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110

There are a few things you need to be aware of if you want to build your own solar power supply. The main thing is that the voltage output of solar cells can vary wildly based on the incident sunlight (how sunny it is). Simple unregulated solar panels sold as 'battery chargers' are often designed for deep-cycle 12v 'leisure' batteries, but can be measured ...


61

You question is more suited for the Electrical Design Stackexchenge site - Because you can always rely on the Gurus there, like Oli, to help design easy, up to date circuits. I think that this question will be asked by many more Raspberrians to come so this is actually a very good place to answer your question. My answer will go more into engineering your ...


49

Standard USB uses 5V, and the Model B Pi claims to need 700mA. Taken from the Raspberry Pi FAQs: The device should run well off 4 x AA cells. If you were using 1.5V alkaline batteries, you would be oversupplying the board. As with most SoC-based computers, you should use NiMH batteries, as they supply an average 1.25V. This would leave your board at a ...


37

It might be worth looking into the Solio Chargers, which have built in solar panels, voltage regulators, and battery backup. They will also most likely have the proper power connection for the Raspberry Pi.


26

Yes it is possible. But not with PoE. The board can be powered using the GPIO. Here is a pin diagram showing the pins for power at the top. Maximum permitted current draw from the 3v3 pin is 50mA. Maximum permitted current draw from the 5v pin is the USB input current (usually 1A) minus any current draw from the rest of the board. Model A: ...


24

Go to a hobby store (or DX.com) and buy a BEC (battery eliminator circuit) intended for model aircraft. $5 gets you a very efficient switch mode voltage regulator, good for around 3A. I use these with all my Pis. Here is an example: http://dx.com/p/hobbywing-5v-6v-3a-switch-mode-ultimate-bec-ubec-15149


20

Here's some comparison of various cheap options for battery power, that will all supply the Pi well within its specs: Running a Raspberry Pi from batteries [This link is actually dead -- and searching the domain for "raspberry batteries" fails -- but Pikamander2 suggested the below as edit which supposedly contains the original content(??). Hopefully this ...


19

I have built a converter from 12v to 5v That's enough for RaspberryPi's 5v requirement. IT also gives power for fan with adjustable thermostat (12v) and even active usb hub (in the future). Everything (Raspberry Pi, converter and thermostat) is enclosed in a router-box (I even have space for an additional 2.5" hdd, 3G modem and/or GPS unit ;) ) Such a ...


18

Short answer Yes, most (but not all!) USB power banks are capable of powering a Raspberry Pi, since they usually have an output voltage of 5 V. And yes, by using a (quite large) 50 Ah power bank, you can definitely expect your Pi to run for at least 24 h. See the long answer below for reasoning and further relevant aspects. Long answer According to actual ...


16

The Raspberry Pi Wiki entry on power suggests this is possible (emphasis mine): Back-Powering; (powering the Raspberry Pi from a USB hub through the uplink/data port, single cable) Back powering is possible on the Raspberry Pi. Revision 1.0 boards have to be modified to back power, this is due to the 140ma "polyfuses" that are installed in the USB port ...


14

I found the question very interesting but my self am not really interested in soldering and fiddling with resistors and stuff and I am sure other people might stumble upon the OP question with hope of a ready product. So I did find this which for my needs would actually be great. Buy, wait a few days, plug in and viola. I found it on DX.COM As pointed out ...


14

The Ethernet port does not support PoE. Therefore, you cannot use PoE without external hardware; it would be necessary to convert the 48V down to 5V. It should limit the current to 1A. Untested (Possibly) Useful Hardware TP Link Multipurpose PoE Splitter @ LinITX See also: What do I need to know when choosing a dedicated power supply?


11

It's possible to power your RPi through your USB hub on two conditions: the hub does not backfeed: this is easy to test; remove the SD card, connect the RPi's USB port (not micro USB port) to the hub. If the RPi's led doesn't come on the hub doesn't backfeed. If the hub does backfeed you can't use this hub with the RPi. the power supply of the hub is ...


10

As long as the power bank outputs 5V it will power the Pi. It claims 50000mAh so it claims 2.5 amps per hour for 24 hours. Assume it will deliver half that so 1.25 amps for 24 hours. If that is enough or not will depend on what you have connected and what the Pi is doing.


9

Here is my setup: 30 watt solar panel with a 12 volt charger hooked up to a 33 amp hour, 12 volt battery. Off of the battery I have a 12 volt to 5 volt battery eliminator that drops the voltage safely to 5 volts that I spliced into a micro USB cord. It's been running successfully for two days now. I would like to experiment with a smaller battery and panel ...


9

Yes, should do Just double checking the datasheet of the MT3608: if using AA rechargables instead of batteries, mind the lower voltage (cell voltage 1.2 V), but for two cells in series still above the lower lockout voltage (2 V) of the MT3608 at very low input voltages the efficiency could be lower than 80 %, the datasheet (p. 5) lists 80 % at 3 V and a ...


8

I got this battery powered USB cell phone charger, and a couple of lithium 18650 batteries. It did a pretty good job and ran for 5.5 hours when idle and over 4 hours when running a Quake 3 demo loop. You can read about my testing methodology here. These 18650 lithim batteries work great because they are high enough voltage that just 2 batteries will easily ...


8

No you cannot power the Raspberry Pi using its USB ports. The micro usb is the only way to power the RPi, apart from some other hacks I've seen involving solder (read the update). Although it's not completely impossible, but you'd have to modify the RPi quite a bit to get that right. Please have a look to the Model B Rev 2.0 schematics. UPDATE: As ...


8

The Pi should not be powered from it's own USB ports. It's not a safe way of supplying power. The correct way is to use either the micro USB port or the correct GPIO pins. The hub you have is at fault here - it shouldn't be supplying power upstream along the data feed cable. You may have to take it apart and cut a wire. Powering the Pi from two places is ...


8

The question seems to be inadequately answered. The best alternative would be a switching mode power supply with simple circuitry such as this: Although 7805s work well, it's not scalable in the long run. Say you want to add a Camera Module or some other module. It'll be able to drive the circuit but cannot withstand high loads for a long time. The data ...


8

You have to be careful with those 7805's. If you remove power from the 6V side while a powered hub is connected for instance - the 7805 will be reversed biased. This is the archilles heal of the 78XX series. You can help it out somewhat by putting a reverse biased diode (anode to the 5V side) from the input to the output. Additionally, the 7805 are old ...


8

The batteries won't force current through the system. Your bigger problem, though, will be running the Raspberry Pi 2 at all on 4.8 V. It's very close to under-voltage warning (which I saw quoted as 4.65V for the B+). You'll need some kind of DC-DC converter to get the voltage to consistently ≥5V.


8

Based on your picture, it looks like the power switch is flipped off. If you look at the board oriented with RPi PowerPack V1.2 at the top, you'll notice there's a switch at the very bottom of the board. Switch it to On. I'm not sure if this matters, but in the images provided by your link, they all show the RPi being plugged into the top USB port. If they'...


7

As far as I know, you can't. But by using some very simple electronics you can. The most simple and straight forward option is to use 2 GPIO pins as input (one for each power supply). Connect both power supplies (besides to their normal connection to actually supply the power) through some resistors (for safety and voltage level adjustment!!) to these GPIO ...


7

Yes. You can power it via the ground and 5V pins on the expansion header. Once it's booted you can also back power it via the USB (although I doubt that this is sensible). Both those methods bypass any protection afforded by the 2 amp polyfuse.


6

http://elinux.org/R-Pi_Troubleshooting#Troubleshooting_power_problems suggests that the voltage needs to be between 4.75 and 5.25 V, suggesting that 4 NiMh batteries at 1.2V each should be 4.8V, within range. However, fully-charged NiMH batteries can go up to 1.4V * 4 = 5.6V, well over the maximum. If you test your batteries and find that they only go as ...


6

It is inadvisable to run the RPi on batteries, as it has been designed to be powered by USB; USB power is regulated and accurately 5V. Most USB ports can supply ~500mA, whereas most USB chargers are designed to supply 1A. The RPi requires a minimum supply capable of 700mA, otherwise it may not boot properly. It would be advisable instead to use a battery ...


5

At a minimum you need: a solar panel, a charge controller, a deep cycle battery, a DC-DC buck converter (to reduce battery voltage to 5V), hardware to mount the panel, something to house all the components. The trick is in sizing the solar components, and that depends on how much sunlight you get and how much reserve power you want. However, even under the ...


5

Here is what I did and it seems to work well: You will need a 8xAA battery pack with a 9v battery like power connector. A 2Amp USB car adapter Optional - A plug to plug into the car adapter, otherwise just take the adapter apart. Solder the center pin on the car adapter to the positive from the battery pack, or if you used the cable the appropriate wire. ...


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