Power system visual guide: outlets, downstream load, and battery layouts

What the power system actually counts

Facility outlets switch off at 9:00 PM and return at 6:00 AM. Those are nine in-game hours, not nine real hours. On standard settings, the night lasts 270 real seconds. Batteries discharge according to real seconds and the number of powered devices downstream from them.

Three rules explain most base failures:

1. A live facility outlet has unlimited power throughput. Splitting a live outlet does not reduce daytime supply.
2. A battery's charging rate does not slow down because more devices are connected.
3. Once the outlet is off, battery drain increases with every downstream device it powers. Other batteries in series also count as downstream devices.

That third rule is why real-world intuition about daisy-chained batteries can produce a worse layout in the game.

Day and night state diagram

Diagram basis: current Mechanics power rules. Times assume standard settings; changing the day-night cycle changes the duration but not the battery's real-time discharge rule.

Runtime formula

When no live outlet is feeding a battery, the current rule is:

Runtime in seconds = 5 x battery charge / downstream device count

The battery rules explicitly exclude Plug Strips and Plug Boards from the load count; their connected appliances still count. A battery placed farther downstream also counts as a device for every battery upstream of it. Cable Reroutes extend the cable, but do not infer an exact load exclusion from that placement description alone. Read the upstream battery's blue indicator after adding a reroute, and use the observed count for the installed network rather than silently treating every pass-through component as identical.

This counting rule covers ordinary wired loads, not every power arrangement. The advanced power section identifies a Laser Emitter as one battery load regardless of appliances powered beyond its beam, including through a Laser Power Converter. Keep that exception out of an ordinary wired-device count, and check the beam's unobstructed path separately: a sufficient battery estimate does not fix interrupted delivery.

For a fully charged Makeshift Battery:

• Charge is 50.
• One downstream device gives 5 x 50 / 1 = 250 seconds.
• Two downstream devices give 5 x 50 / 2 = 125 seconds.
• Five downstream devices give 5 x 50 / 5 = 50 seconds.

A standard night lasts 270 seconds, so one Makeshift Battery powering one device leaves a 20-second gap before outlets return. This is small enough to miss in a casual test but important for a Refrigerator, Crafting Bench, or defense device that must remain available through the whole outage.

Downstream load diagram

Three starter layouts and their limits

One battery, one critical device

Outlet -> Makeshift Battery -> one device

This is simple and easy to diagnose, but it does not cover the final 20 seconds of a default night. Use it for a device that can tolerate that gap, or upgrade the battery plan for a critical load.

Two Makeshift Batteries in series, one device

Outlet -> Battery A -> Battery B -> one device

The downstream battery and final device both count against Battery A. Battery B counts only the final device. The current reference gives a total of 375 seconds, not 500. That covers a standard night but demonstrates the diminishing return from series wiring.

Separate battery branches

Outlet -> Plug Strip -> Battery A -> device A

Outlet -> Plug Strip -> Battery B -> device B

Each battery sees one downstream device and therefore lasts 250 seconds. This is easier to inspect and isolates failures, but each branch still has the same 20-second default-night gap. Parallel branches improve isolation; they do not magically extend a Makeshift Battery's charge.

A six-device starter network

The current Mechanics reference describes a more efficient whole-night pattern for six devices: one Makeshift Battery as a root feeding branches to six more Makeshift Batteries, with one final device behind each branch battery. The root sees twelve downstream devices: six batteries and six final loads. Applying the listed runtime formula gives 5 x 50 / 12, about 20.83 seconds for the root, then 250 seconds for each fully charged branch: about 270.83 seconds of estimated total coverage. This is a formula-based estimate, not an in-game stopwatch result.

The Wiki's night-length example instead quotes 25 seconds for that root and 275 seconds overall. Those example values do not equal the continuous formula with twelve downstream devices; the page does not explain the discrepancy. In a September 2025 Steam discussion, players discuss the same seven-battery layout and recommend leaving slack for timing or rounding, but they do not establish a current-build timing rule. Treat this as a narrow-margin layout, not a measured five-second safety margin. Start with every battery fully charged, verify the root's downstream count, and check critical devices through an actual night in your save before relying on it. A larger battery or fewer loads is the safer planning choice when an interruption is unacceptable; do not infer a new discharge tick or guaranteed rounding behavior from the difference between the two source calculations.

This pattern is useful when exactly six important loads need full default-night coverage. It is not a universal base layout. Fewer devices may be simpler with two batteries behind one load; later battery tiers or laser power can change the decision.

Plug Strips and Cable Reroutes

A Plug Strip provides three cable slots. It splits one source into up to three immediate connections, and more strips or boards can extend the network. The strip does not consume battery charge as a downstream powered device, but every powered appliance after it does.

A Cable Reroute extends a power cable. While holding a power socket, the player can place one with the Fire action when at least one Tech Scrap is available. The placement ghost changes color as the cursor approaches the cable's range limit. Cable Reroutes can be mounted on walls or ceilings, and an unlimited number can be chained; practical limits are Tech Scrap, placement range, and the ability to understand the finished network.

Use reroutes to make paths readable:

1. Follow walls or ceilings instead of crossing walkways.
2. Place a reroute where the next segment remains visible.
3. Label critical branches by the device they support.
4. Stop adding branches when the downstream count is no longer obvious.

Levers and noncritical loads

A Lever can disconnect a branch that does not need overnight power. The key is electrical separation: a lamp, charger, or optional workstation still counts if it remains connected downstream, even when the player is not actively using it.

Switching output off is not a guaranteed zero upstream drain. In an August 2025 community test, the author reported slightly faster upstream discharge with an off Lever and device than with the comparison battery chain alone. They did not isolate the cause or establish a current-version amount. Treat that as a community observation, not proof of a specific passive draw or a replacement formula. The Lever's documented purpose is power control; check load accounting separately before relying on an assumed runtime saving.

For a reversible check, note the battery's charge and blue indicator with the optional branch connected, then switch the Lever off and record both again. Compare with the branch cable physically disconnected while leaving the critical branch intact. During a real outage, start each comparison with the same charge, topology and world settings. Keep critical equipment on its own adequate supply while checking the optional circuit. This is a method for your save, not a claim that this site performed the experiment or that a single indicator snapshot proves a precise discharge rate.

Before 9:00 PM:

• keep the Crafting Bench, Refrigerator, or required defense line connected;
• disconnect decorative or temporarily idle powered devices;
• read the battery's blue downstream-device indicator;
• compare expected runtime with the 270-second default night;
• reconnect optional branches after facility power returns.

Failure diagnosis

Completion checklist

A power plan is ready when:

• the standard 270-second night assumption is correct for the world settings;
• each battery's downstream device count is known;
• the formula uses real seconds rather than nine real hours;
• critical loads have enough documented runtime;
• Plug Strips and Plug Boards use the documented exclusion, while the installed reroute and Lever states have been checked against the upstream indicator;
• batteries in series are counted as downstream devices for upstream batteries;
• optional branches can be disconnected without cutting critical power;
• the network remains readable enough to diagnose after a change.

Use the battery runtime check for a focused calculation and the laser power guide when late-game wireless generation becomes available.