Storage: high or low Voltage battery?

An issue that has been discussed among the photovoltaic professionals is that of the battery voltage in the residential storage systems.

Is there a better configuration than others?

Basically there are three type of systems:
» those in low Voltage, about 48V;
» those said in “high Voltage”, 400V approximately;
» high voltage modular systems (from 250 to more than 500V). The latter are realized by composing several battery packs, like in Lego^® bricks, until the wanted capacity is reached.

Power electronics

In addition to assessing the type of battery, we need to consider the complete system, including the electronic power that performs the coupling with the network or with the build system: you can think that the greater economy and efficiency is obtained by connecting the battery to the DC side of a standard photovoltaic inverter and using the DC/DC converter input stage.

With this configuration, the most suitable battery voltage would be starting from 1/3 – 1/4 of the inverter DC bus voltage and the system would see an economy as regards installation costs (cables of reduced sections and switches).

The advantageous battery

The producers of residential storage systems consider advantageous the use of that kind of cells that are spreading also for other use, especially in the car industry, that makes the price competitive in terms of €/kWh.

This leads to the use of cells with a capacity in the range from 40-60Ah and voltages of about 48V.
High voltage systems contain lower voltage batteries (around 100V) and a DC/DC converter that raises the voltage up to the rated voltage.

Compared to this type of configuration, high voltage modular systems do not need an additional converter and potentially have a higher efficiency.

Battery standard configuration and conversion system

It should be pointed out that today the standard configuration battery and conversion system has not yet been consolidated: 48V batteries have economic advantages, those in high voltage have potentially higher return.

The range of storage systems offered by OSM are present in the custom price list that resellers can find in their private area.

OSM Industrial high voltage battery 512v three-phase output

Many countries around the world are facing difficulties in industrial power consumption, especially high-voltage systems. They all need 380V three-phase high-voltage systems in factories, schools, reservoirs, farms, hotels and so on. During the day, they can use solar photovoltaic or power grid to charge the battery system. In case of power failure or instability, they can use the battery system.We can design different schemes according to different power consumption.

If your equipment consumes 5kwh per hour and you plan to provide 8-10 hours of power supply for it, you need a 50kwh lithium-ion battery system. Then through the power of your equipment, we can match you with different three-phase inverters, 10kW, 20kW and 30kW, so that they can work together, The high-voltage system ranges from 200V, 300V, 400V, 500V, 600V and 700V. We can design different schemes according to different power demand.

We have a customer from a farm in Europe . His farm consumes 45kWh of electricity every day. He needs to use three-phase 380V output and the equipment load is 15kw. The scheme we designed for him is a battery system with 512v rated voltage and 20kW three-phase inverter. The system can bear the maximum load power of 20kw. Such a battery system can provide him with a perfect solution.