APC BK500EI Back-UPS 500VA Cs
The reinvention of the UPS that most users have relied on for years: the Back-UPS! The Back-UPS CS provides cost-effective protection for business environments and office computer systems. The UPS protection allows for bridging short and medium-duration power outages. Additionally, the Back-UPS CS protects your devices from harmful voltage spikes and surges that can be transmitted through power and telephone lines. In the event of a longer power outage, the award-winning shutdown software automatically disconnects the computer system from the mains power. Other features, such as audible alarm signals, LED status indicators, a user-replaceable battery, power interruption buttons, and transformer-compatible outlets, make the Back-UPS CS the ideal component to safeguard your business's productivity against the constant risk of power outages and data loss. Optimal UPS protection for professionally used computers. Included: Software CD, documentation CD, 2 detachable IEC C13 to IEC C14 power cables, USB cable.
The reinvention of the UPS that most users have relied on for years: the Back-UPS! The Back-UPS CS provides cost-effective protection for business environments and office computer systems. The UPS protection allows for bridging short and medium-duration power outages. Additionally, the Back-UPS CS protects your devices from harmful voltage spikes and surges that can be transmitted through power and telephone lines. In the event of a longer power outage, the award-winning shutdown software automatically disconnects the computer system from the mains power. Other features, such as audible alarm signals, LED status indicators, a user-replaceable battery, power interruption buttons, and transformer-compatible outlets, make the Back-UPS CS the ideal component to safeguard your business's productivity against the constant risk of power outages and data loss. Optimal UPS protection for professionally used computers. Included: Software CD, documentation CD, 2 detachable IEC C13 to IEC C14 power cables, USB cable.
The reinvention of the UPS that most users have relied on for years: the Back-UPS! The Back-UPS CS provides cost-effective protection for business environments and office computer systems. The UPS protection allows for bridging short and medium-duration power outages. Additionally, the Back-UPS CS protects your devices from harmful voltage spikes and surges that can be transmitted through power and telephone lines. In the event of a longer power outage, the award-winning shutdown software automatically disconnects the computer system from the mains power. Other features, such as audible alarm signals, LED status indicators, a user-replaceable battery, power interruption buttons, and transformer-compatible outlets, make the Back-UPS CS the ideal component to safeguard your business's productivity against the constant risk of power outages and data loss. Optimal UPS protection for professionally used computers. Included: Software CD, documentation CD, 2 detachable IEC C13 to IEC C14 power cables, USB cable.
The reinvention of the UPS that most users have relied on for years: the Back-UPS! The Back-UPS CS provides cost-effective protection for business environments and office computer systems. The UPS protection allows for bridging short and medium-duration power outages. Additionally, the Back-UPS CS protects your devices from harmful voltage spikes and surges that can be transmitted through power and telephone lines. In the event of a longer power outage, the award-winning shutdown software automatically disconnects the computer system from the mains power. Other features, such as audible alarm signals, LED status indicators, a user-replaceable battery, power interruption buttons, and transformer-compatible outlets, make the Back-UPS CS the ideal component to safeguard your business's productivity against the constant risk of power outages and data loss. Optimal UPS protection for professionally used computers. Included: Software CD, documentation CD, 2 detachable IEC C13 to IEC C14 power cables, USB cable.
in 34 offers
The lowest price for APC BK500EI Back-UPS 500VA Cs right now is $159.00 at Umart, compared across 32 retailers.
The all-time low was $120.00 on 20 Jan 2026 — today's price is 33% above the lowest ever. It has been notably cheaper before — worth setting a price alert.
Prices last updated 1 July 2026.
Last updated at 01/07/2026 22:39:43
APC Back-UPS CS 500VA 230V USB/Serial
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
APC by Schneider Back UPS 500VA 300W Tower UPS - UPS #38 Power Protection
Delivery $26.66
Apc standby back-ups (cs), 500va, iec(4), usb, serial, 2yr wty bk500ei
Delivery between 3–9 July $57.55
APC Back-UPS BK500EI 500VA/300W Tower UPS — 4x C13
Delivery between Fri – Tue $14.95
APC Back-UPS CS 500VA 230V
Delivery $11.30
APC Back-UPS 500VA / 300W Standby UPS, Tower, 230V / 10A Input, 4x IEC C13 Outlets, Lead Acid Battery, User Replaceable Battery
Delivery between 9–14 July $9.95
APC Back-UPS 500VA/300W Standby UPS, Tower, 230V/10A Input, 4x IEC C13 Outlets, Lead Acid Battery, User Replaceable Battery BK500EI
Delivery $23
Apc Standby BACK-UPS (CS) 500VA IEC(4) USB SERIAL 2YR WTY
Delivery $16.95
APC Back-UPS CS | 500VA|300W | Input 230V|Output 230V | Interface Port DB-9 RS-232 | USB (BK500EI)
Delivery $25
APC Back-UPS 500VA 230V 300 Watts
Delivery between Fri – Wed $36
originally posted on staples.com
This APC Back-UPS CS 500VA with 6 Outlets was so easy to install. My husband and I followed the instructions that walked you through each step. We are confident that the electrical surges in the woods of New Hampshire will not plague us any further! Thank you APC for another great product. With this particular model, when the battery has come to its end, you can easily replace the battery...not necessary to purchase a brand new piece of equipment. Another great feature. This is our second purchase from APC as they are extremely reliable.
originally posted on bhphotovideo.com
Great little UPS, it's already come in handy a variety of times.All 6 outlets are surge/battery backup. I have several UPSs in my office for avariety of equipment and this one is used for my laptop and several externalhard drives.
originally posted on neweggbusiness.com
I've had three APC units of varying size, all over $100. Each one expended it's battery (two batts in the most recent episode) in a few years. That's fine and expected. But after purchasing replacement batteries each of them would not come back to life. They design them to get fried once the batts croak so you have to buy another. So after flushing $85 on replacement batts for my XS900 (same as this one with different stats.) I'm done with APC. Looking for a better option now. Since the flaw doesn't come for years and they have so many models, you'd never know from the reviews. But charging circuits are simple so three strikes and I have to assume it's on purpose. The XS didn't die under any electrical turmoil, it just started complaining about the batteries, so ... MoreI've had three APC units of varying size, all over $100. Each one expended it's battery (two batts in the most recent episode) in a few years. That's fine and expected. But after purchasing replacement batteries each of them would not come back to life. They design them to get fried once the batts croak so you have to buy another. So after flushing $85 on replacement batts for my XS900 (same as this one with different stats.) I'm done with APC. Looking for a better option now. Since the flaw doesn't come for years and they have so many models, you'd never know from the reviews. But charging circuits are simple so three strikes and I have to assume it's on purpose. The XS didn't die under any electrical turmoil, it just started complaining about the batteries, so that's the final straw.
| Power | |
| Input frequency | 50/60 Hz |
| Input operation voltage (max) | 300 V |
| Input operation voltage (min) | 160 V |
| Output power | 300 W |
APC Back-UPS CS 500VA 230V USB/Serial
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
APC by Schneider Back UPS 500VA 300W Tower UPS - UPS #38 Power Protection
Delivery $26.66
Apc standby back-ups (cs), 500va, iec(4), usb, serial, 2yr wty bk500ei
Delivery between 3–9 July $57.55
APC Back-UPS BK500EI 500VA/300W Tower UPS — 4x C13
Delivery between Fri – Tue $14.95
APC Back-UPS CS 500VA 230V
Delivery $11.30
This APC Back-UPS CS 500VA with 6 Outlets was so easy to install. My husband and I followed the instructions that walked you through each step. We are confident that the electrical surges in the woods of New Hampshire will not plague us any further! Thank you APC for another great product. With this particular model, when the battery has come to its end, you can easily replace the battery...not necessary to purchase a brand new piece of equipment. Another great feature. This is our second purchase from APC as they are extremely reliable.
Great little UPS, it's already come in handy a variety of times.All 6 outlets are surge/battery backup. I have several UPSs in my office for avariety of equipment and this one is used for my laptop and several externalhard drives.
I've had three APC units of varying size, all over $100. Each one expended it's battery (two batts in the most recent episode) in a few years. That's fine and expected. But after purchasing replacement batteries each of them would not come back to life. They design them to get fried once the batts croak so you have to buy another. So after flushing $85 on replacement batts for my XS900 (same as this one with different stats.) I'm done with APC. Looking for a better option now. Since the flaw doesn't come for years and they have so many models, you'd never know from the reviews. But charging circuits are simple so three strikes and I have to assume it's on purpose. The XS didn't die under any electrical turmoil, it just started complaining about the batteries, so ... MoreI've had three APC units of varying size, all over $100. Each one expended it's battery (two batts in the most recent episode) in a few years. That's fine and expected. But after purchasing replacement batteries each of them would not come back to life. They design them to get fried once the batts croak so you have to buy another. So after flushing $85 on replacement batts for my XS900 (same as this one with different stats.) I'm done with APC. Looking for a better option now. Since the flaw doesn't come for years and they have so many models, you'd never know from the reviews. But charging circuits are simple so three strikes and I have to assume it's on purpose. The XS didn't die under any electrical turmoil, it just started complaining about the batteries, so that's the final straw.
APC makes great products. We have 70 some of this battery backup. We use one on each one of our cash registers at our stores. We have had many for four years or more and have only had to replace a few batteries. They have protected our registers and kept them running in power outages. We have experienced no electrical problems with any of our registers while using these batteries. I recommend APC and use their devices on my electronics at home as well. APC is quality.
Cable and plugs are all located at the back - 6 outlets - so any large odd-shaped plugs can affect the number of useable outlets. Whole unit has to be picked up to remove, add plugs, etc. Quite heavy. Have used this system before and very reliable. Last one lay flat with plugs on the top and lights, power, etc., all easily visible.
I'm really pleased with the performance of this product. I live in an area where the power company provides bizarrely erratic power. It's common for our lights to dim for a few seconds a couple of times a day for no apparent reason. The APC unit smooths out the power to my computer and completely protects it. And I like that it comes with a replacement guarantee for any equipment that is plugged into it. For my purposes the rock solid voltage stabilization is more important than operating on battery, but I do like thatthe APC unit gives me plenty of time to safely power down the computer in the event of a power failure.
I have bought 4 APCs over the past decade and they have all lasted longer than the specs would suggest. I originally bought this for a computer w/ a Radeon R9 280 GPU - but it did not have enough watts. I have put it on networking box and it handles the load fine. The only gripe would be the lack of an LCD w/ information (though it can be obtained via the app).
We've been using APC Battery Backup Units since we got our first computers in 1997. This was a replacement backup unit for my original APC Backup Unit that we bought in 1997. We live in Florida, where there are many brownouts as well as many power failures. The APC Battery Backup Unit has always come to the rescue. If there's a short power failure, the computers and TVs remain on; if there's an extended power failure, there is enough time to safely shut down the computers and TVs. Also after several years of use, rather than buying a new unit, you can replace the battery and it's extremely easy to do so. Overall, it's an outstanding product.
See the following user reported guide about the APC Back-UPS CS 350 BK350EI, as this one (BK500BLK) appears to have the same issue: http://forum.synology.com/wiki/index.php/User_Reported_Compatible_Uninterruptible_Power_Supplies http://www.apc.com/site/support/index.cfm/faq/index.cfm "AS correcty shuts down to safe mode when UPS goes on battery, with settable delay. NAS correctly puts UPS in sleep mode after going to safe mode. When this happens NAS logs confusing entry "UPS battery level low" which should be "UPS is in sleep mode". When UPS is in sleep mode, green Online and red Overload indicaters flash alternatingly. This is confusing and not documented, but APC's knowledge base article FA158840 explains that this shows that UPS has been asked by NAS to go into ... MoreSee the following user reported guide about the APC Back-UPS CS 350 BK350EI, as this one (BK500BLK) appears to have the same issue: http://forum.synology.com/wiki/index.php/User_Reported_Compatible_Uninterruptible_Power_Supplies http://www.apc.com/site/support/index.cfm/faq/index.cfm "AS correcty shuts down to safe mode when UPS goes on battery, with settable delay. NAS correctly puts UPS in sleep mode after going to safe mode. When this happens NAS logs confusing entry "UPS battery level low" which should be "UPS is in sleep mode". When UPS is in sleep mode, green Online and red Overload indicaters flash alternatingly. This is confusing and not documented, but APC's knowledge base article FA158840 explains that this shows that UPS has been asked by NAS to go into sleep mode." In short, this is not a problem and is normal behavior, just not well documented.
This CS500 , is newer version with computer control CPU inside. now, with smarter battery charging and longer life for that feature set. IT has only 1 battery and that is good, 2 are more likely to fail than 1 alone. I have 2 of these one for PC and one for cable modem and router. The battery is an industry standard 1/4" terminals and is super easy to source, same used in emerg. lighting.,etc, etc... mine is a new, UPS. this model has status LED lights that are very useful. if you have VOIP service, this helps keep your modem active for using phone, with no AC power. The battery is easy to replace no cases to split nor screws, seen on some UPS. the CS500 has no recalls like the old did, no worry there. the software will allow logging grid AC power loss events, now ... MoreThis CS500 , is newer version with computer control CPU inside. now, with smarter battery charging and longer life for that feature set. IT has only 1 battery and that is good, 2 are more likely to fail than 1 alone. I have 2 of these one for PC and one for cable modem and router. The battery is an industry standard 1/4" terminals and is super easy to source, same used in emerg. lighting.,etc, etc... mine is a new, UPS. this model has status LED lights that are very useful. if you have VOIP service, this helps keep your modem active for using phone, with no AC power. The battery is easy to replace no cases to split nor screws, seen on some UPS. the CS500 has no recalls like the old did, no worry there. the software will allow logging grid AC power loss events, now that is good thing to have. Using USB cable. that is all..
| Power | |
| Input frequency | 50/60 Hz |
| Input operation voltage (max) | 300 V |
| Input operation voltage (min) | 160 V |
| Output power | 300 W |
