I have always thought temperature could be used in this way. Sent from my iPhone
> On Oct 1, 2019, at 1:30 AM, Gary Krysztopik via EV <ev@lists.evdl.org> wrote: > > 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 <ev@lists.evdl.org> > 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) > _______________________________________________ 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)
