Power Input Requirements and Limits

25 Oct 2021

This article explains the power requirements of the Mesa 3 and provides guidance for managing unconventional power needs.

Caution: Damage caused to a Mesa 3 as the result of using an unauthorized third-party or custom-built power supply is not covered in the product warranty.

Mesa 3 Specifications

The Mesa 3 requires a 30 W power supply with a 12 V output. Here are some details about this spec that may inform your power supply decisions:

Voltages higher than 12 V may damage the Mesa 3.
The Mesa 3 can tolerate voltages up to 20 V, but input transients—especially when first connecting power—can overshoot the DC value, resulting in damage to the Mesa 3.
The watts from the power source can increase without any damage or performance loss to the Mesa 3.
Power sources less than 30 W are not recommended. They may result in an unreliable Mesa 3 performance while charging, likely not charging successfully, but not likely to harm the tablet.
The dimensions of the DC Jack connector on our products is as follows:
- 2.1 mm diameter inside barrel (positive terminal)
- 5.5 mm diameter outside barrel (negative terminal)
Batteries will not charge (or might charge slowly) at temperatures below 32°F (0°C) or above 122°F (50°C).

Charging the Mesa 3 Using Portable Power Sources

The Mesa 3 is designed to work in rugged, all-day, off-the-beaten-path environments. This means our customers sometimes need to charge the Mesa 3 in unconventional ways. Here are some guidelines for choosing safe power sources for your Mesa 3:

Mesa 3 Batteries

The Mesa 3 has two battery configurations:

A 10-hour removable battery
A 10-hour removable battery and a 4–5 hour internal battery that makes it possible to hot-swap the removable battery

Many customers choose to purchase spare batteries to guarantee an uninterrupted power supply during long workdays. If your Mesa 3 has an internal battery, the removable battery can be changed without powering down the tablet.

Vehicles

The most common means for charging the Mesa 3 out in the field is plugging it into an automobile auxiliary power outlet (cigarette lighter port). In most modern cars and trucks this is a safe option. However, here are some details that can help you charge your Mesa 3 safely:

Most cars and trucks run on a 12 V power system, making them generally safe for charging a Mesa 3.
More powerful vehicles (e.g., combines, tractors, industrial trucks) run 24 V power systems, which would damage a Mesa 3.
If a vehicle's battery is dead or dying, the alternator works extra hard to charge the battery. This creates the risk of a load dump event. In a load dump event, the connection between the battery and the fired-up alternator gets interrupted, and the alternator sends a voltage spike through the engine. That voltage spike would damage the Mesa 3 that is plugged into the vehicle.

Power Accessories for the Mesa 3

12-32 V DC Power Conditioner - Connects a Mesa 3 to an automobile auxiliary power outlet. This protects the Mesa 3 from load dump events as well as conditions unregulated 12-32 V DC power sources to a regulated 12V power source for charging and running the Mesa 3.
12 V DC Vehicle Charger Cable - Connects a Mesa 3 to an automobile auxiliary power outlet. This connector does not protect the Mesa 3 from load dump events.
Powered Locking Vehicle Dock - Connects a Mesa 3 to an automobile auxiliary power outlet. This connector protects the Mesa 3 from load dump events.
International Plug Kit - Adapts the Mesa 3 Standard 30 W AC Power Supply plug to fit into various international standard outlets. The adapters don't change the Mesa 3 power requirements. The Mesa 3 Standard 30 W AC Power Supply itself adapts to international differences in power standards.
30 W Universal AC Power Supply Kit - Includes all the adapters in the International Plug Kit as well as a replacement 30 W power supply.
45 W Universal AC Power Supply Kit - Provides extra power for a Mesa 3 Dock with multiple devices connected. It can also provide direct power to the Mesa 3 but does not improve performance or charging speed.
Mesa 3 Removable Li-ion Battery Kit - A spare battery for the Mesa 3.
Mesa 3 Removable Battery Charger - Charges spare Mesa 3 batteries. This connector protects the battery from load dump events.

For the Mesa 3 Windows, starting in February 2021, a hardware modification on all units was provided with additional circuit protection. For more details, see this web page.

Minor charging protection modification on Mesa 3 Windows

For the Mesa 3 Android, starting in October 2021 for some units and starting June 2022 for all units, a new part number 30465/30464 I/O Flex Plus Assembly (bottom ports) with additional circuit protection. This can replace the standard part number 28218 IO/Flex assembly. For more details, see this web page.

Minor charging protection modification for Mesa 3 Android

Original article for older models written 21 May 2007 and updated over time to now be specific to Mesa 3.