Off Grid and Grid Battery Backup Solutions

View this to get an idea of Elon Musk’s Vision for the Future

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Tesla's Powerwall battery system, designed for domestic use.

Tesla’s Powerwall battery system, designed for domestic use.

Local and international energy companies are rushing to support Tesla’s new Powerwall home storage system, with a string of partnerships announced in the days following the product’s launch.

Leading companies including SolarEdge, Fronius, Reposit Power and Vector (New Zealand) have all made announcements regarding partnerships and collaborations with the company, best known for making electric cars.

The low-cost batteries, unveiled to great fanfare at the end of April, are seen as potential game-changers in the domestic storage market.

Among the first to announce its collaboration was PV inverter company SolarEdge, which announced a deal to develop an inverter solution for Tesla’s Powerwall.

“Tesla’s collaboration with SolarEdge unites leading organisations in two rapidly-growing industries – solar energy and energy storage – to bring homeowners a more cost-effective and integrated energy generation, storage, and consumption solution,” said JB Straubel, CTO of Tesla.

“SolarEdge’s commitment to improving the value of PV systems through product innovation, combined with more than 1.3 GW of successful deployments, makes it an ideal partner for Tesla to develop and introduce this new energy storage solution to the PV market.”

The solution will also support upgrading existing SolarEdge systems with the storage solution.

Fronius Symo Hybrid

Fronius Symo Hybrid

Solar inverter manufacturer Fronius also announced a partnership with Tesla, saying it is developing communication compatibility between the Fronius Symo Hybrid inverter and the Tesla Powerwall.
Fronius will offer the Powerwall in combination with the Symo Hybrid inverter as a solution for residential PV systems, starting in Europe at the end of 2015 and later in Australia.
Fronius said the Tesla Powerwall will be available as an alternative to the Fronius Solar Battery. Both options will work in conjunction with the Fronius Symo Hybrid inverter and a Fronius Smart Meter. Fronius is therefore offering a second, wall-mounted storage solution, suitable for outdoor use.

Reposit Power
Canberra technology company Reposit Power secured a slightly different type of deal with the US carmaker, announcing it is combining its GridCredits storage system with Tesla’s Powerwall battery.

The intelligent GridCredits system has been designed to work with battery storage hardware and will be available with other batteries in addition to Tesla’s.

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A day in the life of an off-grid installer

Several weeks back, the customer featured on my 24th April blog, called in and said “Lets go with the 4.5 kwatt Selectronic SPPro Inverter/charger”. “I like the idea of having the generator being started automatically through battery state of charge (SOC) and the larger size inverter will be handy too”

Selectronic SPPro

Selectronic SPPro

I then arranged for a suitable day to install the gear, ordered the SPPro 24-1, a 24 volt 4.5 kwatt model from Selectronic in Mooralbark Victoria, ordered a new 260 Amp battery fuse/disconnect to suit the much higher load currents, arranged for the sparky to attend and waited for the day.

I purchased a 1200 x 2400 mm piece of melamine coated chipboard from the local hardware store and set off in the Radiant van!

The first job was to strip off all of the old switchboard and connections and screw the chipboard sheet to the wall – 50 mm roof screws make a very good fixing and can be easily driven with the battery drill.

 The next job was to make a layout sketch of the system to make sure everything fits. Then the task of screwing the inverter backing plate, the battery disconnect switch, solar DC MCB switch enclosure, the two solar regulators was completed. You will need two people to lift the inverter/charger onto its backing plate – its quite heavy with its rather large toroidal transformer inside!  Having a large, heavy transformer is the key to the SPPro’s high surge current rating.

Soon the wiring started to take shape. The sparky routed a new cable to the house switchboard and extended the generator autostart wiring to the inverter/charger. The batteries were moved closer to the wall mounted panel and wired into the battery fused disconnect. The sparky then attached the generator and 240v AC isolators and wired them into the inverter.

I had to install the renewable shunt to measure the total solar current going in and then I wired the SPPro pre-charge switch, battery sense wires, battery temperature sensor and then wired in the two solar DC MCB’s.

The Selectronic SPPro has a unique feature which is the ability to compare the voltage of each half of the battery. By doing this, it can determine if one 2v cell of the battery bank could be needing attention as the voltage across each half each half won’t be the same.  It can’t pinp

oint which cell but it can warn if one half of the battery is different to the other.  To my knowledge, no other inverter/charger has this feature. The SPPro has many features which are primarily designed to look af

ter the battery and to prolong its life.

By early afternoon it was ready to test. We turned on the SPPro pre-charge switch, waited for all the green lights on the inverter front panel to light up, then we closed the battery disconnect fuse holder. We then pressed the mode switch, top right, to allow AC to flow to the switchboard – It works!


The next job was to connect the SPPro to my laptop using SPLink which quickly sets up most of the required settings via a handy setup wizard.  Settings like battery size in Ahr, generator size in Kwatt, general operation type, Off-grid etc, Sp Link allows you to investigate what the inverter is doing, it takes daily and weekly summaries and also indicates and alarms when something fails.  SpLink also allows you to download performance data and display graphs using Excel.

The last job was to check the operation of the generator auto-start by pressing the top left hand button for 2 secs. Yes, the generator started up and then synchronised with a clunk of the internal contactor. Within a short time it then started to charge the battery – I checked the generator output voltage and frequency, 230 v and 49.7 Hz – All good.

Off Grid system

Off Grid system

To finish off the job, I then put on the various labels and signs in readiness for the inspector to view and approve. These labels can be seen in the photograph.

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A day in the life of an off-grid installer

Last week we installed a battery backup system on an existing grid feed solar system

We had previously installed a 2kwatt grid feed system about 4 yrs ago when the feed in tariff was 66 cents/kwhr.  The owner wanted the system expanded to include a backup battery bank and inverter.

This is the layout:

When the power goes off, thGrid feed with backupe SPPro, which is always synchronised with the grid, instantly takes over supplying house loads. In order to alert the owner that grid supply has stopped, an alarm sounds in the house so that steps can be taken to limit energy usage.

The 140 Amp hr battery set has about 4 Kwhrs of usable energy available to supply loads – which if managed carefully, can last for 4-5 hrs of use. Important loads would be the fridge, lights (especially at night), laptop and other necessary loads.

When running normally in grid mode, the solar system preferentially supplies any battery charging requirements and house load support, then any excess energy is exported via the Selectronic SPPro  inverter. We specified one of Selectronic’s GO series inverters which limits grid export to 2 kwatt (the original size of the array) This ensures that the original agreement with the retailer remains unchanged so that the 66cents feed in tariff is safe!

For the hardware, we selected the Selectronics MY Grid system click on link here
It looks very neat and tidy and the Selectronic mY Gridvery best thing about the whole system is –
It’s all designed and made in Australia


Battery Size – 140 Ahr
Battery Type – Absorbed Glass Matt (AGM)
Battery Voltage – 48v
Array Size            –   2kw
Available Energy for backup – 4 kwhrs
Likely support time – about 5hrs or more depending on usage
System Brand – Selectronic My Grid

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The Grid Battery support market has just hotted up.

AGL are offering the Solis brand inverter from the Chinese company, GinLong.  The inverter has an 8 yr warranty and the Lithium batteries have a 5 yr warranty with an expected lifetime of 10,000 cycles

Fronius will also join the market in July with their 3 phase Symo hybrid inverter.    Solar Phil
AGL Takes on Tesla in Australia With 6kWh Home Battery

by David Fickling BloomBurg Business
12:17 PM AEST
May 2, 2015


Elon Musk – Tesla

Elon Musk, co-founder and chief executive officer of Tesla Motors Inc., unveiled a suite of batteries to store electricity for homes, businesses and utilities and reduce dependence on fossil fuels. Photographer: Tim Rue/Bloomberg

AGL Energy Ltd., Australia’s biggest power producer, said it would debut a 6 kilowatt-hour home storage battery, challenging Tesla Motors Inc. which announced 7- and 10-kWh models last Friday.

AGL’s suitcase-sized battery will use lithium-ion cells and come with extended warranties and finance plans to make it affordable, the company said in a website statement.

See here

It’ll be suitable for a family home with solar panels providing 3 to 4.5 kilowatts of power, AGL said. It’s the first such product to be offered by an Australian energy retailer.

Tesla Chief Executive Officer Elon Musk unveiled a suite of batteries to store electricity for homes, businesses and utilities and reduce dependence on fossil fuels. Tesla’s home batteries will be delivered from late in the northern hemisphere summer at prices starting from $3,000, the company said.

AGL’s product “will provide consumers with backup for essential home services such as lighting, refrigeration and communications,” Ed Lynch-Bell, AGL’s lead for energy storage, said in the statement. That will help iron out “potential disruptions of energy supply,” he said.

AGL, whose assets include the Loy Yang coal-fired power station which provides about 30 percent of Victoria state’s electricity, said April 17 that it would close all its coal plants within 35 years and expand its investments in renewable energy.

Tech Australia Energy Storage Family Energy Coal Energy Supply Renewable Energy

See full story here

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A day in the life of an off-grid installer

Last week, a customer near Colac phoned me and wanted to talk about going off-grid I told him I would come down that afternoon. So I printed off one of our Off-Grid info packs and set off for Colac in the Radiant Van.

The customer lived just out of Colac, quite close to another of our Off-grid customers so I was quite familiar with the area.

Within the hour, I was at his property in the middle of a forested area in a small clearing. The house was owner built, of modest size with water tanks, solar water heating, Nth facing main roof and a grid connection

The customer came out to greet me and proceeded to show me calculations of his daily usage which was around 2-3 kwhrs/day – quite modest and that he was intending to install an LP gas stove which would make the usage even lower. We discussed the shading issues from the tall eucs in winter – it is what it is!! A backup generator was also planned.

He was a perfect candidate for going off-grid – already had water tanks, solar hot water, wood stove for winter heating, gas cooking and was planning for gas hot water backup or using the wood heater with a water jacket.

I took some photos and after discussing the implications of going off-grid, I left him with the info pack and promised that I would draw up a quote and send it to him within the next few days.

Back home that evening, I opened my trusty SPS off-grid design program from JP Energy Technology, put in the likely loads that the customer had indicated and totaled up the kwhrs/day. Sure enough, they totaled about 2.5 in summer and around 3 in winter.

From there I went to the Design Area of the program and selected Cape Otway as the closest solar monitoring station. Then I went to the PV Array area and set the brand, size and numbers of solar modules I thought he’d need to cover his winter load.  I chose 3 kwatt which is 12 by 250 watt modules.

I’ve decided to go AC coupling for the solar array – that is the DC energy from the solar panels goes to the ABB solar inverter and gets converted to 240v AC energy which is then fed to the main AC house switchboard. It then directly supplies any house loads that need energy – the fridge, maybe TV, lights, washing machine etc and then any excess goes into the battery. The DC wiring for this arrangement is very simple and makes for a very neat system.  It is our preferred arrangement.

AC coupled system

The SPS design program produces a graph which shows the solar PV output is above the load requirement. This will minimise the need for a backup generator and with panel prices so low these days, it is much cheaper than petrol in the long run.

system performance

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Tesla announces low-cost batteries for homes

This is the beginning of a new paradigm in home energy storage – Read on:

Elon Musk claims at launch that two billion large batteries could provide enough electricity to meet the world’s needs

Elon Musk
Tesla Motors CEO Elon Musk unveils large utility scale home batteries. Photograph: David Mcnew/AFP/Getty Images

The electric car company Tesla has announced its entry into the energy market, unveiling a suite of low-cost solar batteries for homes, businesses and utilities, “the missing piece”, it said, in the transition to sustainable energy world.

The batteries, which will retail at $3,500 in the US, were launched on Thursday at a Tesla facility in California by the company’s ambitious founder, Elon Musk, who heralded the technology as “a fundamental transformation [in] how energy is delivered across the earth”.

Wall-mounted, with a sleek design, the lithium-ion batteries are designed to capture and store up to 10kWh of energy from wind or solar panel. The reserves can be drawn on when sunlight is low, during grid outages, or at peak demand times, when electricity costs are highest.

The smallest “Powerwall” is 1.3m by 68cm, small enough to be hung inside a garage on or an outside wall. Up to eight batteries can be “stacked” in a home, Musk said, to applause from investors and journalists at the much-anticipated event.

The batteries will initially be manufactured at the electric car company’s factory in California, but will move production to its planned “gigafactory” in Nevada when it opens in 2017.

View The full article here:   The Guardian

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A Day In The Life Of An Off-Grid Installer

Recently, an off-grid customer from Bellbrae called up and related the fact that his Selectronic SPPro had displayed a warning light. The power was still on etc and could you come down and have a look and find out why!

I packed my laptop into the Radiant van and headed off.

When I got there, the inverter was showing 100% in the batteries and no signs of the warning light.

2014-08-29 16.41.00

OffGrid System

The next step was to connect the laptop, run SPLink and download the data held on board the SPPro.

I selected Performance Data and then Custom Download and then set the Time Period to span the last 14 days. The tip is to only download enough data to check for the fault period as Downloading  All Data takes much longer!!

Once the data set was downloaded, I pressed Launch Performance Viewer – this starts up SP link’s graphing program in Excel. You have to Enable Content which will then allow a range of pre-populated graphs to be displayed. I chose Battery Voltage and Net DC Amps which displayed the ranges of battery voltages for the past 2 weeks.

Sure enough, one of the days showed a battery voltage that was well above normal. Looking into the charge settings on the Plasmatronics PL40 solar regulator showed that the equalization voltage was 31 volts – too high . The alarm setting on the SPPro inverter battery voltage was set to 29.5 – perhaps a little too low. The graph also shows the State Of Charge in the battery. It hadn’t moved below 90% over the past 14 days – very good. We specify in our system user manuals that the battery is not to get below 80%. This is to ensure optimum battery life. An auto-start generator is a good way of both automating the charging requirements and to extend battery life. Most systems that we install now have an auto-start generator attached.

As everything else looked OK it was job Done!

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A day in the life of an off-grid installer

We were asked to visit a site near Bannockburn, Victoria last week. The owner believed that his battery charger wasn’t working.

I packed my trusty Woods 24/40 backup charger and headed out in the Radiant van!

The site was known to us as we had upgraded this off-grid system about 10 yrs ago with more solar panels and a new battery bank.

Sure enough, the old 20A, WEA battery charger showed no signs of life with the Lister HR3 20kwatt single phase generator gently humming in the background.  I was amazed that this unit had lasted so long.

So I unpacked the Woods 24/40 charger from the van, set it up in place of the WEA and switched it on. Yes, we have charging now!! The customer was very happy to have backupdialocharge charging once again.

So, the question was what do we do now? Install a new charger – perhaps one of those 80A Zivan’s from MPower or suggest that we look at quoting on a new inverter/charger from Selectronic.

As the previous owner was living by himself, his load requirements were fairly minimal. But the new owner had a teenage family and their loads were much more extensive. The inverter was one of those trusty Selectronic blue series 1200 watt

units and was often overloaded and switching off!! Poor thing – perhaps it was time to upgrade to the more modern Selectronic SPPro.

So, later that evening I drafted up a quote for a new Selectronic SPPro inverter/charger which can also


To This?


From this

auto-start his Lister generator. We will await, with much interest, for a reply from the customer.






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