diff --git a/src/env.ts b/src/env.ts
index ee87105..ab7a276 100644
--- a/src/env.ts
+++ b/src/env.ts
@@ -3,7 +3,7 @@ import { z } from 'zod'
 
 export const env = createEnv({
   server: {
-    DATABASE_URL: z.url({ protocol: /^postgres(ql)?$/ }),
+    DATABASE_URL: z.url({ protocol: /^mysql$/ }),
     LOG_DB: z.stringbool().default(false),
     LOG_FORMAT: z.enum(['pretty', 'json']).optional(),
     LOG_LEVEL: z.enum(['trace', 'debug', 'info', 'warning', 'error', 'fatal']).default('info'),
diff --git a/src/server/battery/mysql.ts b/src/server/battery/mysql.ts
new file mode 100644
index 0000000..c33a2e4
--- /dev/null
+++ b/src/server/battery/mysql.ts
@@ -0,0 +1,75 @@
+import mysql, { type Pool, type RowDataPacket } from 'mysql2/promise'
+
+import { type BatteryInfo, type BatteryInfoSourceRow, toBatteryInfo } from '@/domain/battery'
+import { env } from '@/env'
+
+const historyLimit = 500
+
+type BatteryInfoMysqlRow = RowDataPacket & BatteryInfoSourceRow
+
+let pool: Pool | undefined
+
+function getBatteryPool() {
+  pool ??= mysql.createPool({
+    uri: env.DATABASE_URL,
+    waitForConnections: true,
+    connectionLimit: 5,
+    namedPlaceholders: true,
+  })
+
+  return pool
+}
+
+export async function closeBatteryPool() {
+  if (!pool) return
+
+  await pool.end()
+  pool = undefined
+}
+
+const sourceColumns = `
+  id,
+  user_id AS userId,
+  mac,
+  dev_model AS devModel,
+  dev_name AS devName,
+  is_low_power AS isLowPower,
+  power_status AS powerStatus,
+  power,
+  create_time AS createTime,
+  remark
+`
+
+export async function getBatteryHistory(mac: string): Promise<BatteryInfo[]> {
+  const [rows] = await getBatteryPool().query<BatteryInfoMysqlRow[]>(
+    `
+      SELECT ${sourceColumns}
+      FROM ls_battery_info
+      WHERE mac = :mac
+      ORDER BY create_time DESC, id DESC
+      LIMIT :limit
+    `,
+    { mac, limit: historyLimit },
+  )
+
+  return rows.map(toBatteryInfo)
+}
+
+export async function getLatestBatteryPerDevice(): Promise<BatteryInfo[]> {
+  const [rows] = await getBatteryPool().query<BatteryInfoMysqlRow[]>(`
+    SELECT ${sourceColumns}
+    FROM ls_battery_info AS current_record
+    WHERE NOT EXISTS (
+      SELECT 1
+      FROM ls_battery_info AS newer_record
+      WHERE newer_record.mac = current_record.mac
+        AND (
+          newer_record.create_time > current_record.create_time
+          OR (newer_record.create_time = current_record.create_time AND newer_record.id > current_record.id)
+        )
+    )
+    ORDER BY current_record.create_time DESC, current_record.id DESC
+  `)
+
+  return rows.map(toBatteryInfo)
+}
diff --git a/src/server/plugins/shutdown.ts b/src/server/plugins/shutdown.ts
index 8742f75..c78c48e 100644
--- a/src/server/plugins/shutdown.ts
+++ b/src/server/plugins/shutdown.ts
@@ -1,4 +1,4 @@
-import { db } from '@/server/db'
+import { closeBatteryPool } from '@/server/battery/mysql'
 import { getLogger } from '@/server/logger'
 
 export default () => {
@@ -17,8 +17,8 @@ export default () => {
 
     await Bun.sleep(500)
     try {
-      await db.$client.end()
-      logger.info('DB pool closed, exiting')
+      await closeBatteryPool()
+      logger.info('Battery MySQL pool closed, exiting')
     } catch (error) {
       logger.error('DB pool close failed during shutdown', { error })
     }