Solar PV: Replace Inverter Vs Full System Upgrade

My 5kw solar PV system (installed Jan’15, Perth, on single phase) is faulty, I think the inverter has failed and is out of warranty. I’ll get the condition of the panels checked but would expect another 10+ years out of them. We’d been generating about 20kwh daily from the solar PV while using 30+ kwh daily for a family of four, though I haven’t profiled our use pattern throughout the day.

I’m now considering what the best options from here might be given that tech has improved and I’ll likely get an EV within 3-5 years. I could simply replace the inverter and stick with the current setup for at least the next 5 years, or take advantage of incentives by upgrading the whole system to 8-10kw, perhaps with a medium sized battery, with the aim of reducing my reliance on the grid without going completely off grid. I’m not too bothered with maximising feed in tariffs. I’ll be able to afford a decent upgrade, but would want a reasonable chance of payback from grid savings within 10 years. I’m not keen to send the existing panels to landfill.

Thoughts?

Comments

  • Which inverter has <10 year warranty?

    • +3

      Almost all of them in 2015.

  • You'll find with STCs which only apply to the panels you would probably only pay a bit more for new system and you'll be able to get 6.6kw of panels with a 5kw inverter.

    Sounds cruel. My old 1.7kw system got taken by a guy locally who sent them to Lebanon because they have a failing power grid.

    • I thought there was some rule about not being able to claim STCs on replacement panels (not 100% sure on the ins/outs though)

  • My recent journey to ask sbout updating my system suggested a whole new getup was best option.

  • Used inverter for $300 on marketplace.

    • +1

      I reckon you can beat most of them down to $100 or less.

      Used invertors are worthless. No warranty and cost of installation makes it a risky proposition.

      • How much for sparky to install?

        • How long is a piece of string? Hard to find any tradie willing to get out of bed for less than $500 these days…

          Realistically, it's 30mins of work.

  • My Aurora 5kw inverter finally failed permanently in 2022 so I had the choice: upgrade the whole system or just change the inverter.

    Solar installer 1: Highly recommended the whole system be replaced, panels and all. Said there could be all sorts of problems if I didn't.

    Solar installer 2: Just recommended changing inverter. Was very puzzled as to why the other installer said the whole system should be replaced.

    I went with installer 2, and over two years later the system is humming along nicely.

    You're right about panels/inverter going to landfill. As my installer was heaving the 20kg+ inverter off the wall I asked if they're recycled. "Nup, that's the dirty secret of the industry. Everything just gets thrown out" was the response. There's a couple of kilos of copper and valuable metals in an inverter but it's not economical to recover.

    Now panels do lose efficiency with age. Usually about 1% per year. I know my 5kw system is closer to 4kw now, but it's still useful and I intend to get 20 years out of it before replacement.

    • Thanks for the comments. I'll likely just replace the inverter - aside from the recycling question, the other big constraint is the 5kw limit on inverter size in WA, which makes a panel upgrade almost pointless unless also excess power can be directed to a home battery. I'll go for a full upgrade with battery in a few years rather than add incrementally.

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