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I don’t understand how the SYSMI box works. I see power input going into the Mikrotik router, then feeding D-Link USB hub with (according to the Mikrotik specs
by 404mm 3y ago
I don’t understand how the SYSMI box works.
I see power input going into the Mikrotik router, then feeding D-Link USB hub with (according to the Mikrotik specs) up to 5V/500mA DC.
The USB hub sends power to both Pi’s and somehow splits the 500mA between RPi 3 (officially needing up to 5V/2.5A) and RPi 4(5V/3A). And it still somehow works?
I know all the specs are not set it stone. USB can feed more than 500mA and Pi’s can run on well under their requirement but I’m no stranger to Pi’s and I had experienced power issues due to inadequate supply before. Especially when the CPU is maxed out, like during the boot sequence.
Am I missing something here? This looks quite insane.
- giuliomagnifico 3y agoI was wondering the same but then I discovered that the Mikrotik is able to power both the Raspberry PIs when in full load for 3 days straight. I did some benchmarks, but I think the power output of the Mikrotik is different, more than the official specs.
- dharmab 3y agoThe 5V/500ma number is copied from the USB 2.0 spec; the Mikrotik device may be outputting more than specified by coincidence of the hardware used to manufactured it
- 404mm 3y agoThe original adapter for mikrotik 750 is 24V/380mA (9.12W). This is not a sufficient way to supply power to 3 devices, no matter how you dice it.
- giuliomagnifico 3y agoI agree but how do you explain that it’s actually working? Also on heavy load for days? We was asking the same, for that I tried to run an heavy benchmark for some days on the RPis. Maybe the spec of the power supply are different?