Lee Hart: 1802 Membership Card, electric vehicle work

Last updated Aug 9 2012. Edited by Herb Johnson, (c) Herb Johnson execept quotes from Lee Hart (c) Lee Hart.


Lee Hart and I have been friends and colleagues since the 1980's. Since the 21st century, he's become known for at least two things: electric car related designs and products; and the low-low-power vintage microprocessor from RCA in 1975, the 1802. This page is about his EV and related developments: Lee has a Sunrise EV Web site at this link, contact him there. For his work on the 1802, check the Membership Card Web page, a project I publish on this Web site. - Herb Johnson

The 1802 COSMAC "Membership Card"

Lee Hart is a digital designer with four decades experience, starting with 8-bit microprocessors in the 1970's. He's reproduced a version of one of those classic microcomputers in 2009. "The Membership Card is a reproduction of the original 1976 COSMAC 1802-based Elf computer, repackaged to fit in a pocket-sized Altoids(R) tin. It uses no custom parts, no surface mount assembly, no need for PCs, no megabyte compilers, or secret software to use it. Now you can learn about computers right from the ground up, and really understand how they work!" - Lee Hart

Check the Membership Card Web page for a description of the kit, its development, and 1802 history.

Tribute to Bob Rice; 1802 Membership Card design

Lee talks about his design philosophy from time to time. In 2012, Lee had some thoughts, based on the views of Bob Rice, a well-known electric vehicle visionary, who passed away in 2011. Here's some of Bob's considerations as Lee saw them, plus some links to other sites with their tributes to Bob Rice. I incorporated these thoughts of Lee Hart's, into the background discussion that led to Lee Hart's 1802-processor-based "Membership Card" product.

Electric vehicle (EV) design and development

Lee Hart has contributed a number of products to the EV community. One is the EVILbus specification of Nov 2005 by Lee Hart, John Lussmyer at casadelgato.com, et al. It's a serial data bus spec developed by/for the Alameda Systems EV car. That site has a 2008 HTML version on the page linked. Additionally, there's a 2009 set of versions (and discussion by Lee Hart) of the specification on the casadelgato.com Web site.

Another EV project of Lee's is Lee Hart's Battery Balancer for electric vehicle battery management. He and others have worked on a number of these over time, as Lee describes below.

Lee often posts about electric vehicle (EV) design and components in the EVlist EV discussion list or EVDL. It's a great resource for anyone who wants to build or understand electric vehicles and their parts. The EVDL.org library has a variety of designs for electric vehicle electronics, including submissions by Lee Hart.

Sunrise EV2 open-source car

The original Sunrise was designed by Solectria Corp. Lee Hart and his co-conspirators bought the last prototype from them and hauled it from Florida to Minnesota. He and others are at work to make a master prototype they call the "Sunrise EV2", from which other EV's can be made. It's an "open source" design; they intend for others to make their own from open plans. Most parts are available from "donor cars" and commercial sources: they are working on casting body parts from fiberglass. More on the Sunrise EV car as a user-buildable project is on his Sunrise Web site.

Interviews with Lee Hart about the Sunrise include this 2008 article at manufacturing.net. Even Mother Jones magazine found Lee Hart's work, here's their 2008 article. and the discussion poisted afterward is worth the read. An 2009 audio interview of Lee Hart is on this Minnesota Public Radio Web page about his project. (If that interview link "fails", let me know.)

Battery Balancer

In 2012 Lee Hart described this project to me as follows below. Text in []'s are my edits. - Herb

"Many people have realized that the cells in a battery pack are not all identical, and that the weakest one limits the performance. Small differences tend to get larger over time, as the weaker cells get stressed more and thus wear out sooner."

"Most battery chargers blindly overcharge their pack. This allows time for the worst cells to reach full, but it "pounds down" the best cells to help the weaker ones. It keeps the charger simple and cheap, and provides good capacity per charge, but it shortens the pack life. This approach is especially bad with sealed cells, which die early if overcharged. Some types, like lithium cells, can even catch fire if overcharged."

"Most battery management systems put a simple shunt regulator circuit across every cell. When the voltage indicates that the cell is full, it shunts excess charging current to a resistor or other load during charging. Lee's zener-lamp regulator [as described on the EV Discussion List archive linked here,] is probably the simplest possible version of such a circuit."

"But I found a better way to do it. In 1997, I started building a Battery Balancer system that transferred charge from the stronger cells to the weaker ones. [Here's a reference to one of my designs, that others have adapted.]. It has a DC/DC converter, powered by the pack as a whole, which is switched by relays to charge whichever cell/battery needs it the most. It therefore "props up" the weakest one, so range is no longer limited by the weakest cell. It also allows a pack of mismatched cells to keep being used, thus extending their life and lowering operating cost. Instead of a shunt regulator that must be duplicated for every cell, the Balancer only needs a relay per cell; the rest of the electronics is used for all cells." - Lee Hart

Older references on the Web about it, are at the following links: cameronsoftware.com; at at ntlworld.com; and on this birenboim.com Web site. - Herb

Contact information for Herb Johnson:

Herb Johnson
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This page and edited content is copyright Herb Johnson (c) 2012, except as quote copyrighted by the authors. Contact Herb at www.retrotechnology.com, an email address is available on that page..