Why not go all the way and get one that runs for months off a cup full?
1 Like
Itâs possible, but you still need an approved device to automatically isolate the house electrics from the mains network.
Itâs a bit of a compromise, compared to a battery supported solution!
EG
Some battery inverters provide backup power on a seperate circuit to the remainder of the house. While others provide for a combination of power sources - PV, battery, generator and mains to be managed to ensure continuity no matter what. All legal and approved when installed correctly. Sunny Boy and Victron - not necessarily a product recommendation are easy to research for what is possible.
I use a Honda powered generator, because I have one. If I knew what I know now and still lived in North Qld Iâd have solar PV with a battery inverter able to run the essentials for 24-48hrs. Itâs the near perfect set and forget solution. Unleaded goes off within weeks, unless fuel stabiliser is used, while 20l does not go as far as you might imagine. The latest portable camping battery power packs look like a useful compromise. I think you can recharge from a 12V solar panel and charge regulator.
3 Likes
There are also gas standby generators available⊠about $10,000 to run a typical house. No worries about petrol going off or having to test run it on a schedule to use fuel.
2 Likes
Now that we have had our solar and battery system for 2 years, I have calculated the energy costs for the 6 years we have been living at our present home as it may assist others.
SOLAR SYSTEM PERFORMANCE
ANNUAL SYSTEM OUTPUT
SYSTEM DETAILS
- 6.6 Kw. 22 x Seraphim 300 watt panels. 11 facing East. 11 facing West.
- Sungrow SH5K-20 inverter.
- Sungrow backup box.
- LD RESU10 battery.
SYSTEM PRICE AND PAYBACK
Total installed price $15,733
Deposit $2,733
Qld Government grant $3,000
Qld Government 10 year loan $10,000
The system has slashed our electricity costs from an annual average of $1,979.21 between 2015 and 2018 to an average of $436.78 in 2019 and 2020, a saving of $1,542.43 less the $1,000 annual repayment to the Qld Government, thus a nett saving of $542.43 per annum.
However, the battery does not stack up financially.
If one uses the average annual amount of the solar output used to charge the battery of 1,813.50kwh and multiply it by the 16 cents difference between Tariff 11 and the F.I T., it is a saving of just $290.16 per annum.
The battery is really only viable to keep power on when the mains power goes down.
9 Likes
A company called Sunbank Solar is soliciting customers for battery installation with a Virtual Power Plant feature. Rather than cut and paste, a bit of hype and a bit of information all rolled into one page at
It is not obvious what all the downsides are to joining into what is essentially a âwide area neighbourhood gridâ of sorts. Thoughts?
5 Likes
There has been at least one I know of that was in Germany
A US example
Another German story
https://www.stromnetz.berlin/en/feed-in/micro-grids
I donât think it is much on the downside, indeed often it builds more security and resilience of the power network.
South Australia with Tesla involvement have a VPP:
A few others as well and if a household joins they get a subsidy:
One planâs FIT detail âsolar feed-in tariff of 45c per kWh for the first 300kWh of exported energy, 25c per kWh for the subsequent 300kWh, and 9c per kWh thereafterâ, not that FIT should be the only consideration as why a household should join.
5 Likes
Looking through the marketing.
This suggests the scheme would have closed last year October 2020.
The actual financial arrangements, potential benefits can only be quantified if one submits to requesting a quote, after providing various details for a full assessment - market proposal. Iâm always cautious of such tactics. Itâs impossible to judge the quality of the scheme without stepping forward. Those curious and less cautious may be just the right type of future customer?
In respect of being paid peak rates to feed in during high demand. There are various alternate schemes that offer to take advantage of these events, in a number of different ways. To consider itâs important to understand what has occurred historically provides no assurance of the future. IE the frequency, duration and value of peak feed in benefits in the future are not necessarily the same as any estimated from past events. Itâs a gamble more than a guarantee.
Note:
There is very limited feedback on Sunbank Solar as an installer.
The suggested scheme is potentially going to attract new customers wanting solar installs. The risk with any battery install is that the genuine savings from solar PV generation are being used to pay for a battery system, that reduces rather than adds value. The real winner is the system supplier.
It would be most useful to hear from anyone who has joined the Sunbank Solar scheme.
As a base case it would be useful to compare for Solar PV+battery any such scheme to common standard solar plans or the best TOU offer. If Sunbank Solar is such a great deal, surely we would have heard more?
4 Likes
Some interesting articles posted here.
Seems that designs are moving from simple solar panel systems that may or may not have battery storage but do not have the capability to operate off grid (islanding protection), to designs that are fully capable through smart controllers and inverters that can operate when the grid supply fails.
Maybe for a few hours, or maybe for many days if needed.
DC sources like PV and batteries, and AC sources like backup generators can all be used through smart power management systems.
I would not even consider a home system that was not designed and fully capable of operating off grid, preferably automatically. Looking closely at these recent developments.
1 Like
If the ALP wins the election some competition of sorts for both individual businesses who started up, as well as what might become the accepted norm - individual or community facilties, and how charged/supported.
4 Likes
The latest from ITP Renewablesâ Battery Test Centre:
2 Likes
I found the capacity fade graphs in the linked article and in the parent report very hard to follow.
In the linked article the chart labelled Figure One is not the same as the parent report and the meaning of the coloured dots is not explained nor is the method for aggregating raw data into the summary presented. Which batteries had a capacity that headed south very quickly is not given nor is any explanation why there seems to be two quite different populations.
In the parent report the data for the capacity fade charts is at least not aggregated but nor is its meaning clear. The capacity chart has no meaning given to the horizontal axis! Presumably each dot is one cycle and they were presented in time sequence. At least in the above summary the horizontal axis is labelled as charge/discharge cycles. The commentary on why there were outliers, dips and wobbles is desultory and not very informative. For example one batteryâs capacity did not decrease smoothly but in shelves. Why capacity drops abruptly from time to time and then stabilises one is left to guess. Also the separate graphs for each battery are all in raw capacity not percentage of maximum (as is the above summary) so comparison of batteries is difficult.
It looks to me that many of the batteries could do better and so could the reporting of the monitoring system.
2 Likes
They could, and there were many that had problems after installation and needed replacing.
It might be time for Choice to update their article with the new results.
2 Likes
It may also be time for Choice to seek the feedback of those members etc who have home batteries.
The sample size for Choice may be small, and the brand/model selection limited. It should at least give us some level of assurance or not. Is it 1 in 10 owners that have had a major fault, is it 1 in 20 or is it 1 in 2 or 3.
One possible interpretation of the lab test data is that every Tesla Home Battery sold will have required replacement within the first few years of operation, and most other brands replacement or remedy.
IE it implies there will not be a single satisfied home battery owner out there.
Given the lack of public complaints, the odds are that most home batteries are delivering and highly reliable in the typical home installation. The laboratory stress test may be creating a false narrative, except for the most extreme of circumstances. A home battery may be a nice to have rather than a simple economic benefit for most owners, and they are reliable and cost effective for those off grid.
5 Likes
An article regarding experiences with home battery storage during the recent storms in Victoria.
I am surprised that the Tesla was installed to be able to supply everything in the house.
Our system has the Sungrow back-up box so that when the mains power is off, it will only power a limited number of circuits including the fridge, the lights, the ceiling fans, and a few power points.
No aircons, wall oven, hot water booster, kitchen power outlets, and such like.
Ergon has advised of a scheduled power outage for 6 hours this Wednesday so I will be interested to see how much the battery is drained, especially when it has not been recharged by that time from the previous nightâs usage.
3 Likes
Surely this article just talks about the difference between systems designed to operate off-grid with enough generator capacity and storage capacity to power your home needs full time versus systems designed to simply reduce your grid power costs and provide a short-term backup if the grid is down temporarily.
5 Likes
Thatâs also how I saw it. Itâs a sample of three experiences. Itâs not a solution. There is no technical guidance.
The one âoff gridâ system was actual an on grid system that had access to the grid to make up shortfalls, or perhaps even export from the solar. For the outage it required a generator as backup to meet shortfalls in recharge due to lower solar PV output. The suitability of AGM battery technology in this instance would need some qualification.
The other two systems were less capable, but demonstrated the value of having a backup or alternate source of power short term. Why the Tesla Powerwall fell over is worthy of further explanation. It should not have relied on the owners to prevent it discharging too deeply to recover?
Note:
We have a Honda powered 4stroke generator for the essentials such as the fridge and house water pump. Itâs far less investment and useful for jobs around the place far from the house. Hot water and cooking including oven are all gas.
5 Likes
The only problem with the Tesla battery was its capacity. It ran out of power quicker than the owners expected. And trust me there isnât a lot of good sunlight on most winter days in the Melbourne area to recharge via the panels. Once charged again it is working fine, according to the article.
4 Likes
The articke may not be that well written. There are several contradictions. The ABC also indicated.
The couple got through the rest of a weekâs power outage with a $2,000 diesel generator. That irony is not lost on the passionate retired couple.
Tesla also advised there are two different ways to configure the Powerwall. One can explain what occurred.
"If however, the Tesla Powerwall does not include the solar inverter within the dedicated backup circuit, the solar inverter will not turn on during an outage, and in this scenario, the battery will be utilised until such time as it is empty.
âOnce empty it will not recharge until the grid power is restored.â
4 Likes
Well that is a crappy design and/or install is it not?
As I said, the difference between a system designed to be off-grid vs one to be on-grid but lower your utility bills.
1 Like
One Tesla battery to run a household with in floor heating, and other bits and pieces is just asking for a fail. Our daily usage can be 30kWh or more, we would need at least 3 Teslaâs just to survive a day at full pelt including breathing and temperature control needed support.
If we strictly manage our usage I would say 3 days and thatâs without some sort of recharging. All the other examples in that article didnât survive without backup recharging as I would have suspected was required. Was Tesla a fail, no it did as it was designed to do. Failure was that the users didnât understand the working of their system.
7 Likes
