"peak power" - Trek 4300 20" Magic Pie build.

[iovaykind]

Hey nep.. the same amount of wh of lipo would costed only <$450 if you had gone with 4s hardcase packs. is there any reason other than wiring is easier with 6s that you didnt' go with 4s? it just seems like the wiring mess can be fixed by permenantly paralling packs, to get rid of the complexity of the wiring.

And yeah, I totally talked about money to mess with you

 

[neptronix]

i figured someone would ask.

1) weight - the 6S 5AH 15C stuff i ordered weighs a few grams more than 5S / 20C stuff - it is the lightest lipo per kilowatt hour that hobbyking sells, and probably the lightest lipo per kilowatt on the market.
2) size - it is significantly smaller than the hardcase stuff.. i could remove the hard case sure.. but still, the cells are the 20C stuff which is a bit larger.
3) balancing simplicity - obviously it is easier to balance and deal with.

Let's do some math.

Turnigy 20C 4S 5AH hardcase: 528g
http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.html

Zippy 15C 6S 5AH: 682g
http://www.hobbyking.com/hobbyking/...lightmax_5000mAh_6S1P_15C_USA_Warehouse_.html

2x 6S zippy = $90 x 6 = $540
3x 4S turnigy = $67.5 x 6 = $405

Zippy: 528g x 3 = 1584g x 6 = 9504g = 20.9 Lbs
Turnigy: 682g x 2 = 1364g x 6 = 8208g = 18 Lbs

So for $140, i am shaving 2lbs. off my pack, the dimensions are much smaller ( much like that of 5S ), and i have a hell of a lot less soldering, discharge cycling, and balancing to do. ( and yes, there will be permanent soldering. )

I had also heard that the hardcase packs have a higher dud rate than normal. Maybe this is false. But it was a factor in the decision.

Call me crazy, but it's worth it to me.

I also ordered 1 extra pack ( there will definitely be a dud ).. that's how i got $595 + shipping.. had to split it into two orders, so that drove the cost up a bit too.

 

[chroot]

I bought 4S hardcase 32 pieces from hobbyking USA, No duds yet and I just got it today. Everything excellent condition and I paid only 812 dollars.

If you paranoid, Get Nano-tech LiPo, they are superb excellent and last long.

 

[neptronix]

I bought 4S hardcase 32 pieces from hobbyking USA, No duds yet and I just got it today. Everything excellent condition and I paid only 812 dollars.

If you paranoid, Get Nano-tech LiPo, they are superb excellent and last long.

Now be honest - Did you cycle test them, open them up and inspect them for puffing, or just check their voltages?
There is a big difference.

I have owned 15 turnigy + zippy packs, 2 ended up discarded.. 1 had a puffing cell from the factory.. the other one was missing an entire amp hour, which was discovered during the first cycle test on the iCharger. The third pack had a difference in internal resistance, leading to 1 cell taking the brunt of the load and the entire pack would never stay balanced.. Now i have 12 packs that are good..

Nano-tech is not any higher quality nor is it's longer life proven in any way.
It just has a higher discharge rating / lower internal resistance and fatter wires. That's all.
It is more tolerant to abuse, but if you derate 15C-20C lipo, it will last just as long, put out as many watt hours, and whether or not you get a dud depends on how the lipo fairy feels about you since this stuff all comes out of the same factory.

 

[cwah]

Neptronix, why is the weight mentionned by you different to the one on the site. For example here:
"
Zippy 15C 6S 5AH: 682g
http://www.hobbyking.com/hobbyking/store/__16803__ZIPPY_Flightmax_5000mAh_6S1P_15C_USA_Warehouse_.html
"

But on hobbykind site it's written 817g and not 682g. Am I missing something?

 

[chroot]

I just finished testing all my 4S hardcase and everything looks good. Wait few cycles see what happen in few days. First LiPo was 5s Turnigy and they were superb reliable till I destroyed 2p (extreme overdischarge in high speed riding) then my girlfriend's brother destroyed another 2p puffed badly (without my permission taking my ebike riding ARGH!) but no fire. Leaving me 39v10Ah for survival commuter to UPS work and back home. Right now, My turnigy LiPo got about 350~400 cycles so far still healthy no loss capacity yet. :|

Lastly question, I am out of curiosity - Does the MagicPie III runs 9x10 as used in MagicPie II? I will need double check with magicpie dealer.

 

[neptronix]

Neptronix, why is the weight mentionned by you different to the one on the site. For example here:
"
Zippy 15C 6S 5AH: 682g
http://www.hobbyking.com/hobbyking/store/__16803__ZIPPY_Flightmax_5000mAh_6S1P_15C_USA_Warehouse_.html
"
But on hobbykind site it's written 817g and not 682g. Am I missing something?

That's the packed ( shipping ) weight. You'll notice that for a lot of their lipo packs.
Look at the dimensions - those are rather telling. Compare the 6S 15C 5AH to 5S 20C 5AH. They are almost identical, off by only a few MM.

My zippy 20C packs were definitely a tad lighter and a tad smaller than the equivalent Turnigy 20C packs.
I'm hoping these live up to their spec O_O..

Chroot: i don't know what the X x X wind is for the 20" magic pie, only that it's a slow ~15mph on 36v kind of wind.
I bet the Magic Pie III is the same wind.. but check.

 

[cwah]

Oh, ok I see. Thanks neptronix

For my lipo, the shipping weight and battery weight are the same:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16227

Is it normal that they are both at 1054g?

 

[neptronix]

Oh, ok I see. Thanks neptronix

For my lipo, the shipping weight and battery weight are the same:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16227

Is it normal that they are both at 1054g?

Not really. Browse around the site and you'll see that they often differ.

 

[jmygann]

"Thin - With a thickness of only 60mm, Magic Pie allows users to install both a 6, 7 or 8 speed sprocket and a disc brake plate while still fitting it onto a common bike frame with a 135mm rear wheel mounting width."

http://www.petesebikes.com/products/detail/golden_motor_conversion_kit/


Product Description

Magic Pie II Conversion Kit with External Controller. Larger Diameter and Thinner for use with 6 speed freewheels and Disk Brakes! Can Be run on 24 volt for about 20kph, 36 volt for about 30 kph or 48 volt for about 40 kph .

You must either program the controller with a Golden Motor USB cablle or use a Cycle Analyst to control the speed and power of this motor at 48 volts. With out this it is Offroad use only at 48V please read our legal.

http://www.goldenmotorcanada.com/magic-pie-ii-kit-with-battery/

40 kph = 24.8548477 mph



Is the wheel true ?

 

[cwah]

OK thanks, I'm trying to find discrepancies somewhere. Anyway I already purchased the battery but I don't have precision balance at home.

 

[neptronix]

Well, i have been sick as hell lately.. 50-60deg weather here in Colorado and i'm in home thinking about how cool it would be to ride.. -_-

But... the first round of 15C zippy packs just arrived

As promised, the Zippy 15C 6S packs are actually... get this... the same size overall as the Turnigy 20C 5S, plus or minus a MM here and there.

I do not have a scale, but just going off hobbyking specs..

Turnigy 5S 5AH 20C : 666g
Turnigy 6S 5AH 20C: 793g
Zippy 6S 5AH 15C: 681g
Zippy 6S 5AH 20C: 754g
Zippy 6S 5AH 40C: 834g

( wow, the higher the discharge, the bigger and heavier these get, by a notable amount. )

According to the 'pick it up' test, i cannot feel any difference in weight between the turnigy 20C 5S and the Zippy 15C 6S. For now, i will believe the specs

Let's talk about performance..

When i got my Zippy 20C, average internal resistance was 9 mOhm. 1.5 years later, it's avg. 11mOhm.
When i got my Turnigy 20C, average internal resistance was 2 mOhm. 1 year later, it's avg. 3mOhm.
These Zippy 15C test out at an average of 12 mOhm internal resistance. That's actually not so bad. Not as overrated as the 20C Zippy was.

That's a big difference. The heavier turnigy 20C thus has 1/4th of the discharge rate.

My rule for good RC Lipo performance ( low sag, virtually no heat ) is to run 1/3rd-1/4 the maximum C rate / amps of the battery. This applies to other lithium chemistries such as lifepo4.

So, 5AH X 15C = 75A would be the maximum output for this pack.

1/4th C rate discharge:
5AH = 18.75A
10AH = 37.5A
15AH = 56.25A
20AH = 75A

So anyway.. 100W halogen discharger, at an average of ~4.25A: ( almost 1C )

The watt meter is saying i'm getting 5.5AH out of these during a 100W halogen discharge test.
I know this is wrong.
The iCharger is saying that i'm putting back 4.84 AH back in.
I trust the iCharger more, but i do wonder!
What i'm getting out of this is that i need more expensive measurement equipment ... maybe a CBA-II is really in order..

But thus far, these cells are the real deal. They'll work great in a 30AH configuration with a peak 56 amp draw ( may tune it down to 50A ).

 

[Alan B]

The zippy batteries often come up short on amp hours. Your tests show the Turnigy has much lower impedance too. Both of these differences would tend to explain the size/weight comparison.

 

[iovaykind]

I personally think that no brand is better than the other in this case. There's gonna be trade offs, but if you had the same exact specs on both batteries, and I mean REAL specs, not just what they advertise, you'd find that both batteries are basically the same.

 

[neptronix]

The funny thing is that they both have the same markings.. someone's lying at Hobbyking

To be truthful, i'm still very happy even with the low impedance. I *might* be missing 0.2AH, but i got an extra cell to make up for it over my 5S 5AH 20C Turnigy. The wHr/KG is still higher. And so far, the 3 packs i've tested are staying in good balance down to about 3.25v/cell average.. that's pretty good cuz i have to cut a little bit more off the bottom of the Turnigy discharge as they tend to have more variation in mAH per cell.

I suppose these are not as great as i thought, just a tiny bit better than the 20C turnigy, in terms of what wHr you get per size/weight.

Yeah, so there's no magic bullet with RC Lipo.

 

[o00scorpion00o]

Hi Dave,

I beefed up my 12 fet Infineon from 3kw to 4.8 kw and wow!!!


80 amps and a peak of 107 amps

Though you won't need Thai kind of amps in a 20 inch wheel, it would throw you off

Though thankfully the EB312 is good at helping to keep the front wheel on the ground its not as uncontrolled as the EB2xx generation!

 

[neptronix]

I don't have my cycle analyst set up, but i know i am not pulling anywhere near the 56A limit of my controller even on hills on the 20" wheel at 20S lipo. ( my lipos and controller would be hot to the touch if so )

BTW, that's a lot of amps, you might want to strongly consider doing the classic 12/18FET upgrades at that amp level.

http://endless-sphere.com/forums/viewtopic.php?f=2&t=17680

I'm surprised that the EB2 is jumpy on this thing!.. the 'pie does seem to have lower resistance than the MXUS/9C though, which was very easy to control, at the same time i was gutless in comparison, so go figure..

My 20" pie is very jumpy on the EB3.. there is about 1-2 degrees of rotation in the throttle between throwing you off the bike and moving forward until about 5mph.. it will jerk you pretty rough if you make any sudden motions until about 50% of the top speed. I think it is just a torque problem.. not like on the MAC where the controller didn't know what the hell to do with such a low resistance motor.

( on that note, i will be getting a upgraded 10T stator as soon as cell_man ha one available, i've now seen the light in regards to slow windings and high voltage.. )

 

[o00scorpion00o]

It's a lot of current indeed, I had to back it off today. I was getting mad vibrations from the motor sounding like a horn, a problem of sensorless or sensorless and the pie!

Weird shit, so it's now pulling 4kw still crazy acceleration. Nothing gets hot but I have good airflow to all the wires. Sure if I was running that power constant then I would probably have to change the phase wires battery etc, but because the pie accelerates so quick it's not necessary. If I had 90 volts to 40 mph it would pull a lot of power to get to that for longer so I would be more concerned.

I agree with you that the way to go is a slower wind and higher volts, however I think the pie is just a bit too slow a wind, you need too much voltage to get a decent speed. But you are lucky you have halls for the 120% setting to work!

It's just a matter of getting the right wind for the torque and speed you want. A faster wind pie would still have plenty of torque, you see GM designed the pie without speed in mind. They wanted people to have good hill climbing and a safe speed and I can see the logic behind that now, we are used to power and some of us a lot more, but I would not let anybody on my bike at 4+ kw, it's just too dangerous when they are not used to it, and it would be irresponsible of me to allow anyone on it at that power level. They think because it's electric it's like a kids toy or something!

BTW whay are you going for 10T on the mac ? I think the 8T is the best balance between torque and speed!

 

[neptronix]

BTW whay are you going for 10T on the mac ? I think the 8T is the best balance between torque and speed!

Because i need exactly 40mph to keep up with local traffic here where there are no bike lanes.. I'm thinking that maybe the 10T will hold it's speed a bit better and run at a minimum of 35mph on the most of nasty hills.

..then i can reconfigure my 20S pack for a super huge big 10S/30AH pack, and have high efficiency at 20mph speeds for long distance riding.. with the swapping of a serial to parallel harness

 

[chroot]

I was figure about the 9x10 motor (magicpie II), I seems can't find the label identification of the magicpie II on the ebikes.ca's motor simulator website. I remember someone told me if I am going use 20" wheel and I will need faster turn motor to make it equivalent to 26" speed. Justin's ebikes.ca motor simulation is kinda limited choice.

I need find true motor that measured 150mm wide, I would love get CroMotor and I still waiting for the review before I go ahead pay huge cost about 700 USD for the cromotor.

Anyways, I was trying find the maximum speed in MPH as using 20" if I am going get MagicPie II with Lyen controller 100A burst and 50A continuous (20s4p (20Ah)). I bet the 84v really give me too much torque power and of course I was going drill holes for the cooling.

My goal is the motor capable push 40mph max by doing start to max speed as quick acceleration and fast. Any progressive on your magicpie II?

 

[neptronix]

There is no equivalent on the ebikes.ca simulator.. the closest thing would be the Crystalyte HT motor, due to it's diameter.

If you want the equivalent speed per volt, yes you need a faster wind with less turns. But a slow winding on tons of volts will do the job as well.

This motor will probably not work on 150mm dropouts, sorry .. the axle length is notably shorter than my MXUS/9C style motor and MAC motors.. you'd need to put your torque arm on the inside of the dropouts as well.. not sure if that would be a problem on your bike.

Well, my top speed on 82v fully charged is about 32mph without pedaling, so i'm going to just take a guess and say that 26S would be required to hit 40mph on this motor.

The 56A i'm running provides way too much startup torque and i'm still waiting on a special programming cable.. stupid me for ordering via cell man & using the sea freight option. Cheap, but it takes over a month to get off boat to the USA!

I'm still quite sick.. and I have 9 15C zippy batteries that should arrive tomorrow that will need full discharge testing. I have a cycle analyst that i'm still waiting for help on.. geometry issues to sort out.. the list goes on.

 

[o00scorpion00o]

BTW whay are you going for 10T on the mac ? I think the 8T is the best balance between torque and speed!

Because i need exactly 40mph to keep up with local traffic here where there are no bike lanes.. I'm thinking that maybe the 10T will hold it's speed a bit better and run at a minimum of 35mph on the most of nasty hills.

..then i can reconfigure my 20S pack for a super huge big 10S/30AH pack, and have high efficiency at 20mph speeds for long distance riding.. with the swapping of a serial to parallel harness

the 8T is perfect for 40 mph imo. the 10T will give you more torque but if using 10S you will need more current to get up hills, unless you plan to pedal a lot on the hills ? I still think the 8T is the best or (good) balance between torque and speed, I like the fact it can do 40 on only 16S with 120% setting.

 

[neptronix]

the 8T is perfect for 40 mph imo. the 10T will give you more torque but if using 10S you will need more current to get up hills, unless you plan to pedal a lot on the hills ? I still think the 8T is the best or (good) balance between torque and speed, I like the fact it can do 40 on only 16S with 120% setting.

The 8T can do 40mph just fine, but charging 16S seems like a pain, 20S not so much.. switch from series to parallel, stick in 10S charger, have a nice day.. For daily use, i want the simplicity of 1 charger and 1 plug.. groups of 10S tend to do that very well. I do 15S from time to time, but it's a bit more hassle than i prefer.

I will actually need less current to do the same work up a hill, low speed winds want more volts than amps to get the same speeds, the watts are roughly the same, though the hill climbing efficiency is much likely to be higher. Play around with the ebikes.ca simulator a little and you'll see what i am talking about.

 

[chroot]

You can charge 16s or 20s via Hyperion EOS 1420i NET3 14s Balance Charger networked between 2 charger together (28s). So you can just split 20s to 2 of the 10s pack by 2 of the Hyperion network charging together same time. I have thought about getting Hyperion EOS 1420i NET3 14s Balance Charger from Gooddum (Gary). He has awesome kit that will give you lot easier handle with the groups of pack.

My iCharger 3010B doesn't have network capability like Hyperion 1420i NET has.

but charging 16S seems like a pain, 20S not so much.. switch from series to parallel, stick in 10S charger, have a nice day.. For daily use, i want the simplicity of 1 charger and 1 plug.. groups of 10S tend to do that very well. I do 15S from time to time, but it's a bit more hassle than i prefer.

 

[neptronix]

Yeah, i know that's possible, but i like to keep the $200 worth of charging gear i already have employed. Those hyperions are $150 each, then you need the power supplies to run them, which i don't have.

All my stuff is meant for 10S, or i can charge either 10s or 12S with the meanwell with the flick of a switch to bump up the voltage on the MW. Works great for me. the iCharger will deal with the 12S stuff only when needing a balance ( will be a rare occasion ).

So hooking up my 20S into a big parallel group to charge, then switching it back to parallel on the bike is very convenient for my use.

The less dicking around with multiple chargers, different voltage settings, ETC the better.. am shooting for no accidents in the workplace.. ( it happens! )