I got a strange problem as i added more and more peripherals, the pc gave odd messages, “i cannot detect what you are doing” and things like that. I almost flipped trying to locate the culprit. The problem was not in any peripheral but in the USB port powering the system itself. The SMPS was not loading much. Certainly the peripherals were drawing more and the warning could have been more like “use your own power”. Computer Data Interface
I could not locate a powered USB with any vendor close by, so i built one and it works perfectly, Now it doubles up as a UPS Low Batter Indicator, by rare coincidence. If the Unregulated DC is above 7 volts, then no bugs. When i adjust the unregulated DC to the 7805 to around 6.9V, then i have a advance warning system.
When power fails, i keep working and listening to music from a Flash Thumb drive. When music stops, i turn of computer, the lead acid batteries gone below 20 V DC. This avoids deep discharge of my batteries. The Powered USB gets undetected when the supply falls below 4.5 probably.