Magic Pie 4 with Turnigy 4s

[lotus]

Hi everyone,

I'm starting to assemble my first ebike and I don't know much about this.
I got my self a MP4 rear hub and some RC lipo batteries to go with it.

I haven't put everything together, but soon I will start to do my wiring.

The battery setup that I will use is 3 batteries in series, and 3 of these packs in parallel. 9 batteries in total, with 50.4v and 15Ah.

I have some questions regarding the wiring that I'm using. The batteries come with 12awg wires and the my loom till the end will be with that kind of wire.
I'm using this switch to break from the battery pack and the motor http://www.amazon.ca/002843011-Series-Rating-Battery-Master/dp/B0000AYAFE/ref=pd_sim_hi_1?ie=UTF8&refRID=1K0FHN1CGTTEH10Z2H2M
The controller has it own low voltage switch, very handy.

Behind the big switch I will have a fuse. And here is where my questions begin.

I know that the RC batteries have 2 rates for the current discharge. Maybe I will find out how this works when I start to play with the controller software but...
How do I use the peak discharge from the lipos for those 10 or 20 seconds? Do I have to install a button and set two modes in the controller? If yes, where do I plug that switch?
I know that is up to the motor and the controller to assume how much current is needed but I need some help to understand why there is a 20C and 30C rate and how do I control that (if possible). Because if the normal rate is 20C, then I won't have 15Ah constant. I would have 20x that instead which seems impossible to me because the controller and the motor wouldn't handle that much.

I see online some switches that seem to work like different stages of speed. I don't know if could be related with this.
If I'm using a total of 15Ah, I was thinking to use a 30 amp fuse. But this is if I use the 1C rate of my batteries.
Could some one help me to choose the best fuse for my loom, knowing that I might use that peak of Amps that RC Lipos provide. And should I be worried with the wiring gauge? Although the motor wires are 12 awg.

The same applies to charging. I got a meanwell 48v 350watts. The turnigy manuals says that I shouldn't charge with no more that 1C and at the hobbyking website they say that I can charge with a 5C rate.
Is is recommended to get another meanwell and set it up in parallel for faster charging?

Sorry for my bad english and sorry if these topics are already discussed. I tried to look around and I couldn't find enough information.

Cheers!

 

[lotus]

Here are the batteries that I'm using:

http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_Hardcase_Pack.html

Here's the power supply:

http://www.ebay.ca/itm/Meanwell-NES-350-48-Power-Supply-48V-Volt-350W-Watt-Power-Supply-UL-Listed-/261508259734?pt=LH_DefaultDomain_0&hash=item3ce31b5f96

Here's the balance charger I got:

http://www.dx.com/p/bc168-1-6s-8000ma-200w-high-precision-lcd-intellective-balance-charger-124483#.VTQlhSFVhBd

I've got a power supply for this charger:

http://www.banggood.com/Wholesale-12V-30A-360W-Switch-Power-Supply-Driver-for-LED-Strip-Light-Display-220V-or-110V-p-39987.html

I got also a voltage alarm from hobbyking, just one to check the batteries:

http://www.hobbyking.com/hobbyking/store/__42758__Cell_Log_8M_Cell_Voltage_Monitor_2S_8S_Lipo_US_Warehouse_.html?strSearch=voltage%208s

This is for now all the equipment I have. Now I'm just waiting for some connectors and wires to set everything up and start to play with it.

 

[LockH]

G'Luck! (Many here waaay more knowledgeable that I re Ebikery Magic.) But just FYI:
"What is the difference between a battery and a cell.?
A cell is a single unit at the base voltage. A battery can be a single cell or multiple cells connected together in series or parallel to make the voltage/current rating desired."
Here:
https://in.answers.yahoo.com/question/index?qid=20061010075503AANhQhl

So maybe think of cells in series to make up "4S". Series from more volts, and paralleled for more amp-hours. (A typical "12 volt battery" is six two volt-acid lead cells linked in series.)

 

[Ykick]

Because if the normal rate is 20C, then I won't have 15Ah constant.

That statement alone is enough to avoid trying to offer help in this thread. Ah is NOT the same thing as A.

Just forget about the battery C rate. 3P will be plenty for any controller/motor drawing less than 50A. That big cutoff switch is another stupid thing. It's not designed or intended to handle higher than 12VDC - arcing will eventually destroy it.

If I understand some of what you're saying this will be 12S3P battery pack. Using a total of 9qty 4S "bricks" - the term commonly used to avoid confusing "pack" with the completed battery pack.

That 48V Meanwell will likely need a current limiting mod or you'll be readjusting the voltage output 2 or 3 times to reach full charge. I'd forget that, grab a 400W alloy li-lion battery charger from BMS Battery or EM3EV and install a BMS on the completed battery pack once assembled.

The balance charger is okay for spot work, bringing up low cells, etc. But it's not a viable long-term, daily/frequent use solution.

Use a 30-50A fuse between the battery and controller.

CellLogs are nice. If you use Win computer buy the S version and learn to embrace "logging" cell voltages. Excellent stuff to help qualify pack health. The built-in alarms are pretty weak, they can drive an alarm circuit but just use a BMS and forget the manual alarm notion. It never seems to end well.

Here's one of my 16S1P packs comprised of 4S hardcase bricks.

Here's a discharge log graph from 8 cells using CellLog 8S