Let me start by saying that I've been using UPS units for the past 20 years. I've had almost all the usual suspects out there Tripp-Lite, APC, etc... However, this is my first CyberPower UPS unit. Here are the oddities I find with this EC850LCD unit...
The battery has been charged for 15 hours+, When unplugged to test the battery: within 5 seconds the battery goes from 100% to 99% capacity (No load / nothing is plugged in.) 4 minutes later it is at 98% and at about 6 minutes later it is at 96%. When plugged in to the mains the unit goes from 96% to 100% charge in about 4 sec. (that doesn't seem correct at all...)
This unit has a nice "soft Beep" to let you know it is using the battery. I mean "soft" because all other units I've had in the past have had an ear blasting "building is burning down" style beep... There is also an audible switch sound when going from mains to battery power (which I think is nice...)
When plugged in, the power is always jumping from 122 to 123V... For some reason, I thought this unit would have some sort of AVR / Sine wave filter. When it goes to battery power the output is at a stable 120V. To my surprise, the unit says it has a battery life of 4 hours and 15 minutes... (which seems interesting, the box says 52 min., other users say 2 minutes.)
The EC850LCD unit is super light compared to other 750 - 850 VA units. For example, an RBC4 battery used in many other 750VA units is heavier than the EC850LCD...
When the unit is not plugged to the mains, the unit will not turn on. (To me this seems odd, since the unit has been charged for 15+ hours. and still has ~96% battery) While unplugged from the mains the unit also displayed: "EoF" (which it actually means "End of Life.") Knowing that this is supposedly a new battery in a new unit, I hope it was just a glitch somewhere... (UPDATE: Tried this again, about 30 minutes later and the unit turned on and off as expected. )
About the CyberPower "PowerPanel" software:
Well, here comes the fun part... I installed the software from the website and restarted the computer. Plugged the unit on to the PC via USB... nothing... (Windows 10 did see it and installed drivers, PowerPanel = 0) Restarted the machine once more with the UPS plugged in to the USB (as you would usually have it )... nothing... PowerPanel says: "It is not ready." (it is plugged in and it is providing power) Tried another USB port, same thing... nothing... PowerPanel can't see the UPS... (UPDATE: I had to change the USB cable and reinstall the software for it to work correctly... It seems to be working ok now...)
Currently, the EC850LCD is hooked up to a very modern PC ( 2019 model, no monitor or other items, just the central unit. ) The LCD screen says the battery will last between 8 - 15 min. max. Currently, it is at a load of 37% on idle. When the PC is doing something more intensive the load goes up to about 47 - 50% . The battery time drops to about 2-4 minutes. This is the lowest battery backup time I've ever had from a UPS unit... (pretty disappointing given the price point and the Brandname. )
Overall, it seems like a "So-so" unit to me. It might be a "good" unit ( take it with a grain of salt ) to other users as long as you skip the software and don't expect it to last more than 8 minutes while on load and on battery. It does have a 3 year warranty that covers the battery should anything go wrong ... BUT I've had other UPS units that have lasted well over 7 years without problems on a single OEM battery. So, only time will tell... (By the way, other brands usually include a performance test and QC/QA report with the unit. This certifies the unit works as expected. The EC850LCD does not include a QC test report in the box.)
UPDATE: Sadly, I am returning the EC850LCD due to really poor performance. I plugged in my professional duster and the unit went into "Overload" and it shut itself off. the only item plugged into the unit was the professional duster... nothing else... the unit wouldn't turn on after that... ~ About 15 minutes later it started to work again... but this is not the performance, I want or expect from a UPS...