assadollahi
Posts: 22
Joined: Sun Jul 26, 2015 6:39 pm

max voltage to power the pi2?

Fri Feb 12, 2016 10:13 pm

What's the highest voltage I can put on the GPIOs to power a RPi 2? I have a UBEC delivering 5.46V (specs say it should deliver 5Vm see here: http://www.hobbyking.com/hobbyking/stor ... _21v_.html ) and would like to use it to power the Pi from a 7.4V LiPo, but I don't dare right now...
Official manual says 5.25V. What are the highest voltages you've tried? My USB charger that I normally use to power the Pi2 delivers 5.35V and the Pi runs fine (I know that USB power input of the Pi has a voltage regulator).
Last edited by assadollahi on Fri Feb 12, 2016 10:59 pm, edited 1 time in total.

User avatar
GTR2Fan
Posts: 1601
Joined: Sun Feb 23, 2014 9:20 pm
Location: South East UK

Re: max voltage to power the pi2?

Fri Feb 12, 2016 10:28 pm

assadollahi wrote:What's the highest voltage I can put on the GPIOs to power a RPi 2? Official manual says 5.25V. What are the highest voltages you've tried?
You mean the power pins on the GPIO header. 5.1V. It would be foolhardy to go above 5.25V when that's officially specified as the upper limit.
(I know that USB power input of the Pi has a voltage regulator).
No it doesn't.
Pi2B Mini-PC/Media Centre: ARM=1GHz (+3), Core=500MHz, v3d=500MHz, h264=333MHz, RAM=DDR2-1200 (+6/+4/+4+schmoo). Sandisk Ultra HC-I 32GB microSD card on '50=100' OCed slot (42MB/s read) running Raspbian/KODI16, Seagate 3.5" 1.5TB HDD mass storage.

User avatar
DougieLawson
Posts: 38557
Joined: Sun Jun 16, 2013 11:19 pm
Location: A small cave in deepest darkest Basingstoke, UK
Contact: Website Twitter

Re: max voltage to power the pi2?

Fri Feb 12, 2016 10:36 pm

Er, how about 5.25V?
Note: Any requirement to use a crystal ball or mind reading will result in me ignoring your question.

I'll do your homework for you for a suitable fee.

Any DMs sent on Twitter will be answered next month.
All non-medical doctors are on my foes list.

Rnd(100)
Posts: 9
Joined: Mon Feb 08, 2016 9:19 pm

Re: max voltage to power the pi2?

Fri Feb 12, 2016 11:25 pm

assadollahi wrote:What's the highest voltage I can put on the GPIOs to power a RPi 2? I have a UBEC delivering 5.46V (specs say it should deliver 5Vm see here: http://www.hobbyking.com/hobbyking/stor ... _21v_.html ) and would like to use it to power the Pi from a 7.4V LiPo, but I don't dare right now...
Official manual says 5.25V. What are the highest voltages you've tried? My USB charger that I normally use to power the Pi2 delivers 5.35V and the Pi runs fine (I know that USB power input of the Pi has a voltage regulator).
I've used ubecs and was getting 5.17v, they're cheap but need to check each one !
Drop the voltage with a diode, something like a schottky 1n5822 / 1n5821 / 1n5820, OK for up to 3A and drop approx 0.5v.

Hope that helps.

assadollahi
Posts: 22
Joined: Sun Jul 26, 2015 6:39 pm

Re: max voltage to power the pi2?

Fri Feb 12, 2016 11:35 pm

Rnd(100) wrote:
assadollahi wrote:What's the highest voltage I can put on the GPIOs to power a RPi 2? I have a UBEC delivering 5.46V (specs say it should deliver 5Vm see here: http://www.hobbyking.com/hobbyking/stor ... _21v_.html ) and would like to use it to power the Pi from a 7.4V LiPo, but I don't dare right now...
Official manual says 5.25V. What are the highest voltages you've tried? My USB charger that I normally use to power the Pi2 delivers 5.35V and the Pi runs fine (I know that USB power input of the Pi has a voltage regulator).
I've used ubecs and was getting 5.17v, they're cheap but need to check each one !
Drop the voltage with a diode, something like a schottky 1n5822 / 1n5821 / 1n5820, OK for up to 3A and drop approx 0.5v.

Hope that helps.
thanks very much will try both hints, have another ubec floating around.

UPDATE: ha! the other ubec (same make!) delivers 5.37V, i'll dare this!

Rnd(100)
Posts: 9
Joined: Mon Feb 08, 2016 9:19 pm

Re: max voltage to power the pi2?

Sat Feb 13, 2016 12:05 am

Diode @ less than 20p cheaper than fried Pi ?

assadollahi
Posts: 22
Joined: Sun Jul 26, 2015 6:39 pm

Re: max voltage to power the pi2?

Sat Feb 13, 2016 5:39 pm

Rnd(100) wrote:Diode @ less than 20p cheaper than fried Pi ?
it worked! pretty cool!

User avatar
joan
Posts: 14851
Joined: Thu Jul 05, 2012 5:09 pm
Location: UK

Re: max voltage to power the pi2?

Sat Feb 13, 2016 6:00 pm

I've used 5.8V on all my Pis. I wouldn't approach any closer to 6V which is the real danger point for the Pi.

Some of the devices you attach to the Pi might not be as tolerant as the Pi itself.

gordon77
Posts: 4934
Joined: Sun Aug 05, 2012 3:12 pm

Re: max voltage to power the pi2?

Sat Feb 13, 2016 6:34 pm

joan wrote:I've used 5.8V on all my Pis. I wouldn't approach any closer to 6V which is the real danger point for the Pi.

Some of the devices you attach to the Pi might not be as tolerant as the Pi itself.
Where does the 6v figure come from?

User avatar
joan
Posts: 14851
Joined: Thu Jul 05, 2012 5:09 pm
Location: UK

Re: max voltage to power the pi2?

Sat Feb 13, 2016 6:45 pm

gordon77 wrote:
joan wrote:I've used 5.8V on all my Pis. I wouldn't approach any closer to 6V which is the real danger point for the Pi.

Some of the devices you attach to the Pi might not be as tolerant as the Pi itself.
Where does the 6v figure come from?
I don't remember. It's the figure which always comes to mind when this question is asked.

I have had a quick search for likely posts but can't find the source.

mosespi
Posts: 508
Joined: Mon May 12, 2014 3:35 pm
Location: 34,-118
Contact: Website

Re: max voltage to power the pi2?

Sat Feb 13, 2016 6:58 pm

Most of the Pi schematics list a SMBJ5.0A or similar TVS diode (transient voltage suppressor) at the power input side.
This is a common TVS and starts to conduct at around 6.4v which is probably where the 6v comes from.

FYI: For those not familiar.. note that these diodes are primarily intended for transient voltage events, surges, static discharge, etc.. Most designs don't intent it to be an permanent over-volt protection device. Depending on how much power your supply can provide, if you go over this voltage for a long duration (seconds?).. it will overheat the TVS, probably melt it off the PC board and then proceed to fry your Pi. Haven't tested any of mine yet.. but this is generally what happens.

I wouldn't go much above the 5.25v, but if you decide to experiment, definitely keep it below 6 volts.

Regards,
-Moses
Power problems? MoPower UPS for the Pi
http://www.allspectrum.com/mopower/

Return to “Interfacing (DSI, CSI, I2C, etc.)”