APC SMC1500-2UC battery teardown
Also Sold As / Retail Channel Equivalent: SMC1500I-2UC Same OEM manual or cartridge listing.
- Battery
- Not published
- Max DC draw
- 45.7 A
- OEM cartridge
- APCRBC157
- Cell size
- unverified
- In inches
- unverified
- Terminal
- unverified
- Rating
- 1440 VA / 900 W
- Topology
- Line Interactive
- Waveform
- Pure Sine Wave
- Transfer time
- 6ms typical : 10ms maximum
- OEM list price
- not published
- DC bus
- 24 V (assumed)
- Last verified
- 2026-11-01
- LiFePO4 at full load
- RED
What battery does the SMC1500-2UC actually use?
The SMC1500-2UC uses APCRBC157, which holds a module whose cells the manufacturer does not publish, assumed rated 7 Ah on a 24 V DC bus. No source gives the cell size for this pack. This model has no serial-number split that we could find.
| Spec | Value | Source |
|---|---|---|
| VA and watts | 1440 VA / 900 W | T1 se.com |
| Topology | Line Interactive | T1 se.com |
| Waveform, in the OEM's words | Sine wave | T1 se.com |
| Transfer time | 6ms typical : 10ms maximum | T1 se.com |
| OEM cartridge | APCRBC157 | T1 se.com |
| Why Does APC Assign a Different Cartridge SKU? | APC doesn't publish a reason. APCRBC157, against APCRBC159 on the SMT1500RM2UC at $524. All are 4 x 12 V blocks on a 24 V bus, so the difference we can document is SKU, sled and price, not the cells. | |
APC lists one lead-acid module and publishes no voltage, cell count or size for it. APC assigns APCRBC157, not APCRBC132, to the SMC1500-2UC. We found no teardown confirming four 12V 7Ah cells, so we link none. Current figures assume 24 V. Full APCRBC157 teardown
How many DC amps does the SMC1500-2UC pull?
At its full 900 W rating, the SMC1500-2UC pulls about 45.7 A from its 24 V bus, and about 52.3 A as the battery sags to 21 V cutoff. Those figures assume 82% inverter efficiency, because APC doesn't publish one for battery mode.
| AC load | Nominal | At cutoff |
|---|---|---|
| 25 W | 1.3 A | 1.5 A |
| 60 W | 3.0 A | 3.5 A |
| 100 W | 5.1 A | 5.8 A |
| 200 W | 10.2 A | 11.6 A |
| 300 W | 15.2 A | 17.4 A |
| 450 W | 22.9 A | 26.1 A |
| 900 W | 45.7 A | 52.3 A |
Is LiFePO4 safe in the SMC1500-2UC?
A 12 A BMS limits the SMC1500-2UC to about 472 W, well below its 900 W rating. At full load the verdict is RED. We could not verify a LiFePO4 pack that fits this bay and harness, so we link none. APC doesn't support this swap. Drag the slider below to test your own load.
GREY: load is fine, but no verified cell fits
- DC draw now
- 12.7 A
- At 21 V cutoff
- 14.5 A
- Safe AC load
- 472 W
SMC1500-2UC: lead-acid anchored to OEM half and full-load runtimes, LiFePO4 on a flat energy curve with inverter tare, at 82% inverter efficiency. A real inrush can trip a BMS below this ceiling. APCRBC157 teardown.
| BMS continuous | Safe AC load | Share of 900 W |
|---|---|---|
| 10 A | 197 W | 22% |
| 12 A | 236 W | 26% |
| 15 A | 295 W | 33% |
| 20 A | 394 W | 44% |
The cell layout and bus voltage are unverified. So we show no drop-in link.
How long will the SMC1500-2UC run on each battery?
APC publishes about 21.4 min at 450 W and 6 min at 900 W on the stock cells, and our curve passes through both points. We found no larger cell verified for this bay. Drag the slider for your own load.
| AC load | Stock 7 Ah | Upgraded cell | LiFePO4 10 Ah |
|---|---|---|---|
| 25 W | 10.8 hr | none verified | no verified pack |
| 60 W | 3.8 hr | none verified | no verified pack |
| 100 W | 2.1 hr | none verified | no verified pack |
| 200 W | 56 min | none verified | no verified pack |
| 300 W | 35 min | none verified | no verified pack |
| 450 W | 21 min | none verified | no verified pack |
| 900 W | 6.0 min | none verified | no verified pack |
| Load | APC published | Raw Peukert | This site | Source |
|---|---|---|---|---|
| 450 W | 21.4 min | 20 min | 21.4 min | T1 se.com |
| 900 W | 6 min | 8.7 min | 6 min | T1 se.com |
Upgraded AGM scales from the anchored curve, with k = 1.18 standard and 1.12 high-rate. LiFePO4 uses a flat energy curve with inverter tare. Method.
Which replacement should you buy for the SMC1500-2UC?
There are three routes for the SMC1500-2UC. Path A is withheld, because this pack's cell size is unverified. Path B is withheld, because no verified pack fits. Path C replaces the whole UPS, which makes most sense for units over six years old.
| Path | Best for | Load limit | Main risk |
|---|---|---|---|
| A: bare SLA swap | Lowest cost, any load | 900 W | Cell size unverified |
| B: drop-in LiFePO4 | Light loads, long life | not offered | BMS trip, charger mismatch |
| C: native LiFePO4 UPS | A unit over 6 years old, or high loads | 1000 W | Slower transfer than this UPS |
Path A: the bare-cell SLA swap
Path B: drop-in LiFePO4
Path C: a native LiFePO4 UPS
Worth it if this UPS is 6 or more years old, if a fault above isn't a battery problem, or if you need more than the BMS limit. Listings and reviews put Goldenmate's transfer at 8 to 20 ms, against this unit's 6ms typical : 10ms maximum, so check that your PC tolerates it.
How do you move the SMC1500-2UC harness to bare cells?
You move the factory jumper and leads from the old blocks to the new ones, in the same polarity. Unplug the UPS first, and tape each lead as it comes off, because the battery stays live. Sealed sleds must be opened first. No soldering is needed.
- Shut down the load, turn the UPS off and unplug it from the wall.
- Take a photo of the wiring. Open the battery door or sled and slide the pack out.
- Pull the red clip off the positive tab, and tape it straight away.
- Remove the black lead and tape it. Then lift off the jumper between the cells, with its fuse if your harness has one.
- Check the new cells have the right size and tabs, then add any adapters from the parts list.
- Fit the jumper first, from the positive of one cell to the negative of the other. Fit the leads one at a time, matching your photo, and remove the tape only from the lead you are fitting.
- Measure about 25 to 27 V across the two outer leads before you close the pack. Slide it back, plug in and charge for the time the manual gives before relying on it.
- Recycle the old cells at a battery retailer. Never bin lead-acid.
Sixty seconds is the best case for a loose-cell unit. Sealed sleds need opening first, and opening them may affect your warranty and APC's equipment guarantee.
How much do you save over the APCRBC157?
We can't state a saving for APCRBC157, because we found no published list price for it. Any figure here would be a guess, so this page leaves it out rather than estimating one for you. Compare the list price with your own quote.
| Item | Status |
|---|---|
| APCRBC157 list price | not published |
| Verified bare-cell reference | none |
What do the SMC1500-2UC alarms and fault codes mean?
APC Smart-UPS C user guide lists 3 signals we track for the SMC1500-2UC. Only 1 of them point to the battery, and 1 mean you should not buy batteries yet. Read your signal below first, because a new battery won't fix a charger, a relay or an overload.
| Signal | Meaning | What to do | Battery swap? | Source |
|---|---|---|---|---|
| Beeps for one minute every five hours | The battery must be replaced | Replace the battery. | Path A swap fixes this | T1 manual |
| Two beeps | Battery disconnected | Check that the battery is securely connected. | Check first, then decide | T1 manual |
| Error LED on, constant beeping | Internal error | Look up the code in the manual and contact support before buying cells. | Do not buy batteries | T1 manual |
How do you reach the battery in the SMC1500-2UC?
We have no verified door procedure for the SMC1500-2UC. The manufacturer says this battery should be replaced by qualified personnel. Treat the unit as a service item, and don't open the case to find out how it comes apart. Contact the manufacturer if you are unsure.
| Field | Value | Source |
|---|---|---|
| Battery door access | No procedure captured. Treat as a service item | none |
| Cell orientation | Not stated in the manual we captured | none |
| Harness connector type | Not stated in the manual we captured | none |
| Cell layout | Not published | unverified |