In the winter of C.E. 57, seven-and-a-half-year-old Nangong Wentian woke up from the cold.
Cold.
Bone-chilling cold.
He opened his eyes and found the moonlight streaming through the window unusually bright—not because the moon was particularly luminous, but because the lights in the room were off.
Another power outage.
He sighed, curling up under the covers, listening to the sounds around him.
The dormitory was quiet, but it was an abnormal kind of silence—no snoring, no rustling of turning bodies, only the occasional suppressed shivering. The children were all awake, enduring the cold, none daring to make a sound.
Xiao Guang in the next bed turned over. In the darkness, his face was unclear, but the chattering of his teeth could be heard.
Nangong Wentian sat up, put on his faded old cotton-padded jacket, and got out of bed to walk to the window.
The courtyard outside was pitch black. Most of the lights in the distant village had gone out, with only a few scattered points still glowing. He looked up at the roof—where the orphanage's only solar panel was installed.
A thin layer of frost covered the panel, shimmering faintly under the moonlight.
He then looked at the energy storage battery box in the courtyard—a metal cabinet containing over a dozen lead-acid batteries that had been in use for nearly ten years.
"Same old problem," he thought silently.
"Wentian…" Xiao Guang's trembling voice came from behind, "Why… why are you up…"
"Can't sleep." Nangong Wentian turned around and saw Xiao Guang curled up under his blanket. "Are you cold?"
"Cold…" Xiao Guang admitted honestly, "My feet are numb from the cold."
Nangong Wentian walked back to the bed and draped his own blanket over Xiao Guang. "Hold on a little longer. It'll be better when it's light."
Xiao Guang burrowed into the two layers of blankets, shivering as he asked, "When… when will the power come back?"
"Don't know." Nangong Wentian looked out the window. "Maybe at dawn, maybe tomorrow night, maybe…"
He didn't finish, but Xiao Guang understood.
Maybe longer.
The orphanage's power supply system was old to begin with, and it broke down several times every winter. This year was particularly cold, and the power outages were especially frequent. The last time the power went out, it took a full three days to fix.
Three days.
Nights at freezing temperatures, without heating or electric blankets, relying only on those thin blankets to endure. The children cried from the cold, and the nuns took turns holding them to keep them warm, but some still ended up with fevers.
Nangong Wentian clenched his fist.
He remembered scanning the solar panel's data with the "Star Core" a month ago—it was during a chance opportunity when he secretly climbed onto the roof to check the wiring. The data was terrible, worse than he had imagined.
The solar panels were operating at only 60% of their rated efficiency, with some panels showing surface cracks that caused localized overheating. The energy storage batteries were in even worse shape—at least half of the dozen or so batteries had severely degraded, with internal resistance so high they could neither charge nor discharge properly. The most critical issue was the control system—the rudimentary controller lacked maximum power point tracking, wasting a significant amount of energy.
If it could be optimized...
"Wentian," Xiao Guang suddenly asked, "what are you thinking about?"
Nangong Wentian snapped out of his thoughts, looking into those bright eyes in the darkness and pausing for a moment.
"Thinking about how to fix it."
Xiao Guang was taken aback, then whispered, "Can you fix it?"
"I don't know," Nangong Wentian answered honestly. "But I can try."
Xiao Guang fell silent, but Nangong Wentian could feel his gaze still fixed on him.
Trust.
That kind of unreserved trust again.
Nangong Wentian suddenly felt a bit of pressure.
What if he tried and failed? What if he messed up and made things worse? What if...
He shook his head, pushing these thoughts away.
Thinking about failure before even trying wasn't his style.
"Go to sleep," he said to Xiao Guang. "I'm going to take a look."
Xiao Guang immediately threw off the blanket. "I'm coming too!"
"What are you coming for? It's cold outside."
"To keep watch for you!" Xiao Guang declared confidently. "If someone spots us, I can cough to warn you!"
Nangong Wentian looked at him, warmth welling up in his heart.
"Alright," he nodded. "Put on something warm."
The two quietly dressed and slipped out of the dormitory in the dark.
The courtyard was even colder than inside. The winter night wind cut like a knife against their faces. Xiao Guang hunched his shoulders, his teeth beginning to chatter again.
Nangong Wentian retrieved a flashlight from the corner of the wall—one he had assembled himself from spare parts, with a battery scavenged from the junkyard that still worked. He turned it on, shining the light toward the metal cabinet.
A rusty lock hung on the battery box. He tested it—the lock was loose, likely broken long ago.
Opening the cabinet door, a pungent acidic smell hit them. Nangong Wentian covered his nose and shone the flashlight inside.
Over a dozen lead-acid batteries were neatly arranged, their surfaces covered in dust and signs of corrosion. He examined them one by one, noting each battery's model and condition.
"Why are you memorizing all this?" Xiao Guang whispered beside him.
"It's useful." Nangong Wentian pulled out a palm-sized notebook from his pocket—one he had bound from scrap paper, along with a short pencil. By the moonlight and flashlight beam, he began recording:
GS-YUASA NP7-12
12V 7Ah
Surface corrosion visible
Voltage measurement: 10.2V
YUASA NP4-12
12V 4Ah
End cap cracked
Voltage measurement: 4.5V
PANASONIC LC-R127R2
12V 7.2Ah
Appearance acceptable
Voltage measurement: 11.8V
...
Xiao Guang watched him write, his eyes wide. He knew Wentian understood many unusual things, but he hadn't realized he even knew battery models.
"Wentian," he couldn't help asking, "what's the point of looking at all this?"
Nangong Wentian didn't answer, continuing his notes.
He needed this data. Once he returned and used the "Star Core" for simulation and analysis, he would be able to identify the issues with the entire power supply system—which batteries needed replacing, which ones could still be used, how to adjust the controller, and how to optimize the solar panels...
This was a system.
In his mind, he had countless designs for advanced energy systems—the Minovsky Particle Reactor from the UC Era, the GN Solar Furnace from the 00 Era, and nuclear fusion technology from the SEED world. Those were all things of the future, unusable now.
But this crude solar power system before him—he could optimize it.
And he had to optimize it.
Not for himself, but for the children shivering from the cold.
For Xiao Guang.
"Alright," he said, closing the notebook and shutting the cabinet door. "Let's go back."
The two of them quietly slipped back to the dormitory. Xiao Guang burrowed into his bed, wrapped himself tightly in two layers of blankets, and soon fell asleep.
Nangong Wentian lay flat on his back, staring at the ceiling as he began organizing the data he had just recorded in his mind.
GS-YUASA NP7-12, 10.2V, severely depleted, nearing the end of its lifespan...
YUASA NP4-12, 4.5V, almost completely useless...
PANASONIC LC-R127R2, 11.8V, condition acceptable but capacity severely degraded...
Inputting this data into the "Star Core," combined with the parameters of the solar panels, the efficiency of the controller, and the losses in the wiring, would allow him to calculate the problems with the entire system.
He closed his eyes and activated the "Star Core's" analysis function in his mind.
Although the "Star Core's" hardware was crude and its processing speed pitifully slow, it was sufficient for analyzing such a simple energy system.
Before dawn, he reached a preliminary conclusion:
There were five problems. The solar panels were aging and inefficient. The controller was too basic, lacking MPPT functionality. The battery pack's series connection was poorly designed, leading to imbalance. There was leakage in the wiring. At least half of the storage batteries needed replacement.
There were also five solutions. Adjust the orientation and tilt angle of the solar panels—though not a fundamental fix, it could improve efficiency somewhat. Redesign the controller, requiring the purchase of some components. Adjust the battery pack's connection method, separating the good batteries from the bad ones. Repair the leaking wiring. Replace the worst-performing batteries.
The last one was the most difficult. New batteries were expensive, and the orphanage couldn't afford them.
But perhaps they didn't need to buy new ones.
He remembered the pile of old batteries in Yamada's yard at the scrapyard. Those were salvaged from scrapped equipment, and some might still be usable. If he could find ones with matching models and acceptable conditions...
It was worth a try.
Outside the window, the sky gradually brightened. In the distance, a rooster crowed.
Nangong Wentian closed his eyes and fell into a deep sleep.
Two days later, the electricity still hadn't returned.
The children huddled together under blankets, while the nuns took turns boiling water with firewood to warm their hands. The head of the orphanage stood in the yard, staring at the solar panels with a furrowed brow.
An electrician had come, taken one look, and shaken his head. He said the controller was broken and needed replacing, which would cost over ten thousand yuan. The orphanage couldn't afford it.
Nangong Wentian stood at the back kitchen door, watching all of this, silently calculating in his mind.
He had already simulated the optimal solution using the "Star Core." If he could get a few second-hand batteries of the same model and adjust the connection method, he could at least restore the basic functionality of the power supply system.
The problem was, how could he get them?
He patted his pocket. Inside were a dozen or so yuan—his saved-up pocket money. It wasn't enough to buy batteries, not even second-hand ones.
"Wentian." Xiao Guang's voice came from behind.
Nangong Wentian turned around and saw Xiao Guang clutching a worn-out wallet.
"This is my New Year's money," Xiao Guang stuffed the wallet into his hand, "saved up over several years. Take it and use it."
Nangong Wentian froze. He opened the wallet to find a stack of crumpled small bills, the largest denomination being just ten yuan. Altogether, it probably amounted to two or three hundred yuan.
"You..."
"I know you want to buy batteries," Xiao Guang lowered his head, his voice muffled, "I can't help with anything else, just this."
Nangong Wentian looked at the worn-out wallet and the scattered money inside, a complex emotion welling up in his heart.
In this world, someone was willing to give him their New Year's money saved over several years, just because he wanted to "give it a try."
"Xiao Guang," he said softly, "thank you."
Xiao Guang looked up and grinned, "What's there to thank? We're brothers."
Brothers.
Nangong Wentian tightened his grip on the wallet and nodded, "Right, brothers."
That afternoon, the two slipped out of the orphanage and went to the scrap yard.
Yamada saw them and greeted, "Here again? What are you looking for today?"
Nangong Wentian pulled out the piece of paper with the battery model written on it, "Grandpa Yamada, do you have any old batteries of this model here? 12V, around 7Ah capacity."
Yamada took it, looked it over, and thought for a moment, "Yes, I just received a batch the other day, retired from a communication base station. Follow me."
He led the two to the depths of the yard and pointed at a pile of old equipment, "Right there, pick them out yourselves."
Nangong Wentian's eyes lit up as he hurried over.
There were over a dozen batteries in the pile, of various models, but most were the type he needed. He inspected them one by one, checking their appearance, measuring their voltage, and recording the data.
In the end, he picked four in the best condition—two GS-YUASA and two PANASONIC, all with voltages above 11V, intact appearance, and no leakage.
"How much for these?" he asked.
Yamada glanced at them and waved his hand, "Just junk retired from base stations, not worth anything. Take them, no charge."
Nangong Wentian froze, "No charge?"
"None." Yamada smiled, "Didn't I say last time? I'm accumulating some virtue for promising youngsters."
Nangong Wentian looked at him, then suddenly bowed deeply, "Thank you, Grandpa Yamada."
Yamada was taken aback for a moment, then burst into laughter, "Alright, alright, hurry back now. It's getting dark."
The two carried the four batteries and hurried back excitedly.
By the time they returned to the orphanage, it was already pitch dark. They quietly hid the batteries in a wooden box in the back kitchen, covering them with a tattered cloth.
"Tomorrow," Nangong Wentian said to Xiao Guang, "tomorrow I'll replace the batteries."
Xiao Guang nodded vigorously, "I'll keep watch for you!"
The next night, Nangong Wentian sneaked to the battery box in the dark and got to work.
Replacing the batteries wasn't difficult—disconnecting the wires, swapping their positions, and reconnecting them. But doing it without being discovered required extreme caution.
Xiao Guang crouched in the corner, nervously watching his surroundings, ready to cough at the slightest sign of movement.
Nangong Wentian turned on a flashlight and, under its faint glow, removed the old batteries one by one, replacing them with the newly scavenged ones. Then he adjusted the connections—grouping the four best batteries in parallel to power the most critical loads, while the remaining old batteries were connected in series to supply the secondary loads.
After nearly two hours of work, he finally finished.
He closed the cabinet door and let out a long sigh.
Whether it would work or not would depend on tomorrow.
The next morning, the headmistress went to check the electrical box as usual. She froze.
The power was back.
Not everywhere, but at least the dormitory and kitchen had electricity.
An electrician was called in to inspect it. After examining it for a while, he scratched his head and said, "Strange, did someone fix it? The battery connections have been changed—much more reasonable than before. Who did it?"
The headmistress fell silent for a moment, her gaze drifting toward the direction of the kitchen.
That child.
It was that child again.
She said nothing, only letting out a soft sigh.
In the kitchen, Nangong Wentian and Xiao Guang sat facing each other, drinking porridge. Xiao Guang looked excited, wanting to say something but not daring to speak. Nangong Wentian kept his head down, silently drinking his porridge.
He knew the headmistress must have guessed.
But she wouldn't ask.
She had always been protecting him with her silence.
That was enough.
Outside the window, sunlight streamed into the kitchen, warm and gentle.