Solar Battery Group are currently bombarding our TV's and letter boxes with ads for solar batteries.
$3,740 is the current offer, which after some investigation appears to be a Hive 2.9kWh AC coupled battery.
The price includes the battery and inverter and installation.
We have been inundated with calls and emails from our clients asking whether this is a good deal or not.
I would never usually dream of posting information about a competitor and their products on our website (we sell batteries)
but the astonishing volume of calls about Solar Battery Group ads has forced my hand so that we can direct people to this page and get on with earning a living.
So here goes...
It's a very small battery. 2.9kWh.
Most of the batteries we install are a minimum of 5kWh with 10kWh being the most popular size, to cover overnight power use.
At time of writing the price of power in Perth is 29.5 cents and most people are getting a 7 cent feed-in tariff (REBs).
If you sacrifice 3kWh of your surplus solar power to charge the battery each day, then that makes the value of the battery 65 cents a day.
(29.5 - 7) * 2.9 = 65 cents.
65 cents * 365 = $237 value from the battery a year.
Therefore if you spend $3,740 and get $237 benefit a year, you will have your money back in 15 years, which is 5 years past the battery warranty, and probably the expected life of such a lithium battery.
Should you buy one?
It's too small, and too expensive to be of any practical use but they will sell shed loads of them because TV ads work.
On the plus side, it's not a fortune for many people, it's certainly a bit of fun, and a bit more self-sufficiency.
I'm a little concerned as to how it may conflict with solar inverters with consumption meters (smart meters) but haven't done enough practical investigation yet to be sure.
There is another thing that I intentionally avoided introducing above that impacts more than the economics of the battery.
It would have been too confusing, but if you are game, read on.
Adding any battery to an existing solar installation will switch someone from a 7 cents (REBs) feed-in-tariff to the new DEBs tariff where the payment is just 2.75 cents until 3pm and 10 cents after 3pm. As about 12% of solar is produced after 3pm, let's call it an average 3.5 cents.
This actually helps the battery economics...29.5 cents less an average 3.5 cents * 2.9 = 75 cents a day, or $273 a year... an extra $36.
The halving of the feed in tariff for the rest of the solar surplus is likely to cost you about $175 a year, so in reality, this little battery will end up being worth less than $100 a year and give a 37 year+ payback.
The only way a solar battery can really pay off in a reasonable time frame is if it is large enough to soak up most of the surplus solar production and return it to fully power the house at night.
Then you don't care about feed-in-tariffs.