APC SMT1000RM2UC battery teardown

What battery does the SMT1000RM2UC actually use?

The SMT1000RM2UC uses APCRBC157, which holds four 12 V blocks, assumed to be two parallel pairs, rated 7.2 Ah on a 24 V DC bus. Each block fits a 151 x 65 mm bay with F2 terminals. This model has no serial-number split that we could find.

Battery Mart lists 13.13 x 8.5 x 3.09 in, the same tray size as APCRBC159, and four 151 x 65 mm cells lie flat in that space. APC assigns APCRBC157, not APCRBC132, to the SMC1500-2UC and SMT1000RM2UC. Resellers list four 12V 7.2Ah cells, and APC's manual puts it on 24 V, so we model two parallel pairs. No source states that wiring outright. Listings disagree on the tab, and the F2 comes from sellers of compatible sets, so check your old cell before ordering. The list price is one reseller's printed MSRP. Full APCRBC157 teardown

How many DC amps does the SMT1000RM2UC pull?

At its full 700 W rating, the SMT1000RM2UC pulls about 35.6 A from its 24 V bus, and about 40.7 A as the battery sags to 21 V cutoff. Those figures assume 82% inverter efficiency, because APC doesn't publish one for battery mode.

Is LiFePO4 safe in the SMT1000RM2UC?

A 12 A BMS limits the SMT1000RM2UC to about 472 W, well below its 700 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.

Four independent BMS boards in one pack multiply the balance risk. So we show no drop-in link.

How long will the SMT1000RM2UC run on each battery?

We could not read APC's runtime figures for the SMT1000RM2UC, so these estimates are uncalibrated Peukert and will read long at high loads. The 12V 9 Ah high-rate AGM option adds runtime in the same case. Drag the slider for your own load.

Same footprint, 25% more rated capacity. 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 SMT1000RM2UC?

There are three routes for the SMT1000RM2UC. Path A swaps in four bare cells and reuses your harness. 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.

How do you move the SMT1000RM2UC 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.

1. Shut down the load, turn the UPS off and unplug it from the wall.
2. Take a photo of the wiring. Open the battery door or sled and slide the pack out.
3. Pull the red clip off the positive tab, and tape it straight away.
4. Remove the black lead and tape it. Then lift off the jumper between the cells, with any fuse your harness has.
5. Check the new cells have the right size and tabs, then add any adapters from the parts list.
6. Fit the jumper first, from the positive of one cell to the negative of the next. Fit the leads one at a time, matching your photo, and remove the tape only from the lead you are fitting.
7. 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.
8. 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?

APCRBC157 lists at $596, and four bare cells cost about $139.76 at a non-Amazon single-unit price, saving roughly 77%. That reference is a premium CSB block from one store, so cheaper brands may save more. Check Amazon for its current price.

What do the SMT1000RM2UC alarms and fault codes mean?

APC Smart-UPS SMT user guide lists 4 signals we track for the SMT1000RM2UC. 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.

The manual lists no separate Battery Disconnected or AVR Boost/Trim alarm in the text we captured.

How do you reach the battery in the SMT1000RM2UC?

On the SMT1000RM2UC, the manual says: front bezel comes off first. rack unit. Inside there are four batteries of about 151 x 65 mm. Check the details below before you start, turn the unit off and unplug it first, and photograph the wiring so you can match it later.