Idle Consumption: Is It Standby or Overhead?

[OffGridInTheCity]

No, I'm assuming 30% system loss (difference between IN and OUT) before subtracting idle consumption. With 16 x 455W panels and 5 solar hours, theoretical IN would be 36.4kWh/day. With 30% loss that would give me (36.4 x .7) = 25.48kWh usable OUT. But then idle (overhead) would subtract another 3.12kWh of that, so my actual final usable power would be 22.36kWh. Final efficiency after considering idle consumption would be 61.4%. Ugh.

But, as I recall, you're including Sun -> Panel losses as part of the 30% before idle?

 

[forbin]

But, as I recall, you're including Sun -> Panel losses as part of the 30% before idle?

Yes.

 

[OffGridInTheCity]

Yes.

Inverter component has already been discussed.
Perhaps the thread should turn to Sun -> Panel -> Battery losses.

How do you break down you're losses pre-inverter? - what's your list of issues and what % do you assign for each.

 

[forbin]

Inverter component has already been discussed.
Perhaps the thread should turn to Sun -> Panel -> Battery losses.

How do you break down you're losses pre-inverter? - what's your list of issues and what % do you assign for each.

Good question. I haven't gone so far as to assign granular values. I just read at rimstar.org that overall system loss of 30% from sun to load was not uncommon, so I was using that as a rule of thumb. It did not mention idle consumption, so I was adding that after the fact.

 

[OffGridInTheCity]

Good question. I haven't gone so far as to assign granular values. I just read at rimstar.org that overall system loss of 30% from sun to load was not uncommon, so I was using that as a rule of thumb. It did not mention idle consumption, so I was adding that after the fact.

"....30% from sun to load was not uncommon..."
This would include inverter ( and it's idle)

My list is:
Sun -> Panel - depends on panel mounting, azimuth, angle, etc. Personally, I don't count this as it's dictated by my roof. One could do a custom framework on the roof and/or sun tracking to increase efficiency but the effort - cost, permits, is totally out of scope for a lot of us.
Panel -> Charge Controller - depends on wiring. I have <2% losses, let's say 1.5%.
Charge Controller -> Battery charge/discharge. Charge Controller MPPT has 1-2% loss. Lithium-ion charge/discharge cycle is 2% losses?
Battery -> Inverter -> Load. I have about 15% losses. Wire size can sometimes play a role here as well. But I have 24,000w of inverters (e.g. 240v@100a) so I'm OK with 15% losses.

Overall I have 1.5% + 2% + 2% + 15% = 20.5% losses. This is + or - a few % as I didn't measure some of these. Could be as high as 23%.

A list is a good way to break it down mentally for research and understanding options. It's also a good way to come to terms if you're comfortable with solar or not.

 

[labeeman]

Good question. I haven't gone so far as to assign granular values. I just read at rimstar.org that overall system loss of 30% from sun to load was not uncommon, so I was using that as a rule of thumb. It did not mention idle consumption, so I was adding that after the fact.

Another way to look at it is to consider a generator gas or diesel generator its idle consumption is over 130 watts and you have to pay for that in fuel cost, with panels the fuel is free for 5 hours a day with only a 30% loss, with a generator you have to pay for the fuel and only get 50% efficiency at best.

 

[Ellcon123]

It might be free from the Sun but still energy that is not being stored or used for something useful. I have a no name Chinese LF inverter that idles @ 17W. This is 40W better than my 1st inverter so almost 1kW saved. I consider that a lot wether it is a large or small % of my capacity.

 

[Mattb4]

I call it the cost of doing business. Or it takes energy to make energy. The thing to also keep in mind that the overhead does not stop at the output of the inverter. Loads themselves can eat your precious watts and give you little back for doing so. Many things have inefficient power supplies, always on power supplies, and consumer driven demands such as an always on yard light that add to your daily watt-hour needs. Solar power only works part of the day but your need for power is 24 hours.

Many inverters have a idle setting that reduces self consumption but the drawback is they then have trouble with small loads. If some method could be used to have every load communicate with the inverter to allow it to set how much it needs to output you might reduce total overhead.

Becoming a watt miser where you count each precious watt developed and consumed can lead to madness.

 

[Lilikoi_Heavy_Industries]

I call it the cost of doing business. Or it takes energy to make energy. The thing to also keep in mind that the overhead does not stop at the output of the inverter. Loads themselves can eat your precious watts and give you little back for doing so. Many things have inefficient power supplies, always on power supplies, and consumer driven demands such as an always on yard light that add to your daily watt-hour needs. Solar power only works part of the day but your need for power is 24 hours.

Many inverters have a idle setting that reduces self consumption but the drawback is they then have trouble with small loads. If some method could be used to have every load communicate with the inverter to allow it to set how much it needs to output you might reduce total overhead.

Becoming a watt miser where you count each precious watt developed and consumed can lead to madness.

Yes, the more power you can waste, it is typically a better thing. Let's all try to justify the purchases we've made instead of speak truth.

 

[forbin]

It might be free from the Sun but still energy that is not being stored or used for something useful. I have a no name Chinese LF inverter that idles @ 17W. This is 40W better than my 1st inverter so almost 1kW saved. I consider that a lot wether it is a large or small % of my capacity.

That is extremely interesting to me as I am also considering a no-name Chinese inverter that claims to idle that low (lower, in fact). I was a bit skeptical.

 

[chess-equality]

That is extremely interesting to me as I am also considering a no-name Chinese inverter that claims to idle that low (lower, in fact). I was a bit skeptical.

Got curious; taken a few days ago.

 

[forbin]

Got curious; taken a few days ago.

Is that 8W of idle?

 

[chess-equality]

Is that 8W of idle?

Yes. It has a little annoyance, though. My PC just hates it

5kw inverter drives speakers, USB ports, and oscilloscope-meter nuts

So here goes :( Only affects my 12v basic inverter. My 24v AIO doesn't have this issue. The setup: - 5kw 12v pure sine wave basic inverter, non-AIO, no built-in shore charger - 4 x 200Ah parallel bank - Monitored by Victron SmartShunt; batteries are good - Used only as backup; powered off most...

diysolarforum.com

But other loads, runs fine. Might be calling a technician to look at this soon. Or just don't use the PC with it

My main is a Chinese AIO 24v; haven't measured the idle as I'm lazy to move the SmartShunt over.

 

[forbin]

Yes. It has a little annoyance, though. My PC just hates it

5kw inverter drives speakers, USB ports, and oscilloscope-meter nuts

So here goes :( Only affects my 12v basic inverter. My 24v AIO doesn't have this issue. The setup: - 5kw 12v pure sine wave basic inverter, non-AIO, no built-in shore charger - 4 x 200Ah parallel bank - Monitored by Victron SmartShunt; batteries are good - Used only as backup; powered off most...

diysolarforum.com

But other loads, runs fine. Might be calling a technician to look at this soon. Or just don't use the PC with it

My main is a Chinese AIO 24v; haven't measured the idle as I'm lazy to move the SmartShunt over.

Is your PC connected directly to inverter power? Try putting a cheap APC battery backup between the PC and the inverter. Works great for me.

 

[OffGridInTheCity]

Is your PC connected directly to inverter power? Try putting a cheap APC battery backup between the PC and the inverter. Works great for me.

These burn idle watts as well. An APC 1500 is 40w of idle. After all they have an inverter in them.

 

[chess-equality]

Is your PC connected directly to inverter power? Try putting a cheap APC battery backup between the PC and the inverter. Works great for me.

Yes, it's connected to an APC 1600VA UPS, then the inverter.

It's this:

 

[forbin]

These burn idle watts.

Dammit.

 

[forbin]

Yes, it's connected to an APC 1600VA UPS, then the inverter.

It's this:

But your PC still glitches? Weird.

 

[chess-equality]

But your PC still glitches? Weird.

But if I connect to the AIO, even if the AIO is beside the 5K, the PC works flawlessly

 

[forbin]

But if I connect to the AIO, even if the AIO is beside the 5K, the PC works flawlessly

Seems to me that an old joke about computer programmers applies here.

What are the two questions programmers ask most?
"It doesn't work. I wonder why?"
"It works. I wonder why?"

 

[chess-equality]

These burn idle watts as well. An APC 1500 is 40w of idle. After all they have an inverter in them.

It's only powering the PC, so turned off when I'm not using it. Wife says turn that damned thing off!

No argument

 

[chess-equality]

Seems to me that an old joke about computer programmers applies here.

What are the two questions programmers ask most?
"It doesn't work. I wonder why?"
"It works. I wonder why?"

Yeah it's old. We have Docker now

 

[labeeman]

Yes. It has a little annoyance, though. My PC just hates it

You might try an isolation transformer and see if that helps.

 

[chess-equality]

You might try an isolation transformer and see if that helps.

Interesting, is it the same as an autotransformer?

 

[Supervstech]

Interesting, is it the same as an autotransformer?

No, an isolation transformer is used in electronics to get voltage above the ground plane. It gives same voltage in as out.