Solar system for residential home BrisbaneAustralia

[Matt Green]

We are building with a reputable volume builder and wish to put as much solar panels as possible on our roof with the hope to store enough power to charge 2 electric cars, ducted air con, heat pump for pool and other appliances such as oven, cooktop, 2 washing machines and 2 driers. We expect to put in 2 batteries to store the sun’s power for our own use and hopefully export some to the grid. Expected build time is about a little over a year. The two cars have been bought.
Our builder has offered us these two alternatives:
1 - 41 Panel 15.99kW System with Solis 3P15K-S5 Inverter RRP $14,168 (not battery ready)
2 - 34 Panel 13.26kW System with Solis RHI-3P10K-HVES-5G Hybrid Inverter $13,683. The second one is battery ready.
Would be most grateful if you would comment on these two alternatives re suitability for our wishes outlined above. Panels to be divided equally to East and West facing sides of house roof (colorbond 25 degrees slope) situated in Brisbane.
My dialema is how easy would it be to make the either system ready and how costly. If it is easy I would go with the larger system but as long as it was not to costly, therwise I would go with the smaller system and just add some batteries.
Thank you for the help
Matt

[HGtesla]

According to a study conducted by the Lawrence Berkeley National Laboratory (LBNL) in the United States, a standalone residential property equipped with a solar energy system and energy storage system can effectively manage multi-day power outages without compromising essential loads such as lighting, heating, and cooling. However, the extent of this capability heavily relies on the configuration level of the solar + storage system.

Moderator note: Welcome, but please, no more advertising, links or otherwise

[Matt Green]

You're so right!. Its the configuration I don't understand. Its the bit about battery ready vs non - battery ready. If you buy a system which is not battery ready then how easy is it to add batteries. Do you have to buy another inverter or how? And if you want to add batteries to a system which is not battery ready but already installed - do you have to get the original installer to come out to make it battery ready? And if you do that can you then add the batteries yourself?
Thank you for the info and hoping you know the answers to these questions.
Matt

[Mike 134]

USA here. Solar is so much cheaper there.... Your system would run $30,000 to $40,000 here.

Do you have time of day billing from the utility or frequent power outages? Does the utility buy back excess production at the same price as you purchase it? That factors heavily in my opinion if the additional cost of batteries are worth purchasing.

[J.P.M.]

You haven't written much about your actual monthly/annual loads in terms of kWh, or time of day usage. Do you know anything about your loads, their size and their daily distribution pattern ?

Also, how big are the batteries ? If they're anything like those in the U.S, they're good for about 10kWh or so of output capacity/cycle.

Point is, looks like your planning will give you a system with ~ 20,000+ kWh/yr. output.
If that comes close to matching your load(s) and depending on your daily usage pattern, I've got to wonder if the planned battery storage size is a bit like spitting in the ocean.

Also, what's your utility rate structure look like ? T.O.U. ? straight tariff ? What ? Do you know ?
I appreciate that your PV prices are relatively cheap compared to the U.S. (especially if those quoted prices are AU $), but if your power is cheap and if you're doing the PV for economic reasons, you may also want to look at the economics of what you're doing for a lot of reasons, some of which Mike mentioned.
I'd also get a breakout the installed cost of the storage for the same and other reasons.
Also, any north-facing area available for panels?

NOMB or concern and maybe I'm wrong, but from what you've written it looks to me like you're a bit of a PV neophyte who wants to run before learning to walk.
Respectful suggestions:
Download a free PDF copy of "Solar Power Your Home for Dummies" and then download PVWatts from NREL. Read/Study both and if you're doing this with cost effectiveness in mind, also get very familiar with your utility's rate structure and any NEM availability before you pull the trigger on a commitment to a system.

Welcome to the forum of few(er) illusions.

[scrambler]

The battery ready thing depends on what exactly they meant by it....
.
What I would call a battery ready Inverter is a Hybrid Inverter which has been designed to charge and monitor a battery, but most importantly has the ability to isolate itself from the grid in an outrage and continues producing power using the array and the battery when the grid id down (a regular inverter shuts down when the grid is down).
When you buy such an inverter the easiest way to add the battery is with a battery that the inverter is designed to work with and depending on how flexible Installers are over there (compare to inflexible over here in the US), with either the original installer or one that supports that configuration.

If by Not battery ready they meant an inverter that is NOT a Hybrid inverter, then such an inverter is not by itself capable to isolate itself from the grid and produce power from the array and a battery during an outage.
That said, some battery systems like the Tesla Powerwall CAN be retrofitted to such an inverter, as they provide a Gateway and a battery management that allows a regular inverter to work that way.
If Tesla is available where you are, then any Tesla Installer could add the Powerwall to your system afterward.

I actually do not know of any other battery system right now that can be retrofitted on a non-hybrid inverter, so your options may be more limited

[Matt Green]

Hi there, Thanks to Mike 134, J.P.M. and Scrambler for all the suggestions. Indeed I'm very new to this. Ive had to knock down and re-build a house at short notice. Unfortunately I spilt washing liquid on my system and the monitor keeps shutting down. I have ordered a new monitor for tomorrow and will be able to reply to all your excellent suggestions, thanks again.
Matt

[Calsun]

Solis inverters are the best one can buy at this time and the 5G versions are battery ready as you mentioned. I would also look at the number of strings supported as it generally is better to be able to separate panels into groups and feed in on separate strings. This makes it easy to place panels in different locations or with different amounts of tilt or on different sides of a roof and maximize the power out of the inverter.

There are different 5G inverters available from Solis and easy to download a product sheet that provides the specifications for each model. Their standard 5G inverters only handle 4 input strings which may not be enough for your large installation.

Have the Solis WiFi adapter and firmware USB adapter added into the package.

Battery costs are continuing to decrease so I would only put in the bare minimum at this time. The Tesla power banks can catch fire and produce toxic fumes so best to have them installed outside of the building envelope. One can expect one to provide enough power for 2 days of power demand for a house. I priced out the cost of one and decided to put the money in a fossil gas generator instead. The generator can run indefinitely and where I live the power outages can be for 2-7 days duration.