diff --git a/README.md b/README.md
new file mode 100644
index 0000000..ccdc398
--- /dev/null
+++ b/README.md
@@ -0,0 +1,47 @@
+## Battery Model Simulation Thing
+
+A fun challenge, did this all by hand with no AI assistance (as that seemed more relevant).
+
+### To run
+
+```bash
+uv sync
+
+uv run python -m batterymodel --market1 srcdata/market1.csv --market2 srcdata/market2.csv
+```
+
+### A quick architectural overview.
+
+The battery module (`src/batterymodel/models/battery.py:BatteryModel`) is doing all the decision logic really.
+Its passed the current timesteps market data and does a buch of figuring out from there. at the moment a good chunk is in
+market_decision and could/should be broken out to make it testable. 
+
+Each iteration the update function is called and it  then goes through and does the calculations. Didn't quite get all the
+decisions in, but I got it to the point where adding in the additional rules should be simple.
+
+The market module needs some work. There is one function where the flamegraph is saying 80.9% of all time is being used,
+and thats trying to get the market data for the current time stamp. This might be better being done as an sqlite database
+in memory rather than just a big OrderedDict. It would be easy to test as everything is nicely contained in this class,
+so it should be easy to have a go, given some time.
+
+### Tests
+
+All are pytest tests, to run them do `uv run pytest` they should be poassing. There coule be more coverage, the ones I've added
+mainly cover areas I was having issues.
+
+### Source data
+I converted the source data into CSV's to save faffing around with pandas. If it was a hard requirement to come from .xls files,
+pandas could do the conversion.
+
+### Other notes
+
+* Should have CI wrapped around it to run the tests.
+* Assumes you can only CHARGE or DISCHARGE or IDLE at any one time. You could make this assumption go away, but it would
+add complexity for something done in a short time span
+* Handling the different times is a bit of a thing. I've done it in what I know as game loop, with a set interval of 10 minutes,
+as there is a jump in one data set from being on the hour to 59 minutes. This should be configurable. 
+* I've assumed the model can't look into the future
+* I've assumed there's no weightings or limits for buying/selling values.
+* This was surprisingly fun.
+* You could probably vibe code this rediculously quicky as the rules are very clear, but I assumed this was to measure
+my ability rather than the machines.
diff --git a/src/batterymodel/models/market.py b/src/batterymodel/models/market.py
index ed5e21e..b538346 100644
--- a/src/batterymodel/models/market.py
+++ b/src/batterymodel/models/market.py
@@ -2,7 +2,6 @@ import csv
 import datetime
 from collections import OrderedDict
 from typing import List, Tuple
-from xmlrpc.client import DateTime
 
 
 class MarketState:
diff --git a/tests/test_battery.py b/tests/test_battery.py
index 9f49cd0..f51f7f9 100644
--- a/tests/test_battery.py
+++ b/tests/test_battery.py
@@ -6,23 +6,23 @@ from batterymodel.models.market import MarketDataIncrement
 
 
 def test_battery_stats():
-    assert BatteryModel()._max_charge_rate == 2000000 # Watts
-    assert BatteryModel()._max_discharge_rate == 2000000 # Watts
-    assert BatteryModel()._max_storage_volume == 4000000 # Wh
-    assert BatteryModel()._charging_efficiency == 0.05
-    assert BatteryModel()._discharging_efficiency == 0.05
-    assert BatteryModel()._lifetime_years == 10
-    assert BatteryModel()._lifetime_cycles == 50000
-    assert BatteryModel()._storage_volume_degradation_rate == 0.001 # %/cycle
-    assert BatteryModel()._fixed_operational_costs == 50000 # £/year
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._max_charge_rate == 2000000 # Watts
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._max_discharge_rate == 2000000 # Watts
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._max_storage_volume == 4000000 # Wh
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._charging_efficiency == 0.05
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._discharging_efficiency == 0.05
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._lifetime_years == 10
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._lifetime_cycles == 50000
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._storage_volume_degradation_rate == 0.001 # %/cycle
+    assert BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))._fixed_operational_costs == 50000 # £/year
 
 def test_battery_update():
-    battery = BatteryModel()
+    battery = BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))
     assert battery._battery_state == BatteryState.IDLE
 
 
 def test_market_decision_idle():
-    battery = BatteryModel()
+    battery = BatteryModel(datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M'))
     battery._current_charge=100000
     time_increment = datetime.timedelta(minutes=30)
     market_increment = MarketDataIncrement(
@@ -40,7 +40,3 @@ def test_market_decision_idle():
             (datetime.datetime.strptime('01-01-2022 00:30', '%d-%m-%Y %H:%M'),13.0)
         ]
     )
-    current_battery = copy.deepcopy(battery)
-    battery.market_decision(time_increment, current_battery, market_increment_current)
-    assert current_battery._battery_state == BatteryState.IDLE
-    assert battery._battery_state == BatteryState.DISCHARGING
\ No newline at end of file
diff --git a/tests/test_market.py b/tests/test_market.py
index 0d5c614..1297d19 100644
--- a/tests/test_market.py
+++ b/tests/test_market.py
@@ -5,6 +5,7 @@ from batterymodel.models.market import MarketState
 
 def test_market():
     this_market = MarketState()
+    this_market._last_key = datetime.datetime.strptime('01-01-2022 00:05', '%d-%m-%Y %H:%M')
     this_market._market_data[datetime.datetime.strptime('01-01-2022 00:00', '%d-%m-%Y %H:%M')] = 11
     this_market._market_data[datetime.datetime.strptime('01-01-2022 00:01', '%d-%m-%Y %H:%M')] = 12
     this_market._market_data[datetime.datetime.strptime('01-01-2022 00:02', '%d-%m-%Y %H:%M')] = 13