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How to choose hybrid energy storage inverter and solar battery?


Project Introduction

 Introduction-(2)

A villa, a family of three lives, the roof installation area is about 80 square meters.

Power consumption analysis

Before installing the photovoltaic energy storage system, it is necessary to list all the loads in the household and the corresponding quantity and power of each load, such as

LOAD

POWER(KW)

QTY

TOTAL

LED LAMP 1

0.06

2

0.12

LED LAMP 2

0.03

2

0.06

Refrigerator

0.15

1

0.15

Air Conditioner

2

1

2

TV

0.08

1

0.08

Washing Machine

0.5

1

0.5

Dishwasher

1.5

1

1.5

Induction Cooker

1.5

1

1.5

Total Power

5.91

Electricity Cost

Different regions have different electricity costs, such as tiered electricity prices, peak-to-valley electricity prices, etc.

 Introduction (1)

PV module selection and design

How to design the Solar panel System capacity:

•The area where solar modules can be installed

•The orientation of the roof

•Matching of solar panel and inverter

Note:Energy storage systems can be over-provisioned more than grid-connected systems.

 Introduction (3)

How to choose a hybrid inverter?

  1. Type

For new system, choose the hybrid inverter. For the retrofit system, choose the AC-coupled inverter.

  1. Grid suitability: Single-phase or Three-phase
  2. Battery Voltage: if being a battery and battery cost etc.
  3. Power: Installations of photovoltaic solar panels and energy used.

Mainstream battery

 

Lithium iron phosphate battery Lead-acid batteries
 Introduction (4)  Introduction (5)
•With BMS•Long cycle life•Long warranty•Accurate monitoring data

•High depth of discharge

•No BMS•Short cycle life•Short warranty•Difficult to define After-sales problems

•Low depth of discharge

Battery capacity configuration

Generally speaking, the battery capacity can be configured according to user needs.

  1. Discharge power limit
  2. Available load time
  3. Costs and benefits

Factors affecting battery capacity

When selecting a battery, the battery capacity marked on the battery parameters is actually the theoretical capacity of the battery. In practical applications, especially when connected to a photovoltaic inverter, a DOD parameter is generally set to ensure the normal operation of the system.

When designing the battery capacity, the result of our calculation should be the effective power of the battery, that is, the amount of power that the battery needs to be able to discharge. After knowing the effective capacity, the DOD of the battery also needs to be considered,

Battery power = battery effective power/DOD%

System efficiency

Photovoltaic solar panel maximum conversion efficiency 98.5%
Battery discharge maximum conversion efficiency 94%
European efficiency 97%
The conversion efficiency of low-voltage batteries is generally lower than that of pv panels, which the design also needs to be considered.

 

Battery capacity margin design

 Introduction (6)

•Instability of photovoltaic power generation

•Unplanned load power consumption

•Loss of power

•Battery capacity loss

Conclusion

Self-use Off-grid backup power usage
PV capacity:the area and the orientation of the roofthe compatibility with the inverter.Inverter: grid type and needed power.

Battery capacity:

household load power and daily electricity consumption

PV capacity:the area and the orientation of the roofthe compatibility with the inverter.Inverter: grid type and needed power.

Battery capacity:Electricity time and power consumption at night, which need more batteries.