Trying to make a one computer for everything in the house i have had to buy an active USB extension cable.
I know you have to supply them with extra power and the cable has an extra USB male connector for that.
My question is how much power do i supply it?
Will it be enough with a random phone charger and should i be careful if said charger has fast charging so as to not supply to much power?
While i see my self as quite capable when it comes to computers i have very little knowledge when it comes to power/electricity.
Thank you in advance for any help.
There’s a lot of ‘it depends’ in this situation. I would first look to the manufacturer to see if they give any insight. One of the main limiting factors is the conductor size. Smaller and/or copper clad aluminum conductors will have higher resistance, which will cause more voltage drop. Some devices can handle running at voltages below specifications and some can’t. Whatever you do, I would try to find a good quality cable with larger gauge copper wire as short as is reasonable for the supplementary power connector.
If you can’t find any info for your extension cable, I would try approaching it from the other direction. I would gather all the devices I intend to use and add up the current draw of all the devices. They may not use that amount at all times, but it’s likely you will end up with intermittent issues when the combined current draw causes the voltage to sag in my experience. You may need to add a second cable to split the load, or find alternate methods to do certain things like using Bluetooth or adding a network drive as opposed to using their USB counterparts.
It’s my understanding that the voltage range for standard USB is 4.75V to 5.25V. There are a few USB power supplies that output the maximum 5.25V for higher current draw applications to combat voltage sag. That extra quarter of a volt can be the difference between no problems and lots of problems, as people with older versions of the Raspberry Pi can attest to. The higher voltage supplies that I have seen were usually advertised as being for Raspberry Pi’s, but it is within USB spec and can be used for other USB devices. The one from Adafruit has a really good description worth reading:
Off-topic but since I’m here, quick Electrical 101: you can’t supply ‘too much’ power - a power source doesn’t push power into devices, they generate a constant voltage and the device draws as much current as it needs.
Ohm’s Law and Watt’s Law, the two most important electrical concepts:
VVoltage (V) = ICurrent (A) × RResistance (Ω)
PPower (W) = ICurrent (A) × VVoltage (V)
The current drawn changes because the resistance of the load changes as it does things. As you put a processor under load, for example, the resistance drops. Lower resistance means more current flows into the device (remember that the supply is generating a constant voltage); more current at the same voltage means higher power dissipated.
USB 2.0 for example is +5V at a max current of 500mA. A USB device can draw anywhere up to that much current, but the power supply will always be generating +5V. +5V at 500mA is 2.5W.
I used to have a dedicated computer for the TV but got tired of having to upgrade it every few years, that plus the insane energy prices we have here in EU atm forced me to rethink my situation.
One computer for all my things does work surprisingly well though after i found a solution to switching screens.
Only worry was to supply enough power for a controller since the rumble seemed to overwhelm the power needs, but with help from you guys it should be ok now, going to test a little later.
I’m running fiber cables from the computer to my TV and my monitors.
The TV is an Android TV so can send WoL to the computer when needed, when sitting at the monitors i have soldered a physical power button to be near them as the computer is only a couple of meters away there.
Using display fusion to make some profiles for when different screens are turned on.
Really love how it works and think an extra computer would just be an unnecessary cost of electricity atm.
I do have a Raspberry Pi i plan to do some things with for when just wanting to watch a fast movie or something streamed from my server so i don’t have to turn on the PC.
