diff --git a/health/aidl/default/HalHealthLoop.cpp b/health/aidl/default/HalHealthLoop.cpp
new file mode 100644
index 0000000..c9a081e
--- /dev/null
+++ b/health/aidl/default/HalHealthLoop.cpp
@@ -0,0 +1,67 @@
+/*
+ * 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 <health-impl/HalHealthLoop.h>
+
+#include <android-base/logging.h>
+
+#include <health-impl/Health.h>
+#include "health-convert.h"
+
+namespace aidl::android::hardware::health {
+
+// Unlike the HIDL version android::hardware::health::V2_1::implementation::HalHealthLoop,
+// do not define HalHealthLoop::Init because we no longer have Health::getHealthConfig.
+// Let the Health class handle Init.
+void HalHealthLoop::Init(struct healthd_config* config) {
+    callback_->OnInit(this, config);
+}
+
+void HalHealthLoop::Heartbeat() {
+    callback_->OnHeartbeat();
+}
+
+void HalHealthLoop::ScheduleBatteryUpdate() {
+    // ignore errors. impl may not be able to handle any callbacks, so
+    // update() may return errors.
+    if (auto res = service_->update(); !res.isOk()) {
+        LOG(WARNING) << "update() on the health HAL implementation failed with "
+                     << res.getDescription();
+    }
+
+    HealthInfo health_info;
+    auto res = service_->getHealthInfo(&health_info);
+    CHECK(res.isOk()) << "getHealthInfo() on the health HAL implementation failed with "
+                      << res.getDescription();
+    OnHealthInfoChanged(health_info);
+}
+
+int HalHealthLoop::PrepareToWait() {
+    return callback_->OnPrepareToWait();
+}
+
+void HalHealthLoop::OnHealthInfoChanged(const HealthInfo& health_info) {
+    callback_->OnHealthInfoChanged(health_info);
+    set_charger_online(health_info);
+    AdjustWakealarmPeriods(charger_online());
+}
+
+void HalHealthLoop::set_charger_online(const HealthInfo& health_info) {
+    charger_online_ = health_info.chargerAcOnline || health_info.chargerUsbOnline ||
+                      health_info.chargerWirelessOnline;
+}
+
+}  // namespace aidl::android::hardware::health