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Raspberry Pi Zero – Conserve power and reduce draw to 30mA

midwesternmac.com

11–20 of 90 posts

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#11
post #8

We've actually found that the RPi doesn't draw enough power, specifically to the USB ports. Our peripherals are within the USB spec of a 500ma max pull, but even so we are experiencing sporadic CPU brownouts. The first thought was to double the max_usb_current in /boot/config.txt, but that only lengthened the time between brownouts. We looked into hacks that could increase the current even more, such as this bypass m…

I thought USB 2.0 had 500ma max current?

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#13
post #8

We've actually found that the RPi doesn't draw enough power, specifically to the USB ports. Our peripherals are within the USB spec of a 500ma max pull, but even so we are experiencing sporadic CPU brownouts. The first thought was to double the max_usb_current in /boot/config.txt, but that only lengthened the time between brownouts. We looked into hacks that could increase the current even more, such as this bypass m…

I'm not interested personally, but your HN profile doesn't seem to include any contact info.

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#14
post #11
post #8

We've actually found that the RPi doesn't draw enough power, specifically to the USB ports. Our peripherals are within the USB spec of a 500ma max pull, but even so we are experiencing sporadic CPU brownouts. The first thought was to double the max_usb_current in /boot/config.txt, but that only lengthened the time between brownouts. We looked into hacks that could increase the current even more, such as this bypass m…

I thought USB 2.0 had 500ma max current?

indeed, you are correct https://en.wikipedia.org/wiki/USB#Power

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#15
post #13
post #8

We've actually found that the RPi doesn't draw enough power, specifically to the USB ports. Our peripherals are within the USB spec of a 500ma max pull, but even so we are experiencing sporadic CPU brownouts. The first thought was to double the max_usb_current in /boot/config.txt, but that only lengthened the time between brownouts. We looked into hacks that could increase the current even more, such as this bypass m…

I'm not interested personally, but your HN profile doesn't seem to include any contact info.

thanks for pointing that out. I've updated the OP to add that + correct the typo pointed out below

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#17
post #8

We've actually found that the RPi doesn't draw enough power, specifically to the USB ports. Our peripherals are within the USB spec of a 500ma max pull, but even so we are experiencing sporadic CPU brownouts. The first thought was to double the max_usb_current in /boot/config.txt, but that only lengthened the time between brownouts. We looked into hacks that could increase the current even more, such as this bypass m…

Hey, I poked around your website and like what you do! I'm a tinkerer too and have messed with LEDs and mirrors, but was wondering if you've heard of HeavyM [1]? I enjoyed a lot and it looks right up your alley. It uses a projector for cool visual stuff.

Also - get wordpress and analytics.

[1] http://heavym.net/en/

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#18
post #8

We've actually found that the RPi doesn't draw enough power, specifically to the USB ports. Our peripherals are within the USB spec of a 500ma max pull, but even so we are experiencing sporadic CPU brownouts. The first thought was to double the max_usb_current in /boot/config.txt, but that only lengthened the time between brownouts. We looked into hacks that could increase the current even more, such as this bypass m…

It is normal that you are experiencing brownouts if you assume 500 mA is available.

If you power a RPi via micro USB, then the 500mA budget is shared between the RPi and all your peripherals. Your post doesn't say which RPi model you have, but a B+ or a gen2 B will draw anywhere from 230-420 mA idle, so your periphals only have 80-270 mA available.

[1] http://www.midwesternmac.com/blogs/jeff-geerling/raspberry-p...

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#19
post #6

After posting a comparison of power consumption of the Pi Zero vs other Raspberry Pis a couple days ago, I spent another couple hours today testing various methods of reducing power consumption, and was able to get the idle power usage down to about 25-30 mA on the Pi Zero! Thanks to a few suggestions from others on the Raspberry Pi forums, Hacker News, and Reddit, I am able to disable the ACT LED and HDMI, and that…

How much of this applies to the bigger RPi models? Also, can you throttle the clock speed of the microprocessor and further reduce current consumption?

You can underclock and use the ondemand cpu governor

Re: Raspberry Pi Zero – Conserve power and reduce draw to 30mA

#20
post #8

We've actually found that the RPi doesn't draw enough power, specifically to the USB ports. Our peripherals are within the USB spec of a 500ma max pull, but even so we are experiencing sporadic CPU brownouts. The first thought was to double the max_usb_current in /boot/config.txt, but that only lengthened the time between brownouts. We looked into hacks that could increase the current even more, such as this bypass m…

Also, having a good power supply makes a big difference. I have 2 RPIs running OSMC and used to suffer random lockups/reboots/corruption using a random power supply. Once I switched to a decent supply, they have been rock solid.
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