Battery powered Raspberry Pi

Well, I didn’t get the result I was hoping for, but still, found a way of reliably running a Raspberry Pi for several hours without it being plugged in. Oh the possibilities!

Raspberry Pi UPS

The accessory is a BlackBerry ACC-50256-201 which is a spare battery pack for a BlackBerry Z10 smartphone. This portable power pack has a nice little feature which sets it aside from other smartphone spare battery packs – the ability to plug it into any micro USB device – including a Raspberry Pi.

The aim was of course, to see if it would work as a low-cost Raspberry Pi UPS (uninterrupted power supply). Did it work? The answer to this is, well, sort of…

After plugging it in, the Raspberry Pi began booting – a good sign to see it had the output to run the Raspberry Pi. Then I plugged in the charger to the battery pack (which was still plugged into the Raspberry Pi) and found that the Raspberry Pi went off for a split second, but quickly began booting again.

Once the battery pack was fully charged, it was time to see if pulling the plug would maintain the Raspberry Pi’s on state. I pulled the plug, and bump! The Raspberry Pi went off again for a split second – fail!

Why didn’t it work?

After doing some testing, I found that when the charger is plugged into the battery pack, it charges the battery and also supplies enough power to the attached device. By unplugging the charger, the battery pack’s power manager switches the supply from the charger to the battery itself. In the process of doing this, the power is momentarily dropped. This causes the Raspberry Pi to turn off for a split second, and begin the boot procedure again.

Conclusion

Well, the bad news is, you can’t use the BlackBerry ACC-50256-201 can’t be used as a UPS, but the good news, it is a brilliant little bit of kit which will reliably run your Raspberry Pi for at least a couple of hours off-grid.

Ste

Web Developer living in Manchester, working for Studio Skylab (http://www.studioskylab.com). Views and thoughts are my own.

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9 Responses

  1. David R says:

    Will this work if I use a Duracell USB backup battery?

    Will let you know when I’ve given it a shot.

  2. ISbit says:

    How about adding a large enough capacitor at the battery’s output?
    I guess that the capacitor maybe could mess with the charging-circuit though.
    A rectifier diode would solve that problem, but also drop the voltage a bit.

  3. Michael says:

    I hooked up a 10v 10000uf capacitor and it worked flawlessly. I’m sure someone with a scope could determine the amount of time it is off and determine the optimal capacitor size based on the power consumption…

  4. J says:

    Did you atleast test to see how much runtime you could get off the battery when the Pi was hooked up and active? That’d be helpful to know because this could be a great portable powersource, even if it didnt work at as you origianlly intended.

  5. ninety47 says:

    Could make little filter out of capacitors that holds and trickles out enough charge to run the RaspberryPi until the powers supply cuts in…. just and idea not sure if is possible.

  6. Murray says:

    I expect this post is rather blasphemous, but I’d like to do something similar thing with a (sorry) Beaglebone Black. (I’m helping my son with a science fair project and we’d like to be able to reliably collect data around the clock for long periods of time — months, years.) Michael’s post suggests that this charger works fine for the Raspberry Pi if you use a large enough capacitor — and that sounds great. The Beaglebone Black draws more current than the Pi, I think, plus we’ll need to power our sensors, a USB flash drive to store data, and a wifi device to transmit the data. I’m not sure how much current we’ll need, but it could be as much as 2 amps (at 5 volts). The battery in this charger (BlackBerry ACC-50256-201) is an 1800 mAh battery, so I expect we could go without power for more than 1/2 hour on the battery, but I can’t find any info anywhere on how much current the charger can supply. Any one know?

  1. 21st May 2013

    […] powered Raspberry Pi Posted on May 21, 2013 by News Collector — No Comments ↓ By Ste W Can a BlackBerry ACC-50256-201 be used as a UPS for a Raspberry Pi? The answer is, not quite, but […]

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