Standard computer models deliver less-than-substandard performance if they are consistently used inside freezers or exposed to frequent temperature changes. In fact, moving the computer between normal and cold areas is extraordinarily hard on just about every part of the device, even if it’s ruggedized. It’s a fact of life that LCD screens fog up, batteries won’t release enough energy, and processors may not perform as intended.
What Changes in the Cold?
- Frost obscures LCD screens, so users can’t see prompts or verify the data they enter. Barcode readers and image capture devices will not function if frost covers their optical ports. Frost can also cause keys to stick if the device is improperly constructed or insufficiently sealed. Error rates grow exponentially.
- Condensation causes the same problems as frost by making screens and scanners unusable. Condensation presents more of a problem because it can occur inside the screen or scan window, and thus can’t easily be cleared away. It’s a very serious problem because it can cause internal components to corrode, short-circuit and fail, making the device unusable until it is repaired or replaced.
- Cold Air effects batteries. Battery-powered mobile devices are challenged by cold air because batteries can’t release their energy when temperatures drop below certain levels. Radio waves travel differently through cold, damp air than they do in warmer, drier conditions, so users may experience less range throughput from their wireless LAN systems unless adjustments are made.
- Insulation used to keep cold air from escaping can also restrict the movement of radio waves. Insulation absorbs RF signals, and commonly creates what is known as the “multipath effect,” which occurs when signals bounce off obstacles and arrive at the access point at slightly different times.
Mobile Computers designed for the harsh freezer environment must contain:
- Heaters — Integrated heaters are the components that truly set cold-environment computers (otherwise known as cold storage computers) apart.
- Housing — Mobile computers should be made from durable material suitable for industrial applications and be well constructed to limit the effects of exposure. A strong seal is essential for preventing moisture and condensation from damaging the inside of the computer.
- Batteries — Mobile computers typically use Li-Ion batteries. Cold temperatures prevent common Li-Ion batteries from releasing their charge, making the powered device unusable until the battery is warmed. Li-Ion batteries also tend to fail completely when temperatures reach – 22°F (-30°C), which are common in frozen storage areas. Low-impedance lithium-ion batteries specially formulated for cold-temperature use are available. These batteries will release their charge at colder temperatures than will standard models, and have lower failure points. Lead acid batteries are another alternative. They suffer less cold degradation than Li-Ion batteries, but are less power efficient relative to their weight.
- Components — Components can be given a protective coating that will prevent short circuits if condensation does occur.