Redflow launches 10kWh “ZCell” into Australian home battery storage market | RenewEconomy

Redflow launches 10kWh “ZCell” into Australian home battery storage market

Buyers of Redflow’s ZCell battery storage product launched on Wednesday won’t get much change from $20,000 for the 10kWh device. But Simon Hackett says Redflow will match Tesla and other high profile brands on price per kWh and on performance.


One Step Off The Grid

Australian battery storage developer Redflow on Wednesday launched its household battery storage product – dubbed the “ZCell” – which it expects to take on Tesla and other high profile international brand names in what is expected to be the first mass market for battery storage in the world.

The 10kWh ZCell will sell for between $17,500 and $19,500, pricey by comparison with its competitors. But Redflow says its ability to discharge 100 per cent of its power, and its longer life, and its greater size, means that its delivered cost of energy will match its rivals.

redflow logo zcell

“ZCell breaks many of the rules that apply to legacy batteries, making it ideal for the home market,” said Simon Hackett, the IT guru who has emerged as executive chairman of Redflow and its largest shareholders, and who has taken responsibility for writing in the “smarts” that will enable the battery to integrate with home energy systems.

“ZCell lets you discharge 100 per cent 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. ZCell is a unique flow battery that loves to be fully charged and discharged daily.”

Hackett expects the market for battery storage to “explode” – due to a combination of Australia’s high electricity prices, its high level of rooftop solar installations, a desire for more “independence” from utilities, and because people care about the environment.

Hackett says he is the biggest fan of the Tesla brand in Australia – having bought its $250,000 roadster and several models of its Model S electric vehicles. And he says that Tesla’s marketing success for its Powerwalls has been a “catalyst” rather than the cause of huge consumer interest.

But he says that Redflow has a better battery storage product for households.

“We have got a better technology for stationary storage,” Hackett told RenewEconomy in an interview. “Tesla will sell a hell of a lot of Powerwalls. But it’s not a matter for them to lose or for us to win.”

Hackett says the reason for his optimism is the “durability” of the Redflow battery. Unlike competitor batteries, it can fully discharge, is long-lasting, and does not have overheating issues.

Residential installations for the ZCell battery will start mid year, initially via an introductory rebate offer to eligible shareholders in the ASX-listed company. Full details of ZCell and the opportunity to reserve a ZCell battery are available at

Redflow says its battery storage product, using zinc bromine flow battery technology developed at the University of Queensland, and then later through the company, will allow people to ‘timeshift’ solar power from day to night, store off-peak power for peak demand periods and support off-grid systems.

The Australian company is playing hard on its durability, emphasising the fact that ZCell is “warranted to deliver its full 10kWh of stored energy each day for as long as 10 years.” During that period, it says, rival lead acid and lithium batteries can lose a significant portion of their storage capacity.

It is also emphasising the fact that the materials in the battery – mostly plastic, aluminium and steel – are easily recycled. Its fluid electrolyte, less environmental benign, can be re-used or repurposed. And there is no risk of explosion or “thermal runaway” that can afflict other products.

Redflow says the core of ZCell is a Redflow ZBM2 flow battery, which will sit in a “custom-designed outdoor-rated enclosure” that sits on the ground, connecting to a battery inverter/charger unit that delivers stored energy to the home.


The battery is managed and protected by a sophisticated on-board computer control system, written and developed by Hackett’s IT team at his company Base64.

Hackett expects the first large batch of systems to arrive in the country mid-year.

“Redflow does not set the total installed system price as we supply only part of the overall system,” he said in a statement.

“Final system cost will be set by your system installer, depending on your requirements and upon any additional items, such as solar panels, you may elect to include. We expect the fully installed cost of a 10 kWh ZCell-based energy storage system will start from $17,500 – $19,500 including GST.”

He said it was easy to construct larger systems that use multiple ZCells where more energy is required, such as in larger homes or commercial installations. The ZBM2 core battery is already delivered in systems all the way up to Redflow’s grid-scale Large Scale Battery (LSB), which features as many as 60 batteries in a single LSB.”

Redflow is installing some exemplar ZCell systems between now and June and is also inviting energy storage system designers and installers to register their interest to become a qualified installation partner at It is also offering eligible Redflow shareholders a $1000 rebate for installation of a ZCell-based energy storage system.

This article was first published in One Step Off The Grid, where you can read more stories about people’s experiences with solar, storage, energy efficiency and other technologies, both on and off the grid. To sign up for the weekly newsletter, click here.

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  1. Pfitzy 5 years ago

    Will be interested to see how the entry cost affects the market for these over the next 12 months. Early adopters probably don’t see it as an issue, but bringing it to the average consumer is going to require considerable effort.

  2. Phil 5 years ago

    I don’t think you can compare this technology to other common in use battery types , and especially for off grid users. Looks like this technology is aimed at “On Gridders” only . Unless you have 2 of them , and that’s getting close to $40k ! Here is why ………

    For “off gridders” The 3kw (5kw peak) max output will not be enough for many so will require 2 units. The 80% efficiency (i assume round trip) is similar to lead acid wet cells.

    Also the charge is limited to 2.5kw so if you have a 5kw solar array and are not home to use the excess it may be wasted , especially in an off grid setup. 2 units with your solar array split in 2 would solve this and give you better redundancy.

    If you require continuous power 2 units are needed as there is a zinc strip maintenance cycle required every 120 hours and the battery disconnects itself from any loads to do this.

    Specs taken from the ZBM 2 site
    And here is the Z cell site where a link took me to the ZBM2

    There appears to be a ZBM 3 with a 5kw (7.5kw peak) capcity which could be better for off grid use as it may improve the solar charge current capacity .Link Here

    • onwireless 5 years ago

      Very good points there Phil.
      I had sent a msg to redflow regarding a quote for 2x ZBM 2 a few months ago. As yet no reply.
      An off-grid 700AH x 48V system equates to over 30kWh capacity.
      De-rate this, given the better longevity, and thus long term capacity as compared to LA batteries…say, 20kW is going to cost around $40K which is what we were quoted for a fully managed 33kW LiPo system.
      If there is a zinc strip maintenance cycle required every 120 hours, then at least two units surely will be needed for off-grid.

      • Phil 5 years ago

        Another point to remember is the $40k cost has to be funded and replaced at some stage too.

        Redflow indicate that’s about 50% as only part of the system needs replacing.So that’s $20k when it’s due.

        As it’s a proprietary technology there is some risk they may not be around for that to happen in 10-20 years time. And in many industries i have worked in when availability is limited the prices rarely go down.

        You could always replace the whole thing in 10-20 years with what is mainstream at the time and that’s no big deal . And possibly cheaper. But the 50% replacement cost claimed i would consider carefully in any cost projections.

        With storage batteries the prices are going down and there are many manufacturers and suppliers.

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