Written by Ron/Spinningmagnets, September 2013
I don’t know what’s in the water that they’re drinking down in Australia (or is it the Aussie beer?), but whatever it is, there seems to be a high incidence of “custom E-bike fever” there. Roger (ES member “Rodgah”) lives in Caloundra, on the North-Eastern “Sunshine Coast” of Queensland, Australia. This awesome frame was custom TIG-welded by his friend Paul, (ES member Timma2500)
Our website tracking shows that our readers respond well to stories about the high-end and high-power builds, so…how about an E-bike using 100V?
2005 Specialized Big Hit FSR, custom cut and modified
2011 Rockshox Domain RC forks, with direct mount stem
Hayes Stroker Trail hydraulic brakes
FSA Gravity Cranks
24″ Fire-eye Rims
3.0″ Halo Contra tyres
Carbon fiber quick release battery cover
Crystalyte HT3525 rear hubmotor
12 gauge spokes
12-FET controller, with a 3-speed switch (limited to 50A/5,000W = 6.6 Horse Power)
CA-DP, CycleAnalyst-Direct Plugin
24S-2P / 10-Ah LiPo (86V-100V, 3.6V-4.15V per cell)
Charged by a Hyperion EOS1420i 550W
Four custom 6mm-thick torque arms
Whole bike weighs in at 35kg (77-lb)
Many of the bicycle components were purchased from http://www.chainreactioncycles.com/us/en
Below is a pic of a 24S / 1P string made from four 6S bricks of LiPo, pic from ES member Sacko. Rogers pack is similar to this, but not identical.
There are many different component weight distributions that are acceptable, but whenever it is possible, this is the absolute best place for the weight of a significant battery pack. The large red kill-switch is vital, and needs to be located where it is within easy reach, whenever you are using 100V.
4-minute ride video (second video out of three): http://endless-sphere.com/forums/viewtopic.php?f=6&t=36682&start=25#p759229
Here are some performance quotes from the build-log:
“…The only riding that makes the motor hot is stop/start full-throttle action. If I keep my momentum up, the motor and controller stay dead cool. I could imagine going full throttle up very steep and long hills would heat it as well, but I have yet to find a hill big enough for the motor to even get warm, plus I have a bit of sympathy if I am climbing slowly…”
“…I don’t have a CA [CycleAnalyst E-bike computer] yet, I just feel the motor every now and then [with my hand] and it hasn’t even been what I would call hot, just warm…and that is rare, most of the time it is cold. The HS3540 is a lot faster winding than mine so I would assume it would get warmer riding like that. The 12-FET is modified by Hyena, I don’t know how. I leave mine on the middle setting of the 3-speed since that settings top-speed suits me and the power is fine, I guess it is probably less than 5-kW”
“…I went for a ride yesterday with my friend “thecopterdr” http://endless-sphere.com/forums/viewtopic.php?f=28&t=45409. Great to ride with someone else and have a chat. Managed to get my hub nice and toasty definitely above 50-degC [95C / 200F is a common heat limit], climbing slow and rough technical trails, though I am sure without motor power most people wouldn’t be able to pedal the whole way up. The other bike has a Cyclone mid-drive that was only warm at the top so it was a really good comparison of eggs vs eggs (although the Cyclone was noisy). I have a suspicion that most of the heat may have been caused by the low average speed (pretty tight and technical trail) and not so much the climbing itself, I’ll have to test this more in the future…”
“…I can imagine the motor doesn’t transfer heat very well to the outside, I have only once made it hot enough that I could just hold my hand on it, IR thermometer said 50-degC, but that was from constant stop and start slow monos for more than 5 minutes, the rest of the time it is cool, ie: less than 30-degC after a long ride. I think the trick is to keep the speed up, and have some common sense when climbing or going slow….works for me anyway!…”
Jay’s controller mods (ES builder Hyena):
“My usual mods are beefed up traces and phase wires and then the software flashed to suit. And of course running 4110-FETs. If dealing with noobs I will say “custom firmware tune” as this is easier to say than explain about phase currents, LVC etc. In the past I’ve also added bigger caps laid sideways along the board and fitted thermostats to the FETs to prevent overheating (N/C thermostat in line with the ignition wire) but for general use this isn’t really necessary. And it’s cheaper now to just step up to an 18-FET, than non-Chinese labour for doing these time-consuming mods.
Email is the best bet for contact, firstname.lastname@example.org
or my website hyenaelectricbikes.com , though it’s rather out of date these days and badly in need of an update and freshen up“