The Battery Balancer is a system that tries to keep the set of batteries in an electric vehicle "balanced" by shuttling charge to the weaker/lower capacity batteries in the pack so that the batteries will all reach empty at about the same time when they are discharged and full at about the same time when they are recharged.
It was designed as a research and development tool by Lee Hart for his own EV, but he had additional sets of PCBs made and has made those available to other EV'ers interested in such a device, and willing to accept the challenge of assembling the hardware and writing their own software to control knowing up front that Lee would only be able to offer very limited technical support (by the way, that's why this website exists; to provide a place for Balancer users to access useful reference material and exchange ideas with other users).
As of 05 Apr 2009, the Balancer has has gone through 2 revisions. The original ("Rev A") design, and the new improved ("Rev B") design. Both versions are described in more detail below.
All Balancer users are encouraged to send me details of their [anticipated or actual] installations, including photos, etc., when possible, and I will post that material here for the benefit of other users.
Thoughts on control strategies or other control software issues are also welcome, as are any modifications you have found worthwhile to the original design.
Revision History:
30 Nov 2010: Rev B schematics updated.
01 May 2010: Rev B schematics updated. Rev B overview updated with details of changes.
10 Jan 2010: Rev B schematics updated.
06 Sep 2009: Moved Rev A and B info to their own pages.
05 Apr 2009: Updated with Rev B information.
22 Sep 2002: Added links to bare PCB images.
05 Aug 2002: Initial revision.