A good way of measuring accurately KWH usage?

[Zirak]

Looks like you have 48A charging. Nice!

Do you schedule to start at a specific time or do you use the new departure schedule feature? That heats the cabin and battery and might be an additional draw, though I'm not sure it would explain everything.

I haven't crunched the numbers but it looks like you have a not insignificant load even when not charging at night. 2kw at 3am for example.

I'm away from a computer right now but you could get a ballpark idea of car charging/heavy appliances vs light stuff by adding up all hours >=5 kwh and all hours <=5kwh and seeing how much of each you have.

Edit: maybe 3 or 4kwh is a better cut-off

Yeah, I use the new scheduled departure feature, and that feature automatically adjusts amperage too, from what I can tell, it doesn't always use the max 48amps, I think it does it to prolong the time the battery stays warm maybe?

 

[bijan]

Yeah, I use the new scheduled departure feature, and that feature automatically adjusts amperage too, from what I can tell, it doesn't always use the max 48amps, I think it does it to prolong the time the battery stays warm maybe?

It will use cabin heating which maxes out at 7kw and goes down once cabin is warm to maybe 1kw. It also uses 3.5kw for RWD and 7kw for AWD to heat the battery depending on battery temperature. So something between 18a and even more than 48 amps (though not for long at that high) if battery isn't warm enough.

 

[bijan]

I did some rough math looks like you had about 100 hours of high load and the rest is low. Average is 1.78kwh on low and 2.65kwh overall.

If we assume the high drain hours also average 1.78kwh of low drain. Then you have roughly 1300kwh due to low drain stuff and 600kwh due to charging and dryer, etc.

Edit: this was using my original 5kwh cutoff. I might try repeating with 3 and 4 kwh to see the effect of "medium" load periods.

Edit2: repeating same very approximate calculations with 3kwh cut-off gives about 700kwh due to hours over 3kwh (high and medium drain) vs 1200kwh due to low drain hours.

 

[Zirak]

Just got the meters hooked up today.

 

[5_+JqckQttqck]

You got computers kept on? I know the Rogers and Bell boxes zap a ton of electricity even thought they're suppose to be "sleeping".

 

[Zirak]

You got computers kept on? I know the Rogers and Bell boxes zap a ton of electricity even thought they're suppose to be "sleeping".

Yes, only one (miniITX build) that is on 24/7 as my personal home server, very minimal power consumption. It was always on in my rental place as well, so I don't think that's causing a huge dent in the usage.

A strange thing I noticed is that the car charger reports as 122v, was expecting it to be 240v, but I guess it's because I'm passing only one wire through the CT sensor? When I passed the two cables that was connected to the 60A breaker (Black and Red) through the sensor, the meter wouldn't pick up any load when the car was charging.. so I just put the black wire through it. I did a quick test yesterday, so I don't know if the usage is correct, will have to test tonight to see if it captures correct usage in a span of an hour, otherwise I'm guessing I'd have to multiply it by 2 if it's off?

 

[darkenergy]

A strange thing I noticed is that the car charger reports as 122v, was expecting it to be 240v, but I guess it's because I'm passing only one wire through the CT sensor? When I passed the two cables that was connected to the 60A breaker (Black and Red) through the sensor, the meter wouldn't pick up any load when the car was charging.. so I just put the black wire through it. I did a quick test yesterday, so I don't know if the usage is correct, will have to test tonight to see if it captures correct usage in a span of an hour, otherwise I'm guessing I'd have to multiply it by 2 if it's off?

If you have the voltage feed for the meter connected between neutral and either the red or black you'll get 120V. The neutral sits between the two phases of the 240V, hence the lower voltage. 240V is present across the red and black.

Note the Amazon recommendation from the commenter on those meters regarding 240V and the supply cap rating on the meter.

 

[Zirak]

If you have the voltage feed for the meter connected between neutral and either the red or black you'll get 120V. The neutral sits between the two phases of the 240V, hence the lower voltage. 240V is present across the red and black.

Note the Amazon recommendation from the commenter on those meters regarding 240V and the supply cap rating on the meter.

So my setup right now should be fine as it is, and should measure accurately?

 

[brkaus]

So my setup right now should be fine as it is, and should measure accurately?

What are your 4 meters hooked up to?

 

[Zirak]

From left to right:
1. Dryer
2. Washer (& a bunch of other stuff hooked up to this circuit)
3. Furnace
4. HPWC

 

[darkenergy]

So my setup right now should be fine as it is, and should measure accurately?

I think that if your displays are showing 120V (ish) then you aren't connecting the voltage sensing leads between the two hot conductors on the 240V circuits.

 

[Zirak]

I think that if your displays are showing 120V (ish) then you aren't connecting the voltage sensing leads between the two hot conductors on the 240V circuits.

I wired them like this:
1.CT Sensor cables on the first two pins on the device
2. Black wire from the car charger wired through the CT Sensor
3. Black wire from the third pin of the device (iirc) into the same source as where the black wire for the car charger is connected into the breaker
4. White wire from the fourth pin, into the neutral part of the panel (where all the neutral wires are screwed in the back side of the panel)

In any case, I got about 12kwh usage after one night of charging, which sounds about right based on my car usage.

 

[5_+JqckQttqck]

I wired them like this:
1.CT Sensor cables on the first two pins on the device
2. Black wire from the car charger wired through the CT Sensor
3. Black wire from the third pin of the device (iirc) into the same source as where the black wire for the car charger is connected into the breaker
4. White wire from the fourth pin, into the neutral part of the panel (where all the neutral wires are screwed in the back side of the panel)

In any case, I got about 12kwh usage after one night of charging, which sounds about right based on my car usage.

To have the meter register 220-240V. The sensor needs to be around the black(red) while the "Neutral" is the left over Red(black). Pick which one you want to read and the other as the end loop.

 

[Zirak]

To have the meter register 220-240V. The sensor needs to be around the black(red) while the "Neutral" is the left over Red(black). Pick which one you want to read and the other as the end loop.

It is already around the black wire, not the red wire. Do you mean to move the neutral wire connected from the meter, into the breaker where the red wire for the HPWC is connected, instead of having the neutral wire connected to the back of the panel where all the other neutrals are connected?

 

[5_+JqckQttqck]

It is already around the black wire, not the red wire. Do you mean to move the neutral wire connected from the meter, into the breaker where the red wire for the HPWC is connected, instead of having the neutral wire connected to the back of the panel where all the other neutrals are connected?

I have one of those meters sitting around at home. Just been lazy. I'll hook it up and take a pic

 

[Zirak]

I have one of those meters sitting around at home. Just been lazy. I'll hook it up and take a pic

Haha, that works

 

[anandoc]

I wired them like this:
1.CT Sensor cables on the first two pins on the device
2. Black wire from the car charger wired through the CT Sensor
3. Black wire from the third pin of the device (iirc) into the same source as where the black wire for the car charger is connected into the breaker
4. White wire from the fourth pin, into the neutral part of the panel (where all the neutral wires are screwed in the back side of the panel)

In any case, I got about 12kwh usage after one night of charging, which sounds about right based on my car usage.

That 4th wire needs to be connected to the other hot wire that goes to the car charger (typically the red wire). Then your reference voltage going to the power meter would be 240V.

Do you mean to move the neutral wire connected from the meter, into the breaker where the red wire for the HPWC is connected, instead of having the neutral wire connected to the back of the panel where all the other neutrals are connected?

Correct.

 

[Zirak]

That 4th wire needs to be connected to the other hot wire that goes to the car charger (typically the red wire). Then your reference voltage going to the power meter would be 240V.



Correct.

Awesome, will probably look into that today. Will also be swapping the one of the meters off the dryer circuit, since the usage for that is predictable.

 

[Zirak]

Got the voltage reading fixed thank you for the help!

Also swapped one of the other meter to be on a different circuit, since the dryer wasn’t reading much per usage. It’s on the kitchen fridge now, thinking that might also be draining a lot.

 

[anandoc]

Got the voltage reading fixed thank you for the help!

Also swapped one of the other meter to be on a different circuit, since the dryer wasn’t reading much per usage. It’s on the kitchen fridge now, thinking that might also be draining a lot.

Glad to see it sorted out. Share the amazon link for the ones you bought?