Raspberry Pi Forums

Hi guys I a planning to purchase 4 or more b+ models and use it simultaneously for my project. With that I am wondering if I could power all using the externally powered USB hub. From the spec and he b+ is 1.5A.
So i f I use 4 of them maximum amperage can be as much as 6 A? So when I am hunting for a hub us this something I she consider? Thx

a B+ isn't "using" 1.5A, (its more like 0.4A), but is is capable of feeding external USB devices that amount of current (providing your PSU is up-to the task. It can also be set (in software) to a 2.1A limit.

mahjongg wrote:a B+ isn't "using" 1.5A, (its more like 0.4A), but is is capable of feeding external USB devices that amount of current (providing your PSU is up-to the task. It can also be set (in software) to a 2.1A limit.

Don't you mean 1.2A?

ggrp000 wrote:Hi guys I a planning to purchase 4 or more b+ models and use it simultaneously for my project. With that I am wondering if I could power all using the externally powered USB hub. From the spec and he b+ is 1.5A.
So i f I use 4 of them maximum amperage can be as much as 6 A? So when I am hunting for a hub us this something I she consider? Thx

http://www.raspberrypi.org/forums/viewt ... 62&t=85550

A headless B+ that isn't using the GPU typically uses less than 300 mA. The B with its linear voltage regulators about 100 mA more. Despite the mission creep with power supplies (the current thinking on here seems to be if you can't arc weld with the PSU it won't run a Pi) an old school B (the greediest Pi) will happily run itself, a plain keyboaad, mouse and ethernet on the original spec 700mA power supply. People using crappy PSUs with wildly optimistic labels, hair thin USB cables and misinformation have spawned this subculture of "at least 2 Amps, but prepared to be disappointed".

pluggy wrote:A headless B+ that isn't using the GPU typically uses less than 300 mA. The B with its linear voltage regulators about 100 mA more. Despite the mission creep with power supplies (the current thinking on here seems to be if you can't arc weld with the PSU it won't run a Pi) an old school B (the greediest Pi) will happily run itself, a plain keyboaad, mouse and ethernet on the original spec 700mA power supply. People using crappy PSUs with wildly optimistic labels, hair thin USB cables and misinformation have spawned this subculture of "at least 2 Amps, but prepared to be disappointed".

At Pi Towers, I power my Pi from a dual-channel adjustable bench power supply that weighs 10kg and costs upward of £250.

No blinking red lights here.

At home I use the bog standard 1.2A RS power supply with 2x externally powered HDD caddies and a wifi dongle. No blinking red lights there, either.

I don't get blinking red lights from a repurposed Samsung phone charger rated at 700mA either.

For Model B, my preferred power supply is the Adafruit 1A, 5.25v unit. That works fine for a B+ as well for everything I've tried with one.

I do have a NewIT 2A 5v for the B+ should I enable the high power option for USB (which I might do some time as a test to see if it will directly power a USB CD/DVD writer, rather than using a USB hub as an intermediate).

What I originally got the 2A supplies for is Cubieboards which spec for 2A because they allocate 1A for the power connector that goes with their SATA port.