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Can You Connect a UPS to a Lower-Rated Circuit? Here’s What You Need to Know

Uninterruptible Power Supplies (UPS) are designed to protect critical systems from power failures, surges, and brownouts. But one of the most common installation mistakes we see is connecting a UPS to a supply circuit that’s rated lower than the UPS itself.

At first glance, it may seem harmless — after all, the UPS won’t always be running at full load. However, undersized circuits can lead to tripped breakers, overheating, and unreliable protection. Let’s explore why this happens, and how Power Inspired’s 10kW UPS range can give you a safe and flexible solution.

Understanding Circuit Ratings

Every power circuit is designed to handle a maximum continuous current, typically defined by its breaker rating and cable size.

For example:

  • A 13A circuit at 230V supplies up to about 3kW.
  • A 16A circuit can deliver around 3.7kW.
  • A 32A circuit can support about 7.3kW.

These limits are there for safety — to prevent cables and connections from overheating under sustained load.

Understanding UPS Power Ratings

UPS systems are rated in kVA (kilovolt-amperes), while actual usable power is measured in kW (kilowatts). The difference is due to power factor (PF) — the ratio of real to apparent power.

For example:

  • A 10kVA UPS at 1.0 PF provides 10kW of usable power.
  • A 10kVA UPS at 0.8 PF delivers 8kW.

However, the UPS also needs to draw slightly more power than it delivers to account for charging and efficiency losses. If you connect a large UPS to a small circuit without adjusting for this, you can easily exceed the circuit’s rating.

In addition, if a user inadvertently adds more load to the circuit, the circuit breaker in the distribution board will trip but the UPS may continue to operate on battery power.

The Problem With Underrated Circuits

If your UPS draws more power than the circuit can handle, several issues can arise:

  1. ⚠️ Circuit Breaker Trips – The breaker will trip during heavy load or battery recharge, cutting power to the UPS and connected equipment.
  2. 🔥 Cable Overheating – Sustained overcurrent can overheat wiring, degrading insulation and creating a fire hazard.
  3. ❌ Loss of Power Protection – If the UPS trips due to supply limits, your connected equipment is left unprotected at the worst possible time.

For most UPS brands, the only safe answer is to install a larger circuit — but that isn’t always possible or cost-effective.

Power Inspired UPS: Built for Flexibility

This is where Power Inspired’s 10kW UPS range stands out.

Our systems can be downrated to match the circuit they are connected to — allowing you to safely install a high-capacity UPS on a lower-rated supply without overloading the circuit.

For example:

  • We can configure a 10kW UPS to operate within any circuit from 16A to 63A, by limiting its output current.
  • The UPS automatically adjusts its maximum load ensuring safe operation within the circuit’s capacity.
  • When a higher-rated circuit becomes available later, we can restore the full 10kW capability without replacing the unit.

This flexibility is ideal for environments where power upgrades aren’t immediately practical — such as offices, laboratories, or data closets using existing wiring. Another useful feature is that the UPS can be connected to CEENORM pluggable connections and the UPS rating adjusted to suit.

Example: Adapting to the Site

A customer recently needed to install a 10kW UPS in a building with only 32A circuits available. Normally, this would require costly electrical upgrades.

Using the Power Inspired output current limit, the UPS was safely set to operate within the existing 32A supply. The system still provided full power conditioning, battery backup, and surge protection — without tripping breakers or overloading the circuit.

When the building later upgraded to a 50A feed, the UPS was reconfigured to its full 10kW capacity — a simple software change, not a hardware replacement.

Key Takeaways

  • ⚡ Always match your UPS input rating to your circuit capacity.
  • 🧠 Use configurable UPS features to safely operate within smaller circuits.
  • 🔋 Power Inspired’s 10kW UPS range can be downrated to suit your site today — and upgraded tomorrow.

Conclusion

Circuit ratings matter when installing a UPS — but with the right technology, they don’t have to limit your options.

Power Inspired UPS systems give you the flexibility to deploy advanced protection wherever you need it, even when power availability is restricted. Whether you’re upgrading an existing site or designing a new power protection plan, our team can help you size and configure your UPS correctly for safe, reliable performance.

Contact Power Inspired today to learn more about our 10kW UPS range and how it can adapt to your power environment.

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VFI-RT+ Online UPS Settings

Following on from how to install the battery trays in the VFI-RT+ UPS I thought it a good idea to then explain some of the settings that you can set to ensure the UPS works how you want it to.

Note that some of the settings can cause mis-operation or even damage so should only be performed by persons knowledgeable about what they are doing. Reading this guide will help!

VFI-RT+ LCD Panel

The UPS settings are accessed via the LCD screen. No software is required. First of all make sure the UPS is in standby mode by pressing the OFF/ENTER / ↲ key for several seconds. The unit will either enter bypass or standby mode (if it wasn’t already). Now we are ready to enter the UPS settings screen. To do this press and hold the SELECT /▼ key. After around 3 seconds the UPS will enter the settings menu.

Explanation of Setting parameters on LCD

The Settings screen shows two parameters. Parameter 1 is usually the number of the setting, but maybe some additional information when adjusting the setting value. Parameter 2 shows the settings current value, or the value you want to set it to. To navigate the settings press SELECT ▼ to increment the menu, the ON/MUTE ▲ button to decrement (I know this is counter intuitive with the arrows pointing up and down but think of the arrows more as next and previous). Use the OFF/ENTER ↲ to enter the settings and the ▼ or ▲ to select the desired setting.

Press ↲ at the desired value to exit back to the settings menu.

Note that icons will also appear on the LCD to guide you.

UPS Settings

UPS Setting #1 Output Voltage

Setting # 1 is the output voltage when on inverter. Your choices are 200, 208, 220, 230 or 240V. Note that at 200V the output power is derated by 20%. The default is 230V.

UPS Setting #2 CVCF Mode

Setting # 2 is CVCF mode or Constant Voltage Constant Frequency. In normal use the VFI RT+ will track the input frequency and auto set to either 50 or 60Hz depending upon input. In CVCF mode you can output either 50 or 60Hz regardless of the input frequency. E.g. you can have 50Hz input and 60Hz output – useful for operating high voltage US equipment in Europe that may not be suitable for 50Hz operation. The converse is also true, e.g. output 50Hz from a 60Hz supply. In addition if powering from a generator whose frequency may be unstable this is a good option to ensure the load is always provided with high quality power. Your options are ENA for enabled or dIS for disabled. CVCF is disabled by default.

UPS Setting #3 Frequency setting

Setting #3 is the converter frequency you want to run. If CVCF mode is ENAbled, it will set the frequency to either CF 50 or CF 60. It also sets the initial frequency in battery mode. For example if you cold start the unit the inverter will output either BAT 50 or BAT 60

UPS Setting #4. ECO Mode

Setting #4 is ECO or Economy mode. In this mode the UPS will supply the load in bypass with the inverter ready if need be. In this mode the output is variable and there is a slight break in power during transition, but since there are no conversion losses the efficiency is much higher and therefore running costs lower.

UPS Setting #5 ECO Mode Tolerance

Setting # 5 allows you to vary the amount of out of tolerance voltage the unit will allow in ECO mode before reverting back to an online unit in both high voltage and low voltage. Your options are from +7 to +24V (default is +12V) for high line and -7V to -24V (default is -12V) on the low line.

So if you’re concerned about using ECO you can still have a fairly narrow voltage window by setting to within your acceptable parameters.

UPS Setting #6 Bypass Enable

Setting #6 is Bypass. This is an important setting and should be given consideration depending upon your power quality / power continuity needs. If the UPS goes off for any reason e.g. fault or somebody switches it off, then if the bypass is disabled then power to the load will go off. This may be a desirous situation as you may want to control the output power from the UPS, or you may not wish your load to receive any unconditioned power. However, if power continuity is more important then you should enable bypass. This way if the unit is switched off you will still have power to the load. Note that this sometimes causes people to forget to actually turn the UPS online. As a reminder if the UPS has bypass enabled and power is present it will beep every minute or so to warn you.

UPS Setting #7 Bypass Voltage Limits

Setting #7 is the bypass high and low points. If bypass is enabled the UPS will switch off bypass if the input voltage is outside the parameters set here. You can have between 230 and 264V for overvoltage and from 170 to 220V for undervoltage. The defaults are 170V and 264V.

UPS Setting #8 Bypass Frequency Limits

Setting #8 is a bypass setting again but this time the frequency. Dependent upon which frequency mode is set (Setting #3) the options you have are from 45-49Hz (default 47Hz) to 51-55Hz (default 53) for a 50Hz system and from 55-59Hz (default 57Hz) to 61-65Hz (default 63Hz) for a 60Hz system.

UPS Setting #9 Programmable Outlet

Setting # 9 is the programmable outlet setting. On the rear of the unit there is a bank of outlets that are “programmable”. It is used for load shedding purposes when on battery power. For example you may have some non essential equipment that you need minimal backup for but others you want to maintain for as long as possible. So the equipment that is non-essential (or perhaps will shut down automagically) can be plugged into he programmable outlet to be load shed when this setting is enabled. It is disabled by default.

UPS Setting #10 Programmable Outlet Autonomy Time

Setting # 10 is the number of minutes the programmable outlets will remain active for in the event of a power outage. The range is 0-999. If set to 0 they will immediately switch off.

UPS Setting #11 Autonomy Limitation

Setting # 11 is autonomy limitation. You can set this to DIS (default – the unit will keep going until the batteries become too low), or from 0 (in fact 10 seconds) to 999 minutes. This is useful particularly if you have a very low load and don’t want the batteries to deplete to a critical point and may only needs a few hours runtime.

UPS Setting #12 Battery Capacity

Setting#12 is the connected battery Ah of the UPS from 7-999Ah. If you have a single UPS then this value will (depending on model) be the internal battery Ah so either 7 or 9Ah. Remember if you add further batteries to the UPS (e.g. additional battery cabinets) to add the additional Ah here. For example a VFI1500RT+ has an internal 9Ah battery, so this should be set to 9Ah. If we add 5 cabinets to it, each with a capacity of 18Ah, then we should set this value to 99. (5x18Ah for the cabinets plus 9Ah for the internal).

UPS Setting #13 Battery Charge Current

Setting #13 is the battery charger current. One of the great features of the VFI-RT+ is the ability to extend runtime by the addition of external battery cabinets or even large battery strings. However this additional battery capacity needs a more powerful charger to recharge the system. Luckily the VFI-RT+ has an adjustable battery current up to either 8A or 12A dependent on your model. Options are 1/2/4/6/8 or 1,2,4,6,8,10,12. The default is 2A. You should not set the charge current to a high value with no additional battery cabs connected.

UPS Setting #14 Charger Boost Voltage

Setting #14 is the charger boost voltage. You can adjust this but this is inadvised. To do so may damage batteries.

UPS Setting #15 Charger Float Voltage

Setting #15 is the charger float voltage. Again you can adjust this but this is inadvised.

UPS Setting #16 EPO Polarity

Setting #16 is the Emergency Power Off (EPO) ports control logic. You can set this to AO (Active open) or AC (Active closed).

AO is default, and therefore requires the EPO connector at the rear of the unit to be linked through and present. If you want to remove it or work on a different logic then you can do so by setting the logic here.

UPS Setting #17 External Isolation Transformer

Setting # 17 is for when an external isolation transformer is connected to the output of the UPS. If enabled the unit will attempt to compensate for transformer regulation by adjusting the output voltage depending upon the load power being drawn. E.g. the voltage at low power draw will be lower than at high power draw. It is disabled by default.

UPS Setting #18 Autonomy Display Preference

Setting #18 is a preference for how to display autonomy when the unit is running on battery. Options are either EAT (default) or RAT. EAT will display how much autonomy time the VFI-RT+ thinks you have left based on the connected battery Ah, the current load and battery capacity. RAT will display how much autonomy time has been accumulated already.

UPS Setting #19 Voltage Input Window

Setting #19 defines the acceptable high points and low points before the unit will revert to battery power. The options are from 110/120/130/140/150/160 (default 110) to 280/290/300 (default 300).

The purpose for this is really on the low voltage side, since if you are supplying a fixed KW output then the UPS will draw as much power as required from the input to maintain the output voltage and power. This could potentially mean overloading a circuit if it susceptible to brownouts. (A system at 240V will draw half as much current as a system at 120V for the same power for example)

That’s It!

UPS Setting #00 Save and exit

And finally we are here. Press OFF/ENTER ↲ to accept all the settings. The UPS will then revert back to standby with all the settings enabled and you can now switch it on.

If you made a mistake don’t press the OFF/ENTER ↲ key, just wait a minute or so and the system will time out and come out of the menu. Or you could just switch off the mains power.

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VFI3000RT+ Battery Tray Assembly

The VFI3000RT+ is Power Inspired’s 3KVA Rack/Tower Online UPS System. If you have ordered from our online store the product will no doubt arrive in 2 boxes. This is simply due to the total weight being close to the maximum courier weight limit of 30Kg and also to prevent damage to the unit if the box is manhandled – well dropped to be precise.

What we do is extract the battery tray and send the UPS in one box sans battery and the tray in another. Both boxes will then weigh in at a more manageable 15kg each.

To assemble the system take the UPS and the battery pack out of their boxes.

Remove the front panel from the UPS – it pops away from the left hand side as shown.

Remove the 4 screws indicated from the battery retainer (note the battery won’t be connected as shown here).

Insert the battery tray into the UPS.

Refasten the screws on the retainer and connect the battery

And refit the front panel.

Cold start the UPS to make sure all is well. Then you’re good to go!

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VFI-RT+ Online UPS Battery Pack Assembly

One of the main features of our VFI-RT+ series UPS is that the runtime can be expanded by the addition of our BPRT battery packs. Unlike competitor products the VFI-RT+ has an adjustable charging current – allowing many battery cabs to be connected without any drawback on recharging time. The VFI3000RT+ has adjustable charging current from 1-8A, and the VFI1500RT+ from 1-12A. Comparable systems generally only offer 1A chargers unless you opt for a specific long runtime model.

Our VFI1500RT+ has a 36V battery string, and our BPRT-36-18 cabinets provide a 36V 18Ah addition to battery capacity – provided by 6x 12V 9Ah blocks. For the VFI3000RT+, the battery string is 72V and our BPRT-72-18 cabinets provide a 72V 18Ah addition – provided by 12x 12V 9Ah blocks.

The BPRT-72-18 cab does weigh in at a heavy 44kg however. This means that it needs to be despatched as freight – e.g. on a pallet. However, this makes it difficult to place in position on site and so on occasion we despatch the battery packs in a kit form – with the battery cabinet (sans batteries) sent in its own packaging and likewise the battery trays.

The purpose of this post is to let you know how to correctly assemble the battery cabinet. Our battery cabs are held in stock without batteries but with the empty battery trays inside the units. So before we despatch the battery trays are fitted with brand new batteries ensuring maximum longevity and packed separately.

The battery cabinet will consist of the cabinet, the battery retainer bracket and the two parts making up the front panel – which we call fixed front panel and detachable front panel. The fixed part is the part where you can see “BATTERY PACK”. There will also be sets of screws – 6 for attaching the retainer bracket and 2 for attaching the fixed front panel.

Slide both battery trays into the cabinet. Make sure the cab connectors are out of the way (move them to the top) and the wires on the trays are safely tucked away. Push them home so they are firmly at the back of the cabinet.

Fit the battery tray wires through the holes in the retainer. Push the retainer into position and screw in place. Fit the connectors. [Tip: If you are having difficulty connecting try pushing the cables into the connection housing – sometimes they sit a little deep].

Fit the “Battery Pack” plastic cover. Note that the metal clip on the cover needs to mate with the slot on the retainer plate. If you are having difficulty with this remove the “Battery Pack” section from the cover by simply popping it out. This way you can see the lip and slot allowing you to affix it correctly. Sometime a little persuasion with a flat blade screwdriver helps. Then fit the remaining plastic cover.

Remember to remove the required battery covers from the rear and to switch the circuit breaker to the ON position.

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Don’t Forget Power Backup on World Backup Day

On World Backup Day, we often think about protecting our data by creating copies of important files, but one crucial aspect that gets overlooked is power backup. A reliable backup system is not just about storing data—it’s also about ensuring that power outages don’t interrupt your ability to access, update, or restore that data. Whether you’re working from home, running a business, or simply safeguarding personal files, a power backup plan is essential to prevent data loss during sudden blackouts or voltage fluctuations.

Investing in an Uninterruptible Power Supply (UPS) for your computer and external storage devices can give you the extra time needed to save your work and shut down safely. For businesses and data centers, backup generators and battery backup systems provide continuous power in case of extended outages. Cloud storage is another great solution, but remember that without power, local access to your network and internet might be compromised. So, as you secure your files today, take a moment to ensure you have a robust power backup strategy in place—because a backup is only useful if you can access it when you need it most.

At Power Inspired, we offer a range of high-quality UPS solutions to keep your systems running during power interruptions. Whether you need protection for a single workstation or a full-scale business operation, you can browse and buy our UPS products online. Don’t wait for the next outage—stay powered and protected with Power Inspired.

Image courtesy of File:Wordmark-noyear.png – Wikimedia Commons

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Looking for a Practical Christmas Present

Practical Christmas Present

With all the recent storms here in the UK and with more on the horizon – the loss of power becomes more and more likely. Some unfortunate folk are out of hours or days and some lucky few may only be for short periods. One of the most important things to have when without power is of course…the internet. So, how do you make sure that your kids aren’t bored and can still play games, watch YouTube and TikTok videos on their non cellular iPad, or don’t burn up their data allowance in one day? How do you FaceTime your friends and relatives? Make and receive calls on your VoiP phone? Protect your WiFi from power outages with an iPower – the most practical Christmas present this year.

Get Your iPower Now!

iPowers

iPowers

DC UPS Systems for Modems Routers & ONTs

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Although we’ll ship out immediately your orders we’re in the hands of Royal Mail and so will need orders in by Dec 20th to arrive before Christmas Day.

How to Choose The Most Practical Christmas Present

You need to know what voltage the router works at. Do this by looking at the router input or looking at the AC adapter rating and see what the output is. (Note that if you remove the AC adapter from the wall the router will power off, you’ll lose WiFi and your kids will scream, so do it at night). If it’s 12V and you’ve only the router to worry about then the iPower-H is your best bet. If you have another device then you may need 2. Note that a lot of fibre installations now require power back up for the incoming termination unit and the WiFi router.

If the voltage is 9V then you could pick up one of the last remaining iPower-Minis (there’s only a handful left).

The iPower-DC2 is the best of the best though and makes it the most practical Christmas present. Not only is it good for 12V and 9V systems it has more than one output so provided the voltages on the devices are the same you can use it to power both. You may need an additional power adapter or extra long leads – all of which are available from our store.

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Telecare Battery Backup Solutions

Telecare describes a range of products that are designed to monitor vulnerable or otherwise at risk persons to help them live more independently and safely. Where some products are designed to emit local alarms, others are connected to a monitoring service. This connection is often done over the users landline. With the digitisation of the PTSN network by 2027, ISPs and Telecare providers now have the responsibility to ensure that such users still have access to their services when their existing landline goes digital and so require Telecare Battery Backup Solutions.

What’s the problem?

In a PTSN network the telephone line is a copper wire connected directly to the telephone exchange (via a few street cabs). The telephone exchange contains chargers and large battery strings to ensure that even in the event of a utility power failure, that all devices connected to the PTSN network can operate. E.g., if you have a power cut you can still make telephone calls, activate your help cord or personal alarm and get help when you need it.

OFCOM have already provided guidance to VOIP providers that they should provide a 1hr service availability, and the UK government has recently written to a number of providers asking them to consider 8 hour solutions. Consensus appears to be a 4hr solution may be required in future.

Telecare Battery Backup Solutions

The Power Inspired iPowers are DC-DC systems that simply plug in to the DC port on the equipment to be protected. Backup times of one hour can be met with most products whereas the iPower-DC2 is suitable for 4 and 8 hour solutions for systems depending on average power consumption. To extend available backup time for Telecare equipment we suggest powering each separate device from a different iPower.

Power Inspired PF - Telecare battery backup

Another option is to use AC battery backup and protect all Telecare equipment including other essential equipment for in the home. The PF unit can provide pure sinewave output whilst on battery. The large Lithium battery will ensure that even runtimes of 8 hours are easily achievable for constant loads under 100W or so. In addition, the unit can be connected to solar panels prolonging the available runtime or even achieving total grid independence.

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iPower-Mini Complements DC UPS Series

Power Inspired have complemented their range of DC UPS for broadband applications with the launch of the iPower-Mini. The small unobtrusive device sits between your existing DC power supply and the load to provide typically well over an hour of backup. This allows access to telecommunications for vulnerable people especially important these days as landline calls are now being phased out.

The iPower-Mini sits between the existing power supply and the router providing well over an hours backup for the vast majority of devices. It starts up automagically when power is applied and autosenses 9 or 12V. Simple 3 LED system gives indication of 9 or 12V output, charge / discharge status and battery low.

The unit features an auto-sense 9V or 12V output and an impressive 24W capacity. It contains a dual 3.7V 2500mAh 18650 battery (18.5Wh) giving over 30 minutes at full load (24W) and well over an hour 1 at 12W. A typical 12W 1A router should see backup times in excessive of 2 hours.

Which iPower Do I need?

Power Inspired have 3 iPower models in their range, all contains certified Lithium batteries with full protection circuitry.

iPower-H

The iPower-H replaces the existing power supply providing an extremely simple solution for 12V 1A applications.

The internal 12.4Wh battery provides typically 1hr backup. The unit is fitted with a 2m lead to allow connections that need not be directly adjacent to the load. In addition to which the sprung connector makes it suitable for both 2.1mm and 2.5mm input jacks.

The iPower-H is simple in operation with auto-start, cold-start and a single LED giving device status – ready (solid Green), charging (slow flashing Green), discharging/low battery (quick flashing Green) and fault (Red).

The iPower-H is ideal for bundling with the device to be protected saving on the cost of purchasing the power supply. The unit also contains built in AC surge diverters for added power protection.

Unlike the other iPower models the iPower-H can have the battery replaced without opening the unit.

iPower-Mini

The iPower-Mini is ideal where you have an existing power supply and you need to add backup for a single 9V or 12V application.

The internal 18.5Wh battery gives typically 2hrs backup for a 12V 1A router.

Simple to use simply plug the existing power supply into the iPower-Mini and the output lead into the device to be protected. The unit is designed to sit adjacent to the load being protected and can be wall mounted via the rear keyhole slot.

The three LEDs give indication of set voltage (Red for 9V and Green for 12V) if the unit is running on battery power (Orange LED) and if the battery is running low (flashing orange). The charge indicator (Green) flashes when charging and is solid to indicate fully charged.

Due to the auto-sense function the iPower-Mini cannot be cold started.

iPower-DC2

The iPower-DC2 is a selectable 9V/12V or 24V system with a huge 30W capacity making it suitable for powering multiple devices, including USB powered.

It can be utilised with an existing power supply or bundled with a suitable device (typically bundled with a 12V 3A PSU) and allows battery backup protection for both the ONTs and the hub in a typical fibre broadband installation.

Various output cables can be provided to match the individual installer requirements, with the unit either sitting on a shelf or alternatively DIN rail mounted using an optional accessory.

The large 37Wh battery provides many hours backup for the majority of devices – the 1hr regulatory requirement is met at 25W.

Front LEDS give indication of set voltage (Red / Blue or Purple) and 4 Green LEDS show battery charge / discharge status.

There are 5 output DC jacks and a USB port for connection of multiple devices.

The iPower-DC2 auto starts and can be cold started (since the output voltage is manually set).

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Pharmacy Fridge UPS Applications

Pharmacy Fridge

Why use a UPS on a Pharmacy Fridge?

Unlike applications where sudden power loss causes data loss or other operational issues, power loss to a pharmacy fridge is not such of an issue since the internal temperature is well controlled. In the event of a power cut a solution is simply not to open the fridge. A typical fridge will maintain the internal temperature for around 4 hours in the event of a power cut – provided the door is unopened. However note if the fridge cannot be opened then no medicine in the fridge can be retrieved.

Many laboratory or pharmacy fridges have alarm contacts which can alert to the fact that power has failed and as a result warn users not to open the door. However, a power fail alarm will have to be operated on a secondary power system, such as a battery, due to the obvious fact that a mains powered system would also be rendered inactive during a power outage. Having a battery system, will also require the battery to be maintained in a state of charge. These added complications mean that such alarms are rarely, if ever, implemented.

A pharmacy fridge will be used to house items, typically vaccines, diluents, immunoglobulins and other medicines with temperature requirements. The costs of these medicines can be quite substantial and if the temperature inside the fridge should rise to over +8°C, then, according to the NHS Green Book, the “cold chain” has been broken and these medicines may need to be destroyed. If not destroyed, then a time-consuming process needs to be instigated to determine the effect on the medicine which most likely will include a reduction in the expiry date.

Clearly, protection against sustained power outages has operational and financial benefits.

Fridge Power Consumption

Instead of giving power ratings of the Pharmacy Fridge, the manufacturers specify the energy consumption in KW for a 24 hour period. The method I found for doing this is here: ENERGY STAR® Program Requirements Product Specification for Laboratory Grade Refrigerators and Freezers, and Ultra-Low Temperature Freezers. This value varies from product to product and depends upon a number of factors, including capacity, the type of doors (glass or solid etc.) and the configuration (bench top, under counter etc.). Typically these figures are around 1KW/24 hour for a typical small system in a typical pharmacy. See Note 1.

The test schedule includes opening the fridge door for a period of 15 seconds (plus an additional 4 seconds for opening and closing), 3 times an hour each hour for 8 consecutive hours. This is useful as it allows us to specify a UPS runtime that will allow a degree of use of the fridge during an extended outage.

A typical fridge compressor has a power draw of around 200W, and will require a sine-wave inverter to ensure correct operation.

UPS Selection

In the table below I’ve created a lookup for the number of hours of runtime you could expect (and remember this includes periodically opening the door) given the energy rating of the pharmacy fridge.

The PF-S-Li products are units ideal for Pharma Fridge applications. The units contain an internal high capacity Lithium Ion battery offering long runtimes, long life and low weight. The PF1200S-Li has a continuous power rating of 1200W, but with a surge rating of 2400W. This allows it to easily deal with the inrush current generated by the compressors of the fridges.

Achievable Runtime in hours:

Energy Rating
(KWhr/24hr)		Equivalent
Watts		PF1200Li
Expected Runtime
0.521>24 hrs
0.753221 hrs
14216 hrs
1.56310 hrs
2848hrs
2.51056hrs
31255hrs
3.51464hrs
41674hrs
4.51883hrs
52093hrs

Contact us to enquire about UPS for Pharma Fridge Applications.

The PF1200S-Li has superb surge rating of twice its capacity for 5 seconds allowing it to cope with the inrush demands of high performance refrigeration units. It also has the benefit of fast recharge and can be connected to a solar panel array. Connectivity is via 4xUK socket outlets and it even boasts a wireless charging pad, USB A and USB C outlets. In addition to powering the fridge it can also provide battery backed power for ancillary devices.

Note 1: I’ve used what manufacturers are displaying on their spec sheets in order to avoid confusion, however the correct term should in fact be kilowatt hours per 24 hour period eg. kWh/24