## thread on the techno-fandom list, about electronics and cold weather * * * Subject: cold storage Date: Wed, 29 Jan 2014 14:39:08 From: *Hobbit* I want to raise the spectre of electronics in the cold again, specifically as relates to how Arisia does its logistics. I was an integral part of that this year, and Paul and I have had various discussions about why he insulates and heats his gear trailer, but I think a few basic facts are being missed that simply causes us a bunch of extra work in transit. There are different areas of actual concern: condensation on warm-up, damage to electrolyte in electrolytic caps, and possibly expansion / contraction over thermal cycles of solder joints and such. And the rated storage vs. operating temps of components. Then there's the thermodynamic reality of what we do: normally, push all our gear into a truck over an evening and stash the truck outdoors somewhere for about 12 hours before unloading it into the hotel the next day. Googling around for various combinations of "electronics", "storage", "cold", "freezing", "electrolytic" et al seems to turn up the most concern about condensation when items are brought in from the cold, with the mitigation being to leave devices in their shipping enclosures for at least 4 hours to warm up *slowly* and prevent too much external air circulation. Obviously good practice for laptops etc with hard drives which can develop actual water inside which you wouldn't want to spin them up with. Some mention is made of corrosion but we should remember that condensed water is pure, and doesn't arrive already full of ions. Electrolytic gel has a pretty low freezing point, and most ordinary commercial caps are supposedly good to -20C / -4F worst case which around Boston is still Foxtrot Charlie. We rarely get nights that cold and I'd say the average going-to-Arisia overnight ambient is more like 20F. But there's some additional reality to take into account. The gear we load is generally in roadcases or at least closed-up boxes, and we pack the truck tight with a *lot* of thermal mass. The truck itself provides wind shelter, so the only thermal loss paths are conduction and some radiative coupling. What's the R-value of a roadcase, do ya think, especially if it's lined with foam? So I seriously doubt that most of what's buried in that heap of crap is going to get fully down to outdoor ambient over the 12 hours it's sitting around. Some of that time is also spent driving, where engine and exhaust heat from the truck is helping warm the bottom of the box a little anyways. And remember, heat loss rate decreases as the delta gets smaller, so when the pile of gear is down to 40F the loss curve over time is a lot flatter. If it's any help, the truck may also have frozen food in coolers in the same space, and the food folks aren't concerned about any of that warming to dangerous levels overnight even if it's above freezing. I've seen gear come in from cold overnights, such as the wiggle-lights which have black-anodized aluminum bodies, and with a roadcase opened up from a freshly delivered load in a ballroom I've never actually seen condensation form on it. It feels cold, sure, but it's not acting like an evaporator coil especially in the fairly dry winter air we keep complaining about in the hotels. A little awareness and care in letting critical devices things warm up slowly before trying to use them will go a long way. We often aren't ready to even use them 4+ hours into build, instead working on noncritical stuff like cables, the cyc, wrangling rental stuff that wasn't in a truck as long, etc. My wheezy old Thinkpad for the Hog rig has spent its share of cold overnights and still works fine, and you might recall how paranoid *I* am about hard drive warm-up before one starts thrashing data on it. This apparently wasn't the case with some cameras in previous years, and I want to know the deeper details on that. How were they handled? Did someone pull a 'cam out of a cold case and fire it up right away? What was the failure mode and recovery, if any? Are we sure it was cold and not something else that caused the issues? I think it would be worth stashing a couple of thermometer widgets inside various cases and the truck box on one of these overnights just to see what the live reality is. I think we'd find ample evidence that the extra thrashing we go through to keep certain electronics indoors is completely for naught, given the practical timeframes we work under. And on the out, it comes into play far less because it's generally back in Storage later the same evening. Paul's situation might be different if he stores gear longer-term in the trailer. But has anyone thought about when some of those devices were initially delivered to stores and suppliers? That semi driver headed for Best Buy with the uninsulated 53' dry-van idling and trying to keep warm in the Minnesota rest-stop waiting for his hours of service to reset certainly doesn't give a rats ass about the storage-temp ratings of the electronics that are soon to become yours. This is worth a read: http://yarchive.net/electr/electrolytic_caps.html _H* * * * From: Angela Morley Subject: Re: cold storage Date: Wed, 29 Jan 2014 10:55:53 -0500 One of the things that I've recently become painfully aware of recently is the relative humidity changing at different temperatures. Say, for example, you live in an enclosed space with cold outer surfaces and a source of evaporated moisture, such as my boat. Its a comfy 68 degrees right now with 30% humidity, mostly from my breath, but when I leave for work and turn off the power for my heating, briefly open the hatch to leave and come back again, its 25 degrees or lower with 100% humidity, and frost on the windows. Now, I haven't had any electronics specifically fail due to frost accumulation on circuit boards, but the pre-packaging humidity level is something to definitely consider. If you control the humidity, I don't see the other factors, such as thermal expansion and contraction in our specific application, as having a meaningful effect. For shits and giggles, I did some searching and came up with a worst-case test that was done on a perforated copper-traced PCB with non-beveled holes and solder connections. They ran 500 cycles between -65C and +125C in 30 mins and noticed both copper corner cracking and solder cracking under these conditions at duty cycles over 300. How does this apply to us? We shouldn't take gigs in Antarctica without sufficient warm up time, but the closer look shows that the total thermal mass and longer warm up times between our practical logistics shouldn't have too much of an impact, and if it does at all, 300 cycles is your start point for failure under the worst conditions. What is the acceptable real world lifespan of our fixtures anyways? Let's throw some dessicant packets in the cases and call it a day? Reference: www.espec.co.jp/english/tech-info/tech_info/pdf/a7/e_37.pdf * * * Date: Wed, 29 Jan 2014 10:59:00 -0500 Subject: Re: cold storage From: Michael Leuchtenburg We could actually determine a priori whether condensation may form on a given device. Measure the dew point in the ballroom and compare it to the temperature you expect the gear to be - at coldest the low for the previous night, though probably warmer. If the dewpoint is too high, wait for the gear to warm up a bit first. The dewpoint can be reasonably well measured by a simple humidity-temperature device. They cost about $10. The cheap ones aren't the most accurate but they're probably good enough. On the out, condensation isn't a concern since no one is going to open it up and use it immediately on arrival anyway. - Lucky * * * From: *Hobbit* Subject: Re: cold storage Date: Wed, 29 Jan 2014 16:06:25 +0000 (GMT) Dewpoints and I have become best buds from the energy-retrofit study. In the run-up to that I found digital temperature/humidity toys for way cheap on amazon, and they're still there: http://amazon.com/dp/B007M6WLSO/ so I got three of 'em which have spent time scattered around various places in the house, outdoors, and even with me on roadtrips so I could see just how dry it was in the desert. I should have ordered a dozen and started giving them to people concerned about their indoor air quality. Even though the humidity read isn't the most accurate, one of these and the psychrometric chart http://techno-fandom.org/~hobbit/hse/log/614814/psych_annot.gif can tell you a lot about moisture. Given how leaky that building probably is plus the fact that the whole back hallway gets chilled down from the loading-dock doors being open for hours and people going in and out, that's a lot of exterior air infiltration being warmed up and the dewpoint in the ballrooms is probably pretty damn low by the time we're opening cases. Maybe if the nearby kitchen is boiling huge vats of pasta that could change, but their range hoods probably eject most of that outside. _H* * * * Date: Wed, 29 Jan 2014 11:48:13 -0500 From: Scott Dorsey Subject: Re: cold storage I wouldn't worry so much about caps, although it won't hurt to give them time to warm up properly. Properly designed professional equipment uses electrolytics rated from -20C to +105C. What worries me are lamps... I have had lamps explode when not given enough time to warm up. And, for a xenon projector lamp that costs $1800 to replace, that's very very bad. Lenses? The backfocus distance is set at room temperature in a nicely controlled laboratory. It won't be the same at 0C and consequently zooms aren't going to track properly. Kodak will send you a nice booklet on arctic photography if you ask them nicely, which discusses dimensional issues and how film and cables become brittle when cold. My proposed solution is to move Arisia to Miami. --scott * * * From: Syd Weinstein Subject: RE: cold storage Date: Wed, 29 Jan 2014 13:07:02 -0500 It's not just outright freezing of the electrolytic, as it is drying them out faster. The old cameras we use are just that, old. Most are approaching, if not over 20 years old now. The caps used in the cameras of this quality point in that era were not great and due to the age these were already marginal and this extra cycling did cause them to be non functional. I doubt they totally froze, but it accelerated their decay curve enough to cause failure. I doubt this would be as much of an issue with modern cameras as my Sony EX-1 is rated for Arctic use. We warmed the long before use (they sit in their cases for 1/2 day or more until we actually get them set up for use. I'm less worried about condensation, which would be mostly a lens issue, because we keep them in their cases and they warm slowly. Now, thermal cycling of old solder joints (of poorly made boards) can always be an issue, but I haven't seen many of these once they went to wave soldering. Syd * * * From: Paul Kraus Subject: Re: cold storage Date: Wed, 29 Jan 2014 15:16:25 -0500 > There are different areas of actual concern: condensation on warm-up, > damage to electrolyte in electrolytic caps, and possibly expansion / > contraction over thermal cycles of solder joints and such. Thermal cycling also affects mechanical components besides circuit boards and has a greater affect on aged equipment than on new, for a variety of reasons. Microphones are a special case where both temperature extremes and thermal cycling are destructive. > And the rated storage vs. operating temps of components. I have seen three or four tiers of component ratings: * Commercial grade: 0C to 70C (sometimes -10C to 70C) * Industrial grade: -40C to 85C (sometimes -25C to 85C) * Military grade: -55C to 125C (sometimes -65C to 175C) and sometimes Automotive grade, which is wider than Industrial but less so than Military. The above is from http://en.wikipedia.org/wiki/Operating_temperature and agrees with what I remember from component specifications (back when I read them). Storage Temperature ranges are greater than Operating in almost all cases. > Then there's the thermodynamic > reality of what we do: normally, push all our gear into a truck over an > evening and stash the truck outdoors somewhere for about 12 hours before > unloading it into the hotel the next day. Yup, we cannot assume that if it is 17 degreesF overnight that all the gear will achieve 17 degreesF. It will be someplace between where it starts and 17 degreesF. > But there's some additional reality to take into account. The gear we > load is generally in roadcases or at least closed-up boxes, and we pack > the truck tight with a *lot* of thermal mass. I don't really consider the rolling big blacks boxes with wheels real road cases. There is certainly no foam in them. If we assemble a "flight kit" as is being planned for post-Lunacon for the video gear, it almost certainly will not be in foam packed cases. The insulation value of the cases varies from very good (the cases *hobbit*'s wiggle lights travel in) to very poor (the black boxes of video and program A/V gear). I am limiting my discussion to Tech gear here, there are also plenty of plastic tubs of stuff. > The truck itself provides > wind shelter, so the only thermal loss paths are conduction and some > radiative coupling. What's the R-value of a roadcase, do ya think, > especially if it's lined with foam? So I seriously doubt that most of > what's buried in that heap of crap is going to get fully down to outdoor > ambient over the 12 hours it's sitting around. My goal has always been to keep my gear from getting much below 30 degreesF, perhaps 25 degreesF as best case design limit. If it is 20 degreesF ambient that is easy, if it is 0 degreesF that is much harder. > Did someone pull a 'cam out of a cold case and fire it up right away? What > was the failure mode and recovery, if any? Are we sure it was cold and > not something else that caused the issues? I believe that Patrick's gear sat for more than one overnight in the vehicle, but others with direct knowledge can comment. When we fired up the cameras they showed both condensation issues as well as bad capacitors. It has been reported that patrick had to re-cap a bunch of the gear after that year. Patrick also tested the gear before it was loaded onto the vehicle and it was fine at that point. > I think it would be worth stashing a couple of thermometer widgets inside > various cases and the truck box on one of these overnights just to see what > the live reality is. Great idea. Do we have a half-dozen recording thermometers ? We can do this at Lunacon if we decide to leave the gear in the truck overnight. > I think we'd find ample evidence that the extra > thrashing we go through to keep certain electronics indoors is completely > for naught, given the practical timeframes we work under. Depends on the gear. For my personal gear, I left the trailer loaded with most of my gear unheated Monday night as running the heat would have left me with a dead battery come morning. The ambient temperature in my trailer was 21 degreesF on Tuesday morning when I finished packing. I also kept my sensitive equipment (microphones) in my hotel room and loaded them into the SUV on Tuesday morning. > And on the out, > it comes into play far less because it's generally back in Storage later > the same evening. Paul's situation might be different if he stores gear > longer-term in the trailer. Back at home I run the heater off of 120v from the house. > But has anyone thought about when some of > those devices were initially delivered to stores and suppliers? That semi > driver headed for Best Buy with the uninsulated 53' dry-van idling and > trying to keep warm in the Minnesota rest-stop waiting for his hours of > service to reset certainly doesn't give a rats ass about the storage-temp > ratings of the electronics that are soon to become yours. The major shipper I work with *does* have temperature requirements on deli veries, but they are delivering wine and beer and the product is much less tolerant of temperature extremes. We need to do the best we can, and bias that based on the sensitivity of the equipment in question. The older something is, I am willing to bet, the more sensitive to temperature extremes it is. Same with temperature cycling. We also need to bias it based on how critical something is and how hard to replace. It is not worth the effort to pull a pile of DVD players out of the truck overnight because they are plentiful, cheap, and easy to replace. I can't say the same thing about the video switcher. Finally, there are limits to what we *can* do (such as my limitation on running the heat in my trailer, hopefully that will be resolved before the next Arisia). We should NOT be taking either extreme position (nothing can be left in the truck overnight regardless of weather -nor- everything can be left in the truck overnight regardless of weather). * * * From: Paul Kraus Subject: Re: cold storage Date: Wed, 29 Jan 2014 16:05:39 -0500 > Now, thermal cycling of old solder joints (of poorly made boards) can always > be an issue, but I haven't seen many of these once they went to wave > soldering. Once they got the wave soldering down. The first run of Soundcraft mixers that was wave soldered was the 200B series. We had two of them at WRGB that had horrible solder quality issues. Many years later I got a Soundcraft rep to admit that those were the first products to come through the brand new wave solder process and the staff had to figure it all out. It took very little stress to fail those early wave solder joints. * * * From: Dale Farmer Subject: Re: cold storage Date: Wed, 29 Jan 2014 22:51:55 -0500 As a data point, at ALPS, cold temperature cycling is not even considered with loading schedules, and we have some pretty fancy electronics in the control consoles, moving lights and the newer LED lights. Gear gets left on trucks overnight, sometimes over the weekend and the failure rates are just the same as the summertime. What we do see with gear that is left overnight in cold trucks is increased failure rate of the casters. Rubber and plastic wheels get brittle when cold. Gear is also setup in outdoor venues in miserable cold rainy weather, and the main problems are mud, water and frosting, not condensation. --Dale * * * Date: Thu, 30 Jan 2014 05:52:10 -0500 Subject: Re: cold storage From: Angela Morley On Jan 29, 2014 11:29 PM, "*Hobbit*" wrote: > While modern "fancy electronics" are probably quite immune to such > conditions, affirmation that your old Hog 500s, Mac 250s, Obsessions > et al [and dare I say, Martin 918s if you still have any in stock??] > that go on the road also have no issues would help put this issue to > bed forever where Arisia is concerned. If you haven't yet, check out the link I posted in the bottom reference of my first email in this thread. It talks about the technical hard breaking points of these things. How many cold weather shows does a venue like alps dish out the same equipment? My guess is that it would be so long before the temperature cycle limit is reached that the equipment would be up for technological replacement anyway. 300 worst case cycles per lifetime, and maybe 10 cold weather shows per year for ambitious equipment... You're looking at 30 years before it becomes a problem.