Arduino and co at high temperature

On the read-only part of the forum there are some informations about Arduino temperature range; apparently it's supposed to work from -40°C to 85°C.

But there are not much precisions about how it fares at high temperatures (50°C and higher); does its lifespan shorten? A lot or juste a little? How do SD connectors/cards, 9V batteries or solar panels, LCD panels, communication modules (Xbee, wifi or ethernet shields) react to high temperatures?

I want to put many sensors inside a solar oven that's supposed not to go over 60°C (emphasis on "supposed"). The safest thing is to put the sensors inside and the Arduino card and shields outside, but while I'm testing the whole system I don't want to drill holes if I can avoid it. That means that I have to use existing holes, and then I have more than four meters between the farthest sensor and the card - I'm not that confident that it won't bring artifacts in the measured values.

So, putting the card inside is a simpler way, but I need to put some storage or communicating device with it - will they too resist to 60°C or more?

Most components on the board were present when it was reflow soldered at 220C or so, but that's a one-off stress. Expect it to work at 85C, but don't expect the regulator to handle as much power dissipation and yes component lifetimes are sensitive to temperature (especially thermal cycling - the slower and more infrequently you can arrange any thernal cycling the better).

I hope you don’t want to use Li-ion battery inside :wink:

Solar panels drop in efficiency with increasing temperature as their forward voltage drops with temperature, BTW.

Each kind of LCD will have its own temperature tolerance - this sort of information is best found by consulting datasheets for particular devices.

A solar oven in the tropics that doesn't go above 60C is not what I'd call an oven! Northern Europe in winter then perhaps ;)

"Four de séchage solaire", maybe not a solar oven.

I don't really need one power source or another, I just need a reliable power source, anyone will do...

I'll try to check the datasheet for the LCD i have, what about SD port and card?

To put the Arduino card outside, I need jumper wires of one to five meters long. And I need their isolating material to resist to more than 60°C. How do I do that?

use silicone insulated wires like UL3135 Description: Single conductor stranded tinned copper insulated with .031” silicone rubber insulation. This construction allows for a uniform, flexible, concentric, quality construction. *Operating Temperature: -40°C to +200°C *

Genesis92: use silicone insulated wires like UL3135 Description: Single conductor stranded tinned copper insulated with .031” silicone rubber insulation. This construction allows for a uniform, flexible, concentric, quality construction. *Operating Temperature: -40°C to +200°C *

Thanks, I'll try to find these here. Are you recommanding them for the power source to the arduino card or from the arduino to the sensors? In the later case, will the length (2 to 10 meters) be a problem for the accuracy of the sensors' readings?

silicone insulates cables must be used when you have high/low temperatures conditions and high voltage. about the lenght we must have a schematic/sensor spec (voltage or current out etc)

What sensors are you using (or intend to use)?

dlloyd: What sensors are you using (or intend to use)?

That's a good question... I don't have an exact idea. I want to measure air temperature, air humidity, wind speed. Later I'll probably need to measure the dryness of the fishes we try to dry.

I thought to use the TMP36 for temperature, as it's the one sold with the Starter Kit, but I'm open to any suggestion. Especially since when I tried the TMP36 yesterday and today it gave me erratic values. For the other measures I don't know which one to choose.

As a general rule of thumb, electronic components dont really like going above 70 degrees Celsius. Id suggest trying to keep it below that. If ther temperature is going to be greater, think about making things more heat proof.

Typically, for regular aluminum electrolytic capacitors the life goes down by a factor of 2 for ever extra 10 degrees C. But those new low ESR solid polymer aluminum electrolytics, the life goes down by a factor of 4 for the same rise in temperature!

It is not wise to use parts near their limits. The lifespan is adversely affected, and the weakest link will fail first.

I have replaced a lot of aluminum electrolytic capacitors in consumer and prosumer equipment. The failed parts are typically rated at 85C, I'd replace them with caps rated for 105C. Sometimes I'd increase the rated voltage, too. A 12V circuit with a 16V rated capacitor, I might replace with one rated at 25V.

Play with this capacitor life calculator, it is quite interesting.

http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx

-Edit- mistakenly said 10F, meant 10C.

polymorph: Typically, for regular aluminum electrolytic capacitors the life goes down by a factor of 2 for ever extra 10 degrees C. But those new low ESR solid polymer aluminum electrolytics, the life goes down by a factor of 4 for the same rise in temperature!

That's certainly an answer to my question, thanks. But "extra 10°C" above which baseline temperature?

Oh, and since I'm that a newbie in electronics, I guess there are already capacitors on the Arduino Uno I'm using? Or do you refer only to additionnal capacitors I may use?

Yes, there are capacitors on the Uno board, I've counted 14 from the official schematics, some of which are definitely not ceramic.

Quality and type of those capacitors may vary hugely depending on the actual board you have: if it's a cheap chinese clone you can bet those caps are going to collapse much faster under high temperatures.

You're going to put your arduino in a smoker? :o I think your biggest problem will be the build up of sooty deposits. These will conduct, leading to eventual errors in operation.

No, not a smoker. Just solar drying.