Micro Energy Storage Setup

NOTE: this is a grid-tied system setup with a energy backup to the batteries. This system is grid-tied only. The micro-inverter works only when the grid is present. If the grid is down, the system does not work. It is NOT an off-grid system.

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A practical realization of a small size energy storage solution with 3.2 kWh of energy capacity with 230V/230W AC grid-tied power output. The basic concept of the energy storage with easy expansion.

Components description of the complete setup

* Lithium Battery Pack 36V
Battery pack 36V 90Ah made of 3 finely balanced 12V/90AH LP batteries. The nominal capacity is 3.2 KWh of energy.  There can be more batteries easily added to increase the capacity of the storage.
http://www.ev-power.eu/_d1873.html  (USD430 per unit, total USD 1290 for 3 pcs)

* Solar charge regulator
The solar charge regulator protects the batteries against deep discharge and against over charge. It allows solar panels to be connected directly to the battery. The setting is set for 43V as max charge voltage and 36V as deep discharge voltage.
http://www.ev-power.eu/_d2600.html (USD105)

* DC contactor relay
The relay is designed to disconnect the invertor from the batteries in case of deep voltage discharge.  The 48V DC contactor works OK with this 36V setup.
http://www.ev-power.eu/_d2650.html  (USD20)

* DC/AC Grid-tied MicroInverter
The MicroInveter generates the energy to feed to the local 230V grid.  The nominal power of the inverter is 230W. For higher power demands it is easy to add more inverters in parallel using the same battery.
http://www.ev-power.eu/_d3247.html (USD150)

In addition to the above key components you need the fuse for the battery protection and the cables to make the installation wiring.  You can get these components locally. (Estimated price USD50)

The total cost of the Micro Energy Storage Setup installation is about USD1615.

The purpose of the installation is to store the energy in the batteries and release the energy slowly when needed.

In this setup the MicroInverter is capable running about 11 to 12 hours discharging the battery with 7A current. The connection of few solar panels directly to the solar charge regulator allows getting energy from the sun-shine during the sunny days. With 3 or more 280Wp panels it is possible to charge the battery during 5 to 6 hours of sunshine. 

In addition to the above components you may wish to get additional components to get a complete solution:

* Solar panels
In order to work efficiently with this 36V installation, the solar panels need to have the MPPT at 34V and more. We recommend using the 280Wp panels (MPPT at 35V). It is possible to have more panels in parallel to increase the speed of charging during the cloudy days.
http://www.ev-power.eu/_d3246.html  (USD215)

* 230VAC charger for 36V DC
You may wish to add a 230VAC charger for 36V to charge the battery pack. The battery pack may be charged from the grid at night (at the low/cheap energy tariff). In such installtion the battery pack is charged at night and the energy is released during the peak time of the day.
http://www.ev-power.eu/_d2362.html  (USD305)

The design of the energy storage is fully modular and allows to increase the size of installation easily by adding more batteries, more solar panels or more inverters.

We wish to show that the DC power components from GWL/Power allow making a simple solution for energy storage.

If you need any additional help, be sure to contact us for questions related to this setup.

All the listed prices are valid at the time of publishing of this article.