It SHOULD say "Thanks, may I have more?"...frolen13 wrote:Can I power the pi with the supply the 5 volts coming from the supply is at 22.0 amps how will the pi like that?
Raspruss wrote:It SHOULD say "Thanks, may I have more?"...frolen13 wrote:Can I power the pi with the supply the 5 volts coming from the supply is at 22.0 amps how will the pi like that?
Unless something is really unusual, the Pi will take what it needs and leave the rest for your external peripherals...
22 amps is the "capacity" of the power supply. Since it is 5V voltage generator, it tries to maintain voltage at 5V. If it would be 22A current generator (but it is not), it would try to "push" this amount of the current into RasPi.frolen13 wrote:Can I power the pi with the supply the 5 volts coming from the supply is at 22.0 amps
Perfectly well.frolen13 wrote:how will the pi like that?
I always supply it via a power connector.frolen13 wrote:Also can I feed the 5v directly down the GPIO?
Ah ok thank you.FLYFISH TECHNOLOGIES wrote:Hi,
I always supply it via a power connector.
The reason is that when you feed the RasPi via this USB power connector, its protection is in place (over-voltage, over-current). When feeding the RasPi elsewhere (GPIO or USB ports), this protection is bypassed...
Best wishes, Ivan Zilic.
What is the ground for standby? i know positive is purpleklricks wrote:Many people use the 5V standby power line from an ATX power supply instead of the main 5V. The standby line has enough power to supply the RPi and it is always on even with the main power supply switch is turned OFF.
No fans blowing and no worry about a minimum load to start it up.
If you use the main 5V you will need to have a dummy load such as a fan, light-bulb or even an old hard drive.
Google [computer bench power supply] there are many many tutorials videos etc.
Most relatively recent PC supplies do OK at this. They tend not to require a significant load to regulate, and will generate a decent stable voltage on all outputs even if some are open circuit. The first PC power supply I hacked about needed a dummy load resistor, but none I've done in the last 10 years have needed it.FLYFISH TECHNOLOGIES wrote: But, (there is always but...) there is another problem. You should be aware that these power supplies (so-called switchers) require a load with some power consumption in order to regulate voltage properly... Attaching only a single RasPi to the output might not be sufficient load (it represents just few percents of the capabilities). This is the reason why I would recommend you not to use this power supply.
I'm rather on the safe side... specially when discussing about some remote equipment I don't know much about.achrn wrote:So the regulation could theoretically be an issue, but probably won't
About 20, after which the current limiting circuitry defined in the PSU specs kicks in. 5V at a potential 25A is not a terrifying amount of electricity, in my view.blc wrote:The idea of using a PC power supply for electronics stuff, or the RPi, really scares the crap out of me. Most modern power supplies put out a ridiculous amount of power - my next upgrade will use over 330 watts for the CPU & GPU alone. If there were some sort of problem or short circuit then there would be an awful lot of amps being pumped out...
It might not be terrifying, but 25A is more than enough in my view! That's 125W!achrn wrote:About 20, after which the current limiting circuitry defined in the PSU specs kicks in. 5V at a potential 25A is not a terrifying amount of electricity, in my view.
The power supplies I use are generally ones that are redundant from work, from servers or relatively costly PCs (we'd have called them workstations in the good old days, but I'm not sure where the line is now between PC and workstation) . In some cases they are actually redundant spare power supplies and have been sat doing nothing.blc wrote: To be honest, unless you're using good quality gear then I would seriously doubt the ability of most PSUs to meet the defined ATX specs - many probably can't even meet the +/- 5% voltage regulation spec. The situation is certainly a lot better than it used to be but there's still a lot of guff out there, especially when it comes to spare components you've had lying round for a while; chances are that if you do have a good quality PSU then you're going to re-use it in another PC rather than just chuck it into storage somewhere.
You're right. I totally overlooked the polyfuses.achrn wrote:The dangerous prototypes module annoys me, because it takes a really useful high-power PSU (5V and 12V at 20-odd amps, as discussed) and then sticks polyfuses on the outputs to limit the current to 1.25A. So hey! we can easily convert a 500W high-performance PSU into a unit that performs as well as a 5 quid wall-wart. For about twice the price of the wall-wart (assuming your PC power supply is free). Who would actually want to do that? If you want a 1.25A power supply, you don't want a PC PSU.
Perhaps I should keep quiet about one of my bench power supplies 0-40V and 0-25A, yes max of 1kWblc wrote:It might not be terrifying, but 25A is more than enough in my view! That's 125W!achrn wrote:About 20, after which the current limiting circuitry defined in the PSU specs kicks in. 5V at a potential 25A is not a terrifying amount of electricity, in my view.
Yes I know. I blew the fuse unintentionally from a few months ago and forgot :pklricks wrote:FYI- You cannot measure current by connecting the meter directly to the output of the PS, you will blow the fuse in the meter every time.
Current must be measured in series with the intended load connected.
That's a bench supply though, it's designed to deliver the power in the way that you're using it - it's not being used in a way that it's not intended to be used!techpaul wrote:Perhaps I should keep quiet about one of my bench power supplies 0-40V and 0-25A, yes max of 1kW
Mind you that needs some hefty cabling ...