Switchmode power supplies offer several significant advantages over traditional linear transformer power supplies.They are far more efficient than their linear counterparts. As they do not use power or mains transformers the equivalent power supply weighs considerably less than traditional types
Hi, I am wondering if this power supply would be suitable for powering multiple Raspberry Pis? My understanding is that a Raspberry Pi is best supplied with 5,1 Volts. Can this supply be adjusted to 5.1 Volts?
approx 8 rpis of an 130 watt 5 volt supply… each stock rpi-4 supply is 15 watts approx… so rpi-4`s with some head room would be eight given the actual cpu draw is rather low and not over clocked… its all the surrounding peripherals that you must factor in…
i did some more precise math with the base wattage is 15.3 watts and an outcome of approx left over power if the cabling only exhibits .1 of a volt drop from supply to each board …i figured two power rails of 5.2 volt at the supply setting given total capacity of 130 watts,hence
130 divided buy 5 volts is 26 amps out.
130 divided by 5.1 volts is 25.4901 amps out .
130 divided buy 5.2 volt is 25 amps out or drawn current of the 130 watts at hand.which these supply’s become efficient when driven to 80 % of there rated capacity…
thus when you calculate @ 25 amps and the max of 130 watts supplied and set @ 5.2 volt output if your running 8 devices an average of 3.125 amps per unit available seen only in peak times they idle around an amp approx.
so the only factor then is to work out how much power your going to draw out of the unit by means of usb powered devices and what ever else you have connected to the gpio lines/pins …etc
an ssd should draw no more than 5 watts which is one amp theoretically…mine is a 3.3 volt ssd so it all depends on current…after the primary calculations…
there is the math broken down from which you can decide from may be two clusters of 4 rpi-4`s would be more stable and better suited…in my op…that you could get away with 8 no problems …2x 5.2 volt rails taken from the supply its self then broken into 4 rails after reaching the clusters…
a note here is to respect that once you adjust up the power supply out put voltage amperage changes but total watts never changes … there fore you total watts limit is 130 watts and all calculations are in reference to this figure…you should maintain your calculations to be true… no matter of voltage and current the higher you drive the voltage output up the less you have in available current as such my math points out above…as per ohms law…etc…etc.
a pic of one of my supply’s its an quite versatile unit… 24volt@7amp and 5 volt @25 amps quie a nice cluster supply 300 watt unit 80% efficient
just loged on been doing anoter product range saw this have not even read the thread but yes i modded te output voltage railds with a different resistor cannot remember the output voltage most people just change out the pot…but the oput is proportional on the rails hence it lowers or dropps both rails as it only has one oput transformer…if it had seperate transformes with dual tl494`s its possible to be adjustable wit the either rail going high or low seperately