations and wasn't thinking I would buy the Cycle Analyst. But I got power hungry when going off road and was held back by my too cheap 1C battery. That's why I went a little nuts and tried 74v. It was fun, but I have motorcycle license and that is much faster and not to mention legal.

Now that I have given up on finding a bottle battery I'll probably end up buying a 48v aluminum case rack battery. I'm thinking either the GM battery or one I found from another seller that looks identical to the GM battery with the same looking cells, but with slightly lower stats. They might not have the same BMS. Its a price difference of $160 including shipping. If I'm lucky the battery will fit on the same bracket as my current 36v battery. It seams that good enclosed batteries are hard to find. Most over 2C are shrink wrapped.

EDIT: I decided in favor of the cheaper battery and ordered it. It's decisions like this that costs money in the long run, but I can't bring myself to overspend when there are cheap products around.

[Lollandster]

I have finally gotten around to precisely measure my shunt and can now edit those previous numbers.
It wasn't 22amps 1750w continues, but rather 28amps and 2190w
Peak wasn't 2800w but actually 3500 watts