Solar Panel Advice

• 

  stewy on 22/01/2022 - 03:12

  +1

  I'd only consider a battery if you get frequent power outages and put a lot of value on maintaining power during outages.

  What size (in kW) pool pump do you have and how often is it running?

  What is the input power requirement for your air conditioners and how frequently are they used?

  Are you prepared to install a timer and run your hot water system only during the day instead off using off-peak power like it probably was before?

  Can you show an aerial or plan image of your house, with reference to North provided?

  These days the starting point for solar is basically a 5kW inverter with 6.6kW panels, from there the limit is basically whatever your distributor allows. I'm not familiar with WA rules but from what I can tell WA requires export limiting to 5KW and you need it DRED controlled (you'd be wise to talk to people in the area with DRED enabled inverters to see how often their inverter is being switched off due to excessive solar power being fed into the grid).

  Pending answers to the above questions, I'd be thinking you are probably a heavy enough power user to justify a 7 to 10kW inverter with an extra 33% of panel capacity.

  I'd also err on going the side of a bit larger than needed, to help ensure you get enough power on overcast days (eg. my 8kW inverter in NSW is often only doing around 2-4kW on some of these crappy overcast days that we have had all through summer).

  If someone is using electricity during the day, will there be excess capacity that the battery can store?

  All depends what size system you install. But I think you sound like a power user that could shift a lot of their consumption to the day time and thereby minimise the amount of power you would need in the non-solar generating hours.

  • 

    Quantumcat on 22/01/2022 - 07:51

    +4

    I'd only consider a battery if you get frequent power outages and put a lot of value on maintaining power during outages.

    Batteries don't automatically provide this. You have to pay extra to get blackout protection.

• 

  Quantumcat on 22/01/2022 - 07:52

  +1

  Go to solarquotes.com.au and read a bunch of articles, it will answer every question you could have and you will learn what sort of system you need. Then apply for quotes through their site, pick one out of the ones that come and do a site visit, and use the information you learned in the articles to know which is the best value for money.

• 

  Wt133 on 22/01/2022 - 08:06

  +1

  Was looking into a battery storage when I had my solar system (5kw) installed. The pay back period isn't there yet for battery units after 20 or so years then unit needs to be replaced. One battery most likely wont be able to fully power your house fully with the AC, pool, hot water heater. You are better off using the money you would spend on a battery to put more solar panels on your roof and taking advantage of your peek power export during the day.

  With the pool out the pump on a timer to come on around 10am. Use the delay start on your washing machine to do a wash when the sun will be at its highest then hang it out when you get home or put it in the dryer. same as for your hot water system get an electrician to put it on a timer for around midday when you would be generating the most power

  In my area of NSW every house pretty much has solar. The inverter has turned itself off only 2 or 3 times in the first year. probably because too many people have solar but the power company sorted that out and seems to be rock solid now, had the system for 3 years.

  Keep a look out with your energy supplier and compare the feed in tariffs they can vary quite a bit. and make sure the quality of the install is up to scratch. You do hear some horror stories of bad installs going on.

  • 

    avoidfullprice on 22/01/2022 - 10:01

    Keep a look out with your energy supplier and compare the feed in tariffs

    Perth WA resident has one choice only

• 

  Hiroko on 22/01/2022 - 08:28

  Do it once and do it right.
  look for a local installer that uses in-house certified technicians, make sure they come out and do a proper site inspection prior to installation.
  if budget allows install a Fronius inverter and ask the installer to hook in relays/contacters to your hot water and pool pump circuits to run them off solar.

  • 

    stewy on 22/01/2022 - 15:29

    Fronius are overpriced. Sungrow are decent , have a 10 year warranty out of the box (unlike the 5+5 that Fronius do) and are significantly cheaper. If you want an import meter connected to the inverter, then that is also cheaper too compared to Fronius

    10 year warranty is more than sufficient as I'd say there is a good chance that around the 10 year mark it will be feasible to install batteries.
    So at that point you'd consider replacing the inverter with a hybrid inverter to use DC coupled batteries.

• 

  mskeggs on 22/01/2022 - 09:30

  Battery isn’t an economic decision, it is if you are most concerned about carbon emissions. Although it will likely pay back in around 10years, and protects somewhat from power price rises (so a better deal for somebody like a retired person).
  Seems like you use a lot of electricity, so I second stewy’s suggestion of 6-10kw of panels as the right ballpark.

  Don’t buy the absolute cheapest, make sure the installer is the one doing the work, not a call centre subcontracting. I reckon it’s worth paying a little more for an established local business, but not excessively.

• 

  avoidfullprice on 22/01/2022 - 10:05

  +1

  If someone is using electricity during the day, will there be excess capacity that the battery can store?

  You need to time your consumption throughout the day.

  If you have your dishwasher on, pool pump on, electric hot water boiling, oven on, aircon on all at the same time, you could be drawing from the grid.

  End of day, your total generation may be higher than your total consumption, so yeah the battery maybe charged during the day.

  Also please take time to understand for example what a 6.6kw solar energy system actually means. You don't get 6.6kw all day, but only peaks at that. Read up on inverter size as well.

  • 

    Quantumcat on 22/01/2022 - 14:31

    +2

    6.6 would only peak at 5kw as that's what the inverter would be

• 

  ESEMCE on 22/01/2022 - 10:49

  +2

  Yeah, forget a battery.
  As your aiming to use the power you're generating, you don't care about total output, you care about flattening the production curve across more hours.

  Assuming you have the unshaded roof space, place panels on East and West.
  Something like 2.5kW East, 4kW West. (More West as you trend to use cooking and air con more in the afternoon)

  This will maximize your useful production for the most amount of time, rather than maximize the total output.
  North facing panels would maximize total output, but their optimal generation time will start later in the morning and drop off earlier in the afternoon.
  And a lot of midday production would just go to export.

  You need less than 1kW of production to cover lighting, computer and printer power consumption.
  Pool pump will consume another 1kW or so.
  Air con will suck heaps of course, as does dishwasher/ washing machine when heating water.

• 

  KaTst3R on 22/01/2022 - 12:12

  The general consensus currently is that a battery cost too much and is not great for return on investment as the payback period is about 10-15 years which by the time you breakeven, the battery would probably need replacement. So this asset doesnt generate you any positive benefits.

  Aircon is the largest power draw will require 3-5kw per hour. So your overall system has to be at least 10kw to make sense. Do note that the efficiency of a rated system is usually only 80-90% due to multiple factors like shading, gradient of your roof, season, temperate, etc. So a 10kw system will only generate 8kw to 9kw or so at max in the real world. During peak winter, the entire system will probably be only at 30-50%.

• 

  mskeggs on 22/01/2022 - 17:34

  +1

  While you can get very involved in optimising the size/location/output, the returns accrue highest at the beginning. For example, any 3kW system will deliver better returns than the second 3kW to make 6kW total, and better again than the third 3kW to make 9kW.

  But given how cheap solar is now, and your high usage, I’d just get 10kw, with an inverter at least 6kW or 8kW. If you miss a little power export, because in the middle of the day you produce more than the inverter can handle, big deal. You will make up for it in winter, when cloudy and when you are using more than the total output.

• 

  Euphemistic on 22/01/2022 - 17:49

  It would be worth assessing how much power you actually use during the day and at what times before installing. No point getting a system that won’t meet your demands.

  Battery is unlikely to be worth it. Add to that, I just watched a YouTube clip doing valuations and found (in USA) it’s cheaper to get battery capacity in a vehicle that can also power your house. F150 lightning is cheaper per kWh than Tesla powerwall equivalent.

• 

  vegemite2008 on 23/01/2022 - 02:13

  Thanks for all the replies.

  I have learned heaps. Thank you :-)

• 

  vegemite2008 on 23/01/2022 - 13:46

  I am glad that I posted this. I thought a batter would be a smart investment.

  I think it is better to install a more powerful system with a good inverter that have the option of easily adding a battery later on.

  WA feed in..

  Electricity exported between 3pm to 9pm earns 10 cents per kilowatt-hour
  Electricity exported between 9pm and 3pm earns 3 cents per kilowatt-hour.

  Batteries coming down in price and becoming more efficient. Thanks once again

• 

  vegemite2008 on 11/02/2022 - 19:49

  Most companies seems to offer solar panel systems without a battery (in WA) at similar prices. More established companies might charge $200-$400 more compared to newer companies.

  My question is, have you been able to negotiate a better price on systems (compared to the advertised price)?