Battery to Engine Unit Chain

Lore & Background

In the sparse, rust-streaked world the player inherits, the Engine Unit is less a manufactured part and more a declaration of intent. The Battery, with its dense iron casing and copper windings, hums faintly even when idle—a small, contained voltage that the alien flora seems to sense, curling its pale tendrils away from the nearest conveyor. The Electronic Circuit, by contrast, is quiet, its green board a geometric counterpoint to the organic chaos of the surrounding terrain. Together they form the mechanical heart of every Electric Engine, and the player quickly learns that a factory without them is a factory frozen in the age of steam. The Light Oil requirement is the chain's quiet twist. Where iron and copper are dug from the ground in tidy, predictable veins, crude oil seeps from the earth in black, viscous pools that must be pumped, heated, and split in a dedicated refinery. The player's first Oil Refinery often feels like an alien machine dropped into a world of hammers and furnaces, its long pipes and venting steam a visual reminder that the factory is no longer self-contained. The Heavy Oil by-product, initially useless, becomes a later headache—or a fuel source—depending on how the player's logistics have matured. As the factory sprawls outward, the Engine Unit chain becomes the connective tissue between the solid-fuel world and the electric one. Every Electric Pump that keeps the oil flowing, every Electric Furnace that smelts faster, every Electric Mining Drill that bites deeper into the crust, all of them trace their lineage back to that single Battery pressed between an Iron Plate and a Copper Plate in a modest Assembling Machine.

In Their Own Story

Inside the factory floor, the rhythm was different: the clack-clack-clack of four Assembling Machines in a row, each one cycling through Copper Cable, Electronic Circuit, Battery, Engine Unit in a choreographed relay. The conveyor belts pulsed like veins, iron plates sliding past copper, the occasional Light Oil tank rolling in from the refinery with a soft hydraulic hiss. The player leaned against a wall, watching the Engine Units stack in the output buffer—twelve, thirteen, fourteen—and thought about how, six hours ago, this same floor had been empty dirt and a single Smelter coughing out its first plate. The Battery recipe had been the first time the factory had needed to *think* in more than one dimension, and now the whole operation breathed in three. Somewhere in the distance, an Electric Mining Drill began its slow, grinding rotation, and the ground shuddered just enough to rattle the oil tanks on their mounts. The player smiled, wiped grease from their forehead, and walked back to the control panel. There was a whole Electric Engine to build, and the night was young.

Reader's Guide

Per Engine Unit you need: 1 Electronic Circuit, 1 Battery, 1 Iron Plate. Unpacking further: the Circuit requires 1 Iron Plate + 1 Copper Cable; the Battery requires 1 Iron Plate + 1 Copper Plate + 1 Light Oil; the Copper Cable is 1 Copper Plate. Net raw inputs per Engine Unit are 3 Iron Plates, 2 Copper Plates, and 1 Light Oil (from 1 Crude Oil in the Oil Refinery). Machines involved: Smelters produce Iron and Copper Plates; Assembling Machines produce Copper Cable, Electronic Circuit, Battery, and the final Engine Unit; the Oil Refinery turns Crude Oil into Light Oil (plus Heavy Oil as a by-product). All assembly steps use the same machine type, so they compete for the same pool of Assembler slots. The typical bottleneck is Assembler capacity. You need four distinct assembly recipes (Cable, Circuit, Battery, Engine) all running simultaneously, and early Assemblers are slow. The Oil Refinery can also bottleneck if you under-invest in oil-pumping infrastructure, since it is a separate machine type with its own throughput ceiling. Scaling: the chain is strictly linear. Doubling Engine Unit demand means doubling every upstream item. In practice, players often over-produce Iron and Copper Plates (cheap, fast in Smelters) and let the Assembler row and the Refinery set the true pace. As the factory grows into Electric Engine and Space Age demand, this chain multiplies, and the Oil Refinery count becomes a critical planning number.

Did You Know?

• The Battery is one of the earliest recipes that requires Light Oil, forcing the player to build oil-pumping and refining infrastructure well before they need it for fuels or plastic.
• The Heavy Oil by-product from the Oil Refinery is initially useless in this chain but later becomes a fuel source for Steam Power and a component in other recipes, making the refinery a dual-purpose machine from day one.
• All four assembly steps in this chain (Copper Cable, Electronic Circuit, Battery, Engine Unit) use the same machine type, meaning a single row of Assemblers can handle the entire pipeline if space and logistics allow.
• The Engine Unit is a prerequisite for the Electric Engine, which in turn powers Electric Pumps, Electric Furnaces, and Electric Mining Drills—making this chain a hidden dependency for nearly every late-game upgrade.