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Second prototype build

A project log for LiFePO4wered/18650

LiFePO4 battery technology, made easy for makers - a bigger version

Patrick Van Oosterwijck 11/24/2016 at 00:453 Comments

Second prototype PCBs came in from OSH park, time for a new build! Only small changes, added a resistor, took away an optional cap to make room for the resistor, and changed the schottky diode to a smaller package.

Here's before reflow:

After reflow:

And put together with my production battery holder and battery:

Now it's time for some more testing! Putting it into a LiFePO4wered/Pi and will be running that with a Pi 3 @ 100% for some serious load testing!

Since I'm assuming this prototype will work fine (I'm an optimist, or naive, or maybe both), I also went ahead and created a panel for production:

When my testing has given me enough confidence, this panel will go to the fab!

Discussions

Darren Poulson wrote 11/28/2016 at 02:57 point

Looks awesome! Might be what I'm looking for, are you going to be selling them? (I don't have a reflow oven at this time).

How easy is it to change to use Li-Ion? (I've tons of them laying around). And does it notify the Pi when power is removed? ie, can it send a command to shutdown? 

My needs are that I can remove power to the Pi, and that will trigger it to do an immediate shutdown, the battery will just be there to provide enough power to do that so that I reduce the risk of filesystem corruption.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 12/02/2016 at 15:51 point

Hello Darren,

This project is only the charger, it gets combined with the #LiFePO4wered/Pi power manager to make a complete system for the Raspberry Pi.  I will be selling both this charger by itself, and in combination with the LiFePO4wered/Pi power manager.  In combination with this new charger, the LiFePO4wered/Pi will now finally be able to detect whether external power is present or not! :)

All the circuitry is created specifically for LiFePO4 chemistry cells and will not work with regular Li-ion.

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oshpark wrote 11/24/2016 at 01:57 point

Good to see your progress!

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