Giuseppe Parrello


UPS APC BX series - Review


I bought two UPS devices of the BX series of APC, the first is the 950 va model (480 watts supported), the second is the 1400 va model (700 watts supported). The main difference between the two models is, in addition to the different nominal output capacity (lower on the 950va model, higher on 1400va model), the fact that the 950va model has only one battery, while the 1400va model has two batteries. The 1400va model is heavier than the 950va model, due to the presence of a second battery, although the dimensions of the two models are perfectly the same.
Both models do not support a pure sinewave, both models support only a step-approximated sinewave. It is up to me to start a discussion about the best choice for an end user, if the first or second option is the best one. Refer to the specialized websites on the Internet to know the differences between the two types of wave and what is best for you, also considering your budget.
Inside the package of the two devices are included: a leaflet stuck to the device containing the information regarding the quality test, an instruction booklet and an IEC cable (two cables in the case of the 1400va model) to connect the equipment to the device. The network cable is missing to power the group, the USB type B cable is missing to connect the group to the computer and there is also no software that needs to be downloaded from the manufacturer's website.

Front/Rear Panel

The front panel of the two devices includes only two LEDs (in-line led and battery led) and one on/off button. The battery LED may turn red, either due to an overload (the equipment connected to the device uses more power than allowed by the device itself) or because the batteries need to be replaced. More information can be found in the manual that I always suggest to read before using this type of equipment.
The back panel of the two devices includes:

Installation / Operating

Once the devices have been removed from the packaging, and once the yellow battery connectors on the back of the devices have been placed, the devices have been connected to the power sockets - in the manual it is correctly specified to connect the device cable directly to the wall socket, without using protections against overvoltages or extensions cables. I immediately noticed that the 950va model started to make an annoying buzz (coil-whine), while the 1400va model fortunately had no problems from this point of view. Once connected a USB Type B cable to my computer, I turned on the two devices to test them, meanwhile the batteries are charged - in the manual it is reported that the device must be charged for at least 10 hours to ensure sufficient autonomy.
I did not find particular problems with the functioning of the two groups. Only once I heard the buzzer warning me of a power overload on the 950va device, as I was doing stability tests on my computer and my computer was using almost 520 watts of power, so more than the 480 watts supported by the 950va model. No problem with the 1400va model, as this supports 700 watts.
The only thing to check is the buzz emitted by this type of equipment, i.e. the normal electrical noise when the device is connected to the power sockets and the hum emitted by the device when the device goes into battery mode. If in the first case I had serious problems only with the 950va model (I had to change it with another one, but also the second one gave me problems, so finally I asked Amazon for the final refund), in the second case I immediately inform you that the buzz is quite audible, although perhaps the noise of the relay driven by the device is more annoying during switching from socket power to battery power and vice versa. In any case, this type of buzzing is almost normal in all UPS devices and it is almost impossible to ask more about this by this kind of equipment.
I would like to point out that both devices, once connected to the electric sockets and switched on, they gave off a horrible smell, a smell similar to burnt plastic. This smell is unfortunately already verifiable as soon as the package is opened. The smell is slightly less intense on the 1400va model, but on both models it increases depending on the environment temperature, depending on the operating temperature of the devices and depending on the power load by the equipment connected to the devices. Unfortunately, this smell is often mistaken for smell of burning, as if the device was burning or, even worse, was bursting into flames, creating a little panic in the final user. In my case, on both devices, the smell vanished after almost a month of uninterrupted operation. Keep in mind all above-mentioned matter, I strongly recommend to start a run-in period of these devices in a well-ventilated room. I have no idea if this smell is harmful/toxic or not, it seems more related to the resins/glues/plastics used during the manufacture of the devices.

Read the manual

I suggest to read the manual, if necessary also downloading it in advance from the APC website, in order to know:

Using software to control the UPS device

Both devices adopt USB-HID (USB Human Interface Device class) specifications, therefore they are recognized by the most important operating systems, that is Microsoft Windows and the various Linux distributions.
In Microsoft Windows, once you connect the USB cable to the device, the battery icon should automatically appear on the notification bar. If it does not appear, then you must go to the Device Manager and manually change the device in such a way as to make it look like a "HID UPS" device (I solved with Windows 7 looking for a search engine phrase "apc How to restore HID UPS device driver to Windows ", there is a PDF document of the manufacturer "schneider-electric", after opening it I have performed all the steps described inside and finally the battery icon has appeared on the notification bar).
With Windows, you can also use the "APC PowerChute Personal Edition" application that can be downloaded directly from the manufacturer's website. With this program it is possible to monitor the device and modify some parameters, such as disable the buzzer when the device is in battery mode, as well as the battery intervention parameters, or perform tests to check the correct functioning of the device.
In Linux, you can use both the "apcupsd" daemon and the NUT (Network UPS Tools). The first one uses "UPSCABLE usb" and "UPSTYPE usb" in the apcupsd.conf file. Once this file has been modified, "group status" should appear with "apcaccess status". Instead with NUT you have to use the "usbhid-ups" driver in the "ups.conf" file. Once UPS is configured, the "upsc" command should list all the device data, including the device's production date, the device's serial number and the device's internal firmware number. With NUT it is also possible, using the "upscmd" command, to disable the buzzer ("beeper.disable" parameter) and list the various supported parameters. For example, with this command you can perform a quick test or a thorough test (I suggest to run these tests with the battery fully charged). Moreover, always with NUT, through the command "upsrw", it is possible to change some system parameters, such as the engagement/disengagement voltage of the battery (the default values are: lower point = 155 volts, upper point = 280 volts), the sensitivity of intervention of the battery (the default value is set to "medium"), as well as the various parameters used by the operating system to control the group and switch off the device.
I connected the group to an Asus router, with firmware "Tomato" (one of the few firmwares that allows a router to recognize an UPS). I configured the device as described above, and I connected everything to a web server that allows me, through web server extensions, to have a graphical interface with the device's real-time data. The photos I attach are related to this interface.

Battery replacement

If the device is still under warranty, for example in the first two years of use of the unit, the battery (or batteries in the case of the 1400va model) must be replaced by the Schneider Electric IT (SEIT) customer service. The replacement of the battery, if done by the user when the device is still under warranty, will automatically void the warranty.
If the warranty has expired, usually after two years of device use, then you can replace the battery (or batteries). I suggest this operation to be carried out only by specialized personnel, as high voltage electric currents are present inside the device, even after disconnecting the power supply cables and even after disconnecting the yellow battery connector.
In any case, for those who want to make this operation by theirselves, I firstly suggest to watch some videos on YouTube (just look for the video on YouTube "Back-UPS RS 500", the first video of the research should have a title in Russian language). Unfortunately I did not do this because my 1400va device is still under warranty (the 950va one I returned to Amazon because of the annoying buzz), but the above-mentioned video should be the correct one even if it refers to a device that contains only one battery. Both the 950va and 1400va devices must first be disconnected from the power supply, after disconnect the yellow connector on the rear panel, 4 screws must be removed on the rear panel. So the front panel has to be removed (this is interlocked), then 2 screws must be removed under the panel just removed. Once these operations have been carried out, the device must be turned so to remove a side panel. Be careful, do not touch any component in the printed circuit boards, touch only the area dedicated to the batteries (since the size of the case of both groups is identical, the 950va model should have an empty seat that is instead occupied by the additional battery on the 1400va model).
Before replacing the batteries, take note of the layout of the cables connected to the batteries (if necessary taking photographs) and in the 1400va model you must also note the way in which the batteries are coupled, in order to replicate the same connections with the new batteries. In the manual it is written that the 950va model has only one 9 Ah (12 volt) battery, while the 1400va model has two 7.2 Ah batteries (12 x 2 volts = 24 volts in total). The manufacturer sells the original parts, i.e. for the 950va model the battery is called "RBC17", but if you want you can use a compatible battery, obviously respecting the same capacity of 9 Ah (12 volts) and the same sizes (which are 15.1 x 9.4 x 6.5 cm). Instead for the 1400va model, the battery pack is called "RBC113", but if you want you can use 2 compatible batteries, respecting the capacity of 7.2 Ah (12 volts) per battery, always paying attention to the arrangement of the batteries as they always must be coupled.


APC never fails. After being a happy owner of an APC CS650 device (which after 11 years of work still works without giving problems), now I’ve got a model apparently cheaper, but the essence though remains, APC remains a guarantee for this new BX series. Certainly the competition is increasing, and even APC was obliged to make an entry model, sacrificing something, in order to decrease the selling price. I refer, for example, to the lack of some cables, to the lack of software (however downloadable from the manufacturer's website), to the lack of only-filtered outlets (useful for connecting high-energy consumption devices such as laser printers), but mainly to the difficulty to replace the batteries, real Achilles' heel of this series. Furthermore APC should adjust something during manufacture, such as removing the unpleasant smell emitted by these devices during the first days of operation, smell already verifiable as soon as the package is opened. Again, this smell is often mistaken for burning smell, as if the device is burning or even worse bursting into flames, creating little panic in the end user. For this reason APC should be more careful during production in order to avoid problems for the user of these devices. I have read very negative reviews all over the Internet just about this problem, often the user calls the APC's technical support, and APC accepts to change the device thinking it is an electrical issue rather than a problem caused by plastics or resins/glues used during production.

Pros / Cons

APC quality; Competitive price; USB-HID support; Performance; Control software; Support

Difficulty in replacing batteries; Unpleasant smell in the first days of operation; Some cables are missing in the package; Only-filtered IEC sockets are missing


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