Battery storage and Solar Array sizing in 2019

If only people would understand, most reputable manufacturers offer a 25year production warranty.

I feel, as the standard size Solar array most retailers & installers offer is 6kW solar, this is largely due the the Fact that they get the system owner to sign over there STC to them. That is largely due to a 6kw system providing some $3’600 in STC to Install 20+/- panels odd, onto what is simple roof racking, not bad for what should commonly be a days work!

With the current low cost of Solar panels, NiFe and newer safer LiFePo4 Battery technology cost 550kW, most systems Owners these days would be a lot smarter/better-off investing in a Battery bank, that simply stores the energy usage from sunset through to sunrise, where Solar takes over again.

What that means: A Solar system only needs to provide slightly more kWh energy than a customers largest 24hour consumption, as once the batteries are charged, thay will provide the energy through to the next sunrise, instead of paying (if grid connected) three times the cost of any feed-in-tariff (FIT) rebate the retailers offer during the day!

However, I doubt may retailers guide customers in that direction, as the STC on a 6kW are to tempting to resist, especially where possibly half the panels may only be required.
In my opinion, with battery storage also being so affordable, that is taking advantage out of ill informed !

Hi @TheRaptor

It’s a very competitive market out there, most solar retailers seem to be passing on those extra STCs. Oversizing the inverter has other benefits for the customer too, more thoughts here:
How big a solar system should I get?

As for offering more panels or battery storage, I’m not sure I understand the connection. You can still claim the STCs if you get battery storage.


My point should have been, Why overspent of solar panels that harvest way to much energy for a customers actual daily consumption !
When one should be investing the money saved on panels, into a battery system !

I have actually rang several of those well priced TV specials (even though they are selling 5 odd year old 270W panels), they all double the price, when you say, I may going to claim my own STC, none of them mention the the STC on a 6+kW system is over $3.5k for what should be a days work.
I know everyone needs to earn money, but $3.5k install what should be a days work, is double what a genuine installer should be charging, but that is only my opinion, as I have been self employed for the last 40+ years now.
Such is life in the city.

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Are battery systems capable of handling large air-conditioning units?

Yes, most larger systems can handle air-conditioning units. The modern inverter split systems are actually quite efficienct and a larger 6kW unit will only draw around 10 amps (2000W) when running. (up to 15 Amps during startup though)

The biggest problem is a normal hybrid system (like SolarEdge & LG Chem battery) is limited to 5000W continuous output so the installer has to select the ‘essential loads’ which will be backed up during a blackout. Normal operation will be no problem running an air-conditioner but will usually flatten the battery in a few hours after sundown.

Hi Mikem664,

I have several mates that installed large NiFe battery banks & run there air-con all night long when needed.

Two of these have;

  • 40x 1.2V x 500Ah =24kWh energy storage.
  • 40x 1.2V x 1200Ah cells =57.6kWh.
    Both have UPS inverters & Charge controllers.

The first guy, is on-grid, but uses a Green bio-gas generator that auto starts (AGS) if/when the batteries trigger low voltage & then switches off as programmed, the other guy is a stone mason & lumber jack that uses a lot of energy, they live off-grid.

So, I understand the bottom line with energy storage is the kWh of Energy you have Stored!
Unless someone can correct that.

I have 4 LG Chem 9.8 kWh batteries and 2 SolarEdge SE7600A inverters. Looks like the system may be undersized. I typically use up to 80kWh per day.