1000 Miles Per Gallon with Electric Bike?
In case it's missed your attention, car-based transportation is expensive.
The gas alone at 25 miles per gallon is $0.12/mile at $3/gallon and is closer to $0.13 a mile with this week's spike to $3.20/gallon. When the prices drift toward $4/gallon you're soon paying $0.16/mile for gas.
However, most of the alternatives aren't really that much cheaper. Most hybrids drop the fuel cost from the $0.12-$0.16/mile to more like $0.06-$0.08/mile. Throw the actual cost of $25,000 vehicles, depreciation, insurance, repairs, etc. and even the $0.445 that the IRS allots for car cost seems low.
Now, what about cruising along with the wind in your hair at 20 mph without getting sweaty or even having to pedal? What if that only ran $0.003 in fuel and the complete vehicle costing less than $500? That's what electric bikes offer.
Given that the safe bet is for $4 gas and $5 gas within the next couple of years (hey, we still had $0.85 gas in 1999), and the fact that I can currently take all city streets to get to work (nothing over 40mph speed limits), I decided to do a bit of digging into supplementing my Geo Tracker (which already gets 25-30mpg) to keep my transportation costs down.
Beyond the purely financial benefits is the fact that most of these designs allow for pedaling to supplement the electrical system, meaning some exercise can still take place without the whole dripping-in-sweat experience of normal bike commuting.
So, what are the options?
First, after a first pass of reading about this stuff (which actually happened last year), I had a couple of design parameters.
I knew that I didn't want a dedicated electric bike or scooter. When the system is based on a regular bike, you can easily swap bits out to improve performance, comfort, looks, etc. Whether it's pulling the electrical off of the bike and putting it on a better bike or upgrading motors, batteries, etc., a system based on a regular bike just makes modular sense to me.
I also am not going to consider weight or regenerative braking very seriously. In the bicycle world, lighter components cost more. And, "lighter" usually means by a few ounces. 10 or 20 pounds extra on the bike itself isn't going to affect the project nearly as much as having to spend an extra couple of hundred bucks for lighter versions of things like batteries. Besides, if I want to get rid of weight, it's a lot cheaper to get rid of it off of my body than off of the bike. Before I start worrying about how heavy the bike is, I should drop 30 pounds myself.
That lack of concern about vehicle weight (at this scale it's not nearly as big of a problem as in a car) is driven by another parameter: distance over speed. I'd rather have a system that can go 20 miles on its own and 30 with pedaling, but can only go 12 mph than one that can go 25 mph for 10 miles. That means that I'm heading toward the biggest batteries that make sense, even though they'll weigh more and reduce maximum speed. Somewhere in between the ultra-light batteries and pulling a trailer full of them is a balance between those things.
So, what are the options?
One option is the hub motor kit that is sold in a variety of places. This is currently the frontrunner plan. The 600W motor and 36V system runs about $350 most places. I like this option because it's easy to install, doesn't require any messing with gearing, sprockets, etc. to transfer power from the motor to the wheel.
This kit includes the battery setup too, which you should watch for in other kits. Lots of them are sold at much higher prices and don't include even basic batteries. Installation of these hub motor kits is reasonably simple from what I can see.
Given that I always like to know what all of the options are, I've also looked into a few other designs.
One of them is the Bidwell bike pusher. It's basically a little trailer containing the motor and batteries that pushes the bike along. The guy who wrote it up has filed a patent though the only thing particularly inventive about it is the coupler that hooks it into the bike.
The biggest problem with that design is common to the rest of the R.Q.Riley designs. They all are based around tearing apart a specific existing product and then building the design. That leads to designs that don't age well. Many of their early designs are based on the original VW Beetle, which was plentiful when they designed the conversions, but they're much harder to come by now. I prefer a more off-the-shelf type of design.
This particular design is based on a scooter that runs about $400 where I looked. That puts even the Bidwell + cheap Target bike at the $500 mark.
However, I think that a similar device could be built with individual components and make the result much more powerful. This 1000W motor is $100 instead of the 350 watt motor that comes from the scooter that the Bidwell specifies.
When you pair it with a controller at $50, you're set for a lot more power with lots of money left over for the batteries (the other major component) and the misc wheel/gear bits.
I did buy a copy of their plans and wasn't impressed. Among other things, they have a section where they mention adding an MP3 player and their explanation of how to do that is pretty much, "add some speakers and an mp3 player". If you look at the patent, you've got all of the useful information on the device.
So, at any rate, what I'm planning on for next spring is a basic Target bike and the hub motor kit. Once I run some numbers on that first setup, I'll start tweaking things like smoother tires, bigger batteries, etc. I'm also planning on using a plugin electric meter that I bought a while back to monitor exactly how much juice goes into the charging to measure how many killowatt hours are actually used to move my carcass around.
Eventually, I'd like to have a recumbent trike with a 1000W motor and enough batteries for some serious range. That will have to wait. I'm also curious about what it would take to combine 2 of these hub motors to do the trike.
August 17th, 2006 at 7:23 pm
Thanks for the info on the e-bikes. I am looking forward to hearing about where you go from here. I was debating between those plans and trying to make my own design.
August 22nd, 2006 at 4:16 am
I have made the plunge into electric bikes,
and love them. I have bought 3 Wilderness kits
now and find there product AAA. The kits are
very easy to put together and you can modify
any old bike. I suggest a 7 speed because you
will not need all the gearing. The first
problem I experienced was not being able to
peddle at higher road speeds ( 30/35 MPH )so
I replaced the old 48 tooth sprocket with a
60 tooth sprocket.
My kit is a 36 volt, 600 watt, 12 amp/hr
They say you get 20 miles to a charge, but
that is a sales pitch and not reality. At
full throttle I get about 6 miles. My best
average speed to work has been 23 MPH , with
2 stoplights that day.( 6 mile trip )
This week I plan to put 48 volts to my system
and hope not to overheat my Hub Motor.
If you have any comments or questions, feel free
to email me @ jimshoprat@aol.com
August 22nd, 2006 at 5:11 am
Those are some of the exact issues I had suspected. I picked up a cheap Target bike as my first guinea pig and it's geared so that I can see how at 20mph you'd have to really spin to contribute at all.
Thanks for the amp/hr ratings and your real world numbers. I'm clearly going to have to supplement the battery setup for commuting to be an option (7.5 miles each way).
August 24th, 2006 at 11:08 pm
There's a site you may want to check out — actually a discussion forum — about all things related to electric vehicles:
http://www.visforvoltage.com
I live in Brooklyn Center and work in Robbinsdale — a nice 4-mile commute for my Schwin S-500 eScooter when I have a chance (http://www.currietech.com/html/schwinnCatalog/CTI_SchwinnMainProd.html). Given that I have a 2-year-old son who needs transportation to daycare, it's not always possible, but I use it for errands in the neighborhood too. There is a separate section within that site for "pedelecs" like you're considering. By the way, what's the status of your mayoral push? Campaigning for the primary election or deciding to channel efforts elsewhere? Would love to have a mayor advancing the e-bike cause!
September 8th, 2006 at 6:46 am
Hey Andrew. Somehow I missed this comment. I'll definitely be checking that forum out as I move forward on this project.
The mayors race is still going forward, but part of me doing it this time around was to see how far I could get without having to raise funds, etc. There are also some things that have come up that are much higher priority (most of which I'm honor bound not to talk about publicly).
However, running this time around was sort of a dry run. Given how few people filed for the city council spots, I'm probably going to file for the next one of those that opens up. I'd love to get this whole concept of transportation other than the immediately obvious to the forefront of city planning.
September 25th, 2006 at 6:47 pm
Been riding My Wilderness Kit Since 7/17/06 and shot one set of batteries 736 miles the batteries that come with the kit I hear and have found are not too good I will be switching to Batteries plus Batteries
you can check out my blog at http://www.lockardtechnologies.com/cgi-bin/yabb/YaBB.cgi?board=ebike1
other than that I would have to give the kit an A+
December 25th, 2006 at 1:26 am
I have a Chrystalite Cruiser hub motor with a lithim ion set of 36 volt 15.6 amp hr batteries. The range on flat land must be amazing because I climb 1000 feet for about 3o minutes with mine and still have more than half my juice. On flats I think the range must be at least 5o miles or more. I do pedal a bit though especially on the steep hills. But i absolutely love the bike. Here is my setup. Specialized rock hopper alum mtn bike. Then conveted to a rear hub motor as mentioned but I put the battery on top of the bottom tube for better handling in the hills and for mild jumping performance There rear rack just doesnt cut it from a g force perspective … you want the wait as low and centered as possible. i used a large mtn bike fanny pack (by North FACE) for the batteries and all the wiring.
I Love this setup and being under weather with a cold and still being able to hit the hills with ease… Priceless.
and .0003 cents a mile aint to shabby. I think I get it for even less. But I will settle for .ooo3
steven
January 29th, 2007 at 2:31 pm
This is exactly where I'm going. I'm thinking of using the hubs and trying to find a good deal batteries. A lot of Chinese mfgs have been beefing up the Amp-Hour/kg by doping the lead-acid batteries. The biomod guys (http://groups.msn.com/biomod) have been experimenting with this and the new photovoltaic films.
Thanks for your thoughts!
Jonathan
December 4th, 2007 at 2:59 pm
I think this is great, and fun to build as well. Has anyone thought about building a hybrid that is more like hybrid cars in the way it captures lost some braking and/or downhill momentum energy for re-charging?
May 9th, 2008 at 11:23 pm
I built a Bidwell pusher using a Swhinn 1000 Watt Stealth scooter I had (not street legal). I’m very pleased with it. I was able to use something that was not street legal in my neighborhood and turned it into a lot of fun and made it street legal. I use it to ride to work every day. Get 25 miles out of a charge (72 Volts) at an average speed of 13.5 MPH.
I put it behind a cheep full suspension Mongoose mountain bike I bought from Wal Mart, made a few modifications (tires, seat) and find it a great experience and an introduction to building E bikes.
I’m in the process of building Bidwells Cheetah with a 1000 watt hub motor using Eonyx 48 volt lithium battery system. With a few modification it will resemble an early 20th century Indian motorcycle.
July 14th, 2008 at 1:17 pm
How is the project going? Did it end up looking like an old Indian? How does it run?