Portable Desktop Project
...You mean a Laptop?
I recently built a portable desktop using a M4-ATX-HV 220W Intelligent Wide Input 6-34V Vehicle/Battery DC-DC Power Supply. This power supply is perfect for battery usage because it can accept a variable voltage input and supply a constant voltage to the motherboard, unlike my original picoPSU which needed a constant 12V input and couldn't handle voltage fluctuations. This made it difficult to use with a battery because if the voltage dropped below 12V, the computer would shut off. Instead of trying to create an automatic voltage regulator, I decided to upgrade to the M4ATX and use a high-powered RC car or drone battery pack rated for 60C at 22.2V. This battery can handle up to 120 Amperes of current draw and has a capacity of 3.3 Amp-hours, or 73 Watt-hours.
One of the challenges I faced while building this portable desktop was finding the right connectors to go from the battery to the picoPSU. Laptop charger cables have their own transformers built in, which makes them ideal for providing a constant current input, but they're not very useful for battery usage because they can't easily be powered by a battery. That's why I ended up using the M4ATX along with a 3300mAh battery pack rated for 60C at 22.2V, which is basically a high-powered RC car or drone battery. The 60C on the battery means that the pack is rated for up to 120 Amperes of current draw, while the 3300mAh indicates the capacity of the battery; 3.3 Amp-hours. This can be directly converted to watt-hours by multiplying together 22.2 * 3.3 = 73 Watt-hours. I have included a Watt-hour calculator below for your convenience.
To put the battery's capacity into perspective, my CPU takes 77W at maximum load and the motherboard, SSD, and RAM use a total of 37W. This means that the total Wattage drain is 114W, so I can run my portable desktop for about one hour on this battery as long as I limit CPU consumption. In practice, I drained the battery by about 63% of its total capacity (46 watts) over the course of 45 minutes with low-level machine code compiling. I had to be careful not to drain the battery entirely, as LiPo batteries tend to spontaneously combust.
I'm thrilled with how my portable desktop was able to be deconstructed into more useful parts, and I can't wait to use it for more project components in the future. It's amazing to think that I could have taken my desktop with me wherever I went and worked for minutes on end. The M4ATX power supply and medium-powered battery pack made it possible to run my desktop on battery power, which opens up a whole new world of questions. Namely, why not use my laptop? I found myself asking this question over and over and eventually came up with no good answer.
This is not the end of this project however, I will eventually bring back the portable desktop with beefier components and a longer battery life.
This text has been enhanced with AI (ChatGPT) to make my notes more legible and digestible for the average reader.
Galen Holland 2022 - The photos on this page were taken by me. The mouse pictured is a Zelotes F-18 gaming mouse.