Individual bar graph battery monitor Re: By Gollie Ollie

["JB Straubel" <jb_straubel@hotmail.com>]

It sounds like being able to monitor the voltages on all, or at least one 
individual module is a common desire for an EV driver.

I have an Optima pack in my car (20 series batteries) and have had a very 
rough time keeping things balanced and preventing module voltage reversals 
near the end of charge.

As has been discussed by a few other people, I have also put together a 
voltage measurement system that cycles through the pack and measures the 
voltage on each module roughly every .3 seconds.  I also have a small serial 
LCD display on the dashboard that graphs the voltage data as it is taken.  
One 32 segment-high bar for each battery.  This has been amazingly useful to 
diagnose the pack and simply fun to watch while driving.

Take a look at this site for more info on that system:

http://www.jstraubel.com/batbox/monitor.htm

I have only built one of these systems, but it sounds like other people 
might be interested in it.  If there were three or so drivers that might 
want something like this it could be worth the time to make some more.  Is 
anyone interested?  I'm not really sure what it would cost, but I did put a 
few tentative numbers on the web site.

JB

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