Quelle est l’efficacité d’un système de stockage d’énergie par batterie de 15,36 kWh ?

The 15.36 kWh battery captures energy from the sun to either provide evening power or provide off-peak power. This battery also has the capability of providing back-up power. Remember that the nominal capacity of the battery is not the total energy that will be supplied to the household appliances. Actual energy delivered is influenced by the battery, inverter, battery management system, temperature, wiring, load profile, and state of charge.

To get a proper sense of how efficient a 15.36kWh Battery is, you need to assess the entire energy flow — from charging to being stored, then from DC discharge to finally supplying AC power.

What Does a Battery Rated 15.36kWh Really Represent?

Given a storage application, this battery can store a maximum of 15.36kWh.

To better elaborate on the above concepts, we take into consideration four different values of 'battery capacity.'

1. Nominal capacity refers to the maximum limit of battery capacity defined theoretically.

2. Usable capacity is the battery capacity available for energy withdrawal according to the limits of the state of charge.

3. Delivered DC Energy is the energy that is left after the losses of the battery, the BMS and the wires.

4. Delivered AC Energy is the energy available to the loads after the losses of the inverter and auxiliaries.

Therefore, we can say that a 15.36kWh Battery rarely supplies the full nominal 15.36kWh of usable AC electricity.

How Is Battery System Efficiency Calculated?

Energy-storage efficiency compares the energy supplied by the system with the energy originally used to charge it.

System efficiency = Delivered energy ÷ Charging energy × 100%

If 15kWh enters the storage system and 14.25kWh is later supplied to the load, the measured efficiency is 95%.

Different efficiency figures may cover different equipment boundaries.

Efficiency Measurement	Included Components	Main Purpose
Cell efficiency	Battery cells only	Evaluates electrochemical performance
Battery DC efficiency	Cells, BMS and internal conductors	Measures DC charging and discharging
Inverter efficiency	Power-conversion equipment	Measures DC-to-AC conversion
Efficacité aller-retour	Charging and discharging process	Evaluates complete energy recovery
Overall system efficiency	Battery, inverter and auxiliary devices	Estimates practical site performance

Le SANDISOLAR SD High-voltage ESS specifies system efficiency of at least 97% under defined operating conditions. Actual site efficiency may vary with inverter configuration, load demand, temperature, wiring, and measurement boundaries.

Where Does Energy Loss Occur?

Several causes of energy loss exist in a 15.36 kWh battery system.

•The internal resistance of a cell results in heat generation because energy is dissipated each time the cell is charged or discharged.

•Battery Management System (BMS): The BMS consumes energy for monitoring and managing each battery cell's status including cell balancing and protection in respect to cell voltage and current and temperature.

•Inverter Loss: Each time energy within the battery is converted from DC to AC, energy is lost.

•Cable loss: Terminals of long cables can cause energy losses in the form of heat.

•Standby loss: The inverter, display and other communication and monitoring devices in a standby operating condition consume some energy.

•Thermal management: If extreme operating conditions exist, the optional use of additional heating and/or cooling equipment may further decrease the net usable energy.

•Cell balancing: The balancing process may waste small amounts of energy in the correction of voltage differences across the modules.

Why High-Voltage Architecture Matters

The SANDISOLAR SD High-voltage ESS uses a voltage platform ranging from 153.6V to 409.6V. Its modular configurations cover capacities from 15.36kWh to 40.96kWh.

For the same power output, increasing system voltage reduces operating current.

Puissance de sortie	Tension de batterie	Approximate Current
6kW	48V	125A
6kW	153.6V	39A
6kW	307.2V	20A

Because conductor losses are strongly affected by current, a compatible high-voltage 15.36kWh Battery can help limit heat and cable-related losses in medium- and high-power applications.

The energy delivery capability of a 15.36kWh battery system can be influenced by several characteristics which include:

•Decreased current: Delivering energy at a lower current can help minimize losses due to resistance.

•Managed thermal effects: Lower temperature of cables and connectors can allow the system to operate more stably.

•Scalability: Stackable modules help in designing solutions with varying voltage and capacity based on the project's requirements.

•Inverter compatibility: High-voltage inverters can help control the battery charging and discharging within the allowed operating range of the battery.

For high-voltage systems, suitable insulating and protection devices, and grounding, as well as commissioning and installation, are needed, and must be done by qualified personnel.

What is the Energy Delivery Capability of a 15.36kWh Battery?

The following table shows simplified output estimates at different efficiency levels.

Assumed Efficiency	Estimated Energy Delivered
90%	13.82kWh
92%	14.13kWh
95%	14.59kWh
97%	14.90kWh

The stated calculations do not include a protected state-of-charge reserve. Assuming a system operation of 90% of nominal capacity and a total system efficiency of 95%, we have:

15.36 kWh x 90% x 95% = 13.13 kWh (approx.)

This approximation helps in the estimation of the operational time of an appliance and/or the time of backup.

Real-World Efficiency Factors

Load Profile

•Moderate Continuous Loads: Stable continuous loads help the battery and inverter to operate in the more efficient range.

•Very Light Loads: Fixed standby consumption could be a larger portion of the total energy consumption.

•High Starting Loads: Pumps, compressors, and air conditioning units are examples of equipment that draw a significantly higher starting current than running current. The effect is increased losses in the system.

Température de fonctionnement

The SD High-Voltage ESS is designed to operate in the range of -20°C to +55°C according to the system settings and limits.

•Low Temperatures: To avoid damaging battery cells, the charging current is limited.

•Auxiliary Heating: This optional feature helps to operate in the geared range but adds to energy consumption.

•High Temperatures: Increased resistance and the thermal stress may cause diminished efficiency and increased aging of the battery.

State of Charge (SOC)

•Protected Operating Range: This is the optimal SOC to avoid overcharge and over-discharge.

•Deep Discharge: This can add to energy availability for a longer backup duration, but can affect battery performance for a longer cycle.

•Long-Term High SOC: This can add to the permanent loss of battery performance.

Communication and Energy Management

The SANDISOLAR 15.36 kWh Battery is designed to operate using CAN, RS485 communication protocols with the option for WiFi.

•CAN Communication: This enables the sharing of information on SOC, voltage, current limits, temperature, and fault status to a compatible inverter.

•RS485 Communication: This supports the integration of other equipment, data collection, and control of the system.

•WiFi Monitoring: Features available to operators are the flow of energy, battery status, alarms, and operation history.

Integrations exist for some inverter platforms such as Growatt, Solis, and DEYE. Confirmation of exact inverter model, firmware, voltage range, and communication protocol is required prior to the installation.

Efficiency Over the Battery Lifecycle

SANDISOLAR specifies up to 6,000 cycles and a designed lifespan of at least 10 years for the SD High-voltage ESS under defined operating conditions.

Capacity and efficiency should be evaluated separately. A battery may continue converting energy efficiently while its total available capacity gradually decreases with age.

Factors for Optimal Long-Term Battery Longevity

•Depth of Discharge: Frequent cycling to moderate depths of discharge may cause less damage than frequent cycling to maximum and minimum levels of charge.

•Temperature: Effects of aging on the cell may be more uniform and controllable with the prevention of extreme operating temperatures.

•Charge and Discharge Rate: Controlled current helps to generate heat.

•Cell Consistency: Matching of modules and the active BMS can assist in overcoming any imbalances in the stack.

•Preventive Inspection: Check cables, connectors, records of communication and ventilation to identify losses that can be avoided.

Ways to Improve Efficiency of a 15.36 kWh Battery

•Choose a Matching Inverter: The inverter must have a matching voltage range, charging current, and be in agreement with the battery regarding firmware and communication protocols.

•Choose Correct Cable Size: The correct size of conductor helps in reducing resistance and securing connections aids in reducing voltage drops.

•Avoid Unnecessary Conversions: To avoid the cycling of the battery, solar power may be used directly during the day.

•Control Standby Loads: Unnecessary displays (LED or LCD) and communications, as well as auxiliary devices, must be considered.

•Control Operating Temperature: The installation area must be stable (dry) and be ventilated.

•Analyze Operating Data: Frequent logging of the state of charge, current, temperature, alarms, and the energy processed on a daily basis may help to identify problems.

Derniers mots

A properly coordinated system may help in achieving a high level of usable storage of energy with a 15.36 kWh Battery. The ≥ 97% efficiency of the SANDISOLAR SD High-Voltage ESS may be achieved with proper setup. Actual AC output may vary with configuration of the complete system.

For the user, understanding usable storage, efficiency, backup, and operating conditions may add value. A correctly configured 15.36kWh Battery can support solar self-consumption, load shifting, and backup power while remaining expandable through SANDISOLAR's stackable high-voltage architecture.

FAQ

Q1: Why is a high-voltage battery more efficient?

Batteries operate more efficiently at a higher voltage since it reduces the size and weight of the wiring as well as the resistive power losses.

Q2: How much usable energy does a 15.36kWh battery provide?

The usable battery energy is influenced by the discharge limit, temperature, settings, and inverter efficiency.

Q3: What does 97% battery efficiency mean?

It means that under certain test conditions, up to 97% of the measured input energy is possibly stored or delivered.

Q4: Can a 15.36kWh battery power an entire home?

Potentially yes, but it can only power a home as long as total energy consumption and inverter power do not exceed the limits.

Q5: How long can a 15.36kWh battery provide backup power?

The answer to this question depends on the load connected to the battery. Backup time is determined by the energy consumption of the load.