I’ve received several inquiries about using my ZumSpot mobile (from a USB Battery Pack). Inevitably the conversation turns around to the size of the power supply required. It doesn’t help matters that the US vendors sell a 3-amp USB wall supply to run it, which one might reasonably assume means it needs a several amps of current.
I finally dug my USB power meter out and charged it up and took some measurements. At no time, while booting up, or running on transmit, did I see a peak current reading of more than 250 mA. So I would suggest to folks that a 500 mA supply is more than enough.
In my case the readings came from a combo of a RPiZero and ZumSpot. It was running PiStar version 3.4.16, and was in YSF mode. I would say that the “average” current draw (a mix of TX and RX) was around 170 mA. Again the peak was under 250 mA
I did note that when the RPi was shut down, there was still a 70 mA draw, which is likely the idle current consumption of the ZumSpot, but I did not measure it separately to be sure.
By the way, while the consumption of a RPiZero may vary from unit to unit, there have been several posts that indicate it pulls about 130 mA with WiFi on. That would be pretty consistent with what I saw . Those using it on RPi2/3 will have higher current demand due to the extra features on those boards. But even then I can’t see a case were the current demand would be above 500 mA.
Hi Bob. Came across your site while searching the Zumspot and after spending some time here I went off and got one. Fast forward to today, I’ve linked it into our Fusion repeater system via the FCS00239 Rhode Island reflector and see where that takes us next. Give it a try when you get a chance. I have also played with the Raspberry Pi and you have me interested in the ISS software seen here. Anyway, great job promoting the hobby and 73!
I’ll give that a try. Didn’t hear anyone in the past
73, Bob