John's EV Pages

Custom Search

This site is different than most EV sites in that there will be no evangelizing.  Being of rational mind, scientifically educated and not from California, I know that EVs:

• Won't save the world.
• Probably won't ever constitute a significant form of transportation in the US.
• Are not the basis for some strange alternative religion.
• Won't reduce pollution, at least until electricity is mostly made from nuclear energy.
• Aren't practical as a primary vehicle, at least for normal people.
• Aren't practical for everyone.

What EVs ARE, are fun-to-drive and very cheap-to-operate vehicles that are practical for most in-town errands.  My EVs save wear and tear on my regular cars plus they are much more convenient. 

Convenience is something many people don't realize.  In the summer my CitiCar (an example pictured above left) has its doors removed.  To go somewhere, I sit down, insert the key, flip the switch to FORWARD and go.  The GoBig scooter (pictured above right) is even better.  Jump on, flip the kill switch to ON and go.  Pull right up to the door of my destination, flip the switch off, pull the key and step off.

Most of the contents of the following pages involve modifications and improvements I've made to my EVs. 

Misc items not needing their own pages are below.

Peukert_calculations.xml

This is an interesting accessory that might save an EV driver a lot of grief.  It's a charging plug that can eject the cord when a built-in solenoid is actuated.  This is to prevent one from driving off with the charging cord still attached.  It is designed for ambulances but it is perfect for EVs.  One version is made by Kussmaul.  Another source is here.

The Solenoid is normally wired to the ignition switch so that when the switch is turned on, the cord is ejected.

This is a photo of a contactor economizer.  This is designed to send an initial surge of current through the contactor to pull it in and then reduce the current to a lower holding value.  It is nothing more than a resistor and capacitor hooked in parallel, shown with the heat shrink covering that is applied after soldering.  This assembly is hooked in series with the contactor coil.

This particular one is for a contactor that normally draws about 1 amp at 12 volts.  The resistor is 50 ohms and the cap is 2200 uF at 35 volts.  Both refugees of my junk box.

The file at right is the schematic of the GE EV-1 SCR controller that dates from the 70s.  It was widely used on fork lifts and was about the only production controller suitable for EVs back then.  It's a quite clever design and is worth studying.

Thanks to Lee Hart for turning it into an Orcad schematic that I in turn, converted to a pdf.

 This is the chapter on DC motor controller design from the book "Motor Control Electronics Handbook" by Richard
Valentine,  ISBN-10: 0070668108.  I pulled the scanned GIF images from here and converted them to a pdf for your viewing pleasure!