APC Back-UPS BX750MI review

The BX750MI is a 750 VA / 410 W line-interactive UPS. Add up the rated wattage of the equipment you want to protect and check the total against that 410 W figure before buying.

It is not a fit for every setup. The output is a stepped approximation to a sine wave, not pure sine. The research doesn't say which devices that matters for, so check your equipment's power supply documentation before buying.

Transfer time is 6 ms typical and 10 ms maximum. The input voltage range is 140-300 V. The surge energy rating is 273 J. Input power factor at full load is 0.63.

All four outlets are battery-backed. There is no split between surge-only and battery sockets, so everything you plug in draws on the battery during a cut. That is useful when each socket holds something you want to keep running. It also means a printer or monitor on the unit shortens your runtime.

The input is an IEC C14 inlet. The four outlets are IEC C13, not UK 13A sockets. You need a suitable lead for the wall and C13 leads for each device. Check that each device you want to protect can take a C13 lead. A device with a UK plug needs an adapter or a different UPS.

A retailer spec table gives 8.5 minutes at half load and 1 minute at full load. APC's own page doesn't confirm those figures. The research gives runtime only at those two load points, so treat the half-load number as a rough guide only.

Owner reports praise battery runtime and power-cut performance. That supports the retailer figures in practice, though not with exact numbers.

The battery is sealed lead-acid, 12 V nominal. Recharge time is 8 hours and expected life is 3-5 years. APC doesn't confirm on a page in the research whether you can replace the battery yourself. If you plan to keep the unit beyond the battery's life, check that before you buy.

The spec lists a USB port. The research doesn't confirm that it uses the USB HID protocol, and APC doesn't confirm Synology, QNAP or TrueNAS support on any page in the research. That matters if you want a NAS to shut down on its own when the battery runs low. Because the connection is unconfirmed, this unit is a riskier choice for that job than one with listed support.

Owners praise runtime and power-cut performance. The complaints are more worrying. Owners complain the unit gets very hot and gives off a burning-plastic smell in early use. Other complaints cover build quality, the front LEDs that can't be switched off, and noise on switch-on. Owner complaints also include a unit failing after 1 year and unsatisfactory after-sales answers.

Ratings reflect that split: Amazon UK shows 3.7 out of 5 from 349 ratings, and Galaxus shows 4.3 from 36 ratings. The warranty is 2 years. Given the reports of early failure and weak after-sales answers, keep your proof of purchase.

Because the LEDs can't be turned off, a bedroom or living-room setup may bother you. A cupboard or rack is easier to live with.

APC Australia's page shows no replacement for the BX750MI. APC Sweden lists the BXR750MI as the replacement. A secondary article says APC lists discontinuation on 31 December 2026, but no APC page in the research verifies that. Check current availability and the warranty terms with your retailer.

With 410 W of capacity, four battery-backed outlets and owner praise for runtime, it suits a small NAS, router and switch setup where you already have C13 leads. The stepped sine output, the unconfirmed USB HID support and the owner reports of heat and failures count against it. Weigh those before you commit, especially if automatic shutdown is the main reason you are buying a UPS.