Technical Service Bulletin
Bulletin No.: TSB-001-22
Date: 8/9/2022
SUBJECT: Short & Long-Term Storage Guidelines
Applicability: All 2021-2022 Xos SV05 Trucks
Service Category: Battery
Section: HV Battery Systems
Market: USA and Canada
Introduction:
Xos’s fully-electric last-mile delivery vehicles are built to withstand daily use by
customers and fleets. Occasionally, these unique vehicles are left idle for extended
periods of time. During these idle periods it is necessary to manage and maintain the
vehicle’s battery-electric systems to ensure they are ready for use when put back into
service. This bulletin provides guidelines for short and long-term storage. Adherence
to these guidelines will prevent unnecessary downtime.
NOTE: Component replacement resulting from a failure to follow these guidelines
will not be covered by Xos’s New Vehicle Limited Warranty.
NOTE: Aftermarket modifications that are NOT electrically connected downstream of
the low voltage master switch will affect battery performance.
Overview:

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Short-term storage when vehicles will be idle for 14 days, or less
Long-term storage when vehicles will be idle for greater than 14 days
Xos’s onboard Battery Management System (BMS) operation will be explained

Short-Term Storage Guideline (14 Days or less)

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High Voltage (HV) battery State Of Charge (SOC) must be 65% or greater prior
to storing the vehicle

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Low Voltage (LV) master switch may be left ON to allow the onboard BMS logic
to monitor and maintain 12V and 24V SOC

Long-Term Storage Guideline (More than 14 Days)

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HV battery SOC must be 30% or greater prior to storing the vehicle

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Low voltage master switch must be OFF to eliminate all battery drain for the
duration of the storage

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30 days maximum storage before routine checks and operation is required

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Check tire pressures
Drive the truck as needed to eliminate tire flat-spotting
Inspect for overall operation, damage, fluid leaks and proper fluid levels

Onboard Battery Management System (BMS) Operation:

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System layout

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Low voltage battery box is under the hood,
passenger side

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Low voltage master switch (Image 1) - Disconnects
all systems from battery power

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Low voltage shutoff solenoids - 12V and 24V
automatic disconnect solenoids (Image 2) to
preserve battery life

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24V shutoff voltage = 23V

Instrument cluster will display
“Low auxiliary battery voltage”
(Image 3) in YELLOW

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12V shutoff voltage = 11V

12V < 12.3V
24V < 24.7V

The RED “STOP” (Image 4) fault
indicator will be illuminated at the
following

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12V < 9V
24V < 18V

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Onboard BMS Logic:

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Every two hours the vehicle performs a self-check of the 12V and 24V battery
State of Charge (SOC)

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If the 12V and 24V batteries are below threshold the vehicle will enable high
voltage systems to allow for DC-DC conversion of power from HV to LV (12V
and 24V) to charge batteries.

NOTE: While the vehicle is performing a self-check of the 12V and 24 V battery State
of Charge, the vehicle may appear as though it is in “Ready ON” status, but it cannot
be driven without the key

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Instrument cluster will display “Low voltage charging. Vehicle can be
keyed-on to drive” (Image 5)

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Headlight switch will be backlit
Radio will be ON, and sound may be heard outside the vehicle

HV battery SOC must be above 6% as indicated on the instrument cluster for
the onboard BMS to operate. Once the HV battery SOC is 6%, or less, all
batteries will begin to drain below operational voltages.

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HV battery SOC will diminish as the vehicle wakes up to provide
charging for the 12V and 24V batteries. It is crucial that Xosphere is
utilized to monitor HV battery SOC

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For authorized customers and fleets, the Xos Customer Experience
Team will send alerts to the designated point of contact regarding
low HV battery SOC

12V and 24V batteries will need to be recharged or replaced when this
occurs

NOTE: Replacement of 12V and 24V batteries resulting from failure to follow these
guidelines is not covered by the Xos New Vehicle Limited Warranty and will not be
reimbursed.

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