House & Home I'm too stingy with my Solar

To be honest, the best thing is the backup, since July we have lost power 4 times, one of which was for 44 minutes. We only know about these outages from the logs, we don't physically lose power, the Battery kicks in with no interruption to power, we don't even notice a flicker of lights or anything, Computers and devices don't notice anything.

If your current bill is 2 bucks a day (1 of which will be your connection costs) then you are already set up pretty damn well so I wouldn't see a battery solution as worth the cost for many many years to come.

 

Yeah the backup ability is what I find the most appealling, although I only have about 1 power outage a year in my suburb, even with the recent storms. That said, the weekend storm did knock out power at my in-laws' place for 2 days.

I read somewhere (solarquotes?) that a better solution for back-up power is still a generator. Personally I think the best solution is being able to plug an EV in and use the car's huge battery as the power source; but I don't think that tech is feasible yet, especially for high-draw appliances.

Does your setup still supply juice to the oven / AC etc, or just power points and lights?

 

It won't help me on a 2 day outage, once the battery is drained i will lose power also (providing there isn't enough Solar coming in)

Tesla visited this technology (Vehicle to Grid or V2G as it's known) then abandoned it but Elon said they could revisit it:

Tesla could ‘revisit’ vehicle-to-grid technology, says Elon Musk

Mine is set to power everything including the pool pump, air-con, oven, fridges, absolutely everything in my house. My pool pump has just been replaced with an energy efficient one which use bugger all power but the timer is still set to only run 9am-12pm and 3pm - 6pm so it mostly runs off solar rather than the battery.

 

V2G would be awesome, go Elon go!

Surprised a pw can handle all that load - oven and AC I thought would be out of the question. Even my Hydrotherm water heater (far more efficient than typical electric water heaters) still uses 700W which is a fair chunk of the pw's 5kW sustained output limit.

Only one way to find out for sure I guess... when storage prices come down enough for my particular house/usage patterns

 

Yeah so one day (HOT day) we had the pool pump running, the air-con pumping hard, the dishwasher was running and the oven was on.

The house was using 7kW, the most I have ever seen it use. It took the 5 from the battery and the 2 from the grid but you could almost see the percentage charge in the battery dropping.

We tend to run things between 12 and 3 when the pool pump is shut off and there is sun feeding the solar, typically by then the battery is charged by then so we have 4.5kW coming off the roof to play with, it takes a little practice but you can time things fairly well.

At the end of the day though if we use a bit of power here and there from the grid, it's no big deal .

What I don't get is we have Solar hot water yet in the middle of the day if we take a shower our power shoots through the roof as if it is using the electrical element to heat the water. I might get someone out to check that the pump for the solar is working properly.

Biggest users of electricity in our house (In order):
1) Oven (It's a full family sized oven way more than we need)
2) Kettle (Not on for long though so no biggy)
3) Tumble Dryer
4) Dishwasher
5) Water heater
6) Washing Machine (We use cold water)
7) Air-con on a steamy day it will suck 1kW per unit, once it's at temp it drops to 100W

At night we use around 300W and in the evening if we are just watching TV and have a few lights on and stuff we use around 500W - 700W depending if we have the Air-con on. Our "constantly on" appliances that contribute to the 300W overnight are:
1 Computer (Full Desktop) with a couple of powered external hard drives, 1 NAS, 1 bar fridge, 2 fridge freezers, 5 TV's on standby, 2 Routers, 1 Modem, 1 Alarm System, various misc things like phones on chargers, the clocks on the 2 microwaves, Stick Vac on the charger and stuff like that.

I must say I am surprised how low our consumption is with all that we have running.

 

I just checked our max power draw in the past month and it was only 3.3kW average during a 7-7:30pm block. Suddenly a powerwall seems more appealling now

Our house 'idle' is similar @ ~280W. All standby-capable devices on standby, plus modem NAS gateway 2xAP 2xfridge etc

My maths for Powerwall pay-off time assumes we no longer consume any electricity from the grid... i.e. every kWh used is from storage or the panels directly. Any grid usage could push pay-off time out to 25 maybe 30 years

 

My pre purchase numbers looked like that but in reality you will use power from the grid, don't forget you will be pushing to the grid too. My $100 power bill last qtr was because the credit i earned by feeding the grid was almost enough to pay for the power I drew from the grid (Actual bill was like $105 or something and $91 was connection fee so I was down on the deal by $14).

As with anything you can make the numbers say whatever you like but ultimately I really wanted a PW2 so I made the numbers work that way in my analysis, I am just lucky that they will break even in real world usage because my initial numbers had me making $250 a quarter lol.

 

True, sub-optimal weather (or simply, winter) would force grid usage. My 'best case' simulation has all my usage coming from solar (either directly or via storage) - I currently average 11.5kWh drawn from the grid and 15.0kWh pushed back to the grid every day, both excluding 5.9kWh direct solar usage. So my best case was 17.4kWh solar/battery power, plus 3.5kWh exported each day.

I should probably try harder to use more solar power directly; have never had a week of negative daily net electricity cost:

 

Your numbers are pretty spot on, I just checked mine for the year (Year being since we got the PW2 which was around May 1st (ish)) and we have averaged 3.7 kWh to the Grid per day pulling from the grid our average is 1.76 kWh per day. Weeks like the last one don't help at all.

 

If it wasn't so expensive I would actually switch to 3 phase power, triple my PW2's and add another 2 5.5KW systems (You can only push 5KW to the grid per phase), this would ensure I had enough battery at pretty much most times to power anything we need and get through the bad weather spots without drawing from the grid, after all 3 batteries were full we would be pushing 15 to the grid during the day. It would be "unlikely" you would ever draw from the grid with this setup but it's both expensive and demands a lot of roof space .

 

Maybe I'm just an environment snob - but I put the battery on to save on fossil fuel usage and because I didn't want to have to "think" about what I could use when - it wasn't a cost-saving thing

 

Do you have "off peak hot water" ?
We do, as the off peak is a seperate meter it draws direct from the grid.
It is not connected/wired as part of the solar system, so any use is "grid use".

 

You've inadvertently become the opposite of an environment snob.

Excess energy that you generate would normally flow back to the grid, predominantly the houses around you. Your street as a whole places the same demand on the grid (and thus, fossil fuels) whether you have a battery or not. By opting for a battery, you've incurred the environmental costs of that battery's manufacturer and future disposal just so that you can keep your generated electricity within your lot.

Batteries are a completely selfish endeavour. Do it for your own benefits (e.g. instant backup, cost saving) not for the environment (you're doing more harm than good.)

 

But my retired next door neighbors AC goes wrr wrr wrr all day, whilst in the evening going wum wum wum until long after I pass out
(They cool all day, then it changes to heat at night)
So they get the pensioner discount, but must have a huge bill still.
So am I (or Dan) really selfish by storing the energy we produced for later use by not supplying energy back to the grid for our subsidised neighbor to burn a hole in the earth ??? (whilst getting a pittance/16c feed in from the energy company charging next door 34c).
In all honesty it should come down to a "user pays system", all these ads on TV (syd) telling us to conserve water must cost a fortune, I spent the money on efficient shower heads and dual flush toilets, I mulch my gardens and bang on the door if the kids are in the shower for more than 5 min, but a lot of people think water is CHEAP, and their use ends up raising the base cost for everyone !
Electricity is not much different (other than those base load coal power stations ).....

 

Agree 100%; just because physics dictates it works a certain way, doesn't mean it's fair (especially with the way billing/feed-in is set up)

 

@chylld
I dont agree that having our own batteries is affecting our neighbours. If I had my own battery, it would be because I chose to get it and I somehow managed to pay for it. My neighbours dont give me anything from their household, why would I be obliged to give them my spare sunlight? They can harvest their own if they want to.

Financially, this "luxury item" costs a small fortune, compare it to a Mercedes - does a wonderful job but something cheaper will still keep beer cold in the fridge and the TV running. If I manage my finances in a way to be able to acquire something that benefits me, that is my business and mine alone.

For example I have a humongous water tank which collects rain water and we flush the toilet with it. My neighbours dont have a tank and they dont have solar. They have a pool and a humongous Plasma TV going until at least 11pm each night. They pollute the air with fumes from their enormous 4WD and tear up the sand on Fraser Island. Any spare electricity I generate can operate my fridge and my washing machine and the neighbours can work it out themselves.

 

Of course it doesn't affect your neighbours... they won't know if you have a battery or not, and they'll continue to use power in the same way they always have.

What battery storage does affect though is the environment. How well you manage your finances, how little they deserve your solar-generated kWh, how much you consider your battery a luxury item; doesn't change physics.

Rainwater is a different matter. You're using resources that would normally go straight into stormwater to lower water usage. The electricity you enlarged your environmental footprint in order to store, on the other hand, could have had the same effect of lowering your street's demand on fossil fuels if you simply fed it back to the grid.

 

Fixed that
Also makes ice for scotch on the rocks, and keeps the milk cold for making white russians

I perceived the premise of the thread to be how having solar changes an individuals use of electricity
It doesn't really matter if you only use it for a beer/drinks fridge or into battery storage for another time
The main point is you are conscious of and thereby conservative with your use
(as opposed to some who think there's an endless supply )

 

I did it for the progression through the use of technology factor because i'm a massive geek, I just wrapped numbers around it to change my want into a need .

I wouldn't have done it if it was a significant negative impact to our finances though, there has to be a cost effectiveness element in the decision making process.