Full battery and charge-state monitoring with prediction
Many hidden costs and unplanned outages are traceable to the propensity of bad UPS
designs to fail to fully monitor their batteries so that dwell time and battery lifetime can be predicted with reasonable accuracy.
We aim for full voltage/discharge/temperature modeling with dwell-time and
battery-lifetime prediction, as is done in electric vehicles.
Constant trickle-charging of the battery while on mains power degrades the battery, reducing service life by up to 50%. The UPSide should use battery state monitoring to rest the battery, only trickle-charging when voltage starts to drop. (Some commercial UPS vendors call this "Advanced Battery Management".)
Do control and monitoring right
Historically the event-reporting and control protocols for UPses have been awful,
unstandardized kludges. Now there’s the HID UPS profile. We’ll do that.
Better hardware UI for emergency situations
Idiot lights and alarm beeps, the meaning of which you have to look up in
(probably misplaced) documentation, are just not good enough. In addition
to DTMF monitoring, our design(s) will have a textual status display and
Get beyond lead-acid batteries
Conventional lead-acid batteries are hazardous, have low energy density, and handle deep-cycling poorly. Better alternatives such as LiFePO4 are now available; it’s time
a production UPS actually used them.
It should be possible to enable bypass mode on battery death (routing mains power to connected equipment), not fail to "off" with no power delivered. Unbelievably, many UPSes actually fail this test.
This may have to be a mechanical switch (possibly flipped by a solenoid, but not a traditional spring-loaded relay that resets to a specific state when power is removed). Implementing the option in software seems hard, especially if this UPS is supposed to protect against intermittent voltages and overvoltages as well (i.e. cases where bypass is the wrong response and there’s no software running due to lack of power).
Note that “fail to bypass” and “withhold load power until a reserve battery charge is available” are diametrically opposite goals. No one policy is good for every deployment.
15 minutes, 300W
After some research and power-metering we have settled on 300W for 15 minutes as the dwell-time target for the UPSide-1. We will explore the incremental cost of pushing to 350W.