|Motor||GE Elek-Trak 5BCY56RA6 compound shunt/series DC motor|
|Max RPM||2250 RPM|
|Voltage||36VDC (rated) 48 VDC (operating)|
|Frame||1979 Suzuki GL1000|
|Batteries||4 deep cycle Exide DC22NF batteries (75 min. @ 25A capacity)|
|Speed Control||4-speed resistive golf cart controller|
|Maximum Speed||53 m.p.h. theoretical; 47+ m.p.h. actual|
||The 36VDC-rated compound motor is mounted to the frame using the original mount plus custom brackets into existing frame holes. A 13 tooth motorcycle countershaft sprocket mounted on a custom-made hub is pressed on the motor shaft. The chain then connects to the rear wheel 42 teeth sprocket. The four 12 VDC lead acid batteries are connected in series (giving 48 VDC) to the motor through a golf cart resistive controller mounted on the frame backbone. The motor is connected in series rather than shunt/series.|
The new Exide DC22NF batteries are an improvement over the old wheel chair batteries. Unfortunately, I don't think they can handle the current flowing through them. Andrew Clark and Dean Sumter recommend "encapsulated glass" batteries. These are constructed with a sandwich of purified lead and fiberglass wrapped in a spiral. The electrolyte gel is encapsulated within the glass. Advantages include more storage capacity and no liquid electrolyte. Jeffrey McKnight wrotes: 'You might consider using capacitors instead of batteries. There is a company in East Providence, RI, called Evans Capacitor that makes a product called MegaCap. The MegaCap is a high power capability, high current discharge, unlimited cycle life capacitor that can be used instead of batteries. It's kinda pricey ($750), but the energy to weight ratio is quite high (2.5 KJ/Kg)." Any thoughts? How about caps for starting and acceleration and batteries for constant speed running?
John Stawicki is keeping up on the next generation batteries: Caterpillar's Firefly lead/graphite foam batteries and Ab Europositron's rechargeable aluminum batteries. Check these links out because both technologies are a huge improvement over the lead acid batteries used in the Mk II.
The existing golf cart resistive controller wastes energy through its resistor coils. But as the resistors are only used when accelerating from a dead stop, the period of waste is brief. A solid state controller is much more energy efficient, and permits regenerative braking. Unfortunately these controllers are $500 plus, so the cost outweighs the benefit at present. Cas Borkowski suggests using contactors to switch in different voltages to adjust speed. He has employed contactors in his electric SAAB for 20 years. Pat Quilter write: "If you supply various amounts of DC power to your disused shunt winding, you will be able to slow down the motor while increasing its torque. This will give you a virtually lossless method for about 2:1 speed control, giving you a useful range for cruising in traffic."
The chain, though efficient, is heavy. Several people have suggested going to a toothed belt like the new Harley's. Unfortunately the Harley rear belt sprockets are very expensive. Any recommended alternative is appreciated. Scott (scottmo) writes: " I was told some washing machine pulleys could be used also. " Bill Seifert from NE writes: "I have an old garden tractor that uses [a] spring loaded pulley. The [motor] will have a std pulley and the spring loaded variable will be on [a] jackshaft. Between is an idler pulley hooked to a [hand] lever. The harder you pull [on the hand lever] the faster it goes sinking the belt deeper into the spring loaded pulley." Greg Olson writes, "You could also use the pulley system off of a over-head cam engine. These can be found in most newer 4 or 6 cylinders for cheep or free. You just find the belt and pulley with the ratio you need. Most will be 2:1. You could mix pulleys from other applications with the same tooth size to get the desired ratio. There are a lot of belt drive systems on the front of most modern V8’s as well."
I have been looking
at go-kart centrifugal clutches. A 2-speed or continuously
variable transmission would be nice. David White suggested
using an older model Triumph or BSA pre-unit transmission. Jim
Donovan of MAX-TORQUE and Karen Karpes suggest using a torque
converter from a snowmobile. Eric (AKA Night Shadow) suggests
using a continuiously variable belt drive mechanism driven off
a centrifical clutch from a 1978 Honda "Hobbit" (model PA-50).
Glenn Thomson suggests using a transmission from a small
2-stroke dirt bike since it runs in its own sealed
compartment. I have seen belt-based continuously variable
transmissions in catalogs, any additional suggestions or ideas
would be appreciated. Scott (scottmo) writes: "...a
transmission might be adapted from a rototiller if you could
find an aluminum one to cut weight or a lawnmower, I found one
on a barbecue spit that was lite weight with two speeds."
Richie Bauer suggests, "You might consider using a spindle RPM
assembly from a Bridgeport milling machine. It's 2 pulleys in
a 'V' configuration with one of the pulleys moving in &
out changing the diameter that the belt rides on. It's all
mechanical so a small electric motor will have to be used to
change speed but then the drive motor can possibly be at a
lower rpm for a longer time." Perhaps a hand operated lever
could be used to change the adjustable pulley. See Bill
Seifert's comments in Belt Drive
above. Bill also suggests using a system similar to the drive
used on Snapper mowers.
For extended range, supplementary batteries could be stored in a trailer. Good quality trailers are available for motorcycles. Perhaps one of these models could be suitably adapted. Daemien suggests "...you could build two and have one charging at all times." Rick Nelson suggests using a sidecar. See Carlene's suggestion below.
The Electric Motorcycle is very quiet -- the only sound heard while riding is the whoosh of the wind plus a small amount of chain and motor noise. Several people have suggested adding a boom box with pre-recorded Harley or Ducati sounds to give the bike a more traditional aural presence. Ole Hansen suggests abandoning the boombox to reduce noise pollution.
A small gasoline powered generator could be installed on the bike or in the trailer. This will allow charging the batteries while parked at work for the return trip. Modern portable generators are very efficient because they are optimized for a fixed running speed and load. Alternately, a portable solar panel "awning" can be fabricated. The panels fold out to cover the bike while parked. To supply enough current, however, the panels need to be large. Tim Stewart points out the clever Global Solar folding panels. The 54 watt model folds down to 9.5 X 13.5 inches and weighs only 3.5 lbs. Chuck Knight suggests using a large collapsible mylar mirror concentrate the light. This would reduce the number of cells required and thus the weight and expense. Carlene Ballew suggests storing the panels in the trailer. Scott (scottmo) suggests: "...a weed eater engine and a high amp alternator from a new GM for a light weight charging system that would fit in a saddle bag."
The Importance of Eco Friendly Cars (lots of informative links -- thanks David!)