Two Redflow ZBM2 zinc-bromide hybrid flow batteries
Here is some information about my home energy storage installation.
The live system (with performance charts) can be viewed here.
The Victron Energy Hub-4 software in the Victron CCGX optimises the system for solar self-consumption. In the presence of excess solar generation, that energy is applied first to the home loads, the surplus to charging batteries, and the surplus beyond that to export to the grid (if connected).
When there is less solar generation than the home loads require, those loads are supported by the solar energy that is available, which is then automatically augmented with battery energy. The grid is used as required to further augment home demands as required (either when the peak load exceeds the battery inverter capacity or when the batteries are fully depleted).
The system allows the configuration of an adjustable reserve percentage of the storage battery energy to be kept in the batteries in case of grid failure. It also allows the system to be charge up proactively from the grid in periods of low grid energy cost or ahead of incoming bad weather that might increase the chances of a grid energy failure.
The system automatically reverts to off-grid mode if the grid is unavailable, including recharging the batteries from solar energy to help support loads in the home for extended periods during such outages.
The performance of the system is very good. On a sunny week, most of our home electrical energy is provided by direct and indirect (battery time-shifted) energy. Of course in weather conditions offering reduced solar energy, more grid energy gets used.
Like a home rainwater tank system, this system acts as an electrical energy buffer, doing the best it can to avoid the use of grid energy, and prioritising the use of battery energy first.
This post was published on November 28, 2016 3:09 pm
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The only people talking about Redflow's batteries are Redflow.
That's because of the lack of public exposure of the technology. It will be a viable competitor to Tesla and will get my custom if it produces the good at the right price. :-)
I think for most low energy use households the 10KWh with 100% DOD would be perfect.
However, I have heard the battery needs 2 hours self maintenance downtime per day? which would mean another battery for those keen to go off grid?
Other advantages would be a probable longer life than others on offer ATM and recyclable at end of life.
Hopefully the price will have come down by 2028 when my PFiT expires.;-)
Or maybe sooner if I buy an EV bigger than my electric bike!
And I'll keep some candles handy for those 11 minutes of blackouts per year.
I don't see why the solar panels only contributed at most about 16kWh/day during favourable weather when one expect a 10kW system to output about 40kWh/day. Are the missing kWh charging the battery? In which case the total is 29 kWh maximum. Does this reflect a low energy-out/ energy-in figure for the Redflow battery?
Yes, it does seem a bit low on electricity production. A 5kW PV system should do the job. In NSW, there's a 5kW limit on PV sizes for one phase connections to the grid. :-(
Does the house have solar hot water (ie. solar-thermal)? In Australia hot water is responsible for 28% of average house electricity consumption and is obviously a big burden, and inefficiency, on solar-PV (even if via battery or "off-peak" etc.)