Comparison nJoy Keen 1000 USB 1000 VA vs nJoy Keen 1000 1000 VA

The type of battery installed in the UPS.

— Fiberglass (AGM). An advanced type of lead-acid battery with electrolyte in an adsorbed state: the compartments of such a battery are filled with porous material, which contains acid. At the same time, the battery case is sealed and AGM models are maintenance-free. This technology is the most popular in batteries for uninterruptible power supplies: it is ideal for batteries operating in buffer mode (that is, when they rarely need to be discharged and, as a rule, little by little). In addition, it provides a long service life, and AGM batteries are inexpensive. The disadvantages of this option include the impossibility of replenishing the electrolyte if it leaks, as well as poor tolerance to overcharging (although the latter becomes irrelevant with a high-quality power controller).

— Gel (GEL). A type of lead-acid battery that uses a gel electrolyte. GEL batteries are best suited for operation in cyclic mode - that is, when the battery needs to power the load for a long time, discharge almost to zero, then charge and again provide long-term autonomous power. But for the buffer mode, in which most UPSs operate (standing on standby for a long time in order to briefly maintain power supply in the event of a failure), this technology is not suitable for a number of reasons. Therefore, it makes sense to purchase such batteries only in cases where t...he “uninterruptible power supply” has to be turned on almost every day - for example, in unstable networks with constant and long-term power outages.

— Lithium-ion (Li-Ion). The key advantages of lithium-ion batteries are high capacity with small dimensions and weight. Also, Li-Ion batteries are not subject to the “memory effect” and can charge quite quickly. Of course, this option is not without its drawbacks - first of all, it is sensitive to low and high temperatures, and if overloaded, the lithium-ion battery can catch fire or even explode. However, thanks to the use of built-in controllers, the likelihood of such “emergency” situations is extremely low and, in general, the advantages of this technology significantly outweigh the disadvantages.

— Lithium iron phosphate (LiFePO4). An advanced modification of lithium-ion batteries (see above), designed to eliminate some of the shortcomings of the original technology. Lithium iron phosphate batteries are characterized by a large number of charge/discharge cycles, chemical and thermal stability, low temperature tolerance, short charging time (including high currents) and safety in operation. The likelihood of an “explosion” of a LiFePO4 battery when overloaded is reduced to almost zero, and in general, such batteries cope with high peak loads without problems and maintain the operating voltage almost until they are fully discharged.

The time it takes to fully charge the UPS battery. Note that in this case, this time is calculated according to special rules: not from 0 to 100% of the charge, but from a state in which it is impossible to maintain half the load, up to 90% of the charge. Of course, a full charge will take a little longer. However, this data is closer to practice than the “from 0 to 100%” calculation: the inability to work at half load makes the UPS practically useless, and this condition can be taken as zero, and 90% of the battery is already able to provide a good guarantee in case of a power failure.

The protection functions provided in the design of the UPS.

— Short circuit protection. A short circuit is a sharp drop in load resistance to critically low values, due to which the current strength increases and the UPS experiences significant overloads that can disable the device and even cause a fire. It may be caused by a problem with the connected device, poor insulation, foreign objects, etc. In the event of such a situation, the short circuit protection system turns off the UPS, preventing unpleasant consequences.

— Overload protection. Overload in this case is the excess of the load power consumption over the output power of the UPS. Working in this mode can also lead to unpleasant consequences up to breakage and fire; to avoid this, a protection system is installed that turns off the UPS when an overload occurs.

— Overcharging protection of external battery. The overcharge protection function prevents the accumulation of excess energy in the battery, from which the UPS operates in autonomous mode. Overcharging is highly undesirable for any type of battery. It can lead to various unpleasant consequences - from deterioration in performance to overheating and fire of the battery. The automatic protective equipment on board the uninterruptible power supply turns off the power after the battery is fully charged. This prevents “extra” curre...nt from entering the battery, which could damage it. This system is convenient in that the battery can be left on charge for a long time without fear of overexerting it.

— Noise filtering. A system that suppresses high-frequency interference in an electrical network — these can be either single voltage surges when turning on and off powerful electrical appliances, or long-term interference from constant sources, such as electric motors. These interferences can adversely affect the operation of electronics connected to the network (up to visible failures); the noise filtering system avoids this. Such systems are quite simple, and therefore most modern UPSs are equipped with them.

— Data line protection. High-frequency interference protection system, similar to interference filtering (see above) — only used not in an electrical network, but in a telephone or wired computer (LAN) network. Such networks are also subject to interference from various sources of electromagnetic radiation, which can cause failures of equipment connected to them: PCs, printers, fax machines, etc. UPSs with this feature have at least two LAN standard connectors (input and output), into which appropriate network or telephone (with RJ-11 connectors compatible with LAN) cables are inserted.

— Emergency cut-off. This connector allows you to connect the UPS to an emergency power off system. Thus, in an emergency (for example, in the event of a fire), the entire room, including and with a power reserve, can be completely de-energized by pressing one button. Without this, the UPS would simply switch to battery when the power goes out and leave the equipment energized, which could lead to disastrous consequences.

— Sound alarm. A system that gives an audible signal in various important situations. It is most commonly used to signal a power outage and the UPS is transferring to battery power. Without a sound signal, this could not be noticed at all (the light is not always on in the room, it goes out when the network fails, the contact in the socket itself may disappear, etc.), which is fraught with a sudden shutdown of the equipment, data loss and breakdowns. Also, sound alarm can be used for other events — low battery, end of charge, bypass on / off, etc.

Many modern UPSs can be connected to a computer or other special devices. This provides advanced options for monitoring the parameters of the UPS and managing its functions: without leaving the computer, you can monitor the battery status, network parameters, load, enable special modes, apply automatic adjustment, etc. Such a connection can be made according to the following standards:

— RS-232. It's a COM port. Initially designed to connect various peripherals to a computer. Today it is also quite widespread, however, due to its relatively large size, it is installed mainly on stationary PCs.

— USB. A universal port for connecting various peripherals to a computer, the most popular interface of this kind today — at least one USB port has an absolute majority of computers and laptops.

-LAN. A port used to connect to wired computer networks. Models with this interface can often be connected as a network device, which allows, if necessary, to control them from any computer on this network.

— SmartSlot. A slot in the UPS case for installing expansion cards (SmartSlot cards). The development of APC, is used mainly in the devices of its production. Such cards can provide a very diverse set of features: additional connection ports beyond the standard ones (for example, a LAN control port), a web managemen...t interface, support for SNMP, Secure HTTP and other protocols, connection of temperature / humidity sensors, and much more. To date, a wide range of cards is being produced, making it easy to choose a set of additional functions depending on the specific situation. Most UPS models have one SmartSlot, but if necessary, you can use a special expander and install two cards, and the largest models can have two slots as standard.

— "Dry contact". In uninterruptible power supplies, the term "dry contact" refers to a professional interface used to transfer data on the operation of the UPS to specialized external equipment. Such an interface usually has a whole set of contacts (on the order of 10), often in the form of terminals. And the scheme of its operation can be simply described as follows: when certain parameters are reached, the control relay closes or opens a given set of “dry contacts”, on the basis of which the control device receives information about one or another parameter of the UPS operation.