Batteries and portable power in Project Zomboid

Project Zomboid has two separate battery systems that never mix. The small Battery is an AA-style cell that goes into handheld electronics. The car battery is a heavy block that sits in a vehicle engine bay and can be pulled out, carried and charged. A charger built for car batteries will not accept small cells, and no small device can run from a car battery.

Older wiki pages list the small battery at 0.6 weight. That figure comes from Build 41 era data, and the Build 42 item files used by pzfans list 0.1, so treat 0.1 as the current value.

Battery lights in Build 42 lose one charge step every 10 in-game minutes while switched on, but only when held in your hand or attached to your body. A lit flashlight put into a bag switches itself off. The run times below are in-game hours on a full cell and come from a single Build 42.21 lighting breakdown, which fits the item data (the regular Flashlight has a use delta of 0.006, about 167 steps of 10 minutes).

Radios and walkie-talkies use batteries (the Premium Technologies Radio has a use delta of 0.009 and walkie-talkies 0.007), but no source we found converts that into hours, so we do not give one. Digital watches and crafted remote controllers carry no battery setting in the item data, so they work indefinitely. See lighting and radio for how to use these devices.

Small batteries are common clutter. The loot tables put them on metal shelves and counters in houses, in electronics cases, in walkie-talkie protective cases, on engineer and science desks, and in mechanic electrical shelves. Flashlights and radios that were not left switched on often still hold a cell, so check every one you pick up. The Box of Batteries is the big find: it has the highest weight in battery crates, electronics stores and the electronics shelves of large department stores. How many cells one box holds was not confirmed for this build.

Car batteries come out of parked vehicles (a screwdriver is enough) and also spawn on car-supply battery shelves, mechanic electrical shelves and in garages. About 30 percent spawn damaged, according to the item data. The Car Battery Charger turns up in the same auto shops, in gas station emergency stock and occasionally in service truck beds. It has no crafting recipe. The loot locations and looting pages cover the buildings in more detail.

Hover over a battery or a battery device in your inventory and the tooltip shows how much charge remains. A flashlight also warns you itself: it starts to flicker when the cell is nearly empty. For a car battery, open the vehicle mechanics window or hover over a loose car battery to read its charge and its condition, which are two separate numbers. A battery can be fully charged and still badly damaged.

A partly used small battery keeps its exact charge when you take it out. You can only insert a cell into an empty device, so remove the old one first. The device then takes on the charge of the new cell.

There are two ways to refill a car battery in vanilla Build 42.

• Car Battery Charger. Place it on a floor tile, connect one car battery (fully charged ones do not show in the menu), then Turn On. The tile must have power: grid electricity before the shutoff, or a running generator covering that square after it. The charger adds about one sixth of a full charge per game hour, so empty to full takes about 6 game hours (one source). Electrical skill does not speed it up.
• Running the engine. An installed battery gains about 6 percent per game hour while the engine runs, or roughly 16.7 hours from empty to full (one source). This costs fuel.

A generator does not charge a car parked nearby on its own. That wireless charging was a Build 41 bug and is gone in Build 42. Charging restores charge only, never condition. Jumper cables and push starts are not in vanilla. Load figures from the same source put the generator at 0.02 and the charger at 0.05, so a charger alone is a light load on your fuel. See generators and vehicles.

No, as far as we could confirm for Build 42. No vanilla recipe recharges a small cell and none crafts one from parts. The car charger will not take them. The only battery recipes move a cell in or out of a device, or turn one into an improvised lighter, which you can dismantle to get the battery back. A cell that hits zero is used up.

That makes small batteries a finite resource, unlike car batteries, which a generator or engine can refill for as long as you have fuel. Mods add rechargeable cells and universal chargers, but those are not part of the base game. For wiring and power projects that do not depend on cells, see electrical.

Opinion Treat small batteries like ammunition. Loot every electronics store and battery crate in your first weeks, since cells do not respawn quickly unless your sandbox settings allow loot respawn. Keep them in one labeled container in your storage.

• Opinion Carry a penlight for routine night looting. It runs about six times longer than a full-size flashlight per cell and is enough for reading rooms.
• Opinion Switch radios off between broadcasts and never leave a walkie-talkie transmitting in a bag.
• Opinion Once the grid fails, build lighting around a generator or lanterns and save cells for trips away from base.
• Opinion Keep two charged car batteries and a charger at base. A spare battery means a dead car never strands you.

The late game page covers long-term power planning in more depth.