An assistant may ask if you want an online, or an offline UPS system, if you go to the energy store. Both of these will have a battery or batteries, and an inverter, but the similarity ends there. We summarize the differences in this post, so you can make the right purchasing decision. Our deep-cycle lead-acid batteries work equally well in both types, assuring you a longer, trouble-free life.
Comparing UPS Online and Offline Systems
Wikipedia confirms two main types you may like to consider:
- Online UPS uses a ‘double-conversion’ method. First, it converts the input from alternating to direct current. Next, it passes this through the battery(s). And finally, it converts it back to alternating current to power the device load.
- Offline UPS delivers alternating input power directly to the load, while charging the battery(s) in the background. When the external supply fails, it switches the load so the battery(s) provide the power.
ADVANTAGES OF ONLINE UPS SYSTEMS
An online UPS system does not have to switch modes between the two paths. This considerably reduces the possibility of interrupting the load. The inverter is always operating too, promoting a smooth switch-over without signal distortion.
DOWN SIDE OF ONLINE UPS SYSTEMS
The consumer is likely to pay more, because design and manufacture are more complex. Power consumption is also higher, because both supply and battery(s) are online.
ADVANTAGES OF OFFLINE UPS SYSTEMS
The cost to the consumer should be less, because design and manufacture are simpler. This is because there are two separate energy paths. But this in turn increases efficiency, because only one is online at a time.
DOWN SIDE OF OFFLINE UPS SYSTEMS
The signal quality varies because the inverter is not always turned on. There is a plus / minus 5 millisecond disruption while switching energy paths. Spikes and surges are more likely when running direct, because the inverter is turned off.
We can’t tell you whether to choose an online or an offline UPS product. You’ll have to decide whether to afford online uninterruptible power delivery, or live with the limitations of offline UPS backup.
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