Besst Technologies OÜ Limited Warranty
Applies to: Besst All-in-One (AiO) Battery Energy Storage Systems (BESS)
Effective Date: 29 August 2025

At Besst Technologies OÜ (Besst), we aim to provide the highest customer satisfaction
levels. This includes a comprehensive warranty coverage for Besst-branded devices, that
ensures peace of mind for our customers.

Coverage
Battery modules
Besst warrants that the battery modules contained in the AiO device shall be free from
defects in materials and workmanship under normal use for a period of ten (10) years from
the date of installation (Warranty Period).
Hybrid inverter
Besst warrants that the hybrid inverter contained in the AiO device shall be free from
defects in materials and workmanship under normal use for a period of five (5) years from
the date of installation.
Other components
All other components of the AiO device (including EMS software, sensors, cooling systems,
casing, and communication units) are warranted for a period of five (5) years from the date
of installation.

Performance Guarantee
Besst guarantees that the battery will retain at least 80% of its usable energy capacity at
the end of the ten-year Warranty Period, provided it has been operated in accordance with
the User Manual and within specified operating conditions.

For the purpose of this warranty, “usable energy capacity” shall mean the amount of energy
(in kWh) that can be discharged from the battery under the following test conditions:

• Ambient temperature of 25°C ± 3°C,
• Charge/discharge rate of 0.5C,
• State of charge range 0–100%,
• Measured after the battery has been fully cycled three (3) times to stabilize
performance.

The initial usable capacity shall be measured and recorded at the time of commissioning.

Remedies
During the Warranty Period, Besst will, at its sole discretion:
(a) repair the defective component;
(b) replace the defective component with a new or refurbished component of equivalent
or better performance; or
(c) provide a pro-rated refund based on the remaining Warranty Period.
Replacement parts may be new, refurbished, or functionally equivalent, and the Warranty
Period for repaired or replaced parts shall not exceed the original warranty.

Exclusions
This warranty does not cover defects, malfunctions, or failures resulting from:

• Improper installation, commissioning, operation, or maintenance not performed
by Besst or its authorized partners.
• Unauthorized modifications, repairs, or alterations.
• Use outside of specified environmental or electrical conditions (including overvoltage,
over-temperature, flooding, fire, or other external damage).
• Excessive cycling beyond the limits stated in the User Manual.
• Lack of proper maintenance, including failure to install updates provided by Besst.
• Force majeure events, including lightning, earthquakes, floods, fires, or other
natural disasters.
• Cosmetic defects or damage that does not affect performance.
• Normal wear and tear, including gradual capacity reduction within the guaranteed
level.

Claim Procedure
To make a warranty claim, the customer must:

• Notify Besst in writing within 30 days of discovering the defect.
• Provide proof of purchase, installation date, and installation details.
• Allow Besst or its authorized service partner reasonable access to inspect the
device.

No warranty claim shall be valid unless the above conditions are met.
If a customer believes the battery has failed to meet the guaranteed 80% usable capacity,
Besst or its authorized service partner shall perform a diagnostic test. If the customer
disputes the result, capacity testing may be carried out by an independent certified
laboratory agreed upon by both parties, with costs shared equally unless the test confirms
warranty failure, in which case Besst shall bear the full cost.

Limitation of Liability
Besst’s total liability under this warranty is limited to the original purchase price of the AiO
device.
To the maximum extent permitted by law, Besst shall not be liable for any:

• indirect, incidental, special, exemplary, or consequential damages,
• loss of use of the AiO device,
• loss of profits, revenues, contracts, or opportunities,
• increased electricity costs, business interruption, or loss of data,
• costs of substitute equipment, facilities, or services,
arising out of or in connection with the AiO device, its installation, use, performance, or this
warranty.

These limitations apply regardless of the legal theory of liability (whether in contract, tort,
negligence, strict liability, or otherwise), even if Besst has been advised of the possibility of
such damages.
This warranty is the sole and exclusive remedy available to the customer and replaces any
other warranties, express or implied, including warranties of merchantability and fitness for
a particular purpose.

Transferability
This warranty is transferable once to a subsequent owner of the property on which the
AiO device is installed, provided written notice is given to Besst within 60 days of the
transfer.
Governing Law
This policy shall be governed by and interpreted in accordance with the laws of the
Republic of Estonia. Any disputes arising from participation shall be resolved by the
competent courts of Tallinn, Estonia.