I just finished a project involving a portable device featuring a Raspberry Pi Zero 2 W that drives a 60-LED NeoPixel light strip and a speaker via a MAX98357A amplifier. The Pi draws negligible current and could be powered by a PowerBoost 1000 and a LiPo battery, but the NeoPixel strip and the speaker both increase the load, so I connected them to a USB-C power bank via a USB-C PD trigger board. That option works great for power, but I'm now dealing with a nasty bug that I also encountered in a previous project: when the electronics are powered down and draw negligible current for an extended period, the power bank tends to shut down the USB-C port entirely, and the only option for reactivating the electronics is to physically disconnect and reconnect the USB-C connection. Very annoying.

Since I've dealt with this problem a few times now, I'd like to solicit the community for general advice on power sources for Raspberry-Pi-based portable projects that exceed a typical LiPo battery. The power source needs to be:

1) Capable of providing at least 15W, especially for Raspberry Pi 5 projects, and ideally 25W or more if the project involves a lot of LEDs or any kind of motor;

2) Reliable (i.e., not subject to shutting down USB ports); and

3) A reasonable balance of energy storage capacity (20 amp-hours or more), weight/size, and cost.

USB-C power banks seem like a good option in general - good power delivery, capacity, and steadily increasing power storage capacity and density with steadily decreasing costs. Bonus - integrated recharging. I've had good experience combining a PD trigger board to negotiate a primary voltage and drive the entire set of components with a secondary power regulator solely for the RPi. Unfortunately, the idle-shutdown issue seems to be common with these devices. I ran across a recommendation to look for a "continuous power delivery" type of USB-C power bank, but I haven't found one. As a secondary problem, the outer plastic shell of any USB-C power bank adds a lot of bulk if you want to integrate them into another device, and I'm really not willing to experiment with removing it to embed only the internals.

Any insights are appreciated. Thanks in advance.

(edit) Also noting that I am aware of "trickle charge mode" that causes a power bank to keep a port active even for a small current draw. Unfortunately, that feature seems to be for USB-A, not USB-C, and of course USB-A is not capable of delivering sufficient power for these projects.

sfsdfd wrote: ↑

Wed Oct 29, 2025 1:29 pm

3) A reasonable balance of energy storage capacity (20 amp-hours or more), weight/size, and cost.

20Ah at what voltage? Battery capacity is actually rated in Watt-hours (Wh).

A better approach to determining battery size is to take the desired load in Watts times the desired run time in hours (h) to get a target Wh rating.

Note that Lithium Ion/Lithium Polymer powerbanks are at the nominal cell voltage of 3.7v, so a "20Ah" powerbank has an actual capacity of about 80Wh.

I wonder what range of Pi products you have in mind? Are you including a pi 5?
I assume mains power will not be available at the time of use (eventually things may need re-charging using mains of course)
When you say "portable" it would be interesting to know if you had any particular "portable" in mind, as you say

that exceed a typical LiPo battery

e.g:
Use on the person?
Easy to move around by 1 person but static in use?
Easy to move in a vehicle?
Use in a vehicle?
At sea?(!)
Any/All of the above?
Other?

W. H. Heydt wrote: ↑

Wed Oct 29, 2025 2:19 pm

sfsdfd wrote: ↑

Wed Oct 29, 2025 1:29 pm

3) A reasonable balance of energy storage capacity (20 amp-hours or more), weight/size, and cost.

20Ah at what voltage? Battery capacity is actually rated in Watt-hours (Wh).

I know that batteries are typically rated by Wh or kWh, but power banks typically advertise their capacity as mAh, probably because they're intended for low-wattage devices and usually pegged at 5V. :shrug:

Check out the specs of Anker's power banks: https://www.anker.com/collections/power-banks ... they list maximum output as watts, but capacity as mAh. I agree that it doesn't really make sense.

sfsdfd wrote: ↑

Wed Oct 29, 2025 11:36 pm

W. H. Heydt wrote: ↑

Wed Oct 29, 2025 2:19 pm

sfsdfd wrote: ↑

Wed Oct 29, 2025 1:29 pm

3) A reasonable balance of energy storage capacity (20 amp-hours or more), weight/size, and cost.

20Ah at what voltage? Battery capacity is actually rated in Watt-hours (Wh).

I know that batteries are typically rated by Wh or kWh, but power banks typically advertise their capacity as mAh, probably because they're intended for low-wattage devices and usually pegged at 5V. :shrug:

Check out the specs of Anker's power banks: https://www.anker.com/collections/power-banks ... they list maximum output as watts, but capacity as mAh. I agree that it doesn't really make sense.

It makes perfect sense. 20000mAh sounds better than 14800mAh. The first figure is at 3.7V (what is stored) the other is at 5V (what you get). 74Wh is cell-agnostic, but it's all about marketing.

Oh no, not again.

sfsdfd wrote: ↑

Wed Oct 29, 2025 11:36 pm

W. H. Heydt wrote: ↑

Wed Oct 29, 2025 2:19 pm

sfsdfd wrote: ↑

Wed Oct 29, 2025 1:29 pm

3) A reasonable balance of energy storage capacity (20 amp-hours or more), weight/size, and cost.

20Ah at what voltage? Battery capacity is actually rated in Watt-hours (Wh).

I know that batteries are typically rated by Wh or kWh, but power banks typically advertise their capacity as mAh, probably because they're intended for low-wattage devices and usually pegged at 5V. :shrug:

Check out the specs of Anker's power banks: https://www.anker.com/collections/power-banks ... they list maximum output as watts, but capacity as mAh. I agree that it doesn't really make sense.

Doing the ratings in Ah/mAh is a way for the advertising to deceive you about the actual capacity since the ads don't tend to mention that the Ah rating is at the cell voltage of 3.7v and NOT at the output voltage of 5v. So it makes "sense" in that its a way to exaggerate (lie about) the battery capability.

W. H. Heydt wrote: ↑

Wed Oct 29, 2025 11:50 pm

Doing the ratings in Ah/mAh is a way for the advertising to deceive you about the actual capacity since the ads don't tend to mention that the Ah rating is at the cell voltage of 3.7v and NOT at the output voltage of 5v.

No it isn't.

Steve Learner wrote: ↑

Thu Oct 30, 2025 12:34 am

W. H. Heydt wrote: ↑

Wed Oct 29, 2025 11:50 pm

Doing the ratings in Ah/mAh is a way for the advertising to deceive you about the actual capacity since the ads don't tend to mention that the Ah rating is at the cell voltage of 3.7v and NOT at the output voltage of 5v.

No it isn't.

No what isn't? An intent to deceive? It certainly is. They're trying to imply that the capacity is greater than it really is. Most people don't have enough knowledge of electrical engineering to spot what is being done.

Steve Learner wrote: ↑

Thu Oct 30, 2025 12:34 am

W. H. Heydt wrote: ↑

Wed Oct 29, 2025 11:50 pm

Doing the ratings in Ah/mAh is a way for the advertising to deceive you about the actual capacity since the ads don't tend to mention that the Ah rating is at the cell voltage of 3.7v and NOT at the output voltage of 5v.

No it isn't.

Welcome, new user!

Yes, it is.

Oh no, not again.

Pi5_User wrote: ↑

Wed Oct 29, 2025 11:07 pm

I wonder what range of Pi products you have in mind? Are you including a pi 5?

This post is generally about Pi-based projects that exceed the constraints of a low-power solution featuring a LiPo battery and a PowerBoost 1000 charger or equivalent.

Some projects in that range include a Raspberry Pi 5 (and optionally other components). Others include a Raspberry Pi Zero 2 and power-intensive components such as stereo amplifiers (e.g., MAX9744 supports up to 20W x 2), long NeoPixel LED strips, and/or motors. I suppose it's even possible for a Pico to be included in a project with high-power components.

Pi5_User wrote: ↑

Wed Oct 29, 2025 11:07 pm

I assume mains power will not be available at the time of use (eventually things may need re-charging using mains of course)

Yes, that's right. I've designed some other projects that just use a 5V/5A power adapter, no problem.

Pi5_User wrote: ↑

Wed Oct 29, 2025 11:07 pm

When you say "portable" it would be interesting to know if you had any particular "portable" in mind

Typically, my projects can be described as handheld. Last Halloween, I designed a relatively to-scale portal gun from the game Portal that required two hands (due to size, not weight) for a child's costume. This Halloween, I designed a Minecraft pickaxe - also requires two hands, but for weight rather than size. I've designed a few such projects that fit into a flight case. That sort of thing.

The scale of my projects is limited not only by free time (as they are all one-off hobbyist personal projects), but also by my strong affection for 3D printing. A large handheld object can be designed and printed with a reasonable amount of filament, but for anything larger - e.g., cosplay - the material requirements grow out of scope.

Projects in the general range of "small-to-large handheld" sizes can accommodate an off-the-shelf battery pack, such as an Anker Prime, but the bulk and weight remain undesirable. Hence, my inquiry.

sfsdfd wrote: ↑

Thu Oct 30, 2025 5:56 pm

Projects in the general range of "small-to-large handheld" sizes can accommodate an off-the-shelf battery pack, such as an Anker Prime, but the bulk and weight remain undesirable. Hence, my inquiry.

Some years ago there was a flurry of activity around small, portable fuel cell power supplies (typically using either small compressed Hydrogen containers or alcohol with a reformer). You might look around to see if any of those ever made it to the market at reasonable prices and with sufficient output power. (And if you find any, let people here know about them.)