Grid-Interactive Hybrid Solar System 5kVA 22.275kWh Storage LiFePO4 7kWh

A Complete Residential Grid-Interactive Hybrid Solar System supporting a 5kVA inverter, daily solar yield of 22.275kWh and storage LiFePO4 – 7kWh designed by Specialized Solar Systems


Description

A Complete Residential Grid-Interactive Hybrid Solar System supporting a 5kVA inverter, daily solar yield of 22.275kWh and storage LiFePO4 7kWh

This system is based on common residential meter readings (1 unit = 1 kWh) averaging between 10-15 units per day time use and 4-7 units per evening use, totaling 22kWh of daily energy consumption.

From those readings, Specialized Solar Systems has designed this solar system to completely meet the 22kWh energy requirement with solar energy generation over a 24 hour period using utility power (ESKOM) as backup only.  This means that you should always have electricity, even during power outages (load shedding) and bad patches of weather.

This grid-interactive hybrid solar system will give you many hassle-free years of energy security and cost savings.

THE INVERTER – 5KV 48V 70 Victron Multiplus II Inverter/Charger:

  • From battery and solar PV panel power (DC Power),  this inverter can provide a continuous 4 000W at 25C and manage a peak power draw (spike) of 9 000W.
  • From grid power (AC Power) the inverter can transfer up to 11 500W (Transfer switch).

THE SOLAR PV PANELS: 

  • The 48VDC solar system will include 15 X 330W Solar PV Modules that will provide a 4.950 kWp solar array.
  • In George in the Garden Route South Africa,  this solar system will yield an average of 22.275kWh from the 4.950 kWp solar array.
  • Having a 7kWh LiFePO4 battery may require up to 7kWh of the average 22.275 kWh solar yield to replenish itself.  This will result in 15.275 kWh of energy being available during daylight hours to power household appliances.
  • The system will require a 100A MPPT to facilitate charging the battery during daylight hours from the solar PV panels.

THE STORAGE (BATTERY):

  • The battery will have 7kWhs usable energy available for night-time usage or for overcast days.
  • This is calculated at a 70% depth of discharge (DOD) which includes a 10 Year Manufacturer Guarantee.

MONITORING: 

  • Monitoring is provided by Victron’s color controller that allows online real-time monitoring of your system.

OTHER: 

  • Any additional power can be supplied by the grid power (ESKOM) with the inverter supporting up to 11 500W (Transfer switch 50A at 230V AC).

This Grid-interactive Hybrid Solar System 5kVA 22.275kWh Storage LiFePO4 7kWh includes the following equipment:

  • 15 x 330Watt Solar Modules (10 Year manufacturer guarantee, 25year 80% yield).
  • Rail Mount Framework for standard roof type.
  • 1 x Freedom Lite 200AH 48V – Usable 7kWhrs @ 70% DOD  (10 Year Manufacturer Guarantee).
  • 1 x 150/100Amp MPPT – TR  (5 Year Manufacturer Guarantee).
  • DC DB box with Surge Protection, Breakers, and Cabling.
  • 1 x 5KV 48V 70 Victron Multiplus II Inverter/Charger (5 Year Manufacturer Guarantee).
  • 1 x Color Control GX, VE Direct Cables, Wi-Fi Dongle and SD Card (5 Year Manufacturer Guarantee).
  • System Programming and Maintenance/Owner Training  (Year Workmanship Guarantee).
  • AC Sub Db, Surge Protection, Change-Over, LED Indicators and Assembled Back Board.
  • Installation Costs, Travel, and Consumables  (1 Year Workmanship Guarantee).

If you require expert help with choosing the correct Hybrid Solar System from Specialized Solar Systems, customers should please include the location where you plan to install your Hybrid Solar Energy System.

Notes:

  • All Pictures shown are for illustration purposes only. Actual product may vary due to product type and enhancements.
  • Errors and omissions excepted (E&OE)
  • Please inquire about Specialized Solar Systems T & C’s

A Grid-Interactive hybrid solar system intelligently gives you the best of both worlds with the added convenience of a grid-connected system including the ability to earn Feed-In-Tariff Credits (if your municipality allows) and the added security of a battery backup.

This means that you should always have electricity, even during power outages, during bad patches of weather,  or if your energy demand exceeds your solar systems energy delivery capacity. For more information about Residential Complete Grid-Interactive Hybrid Solar System please view over here

Advantages of LiFePO4 Batteries

Optimise your Stationary Power by using LiFePO4

Lithium Iron Phosphate (LiFePO4) – No one can afford to be outside of this revolution!

It is not a case of LiFePO4 being affordable, it is a case of can one afford to use lead acid? The life cycle cost of LiFePO4 batteries is a quarter of lead acid batteries. The upfront costs for a pack vary from similar to 50% more for lithium depending on the application, but one must consider that in 3 to 6 years’ time the lead-acid batteries must be replaced and the LiFePO4 battery will last 15 to 20 years depending on the application.

LiFePO4 technology has revolutionised the potential and life cycle cost of operating battery-based power systems. LiFePO4 has a cycle life 10 times that of typical deep cycle lead-acid batteries. They only cost 10-50% more to purchase upfront (depending on size), however, the saving on life-cycle cost is massive.

LiFePO4 batteries from Freedom Won are available in a wide range of sizes to accommodate loads of a few amps to over 2000 amps. They can deliver sustained high power without excessive heat generation. There are no gases released and LiFePO4 cells are also thermally stable. They can be charged repeatedly to full capacity in less than 60 minutes with no appreciable loss in performance.

Backup and Off Grid Battery Packs Using Superior Lithium Iron Phosphate (LiFePO4) Cells – the next Generation of Energy Storage

By: Antony J English, Co-founder of Freedom Won Pty Ltd

Lithium Iron Phosphate cells,  or LiFePO4 for short,  are now dominating the alternate energy storage sphere amongst the more discerning designers and customers in the more advanced markets including Europe, Australia and South Africa.

Freedom Won has been using these cells in electric vehicles since 2010 and in stationary storage since 2014.

Freedom Won provides competitive prices made possible by high volume manufacturing in South Africa and guarantees market leading technical backup and design assistance. Freedom Won has the market leading battery warranty of 10 years with no fine print or diminishing value spurred by our confidence gained from our own test programme in electric vehicles, which is far more demanding on the batteries than stationary power systems. The expected life in off grid systems is more than 15 years, and more than 20 years in grid connected back up installations with occasional cycling. The end of life is defined by when the cells contain 60% of their Beginning of Life (BoL) capacity. The capacity deterioration over time is linear (the deterioration does not become substantially more rapid with extended use), and the cells could therefore be used for even longer periods if a lower end of life capacity is acceptable.

The initial cost of installing a LiFePO4 system as compared to Lead batteries is only marginally higher since the 2018 price decreases in the Freedom Won range. For smaller batteries up to 10kWh this premium is about 40% but for batteries larger than 100kWh this premium is only about 10%.

These premiums in initial cost are dramatically overshadowed by the savings in the total life cycle cost, calculated as a cost per kWh delivered by the battery pack during its lifetime. The lifetime cost per kWh can be as low as 25% of the cost of typical lead acid deep cycle batteries. The main reason for this is that the cells offer up to 10 times the number of cycles than your average deep cycle lead battery and as much as 5 times that of the more robust single cell flooded lead acid types.

Another top benefit to the customer is the far greater efficiency of the LiFePO4 technology, which is typically better than 98%. A typical efficiency for lead batteries is 65%, although this can be as low as 55% in a house PV system where the Depth of Discharge (DoD) is limited to 20% as a measure to lengthen the life of the lead acid cells. In a grid connected back up scenario this high efficiency results in significant energy savings when recharging the batteries, and in a Photo Voltaic (PV) installation it enables a reduction of the size of the array by as much as 30% with the same usable energy.

The advantages of LiFePO4 cells over lead cells are extensive so a full elaboration is not included in this article. A summary is however provided in the table below, and further questions posed to Freedom Won will be welcomed.

Table: Summary of Benefits of Using LiFePO4 Cells in Stationary Power Applications

Comparison Aspect Lead Acid LiFePO4
Cycle Life (50% DoD with 70% remaining capacity, 30 deg C ambient temperature) 500 to 1300 cycles depending on manufacturer and model More than 7000 cycles
Calendar Life Average (poor in high temperature or partial/full discharge condition or infrequent cycling) Excellent – no sulphation, partial charge storage is no problem, regular cycling is not required, heat tolerant
Charge – discharge (round trip) efficiency [%] 60-70% typical depending on current. Typically rated capacity is based on 10 hour discharge (C10) 96%, consistent throughout current range. Rated capacity is based on 20 minute discharge (3C), a one hour or longer discharge will actually give 10% more than the rated capacity.
Temperature resilience Poor – temperatures above 25 deg C significantly reduce the calendar life Excellent – ambient temperatures up to 45 deg C will not affect the life of the cell at all.
Up Front Cost Cheaper 10 to 50% more expensive up front than Lead Acid depending on what lead acid cells are used for comparison and the size of the battery – the Lithium premium on a larger Freedom Lite battery is lower.
Life Cycle Cost per kWh R3.00 (USD0,21) to R6 (USD0,41) depending on battery type and model R1,20 (USD0,08) (approx.)
Quick Charge Time Typically should not be done in less than 5 hours 2 hour standard, 45 min quick
Discharge Current Higher discharge than C10 (10 hours), or 0.1xC rating causes substantial loss in efficiency and affects life C1 (one hour discharge) is standard, higher currents are also acceptable up to 3C (3 x Ah rating) continuous with negligible loss in efficiency and cell life
Gravimetric Energy Density Poor Weigh 3 to 4 times less – reduced transport costs and installation effort.Volumetric density more than 2 times higher – less than half the space required
Pack Capacity Loss of 30% in heat (70% pack efficiency) means pack must be larger to meet a specific output objectiveMax practical DoD is 50%, which requires a larger pack to stay above this DoD to prevent rapid life deterioration Pack can be sized to 50% of the “rated” capacity of a lead acid pack because of 98% efficiency and ability to discharge on regular occasion to 90% DoD with negligible effect on life reduction
Charging Energy Source Size The charging energy source must provide an additional 30 to 40% energy to overcome the inefficiency of the pack at substantial cost Only about 2% of the energy is lost to heat – big savings in charging energy and capital on PV installations etc

When sizing a LiFePO4 pack, the rating of the cells cannot be compared to a typical lead acid rating without making some adjustments. Owing to the much higher efficiency and the ability to discharge more deeply without rapid capacity deterioration over time means that a LiFePO4 can be sized to about 50% of the lead battery in terms of Ampere hours. This factor originates simply from the fact that only 65% of the rated total energy is available from a lead acid battery in most high power backup applications, whilst 100% of the rated energy is available from LiFePO4 cells.

Because it is practical to use a lower DoD in LiFePO4 cells and still achieve an excellent cycle life the designer can reduce the LiFePO4 pack size and still provide superior performance over a lead battery pack. A typical scenario could be 50% DoD for a lead acid pack compared to 70% DoD for a LiFePO4 pack. This ultimately makes the LiFEPO4 pack energy capacity (kWh) rating 50% of the lead acid rating.

LiFePO4 cells maintain their rated nominal voltage for about 95% of the discharge, whilst a lead cell voltage drops continuously. When working out the Wh of a lead 12V battery one must use about 11.4V for the average voltage under load (1,9V per cell). The nominal voltage for LiFePO4 is 3.2V per cell or 52V for a typical “48V” system.

An example comparing a 200Ah LiFePO4 pack to a 400Ah lead pack is included in the below table. The theoretical energy capacity for the lead battery is reduced to 85% of the rated capacity to replicate a real world discharge scenario vs the manufacturer’s 10 hour constant current test regime used for the nameplate Ah rating. The usable capacities are adjusted to be in line with the typical DoD expected in the design of 50% and 70% for the lead and lithium examples respectively.  The LiFePO4 pack costs only 40% more than the Lead battery, however, after taking into account the cycle life and the kWh produced in the lifetime of the packs it is clear that LiFePO4 costs only 22% of the Lead batteries used in this example.

Table: Comparison Example of Lead Battery vs. LiFePO4

Lead Acid   LiFePO4
8 200Ah Lead Acid/Gel 16  units of Sinopoly SP-LFP200AHA (Freedom Lite 20/14)
4 Batteries (units) in Series 16 cells in each string
2 Strings 1 Strings
200 Ah Nameplate Capacity 200 Ah Cell Nameplate Capacity
200 Ah each @ 10hr rate 220 Ah at 3 hour rate (one cell per unit)
12 V per battery nameplate 3,4 V per cell nameplate
11,4 V per battery during discharge 3,2 V per cell during discharge
400 Ah total pack 220 Ah total pack
48 V rated total 54 V rated total
45,6 V nom of pack during discharge 51,2 V nom of pack during discharge
18240 Wh @ 10 hr discharge (260AhX44V) 11264 Wh available and rated for 100% DOD
85% Derating of 10hr Capacity 100% No derating required
15504 Wh available for 100% DOD 11264 Wh available and rated for 100% DOD
7752 Wh available for 50% DOD 7885 Wh available for 70% DOD
50% Percent of LiFePO4 pack rated capacity required to match Lead Acid