Motor

Motor has arrived!

This is the new H4040 model, rated at 3.5kW continuous. Bought from Ilia @ EbikesSF.com - buy from this guy, seriously, the quality of his service is unparalleled.

And she's a big gal...

With 64mm outer shell width, there's lots of room for 4-5 kilowatts to live happily together.

 

A  185mm disc doesn't really cover it, with outer diameter being ~243mm.

 

Wires:
3 Anderson Power Pole phase connectors.
5 Hall sensors.
1 Temperature probe

Spoke holes take 12ga spokes snugly.

Batteries, revisited

Well, maybe not.. Looks like the turnigy 5Ah is backordered and I don't know when it'll be back in stock, so I'm going with the ZIPPY Flightmax 3000mAh 6S 20C.
Characteristics:
Capacity(mAh)       3000
Config(s)           6
Discharge(c)        20
Weight(g)           426
Max Charge Rate (C) 2
Length-A(mm)        111
Height-B(mm)        47
Width-C(mm)         43

That means I'll need 20 bricks instead of just 12.
The downside is having more connectors and soldering to do, but on the upside it's a smaller brick meaning a better fit inside the triangle.

I thought about placing the batteries in bags like so:

And without the annoying text we get something roughly elegant:

Batteries

My battery of choice is the Turnigy 5000mAh 6S 20C  from HobbyKing.com.
12 bricks of this one in a 4S3P pattern make up a total of 88.8v 15Ah = 1332Wh.

Trying several positioning patterns, I'm settled on this:

The Lithium-Polymer chemistry is wonderful. It provides a lot of watts in a little package that is able to deliver a lot of amps. But it's also unforgiving when certain rules are not tightly observed. Essential material to get to know by heart with before having anything to do with this battery:

RC Lipo series charging tutorial

Understanding RC LiPo Batteries
Complete Guide to Lithium Polymer Batteries and LiPo Failure Reports
Lithium Polymer Battery
Parallel LiPo Charging – The Faster & Safer Way To Charge?
How-To: Parallel Charging

Behemoth

Here's the Demo (you can have a looksy at the specs here: http://www.specialized.com/us/en/bikes/archive/2008/demo/demo8#specs).

Decision based on MadRhino’s (from endless-sphere.com) previous experience with converting this bike to something really magnificent.

Got it for a bargain @ 1130$, and the nice seller threw in a full-face helmet for free. Yay!

It's a real beast, built to sustain the most difficult of mountain riding. But will it handle the amps? I think so.

The old ride

This is what I've riding on, on a daily basis, 30KM each way to my workplace and back.
Specs:

• Bike: Gary Fisher Big Sur XC 2006.
• Motor: Bafang 350W Front (runs at 500w after controller's shunt was soldered).
• Battery: 36v 16Ah (two 36v 8Ah in parallel).
• Controller: Some 6-FET garbage..
• Watt Meter: Cheap yet fully functional meter from eBay.
• Custom torque arms after original failed.

Handling: 40KM/h max, 50KM range.

I've learned so much from tinkering with this setup and customizing wherever I can.
This bike as it is has probably got 18,000 KM on it, and except for low squeaks that the motor's been doing for a long time, it's otherwise still going very strong.
Batteries have undergone 620 charge cycles and show no sign of fatigue, combined voltage hot off the charger is 42v. But how long can you go on with just 40KM/h..?

Prolog, the plan, and some recap

Cut to the chase:  Finale

In this blog I aim to document the building process of my second electric bike.

Disclaimer: This setup is quite powerful, and therefore FORBIDDEN by law to ride on road, it is meant for off-road use only. This blog exists for demonstration purposes alone and anything you do is on your own bloody responsibility, bla bla bla...

My objective: A high-end bike (DH frame), with a decent & reliable system that can deliver 40-60 KM/h, with short periods (like 2 minutes) of ~70KM/h. Most of the time I'll be cruising ~45KM/h, but I'll want that 70 for whenever I have an option to ride that fast.
My terrain is mostly flat. I plan to use the bicycle as my primary vehicle to work & back. Each way is ~30KM and I can charge at each end.

The following recipe fits that bill (and then some):

• Bike: Downhill/Freeride bike with space in the triangle.
• Motor: Crystalyte H40 Cruiser from Ilia @ebikessf.
• Battery pack: 24S 15Ah of Lithium Polymer high discharge (5C).
• Controller: LYEN Edition 12 FET 4110 MOSFET Extreme Modder Controller.
• Charger: Cellpro Power Lab 6, 1000w.
• Power supply: Some 1000w power supply...
• 3-speed switch, cruise control, multi switch (for lights and bike's on/off), battery alarms.
• Cycle Analyst V3 (with the temp control).
• Wires, connectors, solder, lots of good tools.

This kind of setup should give 44KM of range @ 50KM/h, and an amazing climbing ability even for tough hills, with a maximum of 135nM of torque. The controller will transfer a peak of 5kW to the motor. Not bad :)


Before beginning, a small recap:

• About half a year of research on motors, batteries, etc., focusing on what I really want, researching more ... Started with a 1000w motor in mind, then thought that two 1000w motors would be even better, and finally went back to just one motor that's more powerful than the previous two together - 3.5kW continuous. All in all hundreds of hours' worth of reading. The best read of all is www.endless-sphere.com, THE place for electric vehicles.

• 22/10/2013 - Decided on the Crystalyte H3540 motor from www.ebikessf.com (highly recommended). But found that it's back-ordered, so went for the yet beefier & more powerful 4040 :

• 06/11/2013 - Settled on a used 2008 Specialized Demo 8 as base. Decision based on MadRhino's (from the endless-sphere) very successful experience with converting this bike.