3

I have a LiPo batterery:

EZ-power LiPo 4000mah - 2s 7.4

How could I power the Raspberry, I just know that Pi works at almost 5V.

3

You want to use a step-down power regulator that will take your 7.4V LIPO battery and take it down to 5V. You could, for example, get one of these: http://www.gearbest.com/development-boards/pp_69337.html?currency=GBP&gclid=CJbgve25_cQCFWH3wgod-acA-w which takes in the + and - from the battery, steps it down and then gives you USB ports to connect your Pi to. Be aware that the regulator may get a bit hot due to the dissipated energy and also be careful not to over-use your LIPO.

  • I'm gonna try this device – Mitro Apr 18 '15 at 12:31
2

I just use UBECs (a couple of GBP on eBay). E.g. http://www.ebay.co.uk/itm/111625837178

They take something in the range 5.5V to 26V and convert it to 5V.

I just connect the UBEC inputs to the battery and the UBEC outputs to the 5V and ground pins on the expansion header.

1

I have bought for example this: http://www.gmelectronic.com/powerbank-pd004-5200mah-p751-664 . And I did run timelapse snapshots for many hours (10) before I switched off RPi. I suppose any powerbank for phones (5V) is ok.

The battery you refer is dedicated to RC models, I would be worried to connect to RPi.

Edit: You can use a voltage regulator - see e.g. LM317T http://www.reuk.co.uk/Using-The-LM317T-To-Regulate-Voltage.htm or http://www.learningaboutelectronics.com/Articles/LM317-voltage-regulator. It is based on Zener diode, you will waste some energy to heating the regulator.

  • I don't need a powerbank, I already have lblandmodellismo.it/1/ez_power_4000_2_lipo_7706817.html but I'd like to know how to use it, if possible and I think so, but I'm not an expert – Mitro Apr 17 '15 at 12:30
  • That is jaromrax's point about the voltage regulator. The bank you have is 7.4V, you cannot plug the pi directly into that. It must have regulated 5V input. – goldilocks Apr 17 '15 at 12:44
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This is an old thread but just if somebody needs quick way to solve this issue can use phone car charger that are sold for $5 almost everywhere (they have 2.1A version too). It contains switching regulator (DC to DC converter) inside. Also it has USB port/s that can be used to power your Raspberry Pi .

  • I don't think this actually answers the OP's original question! But it is a valid means to power an (auto)-mobile RPi. 8-) It does help if it isn't one that switches off with the ignition off (unless you detect that as a signal to shutdown -h now whilst keeping the RPi from the "ancillary supply", often used for say, a car radio; AND learn to wait for, say 45 seconds to allow the RPi to complete shutdown process) - otherwise you'll still want something that can keep the RPi running until it HAS shutdown - possibly a UPS device powered by, say, a LiPo battery! 8-) – SlySven Jan 18 '16 at 11:26
0

Adafruit has a couple options that you can plug the lead from your LiPo directly into:

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