Call for Interest: Circuit to add Li-ion/Li-Poly batteries to your project (Bikeshed Board) - Postponed

Hi All!

As many of you know, I’ve been developing and refining a circuit board for helping use lithium batteries in your low power projects (3.3v arduinos, esp32 and such). I’m just about at the point where I can host a build night.

I’ll be hosting this on Monday, April 6th at 7pm.

I need to order parts ahead of time, so to gauge how many sets of components I should order, please indicate your interest here (and if you are going to buy more than one kit, please indicate how many).

Let’s assume each kit is $20 at this point, if we order a bunch, the per-unit price can go down (just how ordering electronic components works).

For those now familiar with the board, here’s a bit of info:

What’s the quick description of this board?

It is a physically small board that manages a 1-cell lithium battery so you can run your 3.3v up to 600ma device without having to think about batteries. It has indicators, a high quality charging methodology, and looks cool.

Why would I want this board over the cheap boards available at [X vendor] that cost half as much?

Most battery management boards don’t implement “Power Path” for their charging circuit. There are at least 3 common methods of dealing with battery charge management.

Have you ever had a device with a depleted battery and you had to charge the battery up a bit before you could even use the device? That device is likely not using power path (some exclusions apply). Power path actively directs power from the source or battery to where it needs to be. If your battery is dead, it will prioritize power to the device, and if there’s any extra current, the remainder goes to charge the battery.

When your power source is disconnected, you won’t have any flickering or brownout when it automatically switches to using battery power.

Furthermore, when fully charged, it won’t keep trying to charge the battery, saving you battery life in the long term.

Simply put, it does all the things an integrated battery management system should do.

I’m really into circuit design, what’s the battery management chip you use?

MCP 73871
Check out the data sheet, it is great.

What batteries can I use with this?

Almost any 1-cell li-ion or li-poly. If you need a lot of juice, you can go for an 18650 (I recommend one with a built-in protection circuit). Buy a high-quality battery with a data sheet. If you don’t have the charge termination current or the maximum charge rate, then you are risking guessing incorrectly. The kit comes with conservative values built in (so it’ll charge slowly without setting these to be safe), but you can replace 2 resistors and tune it to your specific battery. has a bunch of 18650’s if you don’t have a supplier or a battery sitting around.

Do you have a build manual?

Yup! I tried to make a high-quality manual including images to help you identify parts, a testing paradigm, and some background about the board.

What plug does it use to charge?

USB-C. There’s technically pads for micro-usb, but I won’t be supplying the plug for this build.

Any other questions?

Ask them in this thread and I’ll amend this!


Count me in for 2!

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I’m interested in one!

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I’ll take one please!

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Put me down for 2. However, I am unable to make the April 6th date. I can get $ to you in the next week or so or mid-April.

How many do you need for a potential price break?

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No worries on when you buy them, just trying to make sure I have roughly most of them sold.

I think I can offer a couple bucks break if I order 30. I’ll be ordering more than I have people signing up, since I assume I’ll be running this a few times.

I’ll take 1, thanks

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This will likely be postponed to facilitate the COVID efforts, I’ll update this when I know more.