Redflow launches ZCell battery to rival Tesla Powerwall


news Australian battery specialist Redflow has launched a residential energy storage solution called ZCell – a product that will rival Tesla’s Powerwall, which launched in Australia in late January.

Like the Powerwall, the product allows users to store energy derived from solar or other sources of alternative power in the day and use it at night, or store off-peak power for high-demand periods.

The system includes a battery made from easily recyclable or reusable components and can store 10 kilowatt hours (kWh) of energy.

“Importantly, ZCell enables you to reduce your carbon footprint and reliance on fossil fuel-generated electricity by storing energy harvested from your solar panels. ZCell is primarily made of plastic, aluminium and steel, elements that are easily recycled, while its fluid electrolyte can be reused or repurposed,” said Redflow’s Executive Chairman Simon Hackett.

At the core of ZCell is a Redflow ZBM2 flow battery housed in a custom-designed, outdoor-rated, free-standing enclosure looking rather like a tower PC computer.

ZCell’s battery is managed by an onboard computer control system, enabling on-site battery commissioning, monitoring and control using a smartphone-compatible Wi-Fi interface.

“ZCell lets you discharge 100% of its total stored energy every day, whereas other battery types can require a significant amount of their underlying storage capacity to be locked out to prevent battery damage and to extend battery life,” Hackett said.

The system is warranted to deliver its full 10 kWh of stored energy each day for up to 10 years, he added. This compares favourably with lead acid and lithium batteries, which can lose a portion of their storage capacity over the same period.

Redflow added that ZCell’s flow battery design increases safety over other battery types, since mechanical damage “does not risk explosion, dangerously high current output from short-circuit or ‘thermal runaway’”. Additionally, ZCell’s electrolyte is fire retardant, rather than a fire risk.

Further, the system can perform without the need for external cooling until an ambient outside temperature of at least 45ºC.

The firm said it expects the fully installed cost of a 10 kWh ZCell-based energy storage system will start from $17,500 – $19,500 including GST, although this may vary.

“Due to ZCell’s sustainable 10kWh energy discharge capability, the cost per installed kWh – that is, the purchase cost divided by output capacity in kWh – is highly competitive with other systems on the market, while offering superior technical features,” said Hackett.

Where more energy is required, such as in larger homes or commercial installations, larger systems using multiple ZCells can be designed. In fact, the ZBM2 core battery is already delivered in systems featuring as many as 60 batteries, he added.

Residential installations of the ZCell system are scheduled to start in mid-2016.

Image credit: Redflow


  1. Good to see an Australian company doing good things and leading the way in the renewable sector.

  2. So that’s what Simon has been up to. ;)

    My questions are two-fold:

    How are they achieving a daily sustainable 100% drain, which is the Achilles heel of battery technology? Does that also mean that there is no “cycle limit”?

    Is there a wall mountable model? I’m thinking environments where I do NOT want these standing on the ground (our stables, for example).

    • Looks like they’ve discovered some new battery/cell tech as you’ll notice they don’t mention the type of cell they are using other than their ‘branding’. That and 100% discharge etc.

      looking at it I’d say wall mount = shelf.

    • It’s a Zinc-Bromide ‘flow’ battery.
      It uses liquid electrolytes, and the picture is deceiving.
      The Flow battery weighs 290kg and holds 200 litres of electrolyte.
      The electrolyte is not flammable, but it is mildly toxic

      • The electrolyte is not flammable, but it is mildly toxic

        Toxic mostly due to it being corrosive.

      • 290kg? Wow, no wonder it’s designed to sit on the ground. You’d need a seriously sturdy wall to bolt that onto!

    • Does that also mean that there is no “cycle limit”?

      I believe the warranty covers 30MwH.

      I’ve read elsewhere that you can replace the electrode stack and pretty well get another 10 years from it, but I can’t find that anywhere on the RedFlow site, so YMMV.

        • Yeah, there are still in the process of testing various electrode materials and that there are still some decent gains to be made.

          I’ve been following them for a while now. Redflow started out supplying really big units to mines and other industry types (up to 660kWh).

          It’s interesting tech. I especially like how it holds it’s charge no matter how long you let it sit for, and that you can 100% cycle it and it doesn’t harm it.

  3. Looks decent, the genuine 10kWh’s charge discharge per day for 10 years is a winner too, the Tesla system is only 6.5kWh useable capacity and will likely cost about the same once fully installed.

  4. >How are they achieving a daily sustainable 100% drain, which is the Achilles heel of battery technology?
    It’s a flow battery, and the chemistry works differently.

    >Does that also mean that there is no “cycle limit”?
    No. The electrode stack is rated for about 40,000 kWh, which works out to about 10 years of daily 100% cycling.

    >Is there a wall mountable model?
    No, but you could build a sturdy wall mounted structure to support it.

  5. I’m hoping the price comes down on them a fair bit, I’ll need two (well, 21Kwh anyway).

    • With a max continuous load of 2.4kW I’ll need 2 as well, heck I’d need 2 anyway as our average consumption is ~25-30kWh’s per day.

      • Have you done all the power saving stuff already? Mines after switching to LED’s, low power washer, etc, so I blame my PC for it being so high :o)

        • Yeah LED’s for every light, power saving boards on the TV’s etc and I only run 2 servers now so our baseload draw is down to ~443 watts when not home.

          Our issue is the 90’s era reverse cycle AC we have for upstairs, I’ve cut down consumption by installing a Nest Thermostat (manually programmed, learning is bunk imo) and we use the Skylark app to enable geo-fencing so we never need to worry about leaving the upstairs AC or downstairs heating on.

          Oh and the oven is Electric too.

  6. Still need to save $1700 in electricity costs over the 10 years each year to break even on one of these. So I know for me (my yearly total is under that) its not even close to being possible. When the price comes down in a few years time will be really interesting though!

    • Too true, I’ll need them to at least half in price before I plonk down for one, however when I eventually put a solar system on my current house I’ll make sure the inverter is battery compatible.

    • Bear in mind that power prices will go up and battery prices will go down the future. This is still early adopter stuff at the moment.

      On the other hand, if I lived in an area where the power wasn’t 100% reliable, I’d be looking very closely…

    • At $17,000 for a 10KWh system this is obviously priced at very wealthy early adopters.
      This is very disappointing for those of us who wanted to be self sufficient on a modest budget.
      I am surprised they didn’t pursue the modular approach taken with the commercial units and produce 5KWh units.

      • The 17k includes everything installed and the only thing missing are the solar panels.

  7. Simon jumped ship right at the best time.
    Telecoms is dead in Australia, but energy is the future!

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