Powering teensy for portable projects?

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Thank Michael and onehorse. Paul's solution looks very useful but more involved than I was hoping for. As for the add-on, I have the similar Adafruit lipo charger, but that's an expensive solution relative to the cheap lipo phone chargers that are out there (picked up a 4000mAh for $6).

Isn't there something that can be run or turned on in the teensy that would draw sufficient power and largely be a software solution? I've noticed that when using a bluetooth module (HC-06) with the teensy, that the bluetooth -- when in discovery mode -- will keep the USB cell-phone battery on (I currently have a test running that's been on for over 20 minutes). But, once I connect to the bluetooth module and bring it out of discovery mode, the draw drops and the battery does its auto-shutoff.

So, any way of duplicating the draw and timing of Paul's circuit inside the Teensy itself? (Of course, I'm assuming he'd already consider this option)

Eric
 
Well neopixels seem to draw lots of energy if you crank up the brightness. You could flash some lights every so often.

There are USB chargers that don't seem turn themselves off on low power situations, but it might be hard to tell whether they do that from the marketing information.

If your sensors can run at 3.3v, you can power the Teensy directly from the lipo, and then recharge it off line (or use onehorse's custom pcb). Similarly, if you have rechargeable Nimh AA batteries (I have plenty to run flashes, etc.) you can get a 4 battery connector to run at 4.8v, but you would have to charge off line.
 
He did consider the option, it is in the article Michael pointed out; the step where he drove a transistor from an IO pin on Teensy.
 
Not mentioned on that old blog are 2 more battery packs I later tried. All 3 required different timing and pulse durations.

One of them didn't seem to respond to short pulses at all and required pretty much 100% duty cycle current above a certain threshold. It looked exactly like the one in that photo, except black plastic.

Isn't there something that can be run or turned on in the teensy that would draw sufficient power and largely be a software solution?
Click to expand...

No, not really. Nothing inside the chips on any Teensy draws that much current. Of the 3 packs I tested, the lowest threshold was around 100 mA to stay on. Others had higher thresholds, though the pulse timing also had an effect on the threshold for some.

Teensy simply doesn't draw that much current. Using just the on-chip stuff, it's not even close, even at maximum speed with all the peripherals running.
 
I noted elsewhere I came across one pack that seems to stay after clicking its button. SCUD HOBBIT - only 3000 mAh. SCUD has larger capacity models - not sure if they changed their design from always on until they drop out? That unit not available now (amazon or Newegg)- but this $20 FREMO unit may have replaced it (where I got mine half price): http://www.newegg.com/Product/Product.aspx?Item=N82E16875620002

The four brands I've tried 'either' output or charge - they won't charge while in use. As @MichaelM says - the published details make it hard to see these details.

I do have this unit that runs on 4 NiMh and "it powers and charges the device battery, so the device can be used while its battery is being charged." - it is 'empty' just now from disuse - but seems to work as you might need: http://www.tekkeon.com/products-tekcharge1550.html

This 'PQI i-Power 7800' ($60! I paid under $20) unit stays alive with an LC running BLINK: http://www.newegg.com/Product/Product.aspx?Item=9SIA7B42YT2967 and at Amazon maybe the same model for $24: http://www.amazon.com/PQI-i-Power-Portable-Battery-smartphones/dp/B00BF8B56O - as long as they haven't changed the design.

Edit: BTW the PQI unit has no 'pilot' light eating power - it has a button that shows 4 LED charge level that times out in like 3 secs - over an hour later the naked LC still blinking on the PQI, the HOBBIT unit has a single LED 'pilot' light that may change color as charge drops - but is always ON when giving power.

My other 10Ah worthwhile unit is CITUS and it powers down in ~7 seconds when current draw drops - so it only needs a surge about every 5 seconds to stay awake (and does have a 4 LED charge array showing while powered). This unit promises 2.1 Ah output but shuts down charging a Kindle - and just did the same on my Note_4 - even though fully charged and takes a powered plug to the recharge port to reset it (it may not like how they 'ask' for high power charging?). HOWEVER - this unit will restore power when 'called for' - without unplugging USB. Which is of little use unless you can have a primary (onehorse type) battery to run on and then trigger a wake spike on the USB to recharge that - but that primary battery would likely hide a Bluetooth spike until it is (nearly) dead - so you'd need a short spike upstream to initiate that.
 
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I just got two of these that have no or very low current cutoff as it runs a blinking LC :: Fremo Q-02 3200mAh External Battery Pack Power

<edit>: DOUBLE BONUS on this FREMO unit - it will OUTPUT POWER while powered and TAKING CHARGE itself! It is 'only' rated 3200mAh - but is the only one (of 3 types except the SCUD 6K that is also FREMO - with an ON switch) I have that will do this! Most units disconnect incoming power and won't charge themselves while providing power. I just tried this and the red charge LED pops on (when powered by high current USB3 or other but not USB2 port). Seeing the unit below is FREMO too - I now have to order two of those!

<edit 3rd>: Leaving the LC running from the above 3200mAh unit continues continuously, charging or not and even after fully charged it continues running! And plugging LC in to blinking even when powered and fully charged works, unlike the 6000mAh unit in edit #2, and it is also an LED flashlight!

<edit 2nd>: I left my 6000mAh SCUD charging and all was well until the powered unit saw full charge, then it resets the SOFT power switch and turns off the external USB with the LC, and won't stay on until the external power is removed. Doing the same for the 3200mAh unit now. It has no 'soft' on switch so it may be different. I ordered two of the 13000mAh FREMO 'scud' units below.

Todays $17 special looks to have a power button: FREMO P130 13000mAh Power Bank External Battery
One comment says 'too easy to turn on' - so the button may act like my smaller SCUD that just stays on until 'low volts' protection circuit kicks in.
 
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Defragster,

On the second page of reviews for the 13000 one of the reviewers says it auto shuts off when his phone reaches full charge.

Still a good price if it is as advertised.
 
Sounds like they may have a low current draw cutoff - or it may be the phone drops draw to ZERO when charged and the 'soft' power button is reset.

I ordered two for the indicated price ($34 total, now $26 each) - I should see them Thursday and know how they work. A couple days later and that LC is still here blinking on the 3200mAh unit.
 
My two $17 monster 13,000mAh SCUD units showed today. LC or T_3.1 plugged in came right on as if the port was hot and ready. So I don't see a low draw shutoff on these units - just like on the 3200mAh units.

Also the units do put out power while charging.

One thing I did not see on the 3200mAh unit was a power cycle when charger plug was put in or out.

The 13000 mAh unit does cycle power on plugging or unplugging, but runs fine before and after that even when running just blink with no other current draw. Both units came with near 25% charge - so I won't know what they do on full charge until they top off. As noted the [older] 6000mAh unit stopped output on full charge while powered. The 13000mAh unit has a soft switch but it doesn't seem to do anything except maybe power up the 4 charge indicator LED's.

the 13K unit is heavy with a smooth aluminum body - easy to drop and it will hit hard - may be time to buy and apply Sugru.
 
defragster said:
My two $17 monster 13,000mAh SCUD units showed today. LC or T_3.1 plugged in came right on as if the port was hot and ready. So I don't see a low draw shutoff on these units - just like on the 3200mAh units.

Also the units do put out power while charging.

One thing I did not see on the 3200mAh unit was a power cycle when charger plug was put in or out.

The 13000 mAh unit does cycle power on plugging or unplugging, but runs fine before and after that even when running just blink with no other current draw. Both units came with near 25% charge - so I won't know what they do on full charge until they top off. As noted the [older] 6000mAh unit stopped output on full charge while powered. The 13000mAh unit has a soft switch but it doesn't seem to do anything except maybe power up the 4 charge indicator LED's.

the 13K unit is heavy with a smooth aluminum body - easy to drop and it will hit hard - may be time to buy and apply Sugru.
Click to expand...

Sounds interesting, gota wonder what charge controller they are using :)
 
They must use their own combination of charging tech. The fact that both charge while putting out power is unique AFAIK - the 13K unit dropping power on plugging 5v is unique but the The 3200mAh unit - same manufacturer - can it seems charge itself, providing a source of perpetual energy, and not drop output power as noted. Both claim to use PREMIUM LG cells - so I hope for long life and good power.

I left a blinking LC on the 13K battery for 11 days while gone and it was running and showed 1 of 4 charge LEDS left. This unit does not charge itself. I put this unit on charge 8/3 but didn't look for full charge behavior, I just put it on charge again 8/6 and will watch this time.

I need to created a LOG Sketch to track the on time and monitor the chip voltage. then decide some combination of:
> power from bank using the power to VIN pins, and cut USB to monitor on PC
> Log data to EPROM and change blink rate when battery drops, and go to sleep
> Connect to second Teensy over serial to report data from there to USB
> Add an OLED to show ongoing status data.

Question: Doing the above over serial I'd have two power sources to two teensy units tied together serially, one battery one USB or battery - is it enough to just tie their ground together for safe electron usage?
 
You need to tie their grounds together if they connect in any other way - the only way you can dodge connecting their grounds, if you want them to communicate with each other, is if you use proper isolation.
 
Thanks Rob - just wanted to make sure that was sufficient as they will have no other isolation. My other simple tests used a common supply, this use would preclude that.
 
My bad - I followed the lighting cable link and read those reviews but not the battery. Your warning on the review check is good and why I like newegg - the 6K unit I've had some months, others noted here aren't that old - hopefully their unique charge features don't ruin the batteries. May be a bad model or bad batch. I did see that some got warranty support at least.
 
defragster said:
My bad - I followed the lighting cable link and read those reviews but not the battery. Your warning on the review check is good and why I like newegg - the 6K unit I've had some months, others noted here aren't that old - hopefully their unique charge features don't ruin the batteries. May be a bad model or bad batch. I did see that some got warranty support at least.
Click to expand...

Im actually thinking the batteries are fine in those reviews, more likely the designer missed something and the charge/controller is burning out in them.
 
I am working on a power supply add-on for the Teensy 3.1 that will allow both a 2A, 5 V and a 300 mA, 3.3 V source from a standard 9 V battery. This doesn't allow recharging of the battery, but allows the Teensy 3.1 and peripherals to be powered from a cheap and easily replaceable battery source. The source can go up to 12 V IIRC. Unfortunately, my mail was stolen so I have to wait another two weeks to get the boards from OSH Park!
 
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