ELECTRIC BIKE DYNAMICS
I attended a meet up and Evening ride with the Electric Bike Club of San Diego, just the other evening. During a rest stop, required for aching derrieres rather than aching legs, the subject of battery voltage vs motor power came up.
I am an experienced sailor and engineer and first got interested in E- vehicles from Battery power applications on Sailboats.  The over-riding problem for all electric battery powered applications, E-bikes in particular, is the compromise between battery capacity and motor power. E bike batteries come in a range of 36-48 volts and 8-15 amp hour capacities. At Electric Bamboo Bike Co we design for the best efficiency of motor drive and performance. With a 350watt 36volt motor and battery capacity of 13.6 amphours, our lightweight bamboo frame and clean design give outstanding performance. Our FREEFALL Cross Trail weighs in at 41 pounds and will travel 50 miles at an average speed of 18MPH, and still show over 50% battery capacity.    

Freefall electronic display 

The current trend is towards 500watt and  even 750watt motors, requiring heavier 48 volt battery packs. This may be advantageous in certain application like competition short duration riding but the current drain on these battery packs is very high, causing overheating and rapid loss of recharging cycles.
I am always amused by the stories of e-bikes achieving 70MPH - it is possible of course, with high amp controllers and todays Lithium ion batteries, but only for a few minutes duration before recharging is needed
LIVE FAST - DIE YOUNG  [the battery mantra]

HAPPY JULY 4 TH EVERYONE 

Here in San Diego we have a July4th Big Bay Boom firework display and we have LOTS of tourists. Put them together and you have GRIDLOCK around the bay and beach areas. I watched the fireworks from a sailboat anchored out in the bay just about in the middle of the pic - and it was a shock and awe experience !
We felt every snap, crackle and BANG

It is in the summer months [ and they go all the way to November here in SoCal] that your car turns from an asset to a liability . There is nowhere to park in summer ! I took my Freefall Cross Trail Electric bike down to the bay, bypassed the traffic, the parking space hunters and the parking ticket officers out in force. I arrived on time and unstressed. I locked the bike to a stand and unlocked the batterypack and took it with me in my backpack. It weighs  5 lbs but its better than having it stolen - Yes even in this fair city, there are people with no concience about taking anything that is not nailed or bolted down .
This is one reason why we installed the anti theft GPS tracker on all our bamboo bikes -
for more details click here