diff --git a/misc/dump_memory_map.py b/misc/dump_memory_map.py
index c69ef64..f9cbc2a 100644
--- a/misc/dump_memory_map.py
+++ b/misc/dump_memory_map.py
@@ -8,49 +8,12 @@ sys.path.insert(1, os.path.dirname(os.path.dirname(sys.argv[0])))
 from draw_memory_map import memory_table  # noqa: E402
 
 from srnemqtt.config import get_config, get_interface  # noqa: E402
-from srnemqtt.interfaces import BaseInterface  # noqa: E402
 from srnemqtt.protocol import readMemory  # noqa: E402
 
-
-def get_device_name(iface: BaseInterface) -> str | None:
-    data = readMemory(iface, 0x0C, 8)
-    if data is None:
-        return None
-
-    return data.decode("utf-8").strip()
-
-
-def get_device_version(iface: BaseInterface) -> str | None:
-    data = readMemory(iface, 0x14, 4)
-    if data is None:
-        return None
-
-    major = (data[0] << 8) + data[1]
-    minor = data[2]
-    patch = data[3]
-
-    return f"{major}.{minor}.{patch}"
-
-
-def get_device_serial(iface: BaseInterface) -> str | None:
-    data = readMemory(iface, 0x18, 3)
-    if data is None:
-        return None
-
-    p1 = data[0]
-    p2 = data[1]
-    p3 = (data[2] << 8) + data[3]
-    return f"{p1}-{p2}-{p3}"
-
-
 if __name__ == "__main__":
     conf = get_config()
     iface = get_interface(conf)
 
-    print(get_device_name(iface))
-    print(get_device_version(iface))
-    print(get_device_serial(iface))
-
     data: List[int] = []
     for i in range(0, 0xFFFF, 16):
         newdata = readMemory(iface, i, 16)
diff --git a/misc/test_bleuart.py b/misc/test_bleuart.py
index 0d074d6..7e79f1f 100644
--- a/misc/test_bleuart.py
+++ b/misc/test_bleuart.py
@@ -1,12 +1,12 @@
 # -*- coding: utf-8 -*-
 from srnemqtt.constants import MAC
 from srnemqtt.lib.feasycom_ble import BTLEUart
-from srnemqtt.protocol import construct_request, write
+from srnemqtt.protocol import construct_read_request, write
 
 with BTLEUart(MAC, timeout=1) as x:
     print(x)
 
-    write(x, construct_request(0x0E, words=3))
+    write(x, construct_read_request(0x0E, words=3))
     x.read(3, timeout=1)
     print(x.read(6, timeout=0.01))
     x.read(2, timeout=0.01)
diff --git a/misc/test_load_switch.py b/misc/test_load_switch.py
new file mode 100644
index 0000000..c5d7234
--- /dev/null
+++ b/misc/test_load_switch.py
@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+import os
+import sys
+from time import sleep
+
+sys.path.insert(1, os.path.dirname(os.path.dirname(sys.argv[0])))
+
+from srnemqtt.config import get_config, get_interface  # noqa: E402
+from srnemqtt.protocol import ChargeController  # noqa: E402
+
+if __name__ == "__main__":
+    conf = get_config()
+    iface = get_interface(conf)
+    cc = ChargeController(iface)
+
+    print(f"Serial: {cc.serial}")
+    print(f"Load enabled: {cc.load_enabled}")
+    cc.load_enabled = True
+    print(f"Load enabled: {cc.load_enabled}")
+    sleep(5)
+    cc.load_enabled = False
+    print(f"Load enabled: {cc.load_enabled}")
diff --git a/misc/test_serial.py b/misc/test_serial.py
index c55be89..dacf5b8 100644
--- a/misc/test_serial.py
+++ b/misc/test_serial.py
@@ -9,7 +9,7 @@ print(sys.path)
 sys.path.insert(1, os.path.dirname(os.path.dirname(sys.argv[0])))
 # from srnemqtt.constants import MAC
 # from srnemqtt.lib.feasycom_ble import BTLEUart
-from srnemqtt.protocol import construct_request, write  # noqa: E402
+from srnemqtt.protocol import construct_read_request, write  # noqa: E402
 
 # for rate in [1200, 2400, 4800, 9600, 115200]:
 for rate in [9600]:
@@ -19,7 +19,7 @@ for rate in [9600]:
 
         print(x)
 
-        write(x, construct_request(0x0E, words=3))
+        write(x, construct_read_request(0x0E, words=3))
         print(x.read(3))
         print(x.read(6))
         print(x.read(2))
diff --git a/srnemqtt/protocol.py b/srnemqtt/protocol.py
index f371db3..be711ef 100644
--- a/srnemqtt/protocol.py
+++ b/srnemqtt/protocol.py
@@ -6,9 +6,9 @@ from typing import Callable, Collection, Optional
 
 from libscrc import modbus  # type: ignore
 
-from .constants import ACTION_READ, POSSIBLE_MARKER
+from .constants import ACTION_READ, ACTION_WRITE, POSSIBLE_MARKER
 from .interfaces import BaseInterface
-from .solar_types import DATA_BATTERY_STATE, HISTORICAL_DATA, DataItem
+from .solar_types import DATA_BATTERY_STATE, HISTORICAL_DATA, ChargerState, DataItem
 from .util import log
 
 
@@ -19,9 +19,14 @@ def write(fh, data):
     fh.write(data + bcrc)
 
 
-def construct_request(address, words=1, action=ACTION_READ, marker=0xFF):
+def construct_read_request(address, words=1, marker=0xFF):
     assert marker in POSSIBLE_MARKER, f"marker should be one of {POSSIBLE_MARKER}"
-    return struct.pack("!BBHH", marker, action, address, words)
+    return struct.pack("!BBHH", marker, ACTION_READ, address, words)
+
+
+def construct_write_request(address, marker=0xFF):
+    assert marker in POSSIBLE_MARKER, f"marker should be one of {POSSIBLE_MARKER}"
+    return struct.pack("!BBH", marker, ACTION_WRITE, address)
 
 
 def parse(data: bytes, items: Collection[DataItem], offset: int = 0) -> dict:
@@ -87,7 +92,6 @@ def discardUntil(fh: BaseInterface, byte: int, timeout=10) -> Optional[int]:
             if not discarded:
                 log("Discarding", end="")
             discarded += 1
-            print(read_byte)
             print(f" {read_byte:02X}", end="")
             sys.stdout.flush()
 
@@ -106,7 +110,7 @@ def discardUntil(fh: BaseInterface, byte: int, timeout=10) -> Optional[int]:
 
 def readMemory(fh: BaseInterface, address: int, words: int = 1) -> Optional[bytes]:
     # log(f"Reading {words} words from 0x{address:04X}")
-    request = construct_request(address, words=words)
+    request = construct_read_request(address, words=words)
     # log("Request:", request)
     write(fh, request)
 
@@ -134,6 +138,44 @@ def readMemory(fh: BaseInterface, address: int, words: int = 1) -> Optional[byte
     return None
 
 
+# set(255, 266, 1 or 0)
+# ff 06 01 0a 00 01
+# CMD_ENABLE_LOAD = b"\xff\x06\x01\x0a\x00\x01"
+# CMD_DISABLE_LOAD = b"\xff\x06\x01\x0a\x00\x00"
+# REG_LOAD_ENABLE = 0x010A
+
+
+def writeMemory(fh: BaseInterface, address: int, data: bytes):
+    if len(data) % 2:
+        raise ValueError(f"Data must consist of two-byte words, got {len(data)} bytes")
+
+    header = construct_write_request(address)
+    write(fh, header + data)
+
+    tag = discardUntil(fh, 0xFF)
+    if tag is None:
+        return None
+
+    header = fh.read(3)
+    if header and len(header) == 3:
+        operation, size, address = header
+        rdata = fh.read(size * 2)
+        _crc = fh.read(2)
+        if rdata and _crc:
+            try:
+                crc = struct.unpack_from("<H", _crc)[0]
+            except struct.error:
+                log(f"writeMemory: CRC error; read {len(_crc)} bytes (2 expected)")
+                return None
+            calculated_crc = modbus(bytes([tag, operation, size, address, *rdata]))
+            if crc == calculated_crc:
+                return rdata
+            else:
+                log(f"writeMemory: CRC error; {crc:04X} != {calculated_crc:04X}")
+        log("data or crc is falsely", header, rdata, _crc)
+    return None
+
+
 def try_read_parse(
     dev: BaseInterface,
     address: int,
@@ -158,3 +200,82 @@ def try_read_parse(
         else:
             log(f"No data read, expected {words*2} bytes (attempts left: {attempts})")
     return None
+
+
+class ChargeController:
+    device: BaseInterface
+
+    def __init__(self, device: BaseInterface):
+        self.device = device
+
+    @property
+    def serial(self) -> str:
+        data = readMemory(self.device, 0x18, 3)
+        if data is None:
+            raise IOError
+
+        p1 = data[0]
+        p2 = data[1]
+        p3 = (data[2] << 8) + data[3]
+        return f"{p1}-{p2}-{p3}"
+
+    @property
+    def model(self) -> str:
+        data = readMemory(self.device, 0x0C, 8)
+        if data is None:
+            raise IOError
+
+        return data.decode("utf-8").strip()
+
+    @property
+    def version(self) -> str:
+        data = readMemory(self.device, 0x14, 4)
+        if data is None:
+            raise IOError
+
+        major = (data[0] << 8) + data[1]
+        minor = data[2]
+        patch = data[3]
+
+        return f"{major}.{minor}.{patch}"
+
+    @property
+    def load_enabled(self) -> bool:
+        data = readMemory(self.device, 0x010A, 1)
+        if data is None:
+            raise IOError
+
+        return struct.unpack("x?", data)[0]
+
+    @load_enabled.setter
+    def load_enabled(self, value: bool):
+        data = writeMemory(self.device, 0x010A, struct.pack("x?", value))
+        if data is not None:
+            res = struct.unpack("x?", data)[0]
+            if res != value:
+                log(f"setting load_enabled failed; {res!r} != {value!r}")
+        else:
+            log("setting load_enabled failed; communications error")
+
+    @property
+    def state(self) -> ChargerState:
+        raise NotImplementedError
+        """
+        data = try_read_parse(dev, 0x0100, 11, parse_battery_state)
+        if data:
+            data[DataName.CALCULATED_BATTERY_POWER] = float(
+                Decimal(str(data.get(DataName.BATTERY_VOLTAGE, 0)))
+                * Decimal(str(data.get(DataName.BATTERY_CURRENT, 0)))
+            )
+            data[DataName.CALCULATED_PANEL_POWER] = float(
+                Decimal(str(data.get(DataName.PANEL_VOLTAGE, 0)))
+                * Decimal(str(data.get(DataName.PANEL_CURRENT, 0)))
+            )
+            data[DataName.CALCULATED_LOAD_POWER] = float(
+                Decimal(str(data.get(DataName.LOAD_VOLTAGE, 0)))
+                * Decimal(str(data.get(DataName.LOAD_CURRENT, 0)))
+            )
+            log(data)
+            for consumer in consumers:
+                consumer.write(data)
+        """
diff --git a/srnemqtt/solar_types.py b/srnemqtt/solar_types.py
index c79b967..78276ec 100644
--- a/srnemqtt/solar_types.py
+++ b/srnemqtt/solar_types.py
@@ -119,3 +119,8 @@ HISTORICAL_DATA = [
     DataItem(DataName.TOTAL_PRODUCTION_ENERGY, "L", "Wh"),
     DataItem(DataName.TOTAL_CONSUMPTION_ENERGY, "L", "Wh"),
 ]
+
+
+class ChargerState:
+    def __init__(self, data: bytes | bytearray | memoryview) -> None:
+        raise NotImplementedError