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This document is uncontrolled when printed. Before use, check the Knowledge Base
within the McLaren Retailer Portal to verify that this is the current version.

Document Information
Location: Powertrain / High Voltage
Topic: McLaren P1 GEN 2 Battery Software and Charging Limitations
Condition: Temporary
Diagnostic Trouble Codes: N/A

Measure
The release of BMS software 12JA369CP.04 will introduce a further enhancement to protect the
GEN 2 battery from entering a state of unrecoverable deep discharge.
There are some limitations involved with the new software for the charging procedure and how
to recover a GEN 2 battery that enters a deep discharge state.
Please carefully read the following points and make sure you fully understand them before
proceeding with the BMS software uplift to 12JA369CP.04.

Charging Limitations
The charging procedure set out on the previous release of this information has not changed
and must be adhered to prevent the P1 GEN 2 battery from entering a state of deep discharge.
Please see charging requirements listed further down this document.
Recovering from deep discharge (< 3 Volts - min. brick voltage) with Outboard Charger (OBC)
• The battery can be charged with the OBC from any ignition status (IS) below IS5 if the
OBC is connected within 60 seconds of waking the vehicle
• The battery cannot be charged with the OBC in IS5

Recovering from deep discharge status with the internal combustion engine (ICE)
• The GEN 2 battery cannot be charged with the ICE under any circumstances to recover
from deep discharge

Care Point: Opening of the contactors in deep discharge to protect the GEN 2 battery.
When the minimum brick voltage goes below 3 volts, the contactors do not open if IS5 is
maintained.
This is to eliminate opening the contactors in a normal driving situation.
After an ignition cycle, the contactors will open after 60 seconds of returning to IS5 if the
minimum brick voltage is still below 3 volts.

Important Vehicle Charging Requirements

Customer Information
Following the installation of any McLaren P1 GEN 2 battery, it is imperative that the following

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requirements are shared with and understood by the customer or person responsible for the
vehicle.
Checking Suitability and Operation
The McLaren P1 battery charger must be correct for the Region and not plugged in using any
extension cable.
Following connection of the battery charger and pressing the start button, green LEDs must be
displayed across all 5 lights on the battery charger display.
Please refer to the below table and information regarding McLaren P1 HV battery charger
operation should the LED operation not be as expected:

Charging Requirements
Please ensure the following instructions are strictly adhered to:
1. Initiate charging and charge the vehicle for a maximum period of 2.5 hours while the vehicle
is not in drive state
2. Check and ensure the battery charger LEDs indicate correct operation during charging
3. After 2.5 hours has elapsed, disconnect the P1 HV battery charger
4. Lock the vehicle with the key then allow for the vehicle to sleep for 10 minutes
5. Switch on the vehicle ignition and ensure the HV battery has reached ≥80% state of charge

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6. The vehicle should be rechecked at regular intervals to ensure the HV battery state of charge
has been maintained and should be recharged as required
Care Point: If the HV battery state of charge is found not to have reached ≥80% following a 2.5
hour charging period the customer must contact their Retailer immediately so a Technical
Request can be submitted for further guidance
Care Point: The McLaren P1 HV battery charger must not be connected to the vehicle for longer
than 2.5 hours at a time
Care Point: The HV battery must be fully recharged at an interval of no more than 60 days
Care Point: If the charger LEDs indicate correct operation, it is still imperative to check battery
state of charge has reached 100% following charging
Care Point: If any further issues are experienced during this process, please raise a Technical
Request for further guidance

The above measures are a temporary solution to ensure all newly installed McLaren P1 GEN 2
HV batteries are not subject to discharge and potential damage. A software solution is being
worked on and further details will be provided as soon as possible.

Parts Information
N/A

Attachments
N/A

This document is uncontrolled when printed. Before use, check the Knowledge Base
within the McLaren Retailer Portal to verify that this is the current version.