During HackUMass, many people came to M5, with a sleek raspberry pi 5, in hopes of powering it. However, powering a raspberry pi 5 becomes a little complicated, when dealing with higher power requirements.

Previously, the Raspberry pi generally used 5V to power it’s board. This can be very helpful, as the VBUS pin on the raspberry pi will often be at 5V, giving a way to power projects that need 5V power, but can use 3.3v input signals. With the new Pi 5, more power was needed. As a result, the Raspberry Pi Foundation decided to make the Pi 5 draw 25 Watts, from 5 Volts at 5 Amps.

The problem with this is that most charging cables are only designed to supply a maximum of 3Amps. There is usually current sensing circuitry on USB-C compliant power bricks that limits most charging cables from supplying higher current. USB-C can supply higher power, by using higher voltages. Here is the chart for standard voltages that are typically supplied:

As you can see, you would need a charging brick capable of supplying 100 watts AND a weakly designed supporting circuitry to allow the power supply to send 5A in lower voltages, even when it’s non standard. While a Raspberry Pi should just request 9V, to get 25Watts, the Raspberry Pi Foundation instead sells their own power supply, that’s actually rated for 5V at 5A. This means that to take full advantage of your raspberry pi, you NEED to buy a raspberry pi power supply, drmming you into their products.

While you can provide 5V at 3A, the pi 5 will sometimes brown out, and it will limit power to the USB ports at 150mA. This really sucks because the Pi 5 is such a capable board, a common upgrade to it is attaching an SSD, instead of relying on a micro SD card as storage. Other projects also incorporate speakers, microphones, cameras (very common in machine learning projects, due to the Pi 5’s ability to run AI models competently), and most of these heavier peripherals cannot be run on the Pi 5 without the special brick. Even a gaming keyboard with RGB Led’s can draw more than 150mA.

The Raspberry Pi will also actively warn users who use the 5V 3A mode that it’s not supported and to find a 5V 5A charger instead. However, in events such a Hackathon, it’s very inconvenient to source a specific charger, and this led to 2 teams having to spend hours bouncing around maker-spaces to find the correct charger cable.

The Raspberry Pi Foundation has a tough choice here. It’s clear that they value backwards compatibility extensively, with the decision for the new RP2350 dev board to use micro-usb instead of USB-C, and this setup. The backwards compatibility approach would be to include a regulated 5v pin that projects could use instead of a VBUS pin, as well as the supporting charge circuitry to pick 9V at 3A to get 25W instead. This whole decision brings the Raspberry Pi computer into an interesting place.

Originally, the Raspberry pi 3B+ was a 35 dollar mini computer, perfect for small iot projects that needed wifi connectivity, and more compute power than a micro controller. However, the Pi 5 has now ballooned into a far more capable board, but with the same limitations of the same board size, and older power constraints, it’s clear that keeping the Pi 5 as a drop in replacement for previous generations is causing the Raspberry Pi Foundation to make questionable design choices. The Pi 5 is also missing critical functions, such as a lack of any other video codec for decoding other than H.265 (most of the internet still commonly uses H.264), and just no hardware encoding at all. I feel that the Pi 5 is largely irrelevant, when x86 computers are getting cheaper. The main appeal I see are GPIO ports, but aside from that, older laptops, and small computers seem to offer better value. I think that the Raspberry Pi 5 just doesn't make too much sense as a product, and that older generations of Pi are better placed in the computer market.

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