Polisy "Insurance" - Power Supply

[gviliunas]

I was cleaning-up my installation, touched the Polisy wall-wart power supply, and noticed that it was slightly warm. NOT hot but just a little warm. My experience is that these are usually just ambient temperature.

I searched online for the power requirements for this SBC  and found the manual for PC Engines apu2-series boards. In the getting started section was the following:

"Connect a 12V DC power supply to the DC jack. Power supply should be able to supply at least
18W for some margin. To avoid arcing, please plug in the DC jack first, then plug the adapter
into mains."

The power supply shipped with the Polisy is only 12W (1000mA). This is enough for the base board without peripherals per this second statement in the same manual:

"12V DC, 2.5 mm center pin, center positive. About 6 to 10W depending on CPU
load. Recommend 12V adapter rated for at least 1.5A to provide margin for
peripherals."

 I don't know the requirements for the SSD or WIFI boards and haven't made a break-out cable to measure the actual current draw but as quick and cheap "insurance" for my Polisy, I replaced the original supply with a good 2000mA supply from my spares box.

apu2.pdf

[io_guy]

Also worth noting that the included power supply is not UL approved.  

[Mustang65]

I ran the Polisy Pro through the boot and when the unit was running. During the boot it hit 7.5watts a few times and after it was running it leveled off at around 5.6watts on 120VAC. At 12volts that would put it around .5 Amps.

[larryllix]

5 hours ago, Mustang65 said:

I ran the Polisy Pro through the boot and when the unit was running. During the boot it hit 7.5watts a few times and after it was running it leveled off at around 5.6watts on 120VAC. At 12volts that would put it around .5 Amps.

Ouch! My 5W PSU gets fairly warm. I don't like it. May get a larger capacity unit anyway.

The Kill-a-Watt meter has been found very accurate in lab standard accuracy tests (by me) but you are measuring the primary input power draw and not what the polisy draws. Since my PSU gets warm it indicates a few watts are being absorbed by the PSU and not necessarily by polisy. 

Thanks for sharing that!

It does indicate that the limits are likely very tight and possibly over what they should be. Once a few USB items get plugged in, we may be in trouble.