Peakfoto Digital Photo Still n Video wrote:
Is there something cheaper simplier than 2-8 cell log. So I can monitor my 22 LFP cell pack. For like if 1 cell drops below like 50% DOD or a choseable voltage that alarm me while riding.
I guess it depends on what you call "cheap" and "simple". eBay advertises some Chinese ones intended for R/C models that are dirt cheap. But you get what you pay for...
Cedric Lynch made a very simple system for his lithium cell pack. Each cell had an LED, a resistor, and an optocoupler. The LED, resistor, and LED inside the optocoupler were wired in series. They were chosen so the optocoupler was "on" if the cell was above the desired threshold, and "off" if it went below that threshold.
The isolated output side of all the optocouplers were wired in series. They controlled an LED and alarm buzzer. If all cell voltages were good, the "good" LED was on and the alarm was off. If any cell voltage dropped below its threshold, it broke the series chain, turned off the "good" LED, and sounded the alarm.
The three parts cost about 30 cents. Cedric put each circuit in a scrounged prescription pill bottle, so they were free. It's hard to get much cheaper than this.
-- Ingenuity gets you through times of no money better than money will get you through times of no ingenuity. -- Terry Pratchett -- Lee Hart's EV projects are at http://www.sunrise-ev.com/projects.htm _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
