Hybrid Inverters: May Be A Total Reset Button

To make a complete understatement, we’ve noticed some stirring in the electrification industry recently.

It started with something about winning elections, but interest has now switched firmly to storing electrons.

Questions are being asked though; does installing a home battery really require you to bin your existing functional solar equipment?
It’ll sound like a mealy mouthed political answer but, really; it depends.

There’s a dozen things to consider when you’re trying to improve your solar power system, however it’s worth considering another two dozen ways you could improve your electricity bill.

Efficiency Is King

You don’t need a special department of government to realise the cheapest kilowatt hour is the one you never needed to use in the first place.

As winter closes in and the sun hours wane, solar energy to power your house is more limited, while the occupants’ need for warmth and appetite for electricity knows no bounds.

Heat pumps, reverse cycle air conditioning, no matter what you call it, refrigeration can take heat from outside and put it wherever you like in a manner so efficient it’s like voodoo.

So remember, you may already own a cheap battery which likely stores 12 or 14kWh of energy.

If you can keep the drafts out and the heat in, with gap sealing, window dressing and insulation your entire house will be more comfortable and cheaper to run.

Batteries Are Still Expensive

Though our promised new government incentive is creating incredible interest, you’ll still need a fair chunk of private investment to get one installed.

The labour to deliver it is a fair chunk of the cost, no matter what size, so you don’t want to blow a limited state incentive on a disappointingly small battery.

While the federal incentive extends to 50kWh of capacity, if you don’t have say 15kW of solar to fill it on an average day, plus more to meet direct consumption and heat water, the money spent may have a disappointing rate of return.

To get the best return, your battery needs to be sized properly to fit your habits.

Mine Your Solar

If you have some monitoring on your existing solar system then it’s a veritable pot of gold that you or your installer can exploit for data.

Even the most basic solar inverter will have a counter for kilowatt hours produced. Divide that by the number days since it was installed to get an average daily yield. Take away the average daily export which appears on your power bill and the remainder is how much solar you’re self consuming.

It’s difficult to tell how much of your billed consumption is overnight, but you’ll at least get a feel for the numbers.

For those with a retail “smart meter” you can contact your utility and they’re obliged by law to hand it over. Plug that data into our calculator for a better result than the back of any envelope.

Now You Can Plan An Upgrade

If your solar power system is old, there are good reasons to leave it on the roof to continue it’s good work. Throwing things in the bin just because they’re not shiny enough is curse on us all.

With an AC coupled battery like Tesla Powerwall 2 or Sonnen for instance, your legacy system can be a perfectly good solar source.

If your solar power system is old there are some equally good reasons to replace it, not least of all the chance to get rid of the fire risk which is the roof top isolator.

New solar comes with a fresh warranty, up to date monitoring and greater power density. And of course you can add more panels, anywhere they’ll fit is good, no matter the direction.

We'll Lose Some Good Soldiers

Even if your solar isn’t terribly old, integrating new components and bringing it all up to current standards can be difficult.

If you’re in South Australia, new equipment must meet current rules. There’s no grandfathering, and sadly retro integration for flexible exports is likely impossible; unless perhaps you have a Fronius Snap inverter. Fronius take sustainability seriously, so they work hard to make their gear durable and flexible for the future.

Solar Arrays Can Be Kept

Assuming they’re good quality, well installed and pass electrical tests, your solar array can have some “minor repairs” in order to connect it to a new inverter.

Be aware though, some installers are not comfortable to offer a warranty on legacy solar. They deem it a risk to the new inverter and their reputation.

Electricians can be conservative but it’s not wrong to cite AS5033 and point out the rules for wiring through the roof have moved on, so they’ll quote an entirely new, fully compliant, latest specification system.

Hybrids Are The New Black

For more than a few reasons installers are quoting on new hybrid inverters.

• With rules yet to be finalised for the new battery incentive, most hybrids can be installed now with a battery simply added after July 1st.
• Hybrids can also be configured just like an AC coupled battery, with or without additional solar DC coupled straight to them for extra capacity and black start ability
• Many hybrids can control a legacy grid connect inverter, using frequency shift to control it during an outage (but without black start ability)

Going For Grunt

The most compelling reason to install a new inverter may be the outright capacity you can connect.

Some DNSPs will only allow 10kW of inverter capacity per connection, so using Enphase as a sad example, a 5kW solar generator could only have a 5kW backup capacity and 5kWh battery.

Whereas Sungrow (under the same 10kW per phase connection limit) could have 10kW of inverter power (for great backup) 20kW of solar and 76kWh or storage.

Keeping your old inverter may hamstring your future plans.

Seamless Ecosystems

If you have monitoring with valuable history and you’d like to keep everything together and visible on one app, it’s worth keeping to a single brand. For instance Sungrow can have a number of separate inverters on the same site all appear under the same monitoring.

Fronius have a great EV charger that will integrate seamlessly with smart solar charging and a hot water controller.

However if you’d like some annoying examples, Sungrow don’t presently offer an EV charger, Solar Edge don’t have an EV charger that’s OCPP compatible and without third party software, Tesla’s EV charger is dumb.

GoodWe have a nice EV charger but you’re best off using a Catch Control consumption meter to avoid metering problems.

Catch Control can sometimes stitch together a salad of different equipment, but in any case it’s a matter of having a great installer who understands the hardware they use and are willing to solve problems if they crop up.

Plan For Expansion

Adding solar, batteries or other electrification can require more upgrades, so please consult our guides and Factually Answered Questions section. They’re enquiries we’ve written up for you to consume whenever you like.