Whats chewing my power? Diagnosis help!

Rorschach

Paid $250 for this custom title
Those solar assist things on your roof also have a low temperature switch to stop the unit freezing and bursting all the pipes. If it's a cold night 0-4 degrees (or whatever it's set to) the pump will run and send hot water up to the roof to stop it freezing. Sending cold water back into the tank..... You get the idea..
I'm in Perth, chances of that coming on are pretty low

do you have an offpeak meter for your hotwater?
For water or power? Regardless, no.

If you hadn't mentioned a timer switch on your hot water system, I'd be leaning towards a "controlled load" electric hot water system. It's what we've got in our house and it kicks in at 12am then runs for 30 minute cycles through to between 2am 3am depending on the amount of hot water we've used.

As it's a Controlled Load circuit operated by the network operator (Aus Grid) in our case, the Sungrow system doesn't actually pick it up, but the total figures from our retailer Discover show it. Have yet to have any word on being able to get visibility of that through the Solar system, but as they're 2 separate circuits it may not be possible. Still in discussions with the solar installers.
Its a solar boosted unit (Chromagen 30SV) with only a GPO plug as far as I can tell, so should be able to stick a timer on that?
 

ozzybmx

Níl aon tóin tinn mar do thóin tinn féin
One of these might help you monitor what's going on, I've had one for quite a few years now but the house I am in now is 3Ph so I could do with the 3Ph model. The aircon and kitchen run off the blue phase so I monitor it only.

2.5kw for 2 hours at the same time sounds like a timed load. Not that you wouldn't know but if its a newish house (to you) check you dont have another small water heater for the other side of the house tucked up in the attic.

 

Rorschach

Paid $250 for this custom title
One of these might help you monitor what's going on, I've had one for quite a few years now but the house I am in now is 3Ph so I could do with the 3Ph model. The aircon and kitchen run off the blue phase so I monitor it only.

2.5kw for 2 hours at the same time sounds like a timed load. Not that you wouldn't know but if its a newish house (to you) check you dont have another small water heater for the other side of the house tucked up in the attic.

Thats pretty much what my inverter does, so don't think that'll help in this instance. I'll see if I can grab a screenshot off my phone as that might help

Edit: see below, a couple from this week. No heater or anything on, but a similar power drain at different times. The later one on 27/4 is likely due to the wife having a shower and the water heater kicking in, and is a comparable load to the mornings.


 
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Bit of a random one, but a wide spread of experience here so thought I'd ask.
Late last year, I had a solar system put in with a smart power meter and a wifi inverter. This means I can have a look on my phone and work out when I'm using power, how much I'm sending to the grid etc. The bills are getting smaller, which I'm happy about, particularly as the wife and kids are at home during the day, so using the 'free' power rather than drawing off the grid.
Since I started looking at the data, something has been chewing my power up for a few hours between around say 3am and 5am. This isn't every day, or at the same time every day. My first thoughts were that it was the water heater coming on when the temperature dropped below a certain level, so I put a timer switch on there but it doesn't seem to be that.
I don't have anything that should be sucking power, other than the standard household appliances that would be on all night like the fridge. Everything else is either off or on standby.
Anyone any ideas, other than my neighbours stealing my power for a hydroponic set-up?
374688
 

Freediver

Likes Bikes and Dirt
Bit of a long shot but when you got your new hot water service did they leave an old electric one plugged in in your roof?
 

fatboyonabike

Wheel size expert
the only thing I can realistically think of is a hot water booster element, as being 2.5KW it wont be a plug in device
2.5KW equates to over 10 amps and therefore will not be fitted with a standard appliance plug and lead, which leaves either a 15A appliance or something hardwired like an oven or HW unit
 

mark22

Likes Dirt
I'll bet it's your HWS having had a PV system for over 10 years and a Heat pump HWS for 15 (on a timer) I have learnt a bit about it.
Speaking generally to all have a look at your bills guys and see how many KW your HWS is using, it is substantial.
IMO a solar HWS is not worth the extra intial cost and installation compared to a Heat pump unit (on a timer) with its installation cost the same as a std HWS. Great for retro fitting.
I am located in SE Qld for ref.
It would not be so a atractive in TAS mind you neither would Solar.
 

mark22

Likes Dirt
You might be surprised...
Top 10 Sunny cities.
View attachment 374713
Depending on how much cloud of the partly sunny value during the day has. The stats could be a bit misleading here.
If you watch your solar output via the Inverter panel when a cloud comes over output drops to a fraction of the full sun output with overall output well down on partly sunny days.
So during Hobart's 149 partly sunny days probably wouldn't put many kW out.
Mine will put out up to 20kw on the best day down to about 1.5 kW yesterday with a day where the sun hardly came out ,( partly sunny?)
 
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Rorschach

Paid $250 for this custom title
Bit of a long shot but when you got your new hot water service did they leave an old electric one plugged in in your roof?
Was a new build, so no other hot water systems installed

the only thing I can realistically think of is a hot water booster element, as being 2.5KW it wont be a plug in device
2.5KW equates to over 10 amps and therefore will not be fitted with a standard appliance plug and lead, which leaves either a 15A appliance or something hardwired like an oven or HW unit
I thought that too, but everything I can find only shows an appliance plug. The only other cable coming out of the system goes to the solar panels and is a signal cable only
 

Calvin27

Eats Squid
I thought that too, but everything I can find only shows an appliance plug. The only other cable coming out of the system goes to the solar panels and is a signal cable only
Don't trust wiring and labels they are usually wrong.

I've had random appliances on wrong circuits and all that. It seems sparkies just wire to whatever is closest to them haha.

At that power level you are looking at major appliances, heating/cooling, hot water, air con, ovens (lol?).

I'd start by trying the following:
  • Switch all appliances off at the power point.
  • Check all the hard wired appliances for timer settings.
 
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