Battery Storage

Solar Battery Storage Systems for Homes & Businesses in the North East

Solar panels generate the most energy during the day when the sun is shining and when you and your family tend to use the least energy or have the lowest consumption levels. With ever increasing energy prices and the on-going phased feed-in tariff reductions, you must make the most out of your solar energy. Reduce your dependence on traditional power providers with an intelligent battery storage system.

What is Battery Storage?

An battery storage system makes it possible to utilise solar power time-independently by storing unused capacity. It converts and directs solar power to where it is needed throughout the house.

When the grid is running properly, your home or business will use power generated from your solar panels or pull electricity from the grid. Any excess power generated over and above your needs is exported back into the national grid.

In the event of grid blackouts, these systems will switch to “off-grid mode” drawing power stored in your battery bank to power your home and using your solar panels to recharge your battery bank. Energy storage systems can even be added to solar PV systems that have already been installed.

How does it work?

While your solar panels are generating energy during daylight, the system will firstly power your usage; subsequently the extra generation will charge the battery back-up system. Once fully loaded, if there is any extra it will be fed back into the national grid. When the panels cease to generate electricity, the inverter will pull the free stored energy from the battery back-up system to power your usage. Only when the system is ’empty’, does the system take power from the grid.

For a typical household that currently only uses 50% of the energy generated, the battery back-up system should increase this to around 85%. Or in other words the system will only actually give 15% of the energy generated to the electricity companies.

We install a number of different energy storage systems to make sure that you’re making the most out of your solar panels. Some energy storage systems are:

SolaX – X Hybrid

solaxThe X-Hybrid ‘Self-use Energy Storage System’ is the perfect solution, enabling you to get the most out of your solar energy both today and in the future. The batteries used in a domestic system are modular and therefore you can opt for the perfect quantity. A typical domestic install will require anything from 2 battery units (100Ah/4.8kWh) to up to 6 battery units (300Ah/14.4kWh). These battery units would be placed in the cabinet as you can see in the image adjacent.

SMA – The Sunny Island 3.0M and 4.4M

sma solar battery storage systemThe new Sunny Island 3.0M and 4.4M systems are the perfect product solutions for stand-alone and grid-connected systems in a power output range of up to 13 kW. Users benefit from SMA’s over 25 years of experience with battery inverter technology. Long battery life thanks to intelligent battery management. Reliable operation thanks to high overload capacity.

Samil – SolarRiver 3000 / 4000 / 5000 / 6000TL-BSS

battery storage system

  • Highest earnings through prime overall system efficiency.
  • Battery backup function for maximum supply security.
  • All-in-one or modular housing concept.
  • Free choice of battery technology and type (Li-Ion, Lead Acid Gel).
  • Simplified system design due to dual MPPT.

Call today for a free solar energy storage quote on 0191 340 7001 or email us at info@susenergy.co.uk.

Energy Storage FAQs

What is battery back-up?

For most systems there will be times during the year when their power being generated by their solar PV system is greater than their power being used in their property. During those periods, for a system without storage, all the surplus electricity is exported into the grid. For systems with storage, some of the energy that would otherwise be exported can get retained for use later in the day.

Why do I need energy storage?

To allow the use of stored surplus PV energy, for use later in the day and to provide a back-up power supply in the event of a power cut.

The provision of a back-up power supply is particularly relevant for sites that suffer regular power cuts (although this is infrequent for most locations in the UK, it has been rumoured that the frequency of these power cuts will increase in years to come) or for sites that need to guarantee they can run on critical load at all times e.g. hospitals

What are Lead-acid batteries?

Lead-acid batteries were invented in 1859 and are the oldest type of rechargeable battery. They are relatively low cost and are widely used throughout the world.

The design of a lead-acid battery varies considerably depending on the application. For example automotive batteries tend to be constructed of many, thin, plate electrodes (to maximise the surface area for chemical reactions and to deliver high surge currents); whereas deep cycle batteries designed for solar applications have larger thicker and more robust electrodes (for a longer life and a deeper depth of discharge). Automotive batteries are not generally suitable and are not advised for use in solar PV storage applications.

Due to their ready availability and low price, “deep cycle” lead-acid batteries currently remain the predominant choice in most off-grid PV systems.

How much power can I use?

The size/capability of battery storage systems will limit what can be run during a power cut e.g. 1kW would run a 100W light bulb for 10 hours.

What is “Deep Cycle”?

“Deep Cycle” describes a battery that is designed to be regularly deeply discharged using much of its capacity.

What are Lithium-ion batteries?

Due to the rapidly growing electrical vehicle market, lithium-ion batteries have climbed to the point where they are increasingly the battery of choice for domestic or commercial grid connected solar storage applications.

The advantages of lithium-ion over traditional lead-acid batteries include:

  • Better energy density
  • Improved efficiency
  • Improved depth of discharge (DOD)
  • Low self-discharge
  • Increased lifetime (better cycle life in deep-discharge applications)
  • Low Maintenance

There are a few disadvantages like the increased cost and some other safety considerations.

Safety considerations for lithium-ion batteries include most significantly the potential for thermal runaway. Protective circuits are built into lithium-ion batteries to protect against the risk of thermal runaway.

What is Depth of Discharge?

DOD describes how fully a battery has been discharged during a discharge cycle. It is expressed as a percentage of battery capacity for example 60%. A discharge of around 80% represents “deep cycle” operation.

What is nominal capacity?

This is provided by the manufacturer and describes how much energy the battery can nominally deliver from fully charged, under a certain set of conditions. Battery capacity is normally described in Amp-hour at a particular discharge current, for example: 500Ah at C100 rate. In general, the quicker the battery is discharged, the smaller the capacity. A real example from a commercially available deep cycle lead-acid battery is shown in the table below.

Battery capacity variations for a 468Ah, C20 battery
Rate Capacity (Ah) Discharge current (A)
C100 605   /100= 6.05
C20 468   /20= 23.4
C10 398 /10= 39.8

 

What is Effective capacity?

Effective capacity is often used to describe the usable capacity of the battery. The effective capacity is less than the nominal (nameplate) capacity. For example a battery with a 500Ah capacity, on a system programmed to limit Depth of Discharge (DOD) to 60%, the effective capacity is 500 x 0.6 = 300Ah. Make sure it is effective battery capacity you are comparing.

What is System (charge-discharge) efficiency?

All batteries are subject to some losses during the charge, storage and discharge cycle. The charge-discharge efficiency describes how effective a battery is throughout the full cycle.

Ask us for an estimate of the charge-discharge efficiency for your system, so you can have a good idea of how much energy you may lose.

System efficiency = power out /power in

What is Self-discharge?

Self-discharge describes a normal characteristic of all batteries to gradually loose charge over time. The degree of self-discharge varies with battery type, age and temperature. A typical lead-acid battery can expect to lose around 5% over a month.

What is stage charging?

A typical full battery charge consists of three separate stages. Stage 1 is Bulk, then Absorption and the final stage is Float

What is Opportunity Charging?

Opportunity charging describes a charging regime that occurs whenever power is available, such as from the intermittent output of a solar PV system. Long term, repeated incomplete recharge cycles can have a significant detrimental impact on battery lifetime. Lithium-ion batteries are more tolerant to intermittent partial charging patterns: they respond relatively well to partial charging and do not need a frequent full charge in the same way that most lead-acid batteries do.

Where the battery capacity is relatively small compared to the PV array, there is a higher chance that sufficient solar charge current is available to perform a full and complete recharge cycle.

What is mains (grid) charging?

Repeated poor recharge can impact on battery lifetime therefore most systems will on occasion draw power from the grid to complete the charge cycle. It is important to determine to what extent the mains (grid) may be used to recharge your battery pack. Ask us for an annual estimate.

For grid connected PV systems, there is not the same imperative to have a large PV array with respect to the battery because:

  1. The mains (grid) can be used to complete the charge cycle
  2. The mains (grid) can be used instead of the battery at times of low solar input

What is discharge control?

As well as needing control of the charging phase, control over discharge is also required. Discharge control functions typically include:

  • Ensuring discharge is halted at a set battery
  • Limiting the rate of discharge (discharge current)
  • Providing temperature feedback (adjusting discharge profile to battery cell temperature)

The discharge control system may also control and restrict when discharge can occur. Examples include:

  • Restricting discharge to certain time windows during the day
  • Preventing discharge until certain recharge/battery voltage thresholds have been reached

What is a DC charge controller?

A DC charge controller is used as a direct interface between a DC source (such as a solar PV array) and the battery. It converts the variable DC input voltage coming from your solar PV array, to the precise required DC charge voltage for the battery.

What is an AC charger?

An AC charger is designed to provide a controlled DC charge sequence from an AC source – such as from the mains (grid) or a generator.