Powering Project with Power Bank

Community Products and Services
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I’ve recently been getting into some fun DIY controls projects (I’m an EE with both hardware and firmware background, and prefer using Arduino since it’s just easier). Primarily, I’ve been using ESP32 development boards for their WiFi and Bluetooth features. Also, I really like to power my projects with portable power banks. It makes them portable (obviously), the power banks are rechargeable and they last longer than normal off the shelf batteries. The problem I’ve run into is, in order to extend the battery life, when I put the ESP32 into light or deep sleep mode, the portable power banks shut off due to the low current draw. I know power banks are designed to do this once charging something like a phone is complete, which is what they’re really made for, so I can’t be too mad. So I started working with several companies and now have a portable power bank that will keep the output alive so long as the current draw is above 20uA (micro amps). I have 10,000 and 20,000mAh power banks I’ve been using with my ESP32 projects and they work great.

For outdoor projects, especially when the temp goes below freezing, I also created a battery heater pouch. My ESP32 device can plug into the power bank and the heater pouch also plugs into the power bank. The battery is drained after 12 hours due to the heater, but for projects that just need to work overnight, it’s perfect. I can also just change the battery with another in a few seconds if it stays cold out.

I’m curious if anyone out there would be interested in a power bank like this. I do not have any inventory but would probably be able to sell a 20,000 mAh battery for $30. I don’t know about the heater pouch. Maybe $10.

It took a long time for me to get to this point so, either I’ve completely missed some low cost option out there or I did make something useful for people who like to make DIY Electronics. Just thought I’d ask all of you to see if there would be any interest. If yes, maybe I’ll pick up a bunch and make them available. I’ve attached a couple pictures. Just curious what people think. Thank you all!

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1 Like
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@d-no ,

I've moved this to products and services as it seems more appropriate for your product.

Judging by how many questions there are here that would be solved by your product I think there is a market for it. Whether the people who need it will notice it is another question. I suggest you change your title to one that clearly suggests that you have these for sale, so as to attract attention.

Are you aware there are sites for selling this kind of thing, such as Tindie?

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Thank you very much!!! No, I was not aware of that but will look into it immediately. Also, I do not have these currently available. For now, I was curious if people who work on these project as a hobby would be interested. If so, then maybe I’d get some inventory so they can take advantage. Thanks again!!!

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Actually they may last last shorter than off the shelf batteries!

A power bank basically consists of off the shelf Li-ion batteries and a boost converter to increase the voltage from the typical 3.7V to 5V. These boost converters are typically 80~90% efficient.

If you use that 5V to power an ESP32, which is a 3.3V device, the liner regulator on the board takes the 5V and converts it to 3.3V at an average efficiency of around 3.3/5 = 67% efficiency.

So by using a power bank, you take the capacity of the off the shelf batteries inside it, loose 10~20% of that capacity converting it to 5V, then lose another 33% converting the 5V to 3.3V.

It's more efficient to convert the typical 3.7V to 3.3V without going via 5V