Sorry, no help to you but I always wondered if thermal imaging could be used for a cheaper/simpler? BMS (assuming one had a clear visual of the entire pack).
On Mon, Sep 30, 2019 at 9:08 PM Mr. Sharkey via EV <[email protected]> wrote: > Time to turn up the dial on the technical channel. > > After converting my car to a lightly-used set of Thundersky 160's, > I've finally gotten around to having some thermal images taken of the > cells after running the car up to temperature. My purpose was to make > sure that none of my cell interconnect wiring (copper strap stock) > was heating up. What I found was somewhat unexpected. One of the 38 > cells was showing an elevated temperature from the rest. > > First, the IR image of the right-hand half of the pack, taken from > behind the car. the suspect cell is at the center cross-hairs: > > http://www.westlanetv.org/~sharkey/evgfx/IR_0677.jpg > > A close-up of the cell, looking from the front of the pack. It's been > photoshopped to blend the IR image with the visible image to provide > some perspective of the actual appearance: > > http://www.westlanetv.org/~sharkey/evgfx/Hot_Cell_2.jpg > > The car ran a 15 mile trip at about 55 MPH, pulling 100 - 125 amperes > most of the way. A couple of 275 - 300 amp sprints pulling out into > traffic, etc. Photos were taken immediately thereafter. > > All of the cells had been carefully (manually) balanced a few days > before the photos were taken. During balancing, this cell was about > 15 ampere-hours lower than most of the rest of the pack, but not the > lowest of the 8 cells that needed attention. It came right up with a > balancing charge. None of the other cells showed any variance in > temperature in this series of photos. > > Questions for the list: > > The cell isn't actually "hot" but it's obviously warmer than the > rest. What's everyone's take on this one cell warming up? Can I just > assume that it may have higher internal resistance, and therefore > more heating under load? Is the heating indicative of a coming > (perhaps spectacular) failure? > > I've got about 1,600 miles on this new pack, and it seems to be > performing well. I'd like to keep using it in this configuration, but > if it seems risky to continue loading this one cell, it ~could~ be > jumpered out of the pack (not my first choice). > > Opinions or advice? > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/index.html > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20190930/2a7a2963/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
