Yeah... I have no idea if it would be practical, or even work... but it's an idea.
I can't imagine that -13F would be a problem inside an enclosure around here, since they're normally going to be enough electronics in there to make a fair amount of heat, but if there was an extended power outage or something like that, it could certainly happen... and that's really not when you want stuff failing. On Mon, May 18, 2015 at 9:40 PM, Adam Moffett <[email protected]> wrote: > Ok, but Forrest is using all industrial components that are rated to > -40C. Are you saying he should add a resistor just to pre-heat the SD slot? > > ...ok maybe you're on to something there. How about that Forrest? Would > a 10cent resistor and 2 minute pre-boot warmup eliminate any issue? > > > On 5/18/2015 10:37 PM, Mathew Howard wrote: > > You could get around that by putting a heater on board to warm up the > components, like the epmp has. > > On Mon, May 18, 2015 at 9:34 PM, Adam Moffett <[email protected]> wrote: > >> The danger you have to consider is a cold start, such as if the power >> was off for awhile. >> >> >> On 5/18/2015 10:32 PM, George Skorup wrote: >> >> This winter was pretty cold. For about a week straight in the middle of >> January and again in February, I had a few base units reporting under 0F >> every night. And I know the outside air temp was -20 to -25F. Obviously >> take the base unit's temp reading with a grain of salt because it's clearly >> generating some internal heat. I would bet inside the enclosures it was >> easily -15F. But I think your -13F is probably OK. >> >> On 5/18/2015 9:09 PM, Forrest Christian (List Account) wrote: >> >> What is the lowest temperature that each of you would normally expect >> to see in your enclosures? >> >> The reason I'm asking is that I'm in the process of developing up a few >> new products. >> >> To date, all of the packetflux products are designed with components >> rated -40 to +85C (I.E way cold to way hot). I'd like to retain this >> rating, but I'm running into a minor snag: >> >> For storage, I'm planning on integrating a SD card (probably microSD) in >> a socket. I only need a GB or so, and SD card memory is inexpensive at >> that range. >> >> Unfortunately, all the reasonably priced SD cards are only rated down >> to about -25C or -13F. which are about ~$3 in qty. "Industrial >> temperature range" ones which are good down to -40C/F are available but >> they add at least $30 to the cost for non-name brand, and even more for >> known brands. When you're talking about a $100 end-user price, a $30 1GB >> SD card seems excessive - and probably isn't even possible if I want to >> meet the $100 price with some margin. >> >> So, I'm currently playing the 'what options do I have' game. I hate >> to ship a product only rated down to -25C/-13F, but I know for at least a >> large chunk of my customer base they never see below this temperature, >> especially when you add a watt of power dissipation in the case with the >> device. Which leads me back to my original question: What's the lowest >> temperature most people would expect to see inside their enclosures. >> >> -- >> *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.* >> Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 >> [email protected] | http://www.packetflux.com >> <http://www.linkedin.com/in/fwchristian> >> <http://facebook.com/packetflux> <http://twitter.com/@packetflux> >> >> >> >> > >
