Book: Electric Bicycles - A Guide to Design and Use

[rsscott]

If anyone is interested, a rather good book is available called:

Electric Bicycles
A Guide to Design and Use
by William C. Morchin / Henry Oman
Publisher: Wiley
ISBN: 0-471-67419-2

It's pretty heavy reading and goes into great detail on the following subjects:

• Estimating motor-performance for wind, hill and crusing power requirements
• Estimating battery capacity and a thorough description of charging
• Motor and motor-control options
• Evaluating motor-to-wheel coupling options
• Placement of propulsion components
• Configurations and performance
• Developments to Watch

Blurb: The text reveals important techniques, data and examples that allow readers to judge various propulsion setups - used in both home- and factory-made bikes - and estimate speed and travel distance for each. Numerous charts clearly present the costs, benefits, and trade-offs between both commercial and user-converted models.


I picked up my copy from Blackwells online who were fantastic and the book arrived the next day. Far better than Amazon who cocked up my order three times!

cheers
Russ

 

[flecc]

Thanks Russ, I'll add this to my cycle science library. I'm also taking your tip and trying Blackwells, though Amazon have never let me down to date.

 

[Tim]

Yes, this particular stocking filler is available at Amazon and in stock

Amazon.co.uk: Electric Bicycles: A Guide to Design and Use (Ieee Press Series on Electronics Technology): Books: William C. Morchin,Henry Oman

I'm going to have a root around foyles later to see if they have it.

 

[allotmenteer]

I bought this book on your recommendation. I got it on the Amazon site through of their other sellers.

It's an interesting read and gives lots of background info on electric bikes. It doesn't however give detailed instructions on building your own bike but provides a discussion of the technical issues regarding electric propulsion, batteries, electric motors and controllers.

I'd recommend it to learn more about the subject, particularly for those who aren't from an engineering background like me.

 

[flecc]

I'm very critical about the way some of the information is presented in there. The chapters on batteries contain both silly and irrelevant statements.

For example:

35000 charge-discharge cycles on 100 Ah Li-ion under lab conditions, none relevant.

Concentration on performance of one type of miniature cell 18 mm in diameter. The cost of a battery using these would be very high and the charger or control element costs astronomic, not to mention the bulk of one or the other.

The performance examples resulting from the author's experience in satellite powering where conditions are utterly different and completely irrelevant to cycle use, both in charge cycling and depth of discharge at typically 15% or less. To have the slightest chance of achieving any of the life figures given would entail using only a 4 or 5 mile range on an electric bike at most.

In the Li-ion battery example given, only 20% of capacity lost after 25000 charge-discharge cycles. When charged once daily for each journey, a service life of 60 years. In their dreams.

There are many other examples of this sort of nonsense, and in my view, much of it totally fails to meet the requirements of it's title "Electric Bicycles, a guide to design and use".

"A speculation on possible future personal transport developments" would better match as a title.

 

[allotmenteer]

I agree with flecc (and bow to his superior knowledge - I'm an Economics graduate and thus don't really understand a great deal about electrickery and the like. I can sit the right way on a toilet though ). I did think the battery chapter was a bit overdone - perhaps to pad the book out a bit.

Yes a 15% depth of discharge on my li-ion might make my battery outlive me (i'm 36) but it would barely get me the 1/2 mile to Tesco and back. Unless I buy a 24V 100 Ah battery but I imagine that would cost about £2000 and weigh 20 Kg!

From my layman's point of view I don't regret reading it, if only because there isn't much out there on the subject. Don't spend your life savings on it though.

 

[flecc]

The very long lives and high performances of Li-ion in that book relate to cells at two extremes, very large and very small. Fairly long life is theoretically available in some small Li-ion consumer batteries like those in cameras.

Echoing the silly performance example of a the Zero car in that book which uses 8600 small cells, I calculated a battery for my Torq using the 810 mAh cell from my Pentax Optio camera. Here's the results:

About 124 cells costing £3700, the battery volume no greater than at present, but without any internal circuitry. It would need a charger connector with 125 contacts, plus more for temperature control, probably over 150 contacts in all.

The charger size and cost would be prohibitive, 124 individual monitoring circuits, voltage and current control circuits, charge balancing circuits etc.

The battery would probably be finished after just a few uses, maybe only one, since there would be no reverse voltage protection between the parallel cells needed to attain the 10 Ah capacity. Adding that to achieve a long life would make the battery very much bigger, no longer able to fit in the bike.

Not exactly practical design.