LIPO for Teensy 4.1 Development Board

teensy_teen

Active member
Hi, Can this board be powered via a laptop's USB port like the Arduino? In case of powering via battery, what LIPO batteries do you recommend?
 
Yes Teensy's run off USB power.

LiPo batteries are not 5V. Thus you need either 2S into a voltage regulator to make 5V, or 1S into a boost-converter to
make 5V.

I recommend using a fuse/polyfuse with LiPo's as they can put out damaging amounts of current if there's a short.

The T4.0/T4.1 have a nominally 5V "Vin" pin that is limited to the range 3.6V to 5.5V. Basically use something
that generates 5V, a powerbank would be ideal apart from the the fact they shutdown if too little current is drawn
(I suspect a T4.0 or 4.1 won't have that problem though, and they have USB connectors already which is
convenient).

There is a trace linking Vin to USB power, which is designed so it can be cut if you want to power via Vin while
still using USB to communicate.

Personally I would recommend using LiFePO4 over LiPo due to the reduced risk of fire. With LiPo its vital
that you have a cell or pack with protection circuit built-in, and LiPo should not be charged unattended as
this is when they are most vulnerable if in a dodgy state.
 
Although I have not graduated to using the Teensy 4.0 or 4.1 just yet, I have made a battery powered project using a Teensy 3.2 with an ILI9341 display. For that I use an Adafruit Power Boost 1000 to monitor and charge the battery and their 2500mA LiPo battery.
 
I just tested this on my bench, the teensy 4.1 in my project continued to run even with Vin all the way down at 2.8 volts. That's well bellow the drop out voltage of my lipos. I was using a DCDC converter boosting to 5V, but now I don't actually think I need it.
 
I've run most of the ARM Teensies (LC, 3.1, 3.2, 3.5, 3.6, 4.0, and 4.1 -- I don't remember if I ran the 3.0 with lipo batteries or not, and I haven't used the micromod) over the years.

One minor thing that I didn't expect is while most lipo batteries use the common JST 2-pin PH cable to connect them, I have run into some batteries that I bought from Amazon that were wired differently from the more common lipo batteries I've bought from Adafruit. In this case, I have extra JST cables, and it was easy to cut the wires and solder them to new cables with the 'proper' orientation.

Another thing that I've learned over the years, is don't carry lipo batteries by the cable, or else the solder joints will loosen and the battery will no longer be connected. Strain relief of the battery cable can be important.

Like most batteries, monitor the batteries, and if it starts swelling, remove the battery and replace it. Be sure to properly dispose of the battery (my town trash transfer station has a place to put old batteries).

One thing that I just picked up is a JST plug puller. It makes it so much easier to remove the JST cable.

In terms of Teensy and recharging the batteries, all ARM Teensies using the 28 or 48 pin layout have a solder pad that normally connects the VUSB pin from the USB connection to VIN which powers the Teensy. You can cut the trace, and wire VUSB to a charger, and feed the output of the charger into VIN. These two chargers were made several years ago to fit on the Teensy where you had cut the trace, and use the USB connection to power the charger and the Teensy:

If you have a Teensy 3.1, 3.2, or 4.0, this Adafruit feather adapter can be soldered directly to the Teensy (or use headers). Even if you don't need to attach feather boards, this board provides a lipo charger for the Teensy. I like this board because the JST connection is real sturdy (the JST connections I solder on to the board can be ripped off if you yank out the cable). You do not have to cut the trace between VUSB and VIN -- this board will monitor the power and only supply battery power if there is no USB power. You can also use the 3.5, 3.6, or 4.1 boards, but you have to make some adjustments due to those boards being larger. A year or two ago, I wrote up some information about adapting the various Teensys to use this board:

Adafruit also made this breakout board that you can attach VUSB, VIN, and GROUND from the Teensy to attach a lipo battery. Like the feather board, this board has the JST plug solidly mounted:

I recently bought this Seeed board from Digikey that has a JST input plug, and it can boost power up to 5 volts to plug into the Teensy via a USB connection. It has a USB-C plug to charge the lipo battery (rather than using the USB connection on the Teensy). It also has an on/off switch that controls whether the power goes out the USB connection or not, and it was fairly cheap:
 
Back
Top