FAQs - UPS Sizes - 500VA UPS
Typical questions clients ask before buying a 500VA UPS (500W uninterruptible power supply) to protect their computers, server rooms and IT networks.
A 500VA 500W UPS is designed to connect to a single-phase electrical supply. It is sometimes called a single-phase UPS for a 1/1 (single phase in and single phase out) installation. The UK electrical supply voltage is 230Vac 50Hz and a 500VA UPS will be supplied with a power cord with a BS1363 3-square pin plug to plug into a wall socket. Power from the UPS is provided typically by IEC320 C13 outlet sockets on the rear of the UPS or on the top for a desktop unit.
How long UPS batteries will last is dependent upon several factors including their design life, type, the number of charge/discharge cycles they are put through and the ambient temperature of the room they are working within.
Lead acid VRLA UPS batteries can be of the 5year or 10year design life type. These will require replacement within 3-4 or 7-8 years respectively. In terms of room ambient, the recommendation for lead acid UPS batteries is 20-25°C. For each 1degree rise above 30°C the design life halves. Lithium-ion UPS batteries have a longer design life from 10years or longer but have a higher cost than lead acid types.
When you purchase a 500VA UPS, the product warranty will generally include the batteries for the warranty period. Some UPS manufacturers limit the warranty to that provided by their battery supplier, and this may be on a pro-rata basis i.e. 100% warranty cover in year 1, 80% in year so and so on. Some UPS companies will offer extended battery warranties and battery cover including testing and replacement as part of their UPS maintenance contracts.
Lead acid batteries in a 500VA UPS will recharge within 4-8 hours up to 80% capacity. The amount of time that it takes to recharge a uninterruptible power supply battery is dependent upon the total size of the UPS charger (measured in Amps – A) and the size of the battery (Ampere-hour – Ah). A guide for long runtime UPS is to achieve a recharge of 80% within 24hours. Lithium-ion UPS will recharge quicker within 2hours
Most 500VA/t00W UPS use a valve regulated lead acid (VRLA) maintenance free battery with a 5year design life. Some 500VA UPS are available with lithium-ion batteries with a 10year design life. Lead acid batteries are the most commonly used as a lead acid battery is the most suitable for standby operation, as required by uninterruptible power supplies. Lithium-ion batteries provide greater energy storage density, faster cycling and are less susceptible to heat and can therefore be used in warmer operating environments. For some server rooms and data centres, the use of lithium-ion UPS batteries allows savings to be made in air conditioning and cooling systems.
nline 500VA UPS are also referred to as double-conversion or even triple-conversion UPS systems. This refers to the AC-DC-AC or AC-DC-DC-AC operation of the UPS as it converts the mains AC (alternating current) into DC direct current via the rectifier charger assembly and then converts the DC back to AC via the online inverter. The inverter generates a digital sinewave without a break in supply whether powered from the mains power supply or battery set. In a line interactive UPS an automatic voltage regulator (AVR) powers the load when mains power is present and an inverter ‘cuts-in’ during a power outage. The break in supply is minimal (2-4milliseconds) and most modern switch mode power supplies (SMPS) – used to power electronics, computers, servers and network devices – can work with a line interactive UPS. The principle benefit of an on-line UPS, aside from its superior waveform and no-break supply, is a built-in automatic bypass. If the UPS has an internal fault or is overloaded the connected load is automatically transferred to the mains power supply without a break in supply.
A 500VA uninterruptible power supply will have a built-in battery pack and the amount of runtime the UPS can provide when there is a mains power outage is dependent on the load connected. At 80% load a typical 500VA/500W UPS can provide 3-7 minutes of battery runtime. This can be extended by oversizing the uninterruptible power supply.