I have Emporia monitoring my loads. I'm seeing a max monthly peak 15-minute demand of 17.6KW. If I went with one EG4-18kpv and I hit my max of > 12KW could the inverter pull from the batteries and or the grid to satisfy the loads and distribute more than the 12KW limit for an extended amount of time? Or would the EG4-18kpv fail?
EG4 18Kpv Load Question
- Thread starter Fearless
- Start date
With a grid connection extra power demand will be pulled from the grid, the inverter will continue to provide it's 12k output(provided there is enough solar and/or battery capacity), so only the amount of power over 12k will be pulled from the grid.
Great! Then I can start out with one inverter for a simpler install.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
The spec is:
If you don't have grid power, It looks like the 18Kpv won't keep up. (Particularly at night) However, if you avoid your high-wattage items when the grid is down the system should still power most of your loads.
ksmithaz1
Solar / EV Junkie
You want to be 25% under not 50% over. Two inverters 240v/100A. I've only hit 18KW a few times. Last thing I would ever want is a failure. If you recorded 17.5 you probably hit 19 or 20. Inverter will handle a small overload for a short time.I've actually recorded a 95A load at one point. You'll need 500A of battery output to feed it 100% (50v*500A=25KW), but to your question, if you are getting 10K from the panels and need 15K for the load they will pull 5k from the batteries to supplement, but you only have 1 inverter, 12k with multiple feed sources. Excess power from your panels can be used to charge batteries, thus 18KW of panels allows you to run 12KW of load and send 6KW to batteries. Reality is you need more inverter and battery before you'll need 18KW of panels.
Dinobot248
New Member
I would say more info is needed.
What is generating those load?
Inductive or resistive loads?
Use of electric based appliances? Dryer, water heater, garage "toys"??
Peak average 15 minute loads do not tell you how long the load is running.
I have the Emporia Vue as well. The 17.6 kwh peak load by itself is not enough info.
For example, what is your daily house load?
You can be drawing 16kw every single hour and it peaks at 17.6kw.
You could be drawing 1kw every single hour and it peaks at 17.6kw
I don't even know how emporia calculates the 17.6 kwh. Not trying to be rude, it just got me thinking. My peak 15min load for the month is 2.90kwh and I average 12kwh per day.
Using my 2.90 kwh per 15 minute, it could be
2.9 x 4 = 11.6kw running at 25% of the time
2.9 / 4 = 0.72kw (this looks wrong already)
Some other way to calculate
Now since this is my house and I know we have used two small electric deep dryers (1.5 kw each with some cycling from thermostat) at one time for dinner, I am more inclined to say that it is X 4 so it would be 2.9 x 4 = 11.6 kwh for an extrapolated hour load draw.
That's my guess on what the app is trying to do at 6am in the morning before my coffee boost.
What is generating those load?
Inductive or resistive loads?
Use of electric based appliances? Dryer, water heater, garage "toys"??
Peak average 15 minute loads do not tell you how long the load is running.
I have the Emporia Vue as well. The 17.6 kwh peak load by itself is not enough info.
For example, what is your daily house load?
You can be drawing 16kw every single hour and it peaks at 17.6kw.
You could be drawing 1kw every single hour and it peaks at 17.6kw
I don't even know how emporia calculates the 17.6 kwh. Not trying to be rude, it just got me thinking. My peak 15min load for the month is 2.90kwh and I average 12kwh per day.
Using my 2.90 kwh per 15 minute, it could be
2.9 x 4 = 11.6kw running at 25% of the time
2.9 / 4 = 0.72kw (this looks wrong already)
Some other way to calculate
Now since this is my house and I know we have used two small electric deep dryers (1.5 kw each with some cycling from thermostat) at one time for dinner, I am more inclined to say that it is X 4 so it would be 2.9 x 4 = 11.6 kwh for an extrapolated hour load draw.
That's my guess on what the app is trying to do at 6am in the morning before my coffee boost.
The biggie is the Tesla charger. It takes up almost 10kw of the 17.6. I have 2 very low-mileage Teslas so they are charged about once every week or two.
Zapper77
Renaissance Man
- Joined
- Jul 23, 2022
- Messages
- 2,344
Reduce the charge amperage. Seems like the easiest solution.
This depends on your use case, your right if you want to be be completely off grid. But for the case where the grid is available, and limited backup when the grid is down is acceptable, using the grid to supplement those peak loads is an acceptable solution, and will still allow solar to offset much of electrical usage.
One option for @Fearless to consider is the partial home backup options given in the 18kpv manual, diagram 4.1 would be simplest if there panel with the 150 amp main has a 200 amp rated bus, or 4.2 if not. For loads that need backup when the grid is down one or more critical load panels(adjacent to existing panels) can be setup to power these loads.(this can be done later then the solar install if time and/or money are limited)
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FilterGuy
Solar Engineering Consultant - EG4 and Consumers
I wonder if the 18Kpv 'Smart Load' function is flexible enough for this. My understanding is it is for turning on loads when the battery is full.... but can it turn off loads when the grid is down? The reason I ask is that it can be a PITA to install two different load panels. I'll have to look into this to see how flexible 'smart load' is.
There are a number of options for the smart load feature, although it is limited 90amps max, here are the available options from the manual:
- Start PV Power (kW): This is the min. PV power limit to function with smart load output.
- On Grid Always On: Once this function is enabled, smart load will always function when grid power is on.
- Smart Load Start SOC (%) / Volt (V): The high limit for battery to turn on smart load.
- Smart Load Stop SOC (%) / Volt (V): The low limit for battery to turn off smart load.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
The second option seems like it would do the job.
Definitely an option, but would still most likely require panel reconfiguration given fearless's current 2 panel setup.
Quattrohead
Solar Wizard
The inverter is not going to blow up from an overload, it will protect itself. If you find this happening more than say once per month, then add another.
Or, is your water heater old ? Replace with a hybrid unit. Is your HVAC old, replace with a heat pump. Dryer...consider a heat pump etc.
Do you pay a minimum monthly bill to your PoCo ? Put the car chargers on utility only.
Or, is your water heater old ? Replace with a hybrid unit. Is your HVAC old, replace with a heat pump. Dryer...consider a heat pump etc.
Do you pay a minimum monthly bill to your PoCo ? Put the car chargers on utility only.
ksmithaz1
Solar / EV Junkie
Put a current sensor on the primaries, start recording. 18KW is not exactly out of the realm of possibility. There is a reason most modern panels are 200A., mine is only 150A circa 1970. If you are hitting even 13KW for any length of time, then 12KW is insufficient. 50A is not enough output to realistically run an all-electric home. While the unit may put out more than 50A, you don't really want to run it for other than a minute or two in an overload scenario. If you are grid tied, it doesn't matter, the grid will pick up the slack. If not, then you should be targeting your maximum demand point. If you don't you are likely to be disappointed.
Quattrohead
Solar Wizard
I beg to differ, that is exactly what I've been doing for this year in Florida. August and the first half of September were absolutely brutal for temperature and humidity but we still made it through without a single shutdown. Modern energy efficiency really does make this possible.
I still do have grid as backup and used it maybe half a dozen times to recharge batteries after a string of poor solar days or particularly heavy load in the house. But with better placement of my solar panels it would have been entirely doable 100%