CyberPower EC850LCD battery teardown

What battery does the EC850LCD actually use?

The EC850LCD uses RB1270B, which holds one 12 V block rated 7.2 Ah on a 12 V DC bus. It fits a 151 x 65 mm bay with F2 terminals. This model has no serial-number split that we could find.

CyberPower lists 5.97 x 3.7 x 2.57 in. CyberPower's RB1270B page omits the EC850LCD from its list, but the EC850LCD page names this cartridge. The UPS page wins. Full RB1270B teardown

How many DC amps does the EC850LCD pull?

At its full 510 W rating, the EC850LCD pulls about 51.8 A from its 12 V bus, and about 59.2 A as the battery sags to 10.5 V cutoff. Those figures assume 82% inverter efficiency, because CyberPower doesn't publish one for battery mode.

Is LiFePO4 safe in the EC850LCD?

A 12 A BMS limits the EC850LCD to about 118 W, well below its 510 W rating. At full load the verdict is RED. A single block avoids series balance drift, so light loads suit LiFePO4. Drag the slider below to test your own load.

How long will the EC850LCD run on each battery?

CyberPower publishes about 7.9 min at 255 W and 2.3 min at 510 W on the stock cells, and our curve passes through both points. 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 EC850LCD?

There are three routes for the EC850LCD. Path A swaps in one bare cell and reuses your harness. Path B adds LiFePO4 for loads under 197 W, by the listing's 20 A claim. Path C replaces the whole UPS, which makes most sense for units over six years old.

How do you move the EC850LCD harness to bare cells?

You move the factory leads from the old block to the new one, 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. CyberPower says only a qualified technician should replace this battery.
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.
5. Check the new cell has the right size and tabs, then add any adapters from the parts list.
6. Fit the leads one at a time, matching your photo, and remove the tape only from the lead you are fitting.
7. Slide it back, plug in and charge for the time the manual gives before relying on it.
8. Recycle the old cell 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 CyberPower's equipment guarantee.

How much do you save over the RB1270B?

RB1270B lists at $50, and one bare cell costs about $34.94 at a non-Amazon single-unit price, saving roughly 30%. 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 EC850LCD alarms and fault codes mean?

CyberPower EC series user manual lists 3 signals we track for the EC850LCD. Only 0 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.

How do you reach the battery in the EC850LCD?

We have no verified door procedure for the EC850LCD. 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.