Home battery systems

Our project is not fundamentally a high tech one. Most of what we plan to do is deliberately relatively low tech and affordable. But a reliable and efficient off-grid electricity generation system is the one exception. A breakthrough in battery technology is a necessity for a renewable energy based society, but is the recently announced home battery system from electric car manufacturer, Tesla, it? As we’re in the process of building an entirely solar-powered house which will be finished when this new battery is supposedly going to be available, we are naturally curious about this…

The Tesla home battery is relatively small and light compared to lead acid batteries

The Tesla home battery is relatively small and light compared to lead acid batteries

The standard battery technology for renewable energy at the moment isn’t fundamentally much different from lots of linked-up old-fashioned lead-acid car batteries, and these need ventilation because of the dangerous off-gassing, and preferably should not be inside a Passive House envelope at all. but Tesla’s electric motor doesn’t work that way at all. It uses a very dense array of Lithium-Ion batteries, familiar to many of us as the basis for most rechargable batteries used in consumer electronics and presumably the new home battery system will be based on similar technology. Lithium-Ion batteries are smaller, less bulky and contain less toxic material than either Lead, Cadmium or Mercury based batteries. There are some suggestions that can be less safe and are vulnerable to overheating, and the consumer varitieties have a life in constant cycling use of no more than 3 years – athough supposedly 30 year lifespans are not impossible in theory.

If these batteries do become available when Tesla is saying that they will, at a price that makes sense, I’ve no doubt we’ll be among the first to install them. However, even if not, there are other less publicized Lithium Ion battery systems available or being developed from Bosch and others. What it means that is we are almost certainly going to have the panels installed but if we have to, wait until we can get a lithium ion battery array rather than buying lead acid.

5 thoughts on “Home battery systems

  1. David Post author

    As an additional comment, I think that it’s important to consider what is behind the recent decisions by right-wing governments in the UK, Australia and other countries from cutting state funding for wind and solar power just as these sectors are becoming vital in the fight against the worse effects of climate change. It’s not simply about reducing budgets and taxes. I would say that it is no coincidence that this is coming just as we seeing transformations in battery technology that will allow households and communities to generate, store and use their own electricity more easily. These policies are entirely the result of corporate lobbying from Big Energy (Coal, Oil, Gas etc. and Distribution companies) trying to prevent their hold on electricity generation and distribution being broken. In Australia, the growth of solar power has led to decreases in energy prices – in other words, whatever the corporate lobbies say about needing coal and oil to keep prices down, the drive for profit in the energy sector is being threatened and they know it and will do anything, even risk the future of life on earth to keep their profits.


  2. Richard Hoenich

    Hi there. I’m enjoying your blog and admire the wonderful work you did on this beautiful home. We are up in the Perth area in a home we built in 2018–and off grid. It’s built to Passive House specifications, but we opted not to certify the project. We’re just happy that we don’t use any heat from mid-March through mid-November, and when we need some in the dead of winter, a simple space heater from Canadian Tire running on low (750 watts) pretty much handles the load.

    Our batteries are repurposed from a 2014 Chevy Volt and have been working seamlessly with our PV system, installed by Quantum Solar in Kingston. The batteries were installed by Bobolink Solar here in Perth. What is amazing is that after pricing other Lithium-based batteries, and more traditional lead acid (and their accompanying maintenance needs) these came in below any other available options.

    Since it is now four years since your blog entries, perhaps you were able to install the Powerwall (version 2?). Otherwise, I am curious to know what you decided upon.

    Great blog…thanks so much for writing it.

    p.s. Before we opted for off-grid, Hydro One sent a tech person out to the property we purchased. Amazingly, it was the tech who recommended we consider PV/inverter/batteries/backup generator. Apparently, to have Hydro design a connection to the grid (the last pole was just over 150 metres from our property line) we would need to pay a non-refundable design fee of $3K. If the cost for connection would be prohibitive (they said it could run to $75K,) we’d be out the design fee. Best advice ever! And, from the big utility to boot.

    Liked by 1 person

    1. David Post author

      Hi Richard, great to hear your experiences. We’re at the point of considering a PV solar install now. We did get a quote from Quantum them a few years ago but it seemed very expensive and what they were offering seemed dated compared to what was available in the rest of the world – but that has been our experience with most of what is available in Canada. We never heard back from Tesla despite registering for both v.1 and v.2 of their battery roll-outs. I can only assume that Elon Musk was exaggerating (lying…) as usual, and that they only focused on high value customers in the USA. We will investigate Bobolink too – I had thought about using an electric car battery, but had figured that there are so few electric cars in Canada and most of them are so recent, that there wouldn’t be any available. Good to know you managed it!


      1. Richard Hoenich

        Hi David…I found that Rick Rooney’s prices were competitive with U.S. sources like Alt-E outside of Boston, when considering the exchange rate at the time. Of course, the Canadian dollar is somewhat lower these days. Prior to going with Quantum, we had been working with Chris Weissflog of Ecogen Energy in Merrickville. Amazing fellow, but his quote was about 10K higher than Quantum’s and didn’t include a generator. So naturally, Quantum appealed to us. Rick’s install team was terrific. The one service call to replace a defective panel was handled promptly.


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