Mindustry Power Problems: Fix the Deficit Before Adding Batteries

A bigger battery bank can keep a factory running through a short demand spike. It cannot keep a permanently undersupplied base running forever. If generation stays below consumption, storage only determines how long you have before the shortage reaches the machines.

The first useful diagnosis is therefore not “How many batteries do I need?” It is “Am I short of generation, short of stored energy for a burst, or looking at two disconnected networks?” Those problems require different repairs.

This guide covers ordinary Serpulo power networks and batteries in vanilla Mindustry. Generator examples assume coal, full operating efficiency and normal speed, without overdrive. Erekir’s different distribution blocks and modded power systems are outside this guide.

Power is a rate; a battery holds an amount

Think of generation and consumption as power per second. Stored energy is the amount available to cover a shortfall over time. A network producing 2,000 power per second and consuming 2,400 has a deficit of 400 per second. That deficit draws down its charged batteries.

When production exceeds demand, the surplus charges connected batteries until they are full. When demand exceeds production, stored energy covers the difference while it lasts. A full battery is not additional permanent generation, and an empty battery is not emergency energy just because its capacity is large.

Use readings from the connected network you are diagnosing. A charged battery on another isolated grid cannot support these factories just because it is nearby on the map.

Worked deficit: 40,000 stored energy is a timer, not a solution

Suppose a network has a steady 400-per-second deficit and 40,000 energy currently stored. Its buffer lasts 40,000 ÷ 400 = 100 seconds if those rates stay unchanged.

Now compare three changes:

The last option buys time, but the network is still losing energy. A lasting repair must increase sustained generation, reduce sustained consumption, or do both. You can also use the extra time to fix a broken fuel conveyor rather than constructing a replacement generator that will suffer the same shortage.

These durations assume constant full demand and production. Once energy runs out, underpowered machines can slow down, and their inputs and outputs can change. The calculation predicts depletion of the buffer under the stated conditions, not an exact simulation of the entire factory after depletion.

When batteries are the right answer: a short burst

Consider a different network with a normal surplus of 300 per second. A group of machines then adds 900 per second of demand for 20 seconds. During that burst, the network is short by 900 − 300 = 600 per second, so it needs 600 × 20 = 12,000 stored energy.

In the ordinary Serpulo block set, a small Battery stores 4,000 energy and a Large Battery stores 50,000. Three fully charged small batteries therefore cover this example’s 12,000 requirement exactly. Exact coverage leaves no margin for another consumer starting, a fuel interruption or a burst lasting longer than expected.

One charged Large Battery has more room for this burst, but capacity is only useful when you can fill it. Choosing the larger block does not replace the need for a healthy supply network.

Recharge time determines whether the pattern is sustainable

After the burst ends, the original 300-per-second surplus returns. Replacing the 12,000 energy takes 12,000 ÷ 300 = 40 seconds.

If you have 40 seconds at baseline between identical bursts, the bank can recover what the previous burst used. That is a 60-second cycle from the start of one 20-second burst to the start of the next. If there are only 20 seconds at baseline, it recovers 6,000 and loses another 6,000 from its reserve on each cycle. A larger battery can hide that downward trend for longer; it does not make the cycle sustainable.

This is the distinction between a temporary peak and an average deficit. For repeated activity, budget both the energy used during the busy period and the surplus available during the quiet period. Do not judge the system from the quiet interval alone.

Compare storage by capacity, space and materials

Nine small batteries occupy nine tiles and store 36,000 energy. One Large Battery occupies a 3 × 3 footprint and stores 50,000: 14,000 more in that same area. However, the small batteries need only copper and lead, can be placed incrementally, and do not require one contiguous 3 × 3 space.

That makes the choice more useful than “large is always better.” Use small storage when its materials and available spaces fit the base you have. Use a large bank when you need greater storage density and can supply its materials. In either case, count charged energy for immediate survival and maximum capacity for future buffering.

Check generator inputs before building duplicates

For coal at full efficiency and normal speed, a Combustion Generator produces 60 power per second. A Steam Generator produces 330 per second and needs water as well as fuel; its water requirement at that operating rate is 6 liquid units per second.

Those figures are operating conditions, not a promise that every placed generator is currently delivering them. Fuel choice and input availability affect production. A generator without a reliable supply chain can make the block count look reassuring while the live network remains short.

As a simple planning example, three coal-fed Combustion Generators provide 180 per second at those conditions. If your essential connected loads need 150, that leaves 30 for recharging. Two provide only 120 and leave a continuing 30-per-second shortfall. The 150 load is an illustrative budget, not a prescribed factory layout.

Before adding a fourth generator, inspect whether the first three receive fuel consistently. Before replacing them with steam, verify that the water supply and the machines needed to maintain it remain operational when the main grid is struggling.

A fuel chain can be the real bottleneck. More generators sharing the same inadequate coal delivery do not create more coal. They can compete for the limited stream and make production intermittent across a larger group of buildings.

A battery must belong to the network it is meant to support

Power nodes connect buildings into networks. Their configurable links can be added or removed, and changing a link can split or join those networks. Physical adjacency can also provide a connection, so removing one visible link does not necessarily isolate a group of buildings if another connection remains.

For a battery that appears full while nearby machines lack power, trace the connection from the battery to the affected machines. Check the node links and any alternate route through adjacent powered blocks. Do not assume that two clusters are connected merely because their nodes look close enough.

The reverse mistake matters during recovery. If you intend to keep a small generator group for essential supply machines but leave a connection to the rest of the base, the larger network can consume the available output. Calling something an “emergency battery” does not reserve its energy for a preferred consumer.

Before relying on an isolated restart network, inspect its actual connections. This guide does not require a diode or logic-controlled priority circuit; the goal is a small, understandable group of generators, storage and essential loads.

Recover a collapsed network in a deliberate order

When the whole base is underpowered, restoring every consumer at once can prevent the production chain from recovering. Work from the source of power outward.

1. Identify which inputs stopped generation. Check fuel arrival and, for steam, water. A missing input is different from insufficient generating capacity with all inputs available.
2. Temporarily separate nonessential production from the recovery network. Preserve the supply machines needed to restore fuel or water rather than giving all factories the same claim on a weak supply.
3. Establish generation that can operate with the inputs available now. A stocked coal supply and Combustion Generators can provide a simpler starting point than a generator whose supporting machines are also starved of power.
4. Compare that output with the essential connected demand. If the essential group itself consumes more than it generates, it cannot rebuild a battery reserve.
5. Let surplus refill a buffer before reconnecting large groups of machines.
6. Reconnect demand in stages and reassess the balance after each group resumes operation.

For the illustrative 180-generation, 150-demand recovery group, the 30-per-second surplus refills an empty small battery in 4,000 ÷ 30, or about 133 seconds, if the rates remain constant. That is much slower than simply observing that the power indicator is no longer empty. A functioning network and a replenished emergency buffer are different milestones.

If reconnecting one group makes stored energy fall continuously, stop treating the restart as complete. Either that group needs more sustained supply, an input chain has become unreliable again, or the combined load needs to be reduced until capacity catches up.

Diagnose the symptom before spending resources

Build batteries to bridge a defined interruption or demand peak. Build and feed generators to support the load that continues. Keeping those two jobs separate makes both your construction budget and your recovery plan much easier to trust.