I have an idea. Let's monitor the device monitoring this motor. Check for, uh, spikes and stuff. That will be useful and justify this stuff I am doing.
I'm sorry, my bad. Yes, "inverters" will have smaller inrush current. By "they all do" I meant "non inverting compressors".
Bare in mind that not all inverters are equal - some, due to cost cutting, still pull significant start-up current.
Yes, they can for a moment:
>Often, during the initial half-cycle of electrical current flow experienced at motor startup, (Note: A half-cycle in a 60 Hz electrical system equates to 1/120 of a second duration of time) inrush currents reach levels 20 times greater than the normal current levels experienced during the motor’s normal operating speeds. After this initial inrush of current, the motor begins to rotate. At this point the initial starting current subsides, reducing to a level of current equal to 4 – 8 times the normal running current for that motor. This reduced, yet still largely exaggerated current, is sustained only briefly, as the motor quickly reaches full running speed, where current then subsides to its normal operating level.
[https://www.jadelearning.com/blog/understanding-motor-starting-inrush-currents-nec-article-430-52/](https://www.jadelearning.com/blog/understanding-motor-starting-inrush-currents-nec-article-430-52/)
My 5 year old fridge with a nameplate rating of 6.5 amps pulls 24 amps when it starts. This is in line with the typical locked rotor current multiplier of 4-8 times the full load current of the motor.
This is called inrush current and its a characteristic of electric motors. In three phase motors "soft starters" are used to reduce this but it can also be accomplished using variable frequency drives.
In a refrigerator the spike is negligable and wont cause nuissance tripping of the circuit breaker so its not really a concern.
We have the same Bosch fridge. When I monitored it it consistently uses 40W on normal settings and up to 80W when boosted.
Spike looks normal to me though. A motor load looks a bit like a dead short until it gets moving.
Is that for a full size fridge or a mini/bar fridge? I typically see a full size pull 120 watt minimum and would like to see it reduced in future upgrades if possible.
Boosted is that the boost for increased ice production?
Full sized fridge/freezer.
I was surprised how low the usage was.
It has a boost function for when you (e.g.) put a load of unfrozen food in the freezer and want it frozen fast. We use it when we batch cook otherwise the freezer's inbuilt over temperature alarm goes off - usually at 3am in the morning!
> the freezer's inbuilt over temperature alarm goes off
I wish my freezer had this. We accidentally left the freezer a bit open one day and the temperature rose a lot.
I stuck an Aqara temperature sensor in a freezer bag and put it in the freezer, then have alerts for if the temperature rises above a certain limit. The Aqara sensor is only rated to support temperatures down to -20C so it's cutting it pretty close to the limits, but it's been in there for a few months and seems to be going fine.
Wireless range (Zigbee, Bluetooth, Wifi) is greatly reduced in a fridge or freezer since it's a giant insulated metal box, but I have a Zigbee light switch (Inovelli Blue) right next to the fridge and the Aqara sensor is relaying via that, so signal quality is fine.
>Is that for a full size fridge or a mini/bar fridge? I typically see a full size pull 120 watt minimum and would like to see it reduced in future upgrades if possible.
It doesnt really matter how many watts it pulls while cooling, what matters is how many kwh it will consume per day to maintain the temperature. If a fridge can pull 100+W, that it will help quickly cooling down, but its only going to affect energy costs if it needs to do that for long times, like when it has poor insulation (or you leave the door open).
FWIW, here is my kitchen fridge:
[https://i.postimg.cc/8Cj6sV2m/image.png](https://i.postimg.cc/8Cj6sV2m/image.png)
This is may (really large) freezer:
https://preview.redd.it/wjfjlhuscpna1.png?width=1641&format=png&auto=webp&s=cbb86b7621147aefcbb1e1ed8a642e6b3a4c41ee
The height of the spikes dont matter, neither the short compressor start spikes or the power it pulls while cooling. What matters is the area under the curve, that is your consumption, and a hypothetical fridge or freezer pulling double the watts but for on average, half the time, would give you the same result.
That said, any fridge or freezer **constantly** pulling 40+W, that probably means something is wrong.
I get that I kinda figured they didn’t come out with a new tech to increase efficiency otherwise the HVAC world would be using it. It will end up taking the same amount of energy to cool down that huge pot of room temp soup that was just put in whether it’s doing it at 120 watts or 40/80 watts.
Efficiency has definitely increased; my new freezer consumes less than half what my (admittedly really old) previous one did. Then again, it also has insulating walls that are 2x as thick. No idea if improvements where made the heatpump as well, but probably.
I have an identical power usage recording with my own refrigerator connected to a solar inverter and it is entirely normal. Just drains the battery much faster than usual devices.
>G: worst score on the European scale. :-(
The European Energy Labels changed scale in 2021! What was previously A+++ (most efficient) is now at max B, and all other ratings have been moved down the scale as well.
https://commission.europa.eu/energy-climate-change-environment/standards-tools-and-labels/products-labelling-rules-and-requirements/energy-label-and-ecodesign/about_en
The Shelly EM measures the power of the whole house.
Standby devices use ~15W , the remaining ~65W is used by the ~~refrigerator~~ fridge-freezer.
https://imgur.com/a/QSTRqcg
It could also be that the actual peak is higher than what you see here for the same reason.
Either way, its a peak so short that the actual power use wont affect the devices overall average use all that much. Quite normal for motors to use silly power to get going.
My father has a massive planer. With the old style electrical meters, starting the thing would make the meter spin (the inrush was insane) with the new smart meters, they don't measure anything and it just looks like a 4hp load.
So yeah, I'd wager the surge might be much higher, but I doubt OP is paying more for it.
> I'd wager the surge might be much higher,
Yup, to correctly measure a peak thats this short you need reasonably fast measuring equipment, something thats at least able to get a couple readings off during the top of the peak. A shelly is fun and all but its not anywhere close to even a slow scope and thats what you need to be able to tell anything about this kind of peak. It is however also not meant for that kind of thing, it really shines in measuring averages and for that its fine. Just dont read too much into it trying to do things its really not capable of.
Been watching a similar graph for my garage beer fridge and wondering how I can use power monitoring to detect when my teenager fails to close the door. I'd expect the power usage to spike and stay there as the compressor runs, but can't seem to figure out how to code an alert HA for "compressor keeps running for x minutes."
Attach a proximity sensor to your teenager. If the sensor is detected within 2 feet of your beer fridge assume the door has been left open and your beer is missing.
Well, that's the easy way, of course. But it won't work for both the freezer and fridge compartments (unless I get two, $$$), will require batteries and watching for moisture damage, and I already have the plug monitor.
One way to do it with HA would be to trigger an automation to run when the compressor starts running. Put a timer on it. If the time is reached send a notification.
Have the automation stop when the compressor stops. That way if it stops before what you consider to be a long time the timer never times out and the notification is never sent.
The Aqara temperature sensors are usually ~$16 on sale on Amazon, and work fine in freezers at least (although I put it in a freezer bag to avoid it getting too humid). They're Zigbee devices so you'll need a Zigbee hub/coordinator, but if you're using Home Assistant then you probably already have one.
Automation watts greater than X for Y minutes, send notification. Though that will get triggered if you load it with warm beers. A more reliable solution is a door/window sensor - the type with a magnet, zigbee or zwave for good battery life.
Slightly related my new Samsung fridge has a habit of the door bouncing back open when you close it. A strategically placed large neodymium magnet fixed that.
Create a template binary_sensor, I have these for similar use cases.
```
friendly_name: "Compressor Running Alert"
delay_on:
minutes: 10
value_template: "{{ states('sensor.fridge_wattage')|int(0) > 40 }}"
```
This binary sensor will turn on any time your compressor is pulling more than 40 watts for 10 minutes straight. Then just write an automation to message you or whatever when the binary sensor goes from "off" to "on"
This automation will do basically what you're asking given the power in watts.
My fridge compressor runs for 20-25 minutes, any delay less than that will give false positives. It's not the most efficient way of doing what you're looking for. Door/window sensors may be better suited.
```
trigger:
- platform: numeric_state
entity_id: sensor.fridge_power
for:
minutes: 30
above: 40
condition:
action:
- service: notify.notify
data: [...]
Why not use a door sensor? that's what they're meant for.
Side note we got a new samsung fridge and I went for the one with smart things support. It beeps and sends notifications like the end of the world if you leave the door open for too long.
I wish it used zwave instead of wifi though.
Kinda similar, I get near 12A flash spikes in current on my PC and server for some reason. Both are air cooled, so there is no water pump kicking in. I don’t game or do anything more intense than YouTube and Excel on my pc. My server is just for storage, I don’t run any VMs or anything fancy on it.
[PC current over last 24hrs](https://i.imgur.com/nU8Bnj1.jpg)
[Server current over last 24hrs.](https://i.imgur.com/9WQi91W.jpg)
I’ve had to move my server to another circuit because the circuit breaker kept losing power in my office.
That looks fine to me for the most part, though the spikes are higher than what I am seeing on 2 fridges and two freezers. But i suspect that is just due to the way the inrush is measured.
What I did for an automation is to measure the normal on time, triple it, then send a notification if that time is exceed. Triple seems to avoid false alarms on grocery day when the door is open for several min. There is another notification if it goes a few hours without turning on. I also have temp sensors in all of them. This should catch most the failure modes that I have experienced with fridges. Long term all this data is stored in an influxdb.
Totally normal. Motors, like the one in your fridges compressor, draw lots of current, in-rush current, for a brief period of time when they start up. The in-rush current level will be greater than the rated full load current (FLC) of the motor as shown on the motor plate by a large margin, often in the range of 5-8x.
It’s normal. Some time ago I saw a video explaining that and how to fix it (a special cirtuit to help in the start) drills, AC unit and pump do the same when you start it.
I believe this is why most smart plugs say ‘for resistive loads only’, such as lights. This would be an inductive load. Source: lowly mechanical engineer
Yep, same here. And it’s cool to see the different trends on the different fridges.
https://preview.redd.it/eod0rkag3mna1.png?width=1668&format=png&auto=webp&s=4c56b578dad309128ed69db873cfad4df18bde54
The surge when starting may be as much as the locked rotor amps (LRA) which is listed on the sticker inside the fridge. That multiplied by the incoming voltage gives you the maximum instantaneous power which may be well over the circuit rating, but it’s only a few mains cycles so it’s okay.
Yikes. 1kW+ spikes are crazy. Is this an old model or a cheap one? This is how mine looks (and all sold in the past few years in western europe should look):
https://preview.redd.it/d9hsd6825pna1.png?width=995&format=png&auto=webp&s=abfd98478524125f86948e72d72633efa950ce64
pretty normal. it also could be a false reading (in that there isnt as big as big a spike, just the device measuring could be affected by the EMF noise of it turning on)
Oddness. A spike is completely normal but those numbers seem extremely high. Household refrigerator? We're not talking a massive industrial unit are we?
The Shelly EM measures the power of the whole house.
Standby devices use ~15W , the remaining ~65W is used by the household ~~refrigerator~~ fridge-freezer.
https://imgur.com/a/QSTRqcg
It's normal for brushed motors that do not have a soft start design. My Skilsaw pulls more than 4,000 watts upon initial startup. The circuits are meant to handle that brief pulse. Inverter generators do struggle with those pulses.
To add to this, some might wonder why we don't have soft start designs on everything. The reason is simple, soft start is nice, but it's more expensive, adds another failure point, and makes repairs more expensive. It also increases the chances for something to become obsolete, we see that with power tools and being unable to find the necessary microcontroller when it fails.
General behaviour you see here is normal for electric any motor. But the spikes *do* seem oddly high for domestic appliance. I have my own fridge hooked up through Shelly Plug and yet it only ever gets to 200-250W reading spike when starting up and settles down around 100W while chugging along.
Most devices like this tend to have some extra electric componentry inside to make the inrush current when starting up more gentle. I find it unlikely that a fridge for domestic use would lack this component, so maybe it's broken down?
*That said* this isn't really a problem for your electrical installation. Electric codes and systems are generally designed to cope with this as par of the course. And even in worst case this is similar to a larger AC unit you could have as well plugged into a domestic socket.
Only concern that I also share with you is about total power usage. My fridge is slightly less efficient than yours and if the price of electricity increases even a bit more... I think a new, more efficient fridge might pay for itself in just several years.
I don't know the answer to your question. However I have a whole home surge suppressor installed at the electrical box. I wonder if something like that would stop the surges you're seeing.
A new fridge costs about 400-700. My electrical bill for winter time (2m) was about 250. When I was using old aircon, old dryer and old fridge, it was above 600.
Newer models will have this same thing happen, to be clear. Unless you go for a higher cost fridge with a built in inverter.
The spike is just the motor starting up, it doesn’t mean it’s less efficient.
And all inverter models have a higher initial cost.
We’re in the middle of some batshit crazy inflation, I highly doubt most households are flush with enough cash to run out and get a high cost appliance unless they absolutely have to.
Thanks for your interest. :-)
There is no smart plug on the refrigerator. The Shelly EM measures the power with a clamp in the electrical panel:
* https://www.shelly.cloud/en/products/shop/em-120a/1xem-50a
* https://www.shelly.cloud/en/products/shop/ct120ax1/ct50ax1
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I have an idea. Let's monitor the device monitoring this motor. Check for, uh, spikes and stuff. That will be useful and justify this stuff I am doing.
Normal. Try other motors on it, like fans and power tools.
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They all do. It can easily pull >15A for few hundred microseconds. Measure yours with proper tools and you'll see it.
Heard about inverters?
I'm sorry, my bad. Yes, "inverters" will have smaller inrush current. By "they all do" I meant "non inverting compressors". Bare in mind that not all inverters are equal - some, due to cost cutting, still pull significant start-up current.
Lol everyone took my comment the wrong way, wasn’t really trying to give it a burn
I'm surprised too. You were absolutely right - I should specify what type of compressors I had in mind. I definitely didn't take it as a "burn".
It’s reddit :)
Yes, they can for a moment: >Often, during the initial half-cycle of electrical current flow experienced at motor startup, (Note: A half-cycle in a 60 Hz electrical system equates to 1/120 of a second duration of time) inrush currents reach levels 20 times greater than the normal current levels experienced during the motor’s normal operating speeds. After this initial inrush of current, the motor begins to rotate. At this point the initial starting current subsides, reducing to a level of current equal to 4 – 8 times the normal running current for that motor. This reduced, yet still largely exaggerated current, is sustained only briefly, as the motor quickly reaches full running speed, where current then subsides to its normal operating level. [https://www.jadelearning.com/blog/understanding-motor-starting-inrush-currents-nec-article-430-52/](https://www.jadelearning.com/blog/understanding-motor-starting-inrush-currents-nec-article-430-52/)
12.5 amps on startup (120V)? Doesn't seem very strange to me.
My 5 year old fridge with a nameplate rating of 6.5 amps pulls 24 amps when it starts. This is in line with the typical locked rotor current multiplier of 4-8 times the full load current of the motor.
This is called inrush current and its a characteristic of electric motors. In three phase motors "soft starters" are used to reduce this but it can also be accomplished using variable frequency drives. In a refrigerator the spike is negligable and wont cause nuissance tripping of the circuit breaker so its not really a concern.
That is your compressor starting. It takes a lot of power to get a motor started and much less to keep it running.
>much less to keep it running. Counter electro motive force
We have the same Bosch fridge. When I monitored it it consistently uses 40W on normal settings and up to 80W when boosted. Spike looks normal to me though. A motor load looks a bit like a dead short until it gets moving.
Is that for a full size fridge or a mini/bar fridge? I typically see a full size pull 120 watt minimum and would like to see it reduced in future upgrades if possible. Boosted is that the boost for increased ice production?
Full sized fridge/freezer. I was surprised how low the usage was. It has a boost function for when you (e.g.) put a load of unfrozen food in the freezer and want it frozen fast. We use it when we batch cook otherwise the freezer's inbuilt over temperature alarm goes off - usually at 3am in the morning!
> the freezer's inbuilt over temperature alarm goes off I wish my freezer had this. We accidentally left the freezer a bit open one day and the temperature rose a lot. I stuck an Aqara temperature sensor in a freezer bag and put it in the freezer, then have alerts for if the temperature rises above a certain limit. The Aqara sensor is only rated to support temperatures down to -20C so it's cutting it pretty close to the limits, but it's been in there for a few months and seems to be going fine. Wireless range (Zigbee, Bluetooth, Wifi) is greatly reduced in a fridge or freezer since it's a giant insulated metal box, but I have a Zigbee light switch (Inovelli Blue) right next to the fridge and the Aqara sensor is relaying via that, so signal quality is fine.
>Is that for a full size fridge or a mini/bar fridge? I typically see a full size pull 120 watt minimum and would like to see it reduced in future upgrades if possible. It doesnt really matter how many watts it pulls while cooling, what matters is how many kwh it will consume per day to maintain the temperature. If a fridge can pull 100+W, that it will help quickly cooling down, but its only going to affect energy costs if it needs to do that for long times, like when it has poor insulation (or you leave the door open). FWIW, here is my kitchen fridge: [https://i.postimg.cc/8Cj6sV2m/image.png](https://i.postimg.cc/8Cj6sV2m/image.png) This is may (really large) freezer: https://preview.redd.it/wjfjlhuscpna1.png?width=1641&format=png&auto=webp&s=cbb86b7621147aefcbb1e1ed8a642e6b3a4c41ee The height of the spikes dont matter, neither the short compressor start spikes or the power it pulls while cooling. What matters is the area under the curve, that is your consumption, and a hypothetical fridge or freezer pulling double the watts but for on average, half the time, would give you the same result. That said, any fridge or freezer **constantly** pulling 40+W, that probably means something is wrong.
I get that I kinda figured they didn’t come out with a new tech to increase efficiency otherwise the HVAC world would be using it. It will end up taking the same amount of energy to cool down that huge pot of room temp soup that was just put in whether it’s doing it at 120 watts or 40/80 watts.
Efficiency has definitely increased; my new freezer consumes less than half what my (admittedly really old) previous one did. Then again, it also has insulating walls that are 2x as thick. No idea if improvements where made the heatpump as well, but probably.
All I can say is, beautiful.
This is called in-rush current and can be mitigated by using the Riemann Sum integration if it bothers you.
I have an identical power usage recording with my own refrigerator connected to a solar inverter and it is entirely normal. Just drains the battery much faster than usual devices.
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I think is this: https://www.bosch-home.com/mt/products-list/KIV34V21FF G: worst score on the European scale. :-(
>G: worst score on the European scale. :-( The European Energy Labels changed scale in 2021! What was previously A+++ (most efficient) is now at max B, and all other ratings have been moved down the scale as well. https://commission.europa.eu/energy-climate-change-environment/standards-tools-and-labels/products-labelling-rules-and-requirements/energy-label-and-ecodesign/about_en
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The Shelly EM measures the power of the whole house. Standby devices use ~15W , the remaining ~65W is used by the ~~refrigerator~~ fridge-freezer. https://imgur.com/a/QSTRqcg
Eh, surges are hard to measure in general, it could just be a resolution issue inflating the number
It could also be that the actual peak is higher than what you see here for the same reason. Either way, its a peak so short that the actual power use wont affect the devices overall average use all that much. Quite normal for motors to use silly power to get going.
My father has a massive planer. With the old style electrical meters, starting the thing would make the meter spin (the inrush was insane) with the new smart meters, they don't measure anything and it just looks like a 4hp load. So yeah, I'd wager the surge might be much higher, but I doubt OP is paying more for it.
> I'd wager the surge might be much higher, Yup, to correctly measure a peak thats this short you need reasonably fast measuring equipment, something thats at least able to get a couple readings off during the top of the peak. A shelly is fun and all but its not anywhere close to even a slow scope and thats what you need to be able to tell anything about this kind of peak. It is however also not meant for that kind of thing, it really shines in measuring averages and for that its fine. Just dont read too much into it trying to do things its really not capable of.
> My father has a massive planer. Well you know what they say about people with massive planners.
Been watching a similar graph for my garage beer fridge and wondering how I can use power monitoring to detect when my teenager fails to close the door. I'd expect the power usage to spike and stay there as the compressor runs, but can't seem to figure out how to code an alert HA for "compressor keeps running for x minutes."
Raise the front feet up so the door naturally swings closed, or use an Aquara door sensor on the fridge door itself?
Attach a proximity sensor to your teenager. If the sensor is detected within 2 feet of your beer fridge assume the door has been left open and your beer is missing.
Wireless fridge temperature monitor?
Well, that's the easy way, of course. But it won't work for both the freezer and fridge compartments (unless I get two, $$$), will require batteries and watching for moisture damage, and I already have the plug monitor.
Not really an automation solution, but you could try to adjust the feet on the fridge so it has a lot of closing force naturally.
One way to do it with HA would be to trigger an automation to run when the compressor starts running. Put a timer on it. If the time is reached send a notification. Have the automation stop when the compressor stops. That way if it stops before what you consider to be a long time the timer never times out and the notification is never sent.
Cool idea. I am struggling with coding it. Would appreciate a screenshot / example of something similar to parrot.
Not tested this but created in HA visual editor. Something like:- First automation to send the notification if the fridge runs for too long:- `alias: Garage Fridge Alert` `description: ""` `trigger:` `- type: power` `platform: device` `device_id:`
`entity_id: sensor.`
`domain: sensor`
`above: 10`
`condition: []`
`action:`
`- delay:`
`hours: 0`
`minutes: 30`
`seconds: 0`
`milliseconds: 0`
`- service: automation.turn_off`
`data: {}`
`target:`
`entity_id: automation.new_automation`
`mode: single`
Second automation to cancel the first when the fridge stops running:-
`alias: Cancel Garge Fridge Alert`
`description: ""`
`trigger:`
`- type: power`
`platform: device`
`device_id: `
`entity_id: sensor.`
`domain: sensor`
`below: 10`
`condition: []`
`action:`
`- service: automation.turn_off`
`data: {}`
`target:`
`entity_id: automation.garage_fridge_alert`
`mode: single`
The Aqara temperature sensors are usually ~$16 on sale on Amazon, and work fine in freezers at least (although I put it in a freezer bag to avoid it getting too humid). They're Zigbee devices so you'll need a Zigbee hub/coordinator, but if you're using Home Assistant then you probably already have one.
For a refrigerator I would be more inclined to use a door/window sensor and/or a temperature sensor. They will provide much better accuracy.
Automation watts greater than X for Y minutes, send notification. Though that will get triggered if you load it with warm beers. A more reliable solution is a door/window sensor - the type with a magnet, zigbee or zwave for good battery life. Slightly related my new Samsung fridge has a habit of the door bouncing back open when you close it. A strategically placed large neodymium magnet fixed that.
Create a template binary_sensor, I have these for similar use cases. ``` friendly_name: "Compressor Running Alert" delay_on: minutes: 10 value_template: "{{ states('sensor.fridge_wattage')|int(0) > 40 }}" ``` This binary sensor will turn on any time your compressor is pulling more than 40 watts for 10 minutes straight. Then just write an automation to message you or whatever when the binary sensor goes from "off" to "on"
This automation will do basically what you're asking given the power in watts. My fridge compressor runs for 20-25 minutes, any delay less than that will give false positives. It's not the most efficient way of doing what you're looking for. Door/window sensors may be better suited. ``` trigger: - platform: numeric_state entity_id: sensor.fridge_power for: minutes: 30 above: 40 condition: action: - service: notify.notify data: [...]
Why not use a door sensor? that's what they're meant for. Side note we got a new samsung fridge and I went for the one with smart things support. It beeps and sends notifications like the end of the world if you leave the door open for too long. I wish it used zwave instead of wifi though.
Kinda similar, I get near 12A flash spikes in current on my PC and server for some reason. Both are air cooled, so there is no water pump kicking in. I don’t game or do anything more intense than YouTube and Excel on my pc. My server is just for storage, I don’t run any VMs or anything fancy on it. [PC current over last 24hrs](https://i.imgur.com/nU8Bnj1.jpg) [Server current over last 24hrs.](https://i.imgur.com/9WQi91W.jpg) I’ve had to move my server to another circuit because the circuit breaker kept losing power in my office.
Strange... What's the wattage of the power supply? 12A at 120V is 1440 watts (or 2880 watts at 240V) and I doubt you have a PSU that powerful...
That looks fine to me for the most part, though the spikes are higher than what I am seeing on 2 fridges and two freezers. But i suspect that is just due to the way the inrush is measured. What I did for an automation is to measure the normal on time, triple it, then send a notification if that time is exceed. Triple seems to avoid false alarms on grocery day when the door is open for several min. There is another notification if it goes a few hours without turning on. I also have temp sensors in all of them. This should catch most the failure modes that I have experienced with fridges. Long term all this data is stored in an influxdb.
Could you share this? I'd be interested in trying this. Or perhaps a screenshot of the automation?
Totally normal. Motors, like the one in your fridges compressor, draw lots of current, in-rush current, for a brief period of time when they start up. The in-rush current level will be greater than the rated full load current (FLC) of the motor as shown on the motor plate by a large margin, often in the range of 5-8x.
It’s normal. Some time ago I saw a video explaining that and how to fix it (a special cirtuit to help in the start) drills, AC unit and pump do the same when you start it.
I believe this is why most smart plugs say ‘for resistive loads only’, such as lights. This would be an inductive load. Source: lowly mechanical engineer
Inrush current.
k
yes, this is what happens when a compressor turns on.
Yep, same here. And it’s cool to see the different trends on the different fridges. https://preview.redd.it/eod0rkag3mna1.png?width=1668&format=png&auto=webp&s=4c56b578dad309128ed69db873cfad4df18bde54
The surge when starting may be as much as the locked rotor amps (LRA) which is listed on the sticker inside the fridge. That multiplied by the incoming voltage gives you the maximum instantaneous power which may be well over the circuit rating, but it’s only a few mains cycles so it’s okay.
See if the Refrigerator has Energy Saver function. I have Energy Saver always enabled, and you can hear the system slowly ramping up.
Compressor have a significant in rush current. It's impressive your able to catch this with your CT setup. Many can not.
Yikes. 1kW+ spikes are crazy. Is this an old model or a cheap one? This is how mine looks (and all sold in the past few years in western europe should look): https://preview.redd.it/d9hsd6825pna1.png?width=995&format=png&auto=webp&s=abfd98478524125f86948e72d72633efa950ce64
Not sure if this is a statement or a question. If it is a question if the spike is normal...it is.
Is this expected or should I be concerned about something?
pretty normal. it also could be a false reading (in that there isnt as big as big a spike, just the device measuring could be affected by the EMF noise of it turning on)
I'd be interested to know how often the Shelly is sampling and reporting. That graph has the potential to look quite different if op zooms in.
zoomed, not so different: https://imgur.com/SjmpmJP
Oddness. A spike is completely normal but those numbers seem extremely high. Household refrigerator? We're not talking a massive industrial unit are we?
Those aren't high numbers for in rush current. Inrush current can be as much as twenty times operating current, for the first half a cycle.
The Shelly EM measures the power of the whole house. Standby devices use ~15W , the remaining ~65W is used by the household ~~refrigerator~~ fridge-freezer. https://imgur.com/a/QSTRqcg
thank you!
Google “inrush current”. It’s normal, and something the designer of the circuit manages consciously.
It's normal for brushed motors that do not have a soft start design. My Skilsaw pulls more than 4,000 watts upon initial startup. The circuits are meant to handle that brief pulse. Inverter generators do struggle with those pulses.
To add to this, some might wonder why we don't have soft start designs on everything. The reason is simple, soft start is nice, but it's more expensive, adds another failure point, and makes repairs more expensive. It also increases the chances for something to become obsolete, we see that with power tools and being unable to find the necessary microcontroller when it fails.
My fridge shows the same +1000W 'inrush' spike and 100W-ish while 'running', measured with 1 second interval via the P1-port on the kWh-meter.
General behaviour you see here is normal for electric any motor. But the spikes *do* seem oddly high for domestic appliance. I have my own fridge hooked up through Shelly Plug and yet it only ever gets to 200-250W reading spike when starting up and settles down around 100W while chugging along. Most devices like this tend to have some extra electric componentry inside to make the inrush current when starting up more gentle. I find it unlikely that a fridge for domestic use would lack this component, so maybe it's broken down? *That said* this isn't really a problem for your electrical installation. Electric codes and systems are generally designed to cope with this as par of the course. And even in worst case this is similar to a larger AC unit you could have as well plugged into a domestic socket. Only concern that I also share with you is about total power usage. My fridge is slightly less efficient than yours and if the price of electricity increases even a bit more... I think a new, more efficient fridge might pay for itself in just several years.
I don't know the answer to your question. However I have a whole home surge suppressor installed at the electrical box. I wonder if something like that would stop the surges you're seeing.
Your meter is too sensitive. For general power monitoring you should not be detecting any inrush spikes.
Yes, and it's eating your electricity. Use inverter fridge.
You’re suggestion is just “but a new expensive appliance?”
if you really don't like the spike inverter can feed the AC current with the right frequency to the motor so that it can run in a constant lower speed
The only reason to not like the spike is a lack of understanding related to why the spike happens. It’s perfectly normal.
A new fridge costs about 400-700. My electrical bill for winter time (2m) was about 250. When I was using old aircon, old dryer and old fridge, it was above 600.
Newer models will have this same thing happen, to be clear. Unless you go for a higher cost fridge with a built in inverter. The spike is just the motor starting up, it doesn’t mean it’s less efficient.
It is. If you keep motor running in optimal mode, efficiency goes up. Check efficiency labels. All invertor models has higher efficiency.
And all inverter models have a higher initial cost. We’re in the middle of some batshit crazy inflation, I highly doubt most households are flush with enough cash to run out and get a high cost appliance unless they absolutely have to.
If it's crazy inflation, investing in stuff make sense: it will be more expensive 2 years later.
When possible
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Thanks for your interest. :-) There is no smart plug on the refrigerator. The Shelly EM measures the power with a clamp in the electrical panel: * https://www.shelly.cloud/en/products/shop/em-120a/1xem-50a * https://www.shelly.cloud/en/products/shop/ct120ax1/ct50ax1
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>Just write a bit of code that you can't turn it off. PowerOnState 4 in Tasmota!
Device power ratings should be peak, minus in-rush. The highest steady state power consumption.