> ...a couple years ago I used a thermal imaging camera to demonstrate > how hot a lighting controller board got under heavy load. > http://forums.lightorama.com/topic/45960-how-warm-does-a-sandevices-e682-g et/
Warning! A common mistake. The "heat" visible on the eithernet connector has nothing to do with that connector. That is nothing but a reflection of something hot (maybe the person taking he picture). Notice how in every view, there is variation in the "heat" image of that shiny connector. This is because SHINY METAL does not radiate heat very much but it does provide excellent specular reflection. So all you ever see of a shiny metallic component is what it is reflecting, nothing at all about its own temp. A very common mistake. The Thermal emissivity of everything in view is *assumed* to be about 0.9. The operator has to know enough to discount any reading of any material this is not 0.9 ish. True, most things are, but definitely NOT shiny metal! Aluminum is 0.03 or 30 times less emissivity. (that is why we wrap it around a baked potato!). Hold up a baking tin, it acts like a thermal mirror to everything in the room. You are seeing nothing about its own temperature. Bob, WB4AAPR -----Original Message----- From: EV <[email protected]> On Behalf Of jim--- via EV Sent: Tuesday, October 1, 2019 2:21 PM To: Electric Vehicle Discussion List <[email protected]> Cc: [email protected] Subject: Re: [EVDL] LiFePO4 Thermal Imaging Opinions? Yes. Heat is going to conduct better through the metal plates of the batter vs the electrolite. Therefore, the heat if generated at the connector is going to conduct along the metal plates. Assuming that the plates in that battery are vertical, I would expect something similar to what is being seen. Also note that the strap is FAR hotter than the portion of the strap visible at the left edge of the IR image, and that the right end of the strap and the top of the cell on the right that is connected to that strap is also warm. There is a lot of heat being generated in the strap or more likely the connection between the left end of the strap and the top of the battery. We use IR images using similar equipment here at work for checking electrical connections quite regularly. For a little entertainment, a couple years ago I used a thermal imaging camera to demonstrate how hot a lighting controller board got under heavy load. I posted the results on a Christmas Lighting forum. You should be able to read it - although you can't post a reply unless you are a member of that forum. http://forums.lightorama.com/topic/45960-how-warm-does-a-sandevices-e682-g et/ Jim -----Original Message----- From: "Peri Hartman via EV" <[email protected]> Sent: Tuesday, October 1, 2019 10:53 To: "Electric Vehicle Discussion List" <[email protected]> Cc: "Peri Hartman" <[email protected]> Subject: Re: [EVDL] LiFePO4 Thermal Imaging Opinions? Wow, hat's a great observation. Question: is it significant that the IR image also shows heat emanating vertically, appearing to be relatively uniform ? Peri ------ Original Message ------ From: "jim--- via EV" <[email protected]> To: "Electric Vehicle Discussion List" <[email protected]> Cc: "[email protected]" <[email protected]> Sent: 01-Oct-19 10:36:24 AM Subject: Re: [EVDL] LiFePO4 Thermal Imaging Opinions? >> 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 > >Carefully check the connection on that cell that is closest to the camera. Note that only the one end of the cell is warmer - not both ends. I would suspect that the connection is marginal and causing the heat. The heat has conducted into that end of the cell. > >73 >----- >Jim Walls - K6CCC >[email protected] > > >_______________________________________________ >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) _______________________________________________ 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)
