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42-1 Calculation of Battery Capacity

Author: Source: Datetime: 2016-12-21 09:59:51
Stable load system

When the load is more balanced, such as the load at a specific time to use the power concentration, the formula (3-12) can be used to calculate

Bkwh    Battery capacity, kW•h

ELBd       Load per day from the battery power supply, kW•h / d

Nd         No sunshine consecutive days, d
RB          Battery design margin;
CBD        Capacity reduction factor (taking CBD = 1 if given a specified discharge time rate);
UB          The battery can use the discharge range;
бBD        The rate of voltage drop during battery discharge.
Here, since the ELBd is defined at the battery output, it is necessary to calculate the power adjustment loop correction factor.

In the formula, EPd is the system power output, kW•h / d.

(2) in accordance with the irradiance control load capacity of the system

Rain or night, the lowest power consumption, often designed to run without power. At this time, the battery capacity is supplied with only the lowest power to the load during the above-mentioned consecutive days without sunshine.

Where ELE is the minimum amount of power required for a load, kW•h;

HAI- The average solar panel surface solar irradiance, kW•h / (m2•d), obtained during consecutive days without sunshine.

The battery capacity, because the discharge time rate varies. In other words, the smaller the discharge time rate, the larger the discharge current, the smaller the capacity of the battery. Therefore, according to the load size and system running time to determine the battery discharge time rate, and then determine the capacity of the battery.

Hybrid system

A hybrid system is a photovoltaic power generation system with an auxiliary generator. According to the requirements of the system can be activated immediately. For hybrid systems with large power diesel generators, equation (3-12) is usually chosen to be Nd = 2 (d). More specifically, it is also necessary to carry out a special study in accordance with a simulation method and the like, because the calculation involved is complicated, and thus omitted here.

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