Now Dumping 5KW into the Pie!

[o00scorpion00o]

 
Yes you did read that right 5KW 

I modded my 40 amp 12fet infineon for about 80 amps, I saw a peak of 117 amps on the cycle analyst the other day, that's 7kw peak! 

Needless to say the torque is incredible and surprises the hell out of anyone at the traffic lights, I take off quicker for sure! It's addictive!

Now all I need is about 100 volts for some serious fun because all I get on 60 volts nominal is 30mph so the fun is over very quickly!

Only thing is I get a very nasty vibration and it makes a really loud noise. I think that might be because I'm running sensorless and to be honest I'm not going to bother repairing the halls. It's fine if I don't hammer the throttle.

So I went from  750 watts with the internal controller, then to 2kw, then 3 and now 5kw, I wonder how much this beast will take?

I have not done long term tests with the pie on 5kw, but rest assured this motor can take 3kw without issues, heat may be a problem on long steep hills but normal terrain and it will never be an issue, I doubt 5kw will either because this power is only  on acceleration or climbing and the pie can shed the heat better than many other motors  out there, going to 40 mph will obviously draw more power for longer and might be an issue, but to be honest I don't plan on going to 90 volts any time soon!

You got to make sure and upgrade phase wires and connectors battery wire etc for this kind of power, and this is LiPo territory for sure!

[Enpro]

What kind of battery setup do you use?
I'm planning to get about 3k into my pie at 72v but not sure my battery's can handle the discharge

[o00scorpion00o]

LiPo  batteries are really the only type you can use at 3 + kw.

I'm using r.c type LiPo bricks.

2x 6s 5ah and 1 x4s 5ah ah connected in series for 60 nominal volts and another 3 packs of the same connected in parallel for 10 ah.

charging is a complicated matter and mistakes May lead to fire!

you would have to disconnect your pack and charge each brick in parallel and connect up the balance leads to the r.c charger.

you can of course bulk charge each time provided each cell is not too out of balance.

you can also use 90 volts and only 40 amps for good speed. about 40 mph with 90 volts. Higher voltage is better than very high current. Helps keep heat of everything low.

[Enpro]

How about lithium metal battery's (LiMn2O4 to be exact) ?

[o00scorpion00o]

LiMn204 can be lighter than LiPo, however you can't get the discharge rates or (C) rates of LiPo.

With LiPO you can have a 10ah pack and discharge at 300+ amps continuous, from most other batteries 1-2C max, you can get some LiFeP04 that can do 10C such as headway cells, or A124 that can do maybe 20C, but the A123 are very hard to get and expensive, and LiFep04 is larger and heavier than LiPo.

The R.C LiPo is good value but you have to make up your own packs, P.M me if you want to know a good place to get it. You need to buy  a R.C charger such as the Ichargers and a power supply to run the charger. Then you got to connect your packs in series to get the voltage you want then parallel the packs together to get the ah you want, then split them all up and charge in parallel, or bulk charge using a charger designed for the voltage and chemistry of your pack ( if it's LiFeP04 or LiPo or whatever )

LiPo has less charge discharge cycles of LiFeP04, but most people only charge to 4.15V per cell and discharge to 3.5 volt per cell to increase cycle life life. So you loose 1-2 amps depending on the size of the pack, but with LiPo to keep all cells in balance it's better to get more ah than you require and that means a lot less times you have to split the pack up to balance.

check out this link

http://endless-sphere.com/forums/viewtopic.php?f=14&t=26554&p=487032&hilit=fetcher#p487032

I don't know if it's reliable, if you are not a forum member you can register and ask more questions there if you want, you will find people there with far more knowledge than me.

I was scared about going LiPo in the beginning but now there is no going back once you get used to the power! 

[Enpro]

But 50 amps continuously would cause any problems?

[o00scorpion00o]

Yes Probably,

50 amps is a lot of current, your phase wires, battery wires, connectors, etc, would all have to be rated for a minimum of 50 amps continuous, but generally if pulling 50 amps continuous you would use cables and connectors rated for more than your continuous current.

Generally you won't pull that kind of power for longer than a few seconds, or climbing the steepest of hills or mountains, then you do have to be careful but you got to design your system to take it. Cruising at 30 mph on the pie I use about 25-30 amps on 60 volts but that doesn't make the pie even warm.

The hills are the more dangerous because motors are a lot more efficient at faster rpm and by having more voltage makes the motor spin faster keeping the motor in it's efficiency range longer, having the benefit of getting you up the hill faster helping the motor to keep cooler. when the motor slows down a lot on a very steep hill pulling max current you can be sure it will heat up very fast, most of the energy is turning to heat instead of turning the motor!

The pie will climb fairly steep hills on 50 volts with an external controller with the 120% speed setting quiet comfortably even on 40 amps. To make it go up faster you need more volts because the pie is a slow wind motor for more torque, so you  got to volt it up.

You still got to be careful on very steep hills at full throttle, you got to check everything for heat. If you can install temperature sensors, that would be ideal. I have never done this yet.

[Enpro]

Thx for the info!
I'm planning on getting my mp3 on a 72v 40 amp controller with 2x 36v 16ah LiMn204 battery's. (one of them measures 40v so that would make 76 volt )
Already got the battery's and the pie just have to wiat a few days for the controller.
I got my cabling all 50 amp ready probably even more.
The thing is I got my pie on a heavy downhill mtb with 3.2 wide tires that do a lot of rolling resistance.
I do want to use it for some fast cross country riding in a local forest but with no steep hills or anything and I only weigh about 60kg so i'm not that worried about the pie itself, but the battery's were pretty expensive and I like them to last at least a few years if possible..

[o00scorpion00o]

No problem 

The Magic Pie III won't be available as an external controller option.

Magic Pie II is perfect anyway and at 72 volts 40 amp controller will be powerful.

If you get an Infineon controller with program cable and software to fine tune it and set the speed from 100 to 120% you should get 40 mph or close!

[Enpro]

I'm getting this controller http://www.crystalyte-europe.com/product.php?productid=16188&cat=271&page=1.
Not sure its an infineon and it isnt programmable but thats not really an issue for me.
Im not that happy about the 60v cut off because that means I cant limit the maximum speed by simply switching the battery's in parallel.
Lets just hope I wont run into some police man that likes to see how fast it will go. 

[o00scorpion00o]

That controller should work fine, 72 volts will be decently fast with the pie. 35 mph+

If you got a programmable infineon then you could set the lvc, current to match your battery, phase currents, and speed the 120% setting would allow an extra 5 mph!

There is a drain brain connector also known as the cycle analyst and I highly recommend you get it, you can set current limits there too and voltage cut off, however if your controller is set to 59 volts then that will be the minimum you can go.

The cycle analyst also tells you how many ah you use from your pack giving you exactly how much is left in your battery, essential !

Just make sure your batteries will take 40 amps!!!

[Enpro]

exactly my point!
How can I be sure they can handle 40amps?
I never got any specs on them. Just the packs,cables and a box. They are from golden motors so I hoped someone here on this forum could give me a little info on them.

[Bikemad]

How can I be sure they can handle 40amps?
I never got any specs on them. Just the packs,cables and a box. They are from golden motors so I hoped someone here on this forum could give me a little info on them.

Unfortunately the 16Ah lithium manganese packs were rated as 30Amps maximum continuous, with peak bursts of 60 Amps max.
I think the BMS is likely to cut out if you try to use more than 30Amps for too long, I seem to recall someone having a similar problem while running dual Pies from a single battery.

Check out this post for more information on the 36V 16Ah pack.

Alan
 

[Enpro]

40amps @ 72v would make about 3000watts so more then enough to take it easy on the throttle .
My bike weighs about 40kg and I weigh about 60kg which makes 100kg vs about 30kg pull from the motor on a 26" wheel.
In other words perfect for me! 

[e-lmer]

From what I can see your phase wires would
have to be about 12 guage to safely run 40A
DC continuously.

Does that fit through the gap?