Circuit for a UPS

I am looking for a circuit for a UPS based on one or more 18650 batteries.

The UPS must be capable of delivering 5V at, say, 500mA for, say, 30 minutes. Yeah, specs are a little hazy - and subject to change at my whim and fancy. :wink:

What are people using? Off-the-shelf or custom made? Links?

Yes, I’ve Google’d but haven’t found anything useful.


Hey Tia,

If you’re looking for a power bank/UPS for 5V or USB devices I’d recommend a Pi Juice setup as it can act as a standalone battery pack, solar or UPS-like power storage system.

All the best with your projects!

Core Electronics | Customer Support

Thx for the reply but the Pi Juice is well beyond my budget. :frowning:

BTW: tia := Thanks In Advance :wink:


Hey Kevin,

All good, what’s the nature of the project the pseudo-UPS is being used for? I may be able to help you find something more appropriate.


Anything from a Pi4 to just a simple board with a power requirement of, say, 100mA.

Of course, that would probably mean two different devices given the power a Pi4 draws.

For the low power case I’ve used one of these in the past:

Hey Kevin,

I’d just go with a standard battery pack or a LiPo/NiMh battery pack with the 5V output you require. You can power a Pi 4 directly from the GPIO so you shouldn’t need more than one battery pack as if it has enough capacity you can simply run both devices in parallel using a splitter or a similar split connection. All the best with your project!