Picture of the APC Smart UPS SU1400NET Uninterruptible Power Supply, about to undergo repairs.

APC Smart UPS Battery Replacement SU1400NET

This week’s tinker project: An APC SU1400NET Smart UPS battery backup system. Rescued two of these from a junk pile bound wagon last week in Pittsburgh.  Both showed their APC replace battery light still on, even after left to run for several hours. We inferred thus, that the batteries had indeed died. So, we set out to replace them.  This post covers the APC smart UPS battery replacement procedure we used.  This method worked well to get our SU1400NET backup power supplies up and running again.

But we had to leave one APC UPS with buddies out there. Why?  Because even with their dead batteries out, each uninterruptible power supply (UPS) still weighs close to 30 pounds. Even with just one supply, we almost could not heave the bag up to the overhead rack in the train.

However the risk of loss in this smart UPS battery replacement effort was pretty low.  How so?  Because with the bad batteries still installed, the unit did power up, and turned on the “replace battery” indicator light.  It also gave a solid beep sound.

But if the new battery does not work, we will try further repairs. If those fail though, other uses for the new batteries abound. Besides, should we not send this unit to APC for fixing, it will make a great tinker box.

Picture of the APC smart UPS SU1400NET uninterruptible power supply, about to undergo battery replacement repaires.
APC Smart UPS SU1400NET Uninterruptible Power Supply, showing front and left side view.

About the New Battery

The smart ups 1400 battery replacement cartridge is actually two 12-volt 18 amp-hour batteries.  They strap them together into one pack.  Then they connect the them in series with a 100-amp fuse, along with a harness and quick-disconnect plug. So the SU1400NET runs on 24 volts of battery power.

Ordered the APC smart ups 1400 battery replacement rbc7 cartridge from Chrome Battery. They had about the best price for this fully assembled cartridge that we could find.  At roughly $83, that price included shipping. Their APC 1400 replacement battery kit comes with the battery pack, the 100-amp fuse, the wiring harness, and plug.

Hopefully, the aged original batteries are all that’s wrong with this uninterruptible power supply. It would be a shame to buy the new cells, only to find that the unit still does not work. But now you see the little bit of gambling spirit in me; though I never visit the casinos. With two of these though, there should be enough working parts to assemble at least one functional unit.

APC Smart UPS Battery Replacement on the SU1400NET Backup Power Supply

Get the New Battery

Received the new RBC7 smart ups 1400 battery several days later. Very fast delivery. As expected, it was HEAVY (roughly 30 pounds).  They also labeled it as FRAGILE.

Below is the new APC 1400 battery, unpacked.

Picture of the unboxed Chrome battery RBC7 replacement kit for the APC SU1400NET UPS.
Unboxed Chrome Battery RBC7 replacement battery kit for APC SU1400NET UPS.

Test the New APC Smart UPS Battery 

We then tested the new smart ups 1400 APC battery for correct DC voltage. For that, we used a Sperry SP-152A multi meter as shown in the next picture.

The vendor said that they charge these to 90% before shipping. So we checked that very little charge faded in travel to us. Further, the RBC7 battery showed no damage.

This APC smart UPS 1400 battery is a sealed lead acid AGP battery. So we expected no leakage. Further, the battery showed the right value of about 24 volts.

Picture of the voltage measurement being taken, of the brand new Chrome Battery RBC7. The reading is around 25 volts after unpacking the battery pack.
Brand new Chrome Battery RBC7 Measures at around 25 volts after unpacking.

Install the New Battery

Then, we installed the APC 1400 battery replacement cartridge into the UPS. We found detailed instructions for that, printed on the top of this UPS unit. Connect the battery before pushing it into its holder within the SU1400NET. Keep the DC power cable atop the battery, as shown below.  See the black and red cable with the gray disconnect in the next picture.

Picture of the front panel of the UPS removed, showing the new battery, installed.
Front panel of the UPS removed, showing the new battery, installed.

Fortunately, we found no other problems with the internal electronics.

Test the APC 1400 SU1400NET with New Battery Installed

We plugged in the APC Smart UPS 1400.  It then ran through its self tests.  The front panel lights blinked a few times and a couple short beeps sounded. It then went into standby mode, as the APC battery backup replacement began charging.

No fans inside run with AC power on. But they do run when main power goes out.  You also hear the power failure alert tones as well.  These sound once or twice each minute until mains power comes back.

Picture of the unit fully assembled and charging after battery replacement.
Showing the unit fully assembled and charging after battery Replacement.

For the REAL test of APC smart ups 1400 battery replacement operation, we fully charged the 1400, for several days. We then connected our network equipment in the home office to it.  Finally, we unplugged it from AC power to mimic a true power outage. The charge level meter showed, as shown above, the battery fully charged before testing the SU1400NET.

APC Battery Status Light

But this APC replace battery light is only so useful.  Why?  Because just an hour into the test run, all but one of the lights in the vertical bar went out. Yet even with just one bar lit, we still got several hours more backup power. So, this meter does not accurately show the charge left in the APC 1400 battery. It’s just a very rough indication.

We’ve replaced batteries in two of these UPS units from APC, and both continue to work very well.

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References for APC Smart UPS Battery Replacement 

  1. American Power Conversions (APC) Web Site
  2. Chrome Batteries Web Site
  3. Where to Buy APC SU1400NET Replacement Batteries

Revision History

  • 2019-03-23: Added tags.
  • 2018-04-22: Revised post content for better keyword targeting.
  • 2015-12-19: Added more appropriate tags.
  • 2015-09-07: Added more appropriate tags.
  • 2015-02-05: Updated content.
  • 2014-10-30: Covered what happened after receiving the new battery cartridge. Also, added more pictures.
  • 2014-10-13: Originally published.