19 Replies Latest reply on Dec 5, 2016 12:09 PM by tgaryet

    Is it safe to power a raspberry pi from battery's?

    tristanb

      I want to make my raspberry pi portable, is  it safe to run it from battery's?

        • Re: Is it safe to power a raspberry pi from battery's?
          gpolder

          Tristan,

           

          it's perfectly possible. The easiest is to use a USB power pack, look for instance at my Raspberry Pi Slow Scan Television (SSTV) Camera .

          You will see the power pack below the raspberry pi on the first photo.

           

          best,

          Gerrit.

          4 of 4 people found this helpful
            • Re: Is it safe to power a raspberry pi from battery's?
              D2113F

              In 2013 I thoroughly tested the first rPi 256MB with four NiMH AA rechargeables.  Finding was that "5V" input won't boot at 5.1V, which is inside USB specification, but after running down the batteries a bit it would boot if 4.9 to 5.0 Volts was supplied.

               

              Suggestion is to buy a buck dc-dc converter, wind its screw until it supplies 4.98 Volts to your test resistor, and then solder to the power rails near to the micro-usb power connector on your rPi.  A pwm buck will accept anything from 6x AA or 2x Li or 6V Pb battery and by regulating that down to 4.98V it won't care when the battery has gone down, and nor will it break your pi when recharging.

                • Re: Is it safe to power a raspberry pi from battery's?
                  Roger Wolff

                  Dear D2113F,

                  Many, many PIs have been running just fine on 5.10V or 5.25V. So even though your experiment shows that in your case your PI had a problem with "5.1V", that is not the case in general. Officially the pi will take up to 5.5V, in practice I've tested it down to 2.8V (for the pi2), and it kept on working, but I am not willing to "sacrifice" a pi to see where it will break if I increase the voltage. I don't expect this to happen at less than 6V, but I could be wrong.

                   

                  When I was testing the lowest-possible-voltage, it became clear that part of the required voltage is to have a little margin to allow for voltage dips. If the CPU is idle and then gets an interrupt and suddenly starts to process again, the current consumption can rise so quickly that the powersupply (what/whereever it is) cannot provide the additional current quickly enough. A buffer (capacitor) close to the pi will help getting enough power to the pi on short notice. So, maybe the effect you were seeing was related to "dynamic effects".

                   

                  Gerrit's suggestion to use a powerbank holds up: those provide the right voltage at enough current to allow a pi to function perfectly without odd stuff like having to "drain the batteries first before you start using them". The come with an included boost converter to provide a stable 5V (usually a little more).

                  • Re: Is it safe to power a raspberry pi from battery's?
                    clem57

                    The Pi power supply has changed since then as I recall. Maybe time to retry on newer models.

                    Clem

                    2 of 2 people found this helpful
                • Re: Is it safe to power a raspberry pi from battery's?
                  Problemchild

                  Yes!! however you havent specified which batteries you intend to use. Remember that a USB power pack is merely a battery at it's heart.

                   

                  As several have alluded to  you can run directly off the batteries and now the RPI2 has a switch mode regulator it's less fussy than before but still all 5V powered sections of the RPI would be at risk of damage at excessive voltages say much more than5.25/5.5V or just not working at low voltages.

                   

                  You will in practice require 5Volts from some where  in the case of batteries this could be 6V(4 AA bateries for example) or more into a decent switchmode regulator.

                   

                  We would need to know your intentions for the device including what batteries you intend using to make more specific suggestions.

                  Personally I would use a USB battery pack as they are cheap and powerful as well as been simple to use

                  2 of 2 people found this helpful
                  • Re: Is it safe to power a raspberry pi from battery's?
                    dyland581

                    Hello, I'm currently working on an Instructable and element14 article about making a Raspberry Pi PowerHAT. It will let you power your Raspberry Pi with batteries, safely. I'll share the links here, once I complete them.

                     

                    First of all, by using the 5V GPIO pin you are bypassing the input fuse that is on the RPi. This means you have no protection in case of a short circuit, or reverse voltage. If you do make an error, a lot of current (depending on how much you power supply can provide) can flow through your Pi and can damage it. You are also bypassing a high-efficiency diode circuit, so you are basically without any protection. I've included a schematic of the power management circuit for a Raspberry Pi Model B+, below.

                     

                    Despite all these cons, it's still possible to power the Pi through the pins, with a simple circuit. First off, a regulated 5V power source has to be inputted to the 5V and ground GPIO pins. Most power adapters won't output a regulated voltage (unless stated otherwise on them) so you would also need to use some voltage regulator circuit. Lastly, there are a few capacitors used to smooth the voltage, which makes power more stable.

                    To power the Pi, you will need to have a regulation circuit, or use a regulated power supply. Then, just add a schottky diode on the input, and maybe a resettable fuse. I hope this helps, and I'll try to provide a schematic of said described circuit.

                    3 of 3 people found this helpful
                    • Re: Is it safe to power a raspberry pi from battery's?
                      sigpaw

                      Absolutely! I Like using these on my Pi's. :-)

                       

                      https://www.piborg.org/battborg

                      1 of 1 people found this helpful
                      • Re: Is it safe to power a raspberry pi from battery's?
                        tonyboubady

                        Consider power as water, current as speed of flowing water and battery as a container...

                         

                        What we really need to power anything is amount of the water(voltage) and throttle of the water(current)...

                         

                        If the water container(battery) is not providing enough amount of water(voltage), add more containers(batteries) in series...

                         

                        If the container(battery) is not providing enough throttle of water(current), add more containers(batteries) in parallel...

                         

                        So, yes we can power anything with this logic

                          • Re: Is it safe to power a raspberry pi from battery's?
                            wek31975@yahoo.com

                            Have raspberry pi 3 w/7inch monitor. Need more voltage. Raspberry pi 3 needs exactly 5 volts or it will throttle. That's why PSU with starter kit is 5.25 volts. I tried my 15.000 m Amp hour battery. It doesn't

                            drain fast, but it does not supply enough voltage for Pi3 not to throttle.

                             

                            Can pi 3 over volt. How far is safe if it can.

                              • Re: Is it safe to power a raspberry pi from battery's?
                                clem57

                                Eric Kazer

                                I believe the problem is the current not the voltage. 15,000 mAh is a measure of current over time. I bet it delivers only 1.0 Amp. A Pi 3 needs more especially with a 7 inch display! If you have two usb connections, each is 1.0 Amp. Then drive one for the Pi 3 and separately drive the 7 inch display.

                                Clem

                                • Re: Is it safe to power a raspberry pi from battery's?
                                  morbee

                                  I am running the same setup as you are, pi 3 with 7" touch screen as well as a mouse and keyboard. I am using the 15000 mAh SNUG power bank which outputs 5.0V at 3.0A and i can run my setup for a full 12 hours with constant use. No problems detected thus far.

                                  1 of 1 people found this helpful
                                    • Re: Is it safe to power a raspberry pi from battery's?
                                      lenwesurion

                                      Hello ! I am trying to build this kind of setup for my first time. I'd like to make a video game emulator station using Retropie, the RPI 3 and the 7" touch screen with a battery so I can play outside.

                                      But I also want to know if I can plug it on my screen using HDMI, so it'd be a mix between portable and desk console.

                                      Any advice on where/what to buy ?

                                      Also, how did you manage with your battery ? Did you let it outside or you found a way to build a little something attached to your screen case ?

                                       

                                      Thanks a lot, I'm quite nervous about this project so a little help would be really appreciated ^^

                                    • Re: Is it safe to power a raspberry pi from battery's?
                                      royleith

                                      The problem is current and voltage. As the current drawn by the Raspi increases, it causes a voltage drop across the USB cable between the PSU and the Pi. The higher the current drawn, the lower the voltage reaching the Pi. The 'Universal' PSU overcomes this problem by increasing the supply voltage a little above 5V (but, within the rated Pi spec.) and by using heavier copper conductors in its connecting cable to reduce the voltage drop at higher currents. This is the only PSU that I now use. The Pi 3 has WiFi enabled, out of the box, and this is often sufficient to cause problems with standard 5V PSUs and USB 'charger' cables even when using 0.5 metre cable lengths.

                                       

                                      I am successfully running a Pi3, a GeChic, 1920 x 1080, USB powered 15" monitor, a Focusrite 2i4 audio interface providing 50v phantom power to condenser microphones and a wireless keyboard and mouse. The screen, audio interface and keyboard/mouse dongle are plugged into the Pi3 USB ports. The power comes from a RavPower RP-PB13 (14,000mAh) phone charger. I connect to a BlueTooth portable speaker or a mains powered amp and a pair of studio monitors using the Pi 3's built-in BlueTooth capability except when using the Focusrite for monitoring (via headphones, for portability).

                                       

                                      Even with the coiled leads supplied with the RavPower, the multi-coloured square low voltage warning was usually present. The answer is to use 10cm charger USB cables (yes, 10cm is not a misprint). The square appears briefly during boot and when the Focusrite is plugged in, but there are no further problems. I might be able to lose even those by connecting the screen via a powered USB Hub supplied from the second RavPower USB outlet (I have built special cables to supply 5v from USB ports to a range of power plugs), but this is not worth the effort.

                                       

                                      If you want to use standard mains 5v PSUs (with a USB socket rather than a captive cable) you might find that a 10cm cable will do the job. Of course, you will need an extension mains lead to get the socket and PSU within 10cm of the Pi.

                                  • Re: Is it safe to power a raspberry pi from battery's?
                                    gergoo

                                    Sorry, but I could not resist the itch.. Today I ordered a RPi3 board and plan to use it as permanent bound to the grid. I think that the 5V power banks sold everywhere will work properly and also filter the intermittent power downs (easiest way to restart the router ) and the high consumption spikes.

                                    Will have to test if such power bank in between will neglect all the above issues.

                                    500mA-1A continuous drain assumes that 2.5-5A spikes should be ok.

                                     

                                    Anyway... I wanted to write that it is shame to have so many shields and not to have proper power. I am a little disappointed that I read about such issues. Currently I'm using another brand of single board computer which accepts 9 and 12V power supply and has battery charger/step up supply (according to specifications it is safe to use 6-15V). Battery (3.7V) is advised if low quality PSU and GSM module (or other high spike accessories) are used.

                                    Tested it also with "rusty" GSM battery that was so empty that it was unable to start charging and the current was auto adjusted to the battery specifications. Can run from the 3.7 GSM battery.

                                     

                                    I am starting to think that the quad 64bit CPU Win10 board might not be as good as I initially thought.

                                     

                                    The PiBorg (described in the upper posts) is another good idea, (I admit-never worked with Pi) but the 15% CPU load does not ring a bell. I thought that the CPU frequency is more important than the load. Anyway the old Pi CPU has rating as the Pi Zero (assuming not lot of additional power is required) which is 160mA (Wikipedia). If CPU is using low multiplier than it can probably last longer than the regular.

                                    The Sanyo batteries are also a good choice but probably has to be considered that NiMH batteries have normal voltage around 1.2 volt (average and 4*1.2=4.8) and the OKI chip is rated 7-36V so the chip might be stepping down only the initial period and then most of the time doing nothing (5mA consumption is neglectable). Anyway over voltage protection is mandatory (4*1.4=5.6 and it is a little uncertain if all boards will handle it). 0.1 capacity (and less) drain per hour is nearly ideal condition. For car battery- the Borg is perfect. With the Borg also regular batteries are applicable.

                                    The old brand, that I currently use, tested comparable board and the power was less than 1W continuous which is nearly as Pi Zero.

                                    Battery pack for Borg: 2.7*1.2*4=13W

                                    Pi Zero is less than 1W. So test has to be valid.

                                    Anyway- good night (have to sleep. it's 1am local) and sorry if i offended someone. Pi is nice, but doesn't seem to be portable and jerk proof . When I test it I might apologize

                                    1 of 1 people found this helpful
                                    • Re: Is it safe to power a raspberry pi from battery's?
                                      tgaryet

                                      I've designed a PowerHAT power controller that is made specifically to make a HAT compatible (40 pin gpio) portable.  It properly manages charging a li-ion battery (included) and the on/off operations by a switch and/or software control for when you poweroff or when the battery gets low. You can check it out here:  PowerHAT. 

                                       

                                      Terry