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I have a raspberry pi zero w. What is the smallest (in terms of weight) that can run the pi? I am not concerned about how long it runs for; 5 mins would be adequate. What about with a camera attached?

I know that 4 AA batteries can run it for quite a few hours, but they weigh about 100g in total. Can I sacrifice run time for weight?

Thanks!

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I think your best chance of success is to find a small LIPO. They are typically used for powering radio controlled aircraft such as quadcopters.

As long as you feed more than 3.3V into the 5V pin a LIPO of large enough capacity will provide the current needed to power the Pi.

Some Pi's have proection mechanisms which kick in at 6V, so I suggest any LIPO you use should be configured to provide less than 6V.

  • Yes, good idea. I could probably source one from an old phone. – Josiki Jul 3 '17 at 8:44
  • @Josiki Will you also carry your old phone around to charge it? – Dmitry Grigoryev Jul 3 '17 at 9:19
  • Phone batteries are unlikely to be LIPOs, probably standard Lithium cells. In either case as Dmitry Grigoryev suggests charging Lithium (including LIPO) batteries is not trivial. You need special chargers. – joan Jul 3 '17 at 9:31
  • I haven't thought that far ahead to be honest. Charging it via my phone is a definite option. Although if that doesn't work, then maybe I should go for a different approach. – Josiki Jul 5 '17 at 8:11
  • I accepted this as the answer, because my main concern was the weight. After getting a battery from an old phone (samsung s3) and checking that it powered the pi, I weighed it an it was around 20g, which is a lot lighter than the other options that were suggested. – Josiki Jul 9 '17 at 19:54
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two 3v cr2032 button cells (190-225mah) should do the trick, considering that it uses at most 230ma on peak load. So half an hour should be easily achievable. Do not forget to use a voltage regulator, as the pi does not like 6v. not sure about the power usage of a camera

  • In fact the Pi itself will run quite happily on 6V, although HDMI and any USB devices or attached peripherals may not. – Milliways Jul 1 '17 at 11:00
  • @Milliways Does the Pi Zero even use 5V? I would think that as long as the voltage regulator supports it then it would be fine. Do we know the tolerance on the 3V3 pin to just connect 2 CR2032 in parallel? – lights0123 Jul 1 '17 at 12:44
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    -1. A single CR2032 only provides 15 mA, you'll need 30 of them to run an RPi Zero. – Dmitry Grigoryev Jul 1 '17 at 13:07
  • @lights0123 You should not ask questions in Comments, but the Foundation warns "Under no circumstances should a power source be connected to the 3.3V pins." – Milliways Jul 1 '17 at 22:52
  • i tried putting two into it (via a micro usb cable that I had stripped apart), but it didn't seem like enough. – Josiki Jul 3 '17 at 8:43
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If the CR2032 button cells don't provide enough current, you could try 4 AAA batteries instead of AA batteries. That should reduce the weight some.

  • Good idea! I will give it a try later :) – Josiki Jul 3 '17 at 8:43
  • It works! But a phone battery is quite a bit lighter. – Josiki Jul 9 '17 at 19:55
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There are boost converters which can provide 5V 300 mA off a single AA battery (example). Of course, the battery won't last long, but it seems that's OK for you.

  • That is cool! Although I don't know that it will give enough amps, I think the pi needs about 1A? Or am I wrong about that? – Josiki Jul 3 '17 at 8:46
  • Depends on how you use it. If you plan to have Wifi and external devices connected, you may actually want to keep you 4 AA batteries. – Dmitry Grigoryev Jul 3 '17 at 9:22
  • Yeah, I plan to use the wifi and (possibly) have a camera connected as well. So perhaps this is not the approach for me. I don't really want to buy something just to experiment with it. – Josiki Jul 5 '17 at 8:12

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