diff --git a/health/aidl/default/ChargerUtils.cpp b/health/aidl/default/ChargerUtils.cpp
new file mode 100644
index 0000000..f8e208b
--- /dev/null
+++ b/health/aidl/default/ChargerUtils.cpp
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android-base/logging.h>
+#include <health-impl/ChargerUtils.h>
+
+namespace aidl::android::hardware::health::charger {
+
+std::optional<bool> ChargerCallback::ChargerShouldKeepScreenOn() {
+    return service_->ShouldKeepScreenOn();
+}
+
+bool ChargerCallback::ChargerIsOnline() {
+    auto hal_health_loop_sp = hal_health_loop_.lock();
+    if (hal_health_loop_sp == nullptr) {
+        // Assume no charger
+        return false;
+    }
+    return hal_health_loop_sp->charger_online();
+}
+
+void ChargerCallback::ChargerInitConfig(healthd_config* config) {
+    auto hal_health_loop_sp = hal_health_loop_.lock();
+    if (hal_health_loop_sp == nullptr) {
+        return;
+    }
+    return service_->OnInit(hal_health_loop_sp.get(), config);
+}
+
+int ChargerCallback::ChargerRegisterEvent(int fd, BoundFunction func, EventWakeup wakeup) {
+    auto hal_health_loop_sp = hal_health_loop_.lock();
+    if (hal_health_loop_sp == nullptr) {
+        return -1;
+    }
+    return hal_health_loop_sp->RegisterEvent(fd, func, wakeup);
+}
+
+void ChargerCallback::set_hal_health_loop(const std::weak_ptr<HalHealthLoop>& hal_health_loop) {
+    hal_health_loop_ = std::move(hal_health_loop);
+}
+
+// Implements HalHealthLoopCallback for AIDL charger
+// Adapter of (Charger, Health) ->  HalHealthLoopCallback
+class LoopCallback : public HalHealthLoopCallback {
+  public:
+    LoopCallback(const std::shared_ptr<Health>& service, ChargerCallback* charger_callback)
+        : service_(service), charger_(std::make_unique<::android::Charger>(charger_callback)) {}
+
+    void OnHeartbeat() override {
+        service_->OnHeartbeat();
+        charger_->OnHeartbeat();
+    }
+    // Return the minimum timeout. Negative values are treated as no values.
+    int OnPrepareToWait() override {
+        int timeout1 = service_->OnPrepareToWait();
+        int timeout2 = charger_->OnPrepareToWait();
+
+        if (timeout1 < 0) return timeout2;
+        if (timeout2 < 0) return timeout1;
+        return std::min(timeout1, timeout2);
+    }
+
+    void OnInit(HalHealthLoop*, struct healthd_config* config) override {
+        // Charger::OnInit calls ChargerInitConfig, which calls into the real Health::OnInit.
+        charger_->OnInit(config);
+    }
+
+    void OnHealthInfoChanged(const HealthInfo& health_info) override {
+        charger_->OnHealthInfoChanged(::android::ChargerHealthInfo{
+                .battery_level = health_info.batteryLevel,
+                .battery_status = health_info.batteryStatus,
+        });
+        service_->OnHealthInfoChanged(health_info);
+    }
+
+  private:
+    std::shared_ptr<Health> service_;
+    std::unique_ptr<::android::Charger> charger_;
+};
+
+int ChargerModeMain(const std::shared_ptr<Health>& binder,
+                    const std::shared_ptr<ChargerCallback>& charger_callback) {
+    LOG(INFO) << "Starting charger mode.";
+    //   parent stack ==========================================
+    //   current stack                                         ||
+    //    ||                                                   ||
+    //    V                                                    V
+    // hal_health_loop => loop_callback => charger --(raw)--> charger_callback
+    //    ^----------------(weak)---------------------------------'
+    auto loop_callback = std::make_shared<LoopCallback>(binder, charger_callback.get());
+    auto hal_health_loop = std::make_shared<HalHealthLoop>(binder, std::move(loop_callback));
+    charger_callback->set_hal_health_loop(hal_health_loop);
+    return hal_health_loop->StartLoop();
+}
+
+}  // namespace aidl::android::hardware::health::charger