Where have the kWh gone?

[Batavian]

EG4 monitor for my new system shows Solar Yield 4667.3 kWh Consumption 3699.6 kWH. Where did the roughly 1000 kWh go?

2ea 6000xp, 8ea 48v Lifepower, 10 kw panels. No grid input.

 

[Ampster]

Most likely to charging battery and inverter overhead.

 

[BentleyJ]

assuming 5 solar hours per day on average a 10Kw array will produce 50kWh per day. The solar yield of 4700 kWh would have taken 94 days.

If so that works out to 10kWh+ per day of losses. Does seem a bit high.
Each inverter consumes 50W standby = 100W total. Over 24 hours that's 2.4kWh and that doesn't include round trip battery charging losses.

What is the actual time period you are referencing in your post?

 

[Burrito5000]

Check out the 'efficiency' section at the end of the spec sheet:
6000XP Spec Sheet

What is the time period here? I'm guessing around 90 days? Each 6000xp will idle 1.2kW per day.
2.4 x 90 = 216kW

According to the spec sheet you lose 1% from the MPPT, and you lose 7% each for battery charging and discharging. That's a whopping 15% total losses. So:
4667 * .15 = 700kW.

700 + 216 = 916kW

So maybe it was closer to 115 day time period. ..?

 

[Batavian]

134 days. Thanks for the info, makes sense, didn't realize so much loss in battery charge and discharge.

 

[GXMnow]

My Schneider XW-Pro inverter/charger is a little more efficient, but that loss still adds up. When I would cycle 10 KWHs into the battery and back out each day, I would lose just about 1 KWH in the losses. That is 10% of the energy lost to store daytime solar to use at night. That was fully AC coupled from my Enphase solar. It was still a win as losing 10% was far better than paying the much higher time of use rate for 4 pm to 9 pm power from the grid. Using the grid to store the energy was only 50% efficient. 90% is way better.

I have since added 2,000 watts of panels and a Victron DC charge controller. I now get about 70% of my battery charge power from that to use at night. Now I lose only about 300 to 500 watt hours a day from the energy I pull from the Enphase system, cutting the losses to less than half.

On a good sunny day, my battery fully tops out early, and I end up throwing away more energy due to the Victron charge controller going into Float mode. With your "All In One" charge controller and inverter system, it should be more efficient at charging the battery while also providing AC with the sun up, but it seems the idle losses are a bit worse. The Schneider XW idle loss is only about 40 watts. But the charging efficiency from Enphase solar in, worked out to just 91-93% efficient. The Victron charge controller is more like 97% efficient from solar panel to battery. I think your EG4 is around 95% so right between my 2 options. Inverting from battery back out to AC is also very close, about 96% efficient for both the XW-Pro and EG4 inverters. So the big difference seems to be mostly the idle losses. The more power you actually use, the less of a percentage that turns out to be. Once the weather get's hot hear and my AC is running a lot, the losses look like nothing. Between the AC compressor and the indoor and outdoor fans, I end up using 4,000 watts while the system is running steady state. At that point, the idle losses are well under 1% of the power coming from the batteries.

 

[Lt.Dan]

Everybody needs to remember that if the inverter is in use, you can not count "Idle consumption". It not at idle anymore if it's in use!

It's all efficiency. Battery Charging, battery discharging.

This is why efficiency is a far more important spec, unless you are planning on the system being idle for an extended period of time during the day, which rarely happens. It's also the reason why I went from MPP LV6548s (90% efficient) to the Sol-Ark 15k (96.5% efficient). That 6.5% efficiency adds up VERY quick!

 

[GXMnow]

Everybody needs to remember that if the inverter is in use, you can not count "Idle consumption". It not at idle anymore if it's in use!

In a way, this is true, but that "idle consumption" is still power being used on top of the power you are using to run loads. The idle consumption does not go away, it is always there as a load power that needs to be supplied. But the more power you are using, the idle power usage becomes less of a percentage of the power being used.

If an inverter system has a 300 watt idle consumption (that would be very bad), and they you turn on a 1,000 watt load, you are now pulling 1,300 watts from the battery. That looks like just 77% efficiency. Up the load power to 3,000 watts, and the battery power is now 3,300 watts. That now calculates out to 91% efficiency. Of course, there is likely a little more loss with the increase load, but the idle current is always still there but looks like less and less as the load increases. The actual inverting electronics may be 98% efficient, so that 3,000 watt load would be about 3,060 watts, plus the idle current coming from the battery. So in the horrible 300 watt example, it's really 3,360 watts from battery at a 3,000 watt load. The is still almost 90% efficient. Up the output load to 6,000 watts, and we are now using 6,420 watts from the battery (idle loss and 98% inverting losses) and the efficiency is up to 93.5% efficient. The idle loss means less, but it's still there.

If you are always using more than 2,000 watts, then 100 to 200 watts of idle power may not be very important, but it is always still there. It is the power consumed by the electronics to make the inverter function. In the case of my Schneider system, the idle power also includes the power to run the Conext Gateway box. And throw in another 15 watts to run my PLC that is controlling the charge current. It all adds up. I also have a network switch and WiFi extender to keep powered to monitor the system. I can call those loads, but they are really more constant idle losses as I would not need them if I was not running the inverter out at the far end of my garage.

 

[Lt.Dan]

In a way, this is true, but that "idle consumption" is still power being used on top of the power you are using to run loads. The idle consumption does not go away, it is always there as a load power that needs to be supplied. But the more power you are using, the idle power usage becomes less of a percentage of the power being used.

If an inverter system has a 300 watt idle consumption (that would be very bad), and they you turn on a 1,000 watt load, you are now pulling 1,300 watts from the battery. That looks like just 77% efficiency. Up the load power to 3,000 watts, and the battery power is now 3,300 watts. That now calculates out to 91% efficiency. Of course, there is likely a little more loss with the increase load, but the idle current is always still there but looks like less and less as the load increases. The actual inverting electronics may be 98% efficient, so that 3,000 watt load would be about 3,060 watts, plus the idle current coming from the battery. So in the horrible 300 watt example, it's really 3,360 watts from battery at a 3,000 watt load. The is still almost 90% efficient. Up the output load to 6,000 watts, and we are now using 6,420 watts from the battery (idle loss and 98% inverting losses) and the efficiency is up to 93.5% efficient. The idle loss means less, but it's still there.

If you are always using more than 2,000 watts, then 100 to 200 watts of idle power may not be very important, but it is always still there. It is the power consumed by the electronics to make the inverter function. In the case of my Schneider system, the idle power also includes the power to run the Conext Gateway box. And throw in another 15 watts to run my PLC that is controlling the charge current. It all adds up. I also have a network switch and WiFi extender to keep powered to monitor the system. I can call those loads, but they are really more constant idle losses as I would not need them if I was not running the inverter out at the far end of my garage.

I disagree. Look at the name itself "IDLE Consumption". If you have a 1w load, you are no longer at idle!

This is why if you actually have an efficiency chart (which is never supplied by any inverter manufacture), then you would notice that the efficiency is downright terrible at low loads. What is happening is similar to what you are talking about, but not as simple. An inverter that has a 300w idle consumption and a 10kw peak, with a 1000w load on it will most likely consume 1400w+. Efficiency makes that additional consumption higher. But at 70-80% load (which is typically where peak efficiency is rated), a 7500w load will actually have around 8333w coming from the battery (assuming peak 90% efficiency).

 

[Tulex]

Idle consumption has nothing to do with idle, it's the cost of doing business. The inverter is going to us X amount of power just to operate regardless of where it's getting it's power from, or whether power is coming or going.

Idle is like your one time cost when quoting work. It gets spread out over all the work costs.

 

[v_green57]

Edit: I see others have responded whilst I was composing this. I am late to the party, as usual.

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"Everybody needs to remember that if the inverter is in use, you can not count "Idle consumption". It not at idle anymore if it's in use!"

Ummm...maybe not.

Say, as an average of most AIO's, your "idle consumption" is 75W DC. That 75W is by definition powering the internal circuitry.

Then throw a 100W load on it.

Measured at the DC side of things, is the input power from ALL sources (panel, battery, etc.) going to be 175W? I believe so. The "idle" still exists, but is now part of the total.

Meaning the 100W "idle" is still NOT powering the load. It is going into the AIO "black hole".

I have a Samlex EVO-2224. It's rated at 25W "no load power consumption" which I think to be a more accurate term than "idle". Along with that, I have 6.4W of DC cooling fans. The inverter never shuts off, so these two combined are 31.4W or .754 kWh daily.

When I get the daily measured DC kWh input from my solar arrays, and subtract the .754 used by the the fans and the self-consumption of the 2224 (which is not measured by my external instrumentation), I am usually within 300 - 500 wH daily of the measured AC consumption going to the load(s). That difference is overall system inefficiency and is about what I would expect from my setup.

The math works. "Idle" doesn't just "go away" when you are pulling power.

 

[GXMnow]

I disagree. Look at the name itself "IDLE Consumption". If you have a 1w load, you are no longer at idle!

I think @v_green57 nailed it. "IDLE" is probably the wrong word to use here.

If your inverter has an "IDLE" consumption of 50 watts, it is ALWAYS using that 50 watts. Turn on that 1 watt load, sure, it's no longer idle, but it is STILL pulling that 50 watts on top of your 1 watt load. I like the phrase "no load power consumption". But now we have a 1 watt load, so it is no longer "No Load" either. But this draw is still there.

 

[v_green57]

I think @v_green57 nailed it. "IDLE" is probably the wrong word to use here.

If your inverter has an "IDLE" consumption of 50 watts, it is ALWAYS using that 50 watts. Turn on that 1 watt load, sure, it's no longer idle, but it is STILL pulling that 50 watts on top of your 1 watt load. I like the phrase "no load power consumption". But now we have a 1 watt load, so it is no longer "No Load" either. But this draw is still there.

Ugh. Semantics.

The bane of humankind.

"When does when mean when?"

In an engineering context, specifics do make a difference ;-)

 

[JakeinCanada]

My numbers, I have 2 lv6548 inverters with 45kw battery and no solar panels, I charge at night when the rates are low and run on battery all day. I monitor the inverter input and output. So far this year the input was 5908 and the output is 4665 kwh. I measured the idle usage @ 131 watts per hour. Approximately 10 to15% of the usage would in the bypass mode during the charging cycle between 11 pm and 7 am.

My load, all electric home with 2 18,000 btu inverter heat pumps, 80 gallon hot water tank timed to heat only during the off peak hours.

Ontario Canada has an ultra low rate plan of 2.8 cents per kwh between 11 pm and 7 am9

I plan on adding solar panels soon.

 

[GXMnow]

Ontario Canada has an ultra low rate plan of 2.8 cents per kwh between 11 pm and 7 am

If you can live on just the 2.8 cent power, that may be cheaper than installing the solar panels.
Our lowest rate here is 17 cents, and with that, we get a $30 a month flat fee added. My lowest rate is 27 cents, but my monthly fee is only $12 so at my current usage, it ends up cheaper with solar. My house needs about 35 KWHs on a hot summer day. 35 / 8 = 4,375 watt hours per hour. Divide again by 240 volts and that means pulling a bit over 18 amps during the cheap rate time. I so wish I had that deal. Just 98 cents a day to run my house on the hottest days.

 

[Supervstech]

So...
What do we call it if not idle?

Overhead consumption?
Efficiency loss?
Constant use?

Some inverters have a standby mode that doesnt use much wattage most of the time, then it senses when a demand starts, and load begins...

 

[Lt.Dan]

I personally consider it efficiency loss. If 300w are going in, but only 100w are going out to loads, then you're 33.3% efficient. Just like stated above, using the word IDLE, is the problem.

 

[Crowz]

Watching the new 10kw sungold I bought I don't consider idle consumption a valid term. I just call it life support. That thing needs x amount of power. It needs it just as much with no load as a load. Heck it probably eats more working than idle I would think.

Normally you can't see what your equipment using when the suns up since its absorbed into the stats your seeing so you have no clue how much actual power your equipment is actually consuming to do its job.

I on the other hand know EXACTLY how much my oddball equipment is using since in hybrid mode the thing draws it off the battery. So I get to watch every watt the damn thing uses all day long via battery drain.

Its not cheap. Its bouncing between 67 and 70 watts right now. It varies between 30 and 150 watts. But on average it hangs around 65 watts.

So in my opinion the term idle consumption isn't a very accurate term.