Existing Home Electric Versus Second EV Meter - Economics

[johnrhansen]

I considered adding a second meter just for my evse, because Seattle City Light charges on a tiered system:

Summer: First 10 kWh per day at 5.06¢ per kWh
Winter: First 16 kWh per day at 5.06¢ per kWh

All additional kWh per day at 11.49¢ per kWh
Base Service Charge: 16.07¢ per meter per day

They multiply the days in the billing cycle by that number and divide up the rates that way. They don't have smart meters.
It would save quite a bit of money, but there's the base service charge to think about, plus they charge a hefty fee to run the new drop. I decided it wasn't worth it.

 

[bbrowncods]

NEC 625.41 (formerly 625.14) defines an EVSE as a continuous load for the purposes of rating. The exception is if there is a hardware solution to manage the load in a way that does not exceed the rated capacity of the circuit. That solution does not include "I know I'm not going to plug it into a Tesla." It would include a "smart" EVSE that knows it's only allowed to pull so many amps for so long and adjusts itself accordingly.

All EVSE's have a set limit. One should set the limit (or buy one with a preset limit) of their EVSE to not exceed the the circuit onto which it is attached (NEC 625.41). My EVSE is set to 28A (30A is acceptable as well), the Leaf that I charge is set to 27.5A max from the factory, and the EVSE has a timer (as well as the Leaf). The Leaf will not accept 27.5 A for longer than 3 hours (I have tested this on a 6.6Kw SL).
This meets the "exception" of NEC 625.41 for a permenant installation (mine is not). This is a non-continuous load. And it didn't cost thousands for an electrician to come wire me a special EVSE circuit. It is not required.

I will tell everyone to get educated and make a proper assessment of their sutuation and not buy into the fear mongering that implies it is unsafe to have a EVSE charging at 27.5A on a 30A circuit just because it is an EVSE. Even if they own a Tesla.

Let me just add that the argument that the circuit needs to be inspected for degraded conditions, insulation, etc. applies to any type of load. Just because one uses 24A instead of 27.5A does not make it any safer.

Continuous load argument aside, there is no doubt that your circuit operates near its limit which is never a good thing as it leaves little room for error. The fact your load is active for prolonged periods of time only makes it worse. There were reports of Leafs drawing more current than they should on 110V due to faulty hardware. It is rarely a single thing that causes bad things to happen, but a combination of your Leaf drawing more than 27.5A, hot summer weather, old insulation, and a sticky breaker can be your recipe for a fire.

Using that argument the circuit would not be safe to use at any load, much less 24A. You are using generalities to make an argument which is hypothetical.

Let's assume the circuit performs as it is designed, if it can't then it should not be used at all (applies to any circuit). Otherwise we unplug and go buy an ICE.
There is a clear line in the NEC that determines where the cutoff is for our use. It is there to provide safe guidelines for installers and users alike. Both sides of that line are safe to operate in. I get your point that if operating at the top edge of the 30A circuit design it is advantagous to upgrade to a 40A circuit. But they are both safe and are designed as such for their use. Otherwise NEC would never allow 30A for 2.99 hours on a 30A circuit. Which is legal and safe.
If one has the choice, put in a 40A circuit and call it a day. But there is no NEED to do that and spend $2000 for fear of dying. My solution works, is within code, is safe by design, and operates well within the limits of a 30A/240V circuit.
1. Up to 3 hours a day, and not to exceed 3 hours a day charging, is not "prolonged use". It is addressed in the NEC as a non-continuous load
2. 27.5A is not the maximum load for a 30A circuit that is designed to work at 30A. Otherwise it would be called a 27.5A circuit.

 

[Valdemar]

The code covers everything from the panel up to and including the EVSE, but not the vehicle. The fact your car needs less than 3 hours to fully charge means very little from the code compliance point of view. Your setup may be marginally safe for your current car, but it is definitely not code compliant.

 

[Rauv]

Bbrowncods. We get it. You are willing to risk your present installation and convince yourself that your installation meets Code and therefore, in your mind is safe. It isn't safe and doesn't meet Code regardless of how hard you try convince us and the electrons that it is.

 

[bbrowncods]

Bbrowncods. We get it. You are willing to risk your present installation and convince yourself that your installation meets Code and therefore, in your mind is safe. It isn't safe and doesn't meet Code regardless of how hard you try convince us and the electrons that it is.

You keep saying unsafe, and risk, and does not meet code. I have shown you where it does. You use the NEC when it suits you and when you're shown that you are wrong you label it as unsafe.

Acknowledge that a 30A circuit can be used to draw 30A safely for up to three hours by code. If you won't, I get it too.

 

[Eire32]

So are we suggesting that the upgraded EVSE of the standard leaf EVSE should operate from a 40 amp fuse?

 

[RegGuheert]

So are we suggesting that the upgraded EVSE of the standard leaf EVSE should operate from a 40 amp fuse?

No, it should be operated from a 30A circuit.

 

[Eire32]

This posting is getting good lol!

Ok so install tomorrow
Permit pulled by electrician
Electrician installing 100 amp panel tomorrow and wiring etc
Then town inspector approves
Power company then drop a line and connect
Then the power co electrician drops the sub meter in!

Hope to be running 240v by Tuesday or so....

Any sign of electric SUVs on the cards apart from the Tesla X?

 

[pchilds]

Any sign of electric SUVs on the cards apart from the Tesla X?

If you are in California, get a RAV4 EV, they are going fast.

 

[Eire32]

Any sign of electric SUVs on the cards apart from the Tesla X?

If you are in California, get a RAV4 EV, they are going fast.

Not the best looking though!
I just like the interior of German cars! Interested to see the EV golf!

 

[Eire32]

So it's all finally hooked up!

12kwh used off peak to refill battery from 45% full. A 45 mile round trip is costing 60 cents. Incredible!

I ended up getting an electrical supply and account just for the car.

Fees involved.
$1,000 electrician
$35 permit
$300 smart meter
$0 electrical drop from the power co
$340 EVSE upgrade.
Process took 3 days.

Let me know if you guys would like more info!

 

[Valdemar]

SA 45 mile round trip is costing 60 cents. Incredible!

It is, at least that's what I thought when I bought my Leaf even though my cost was more like double of what you pay for kWh. The sad reality is that savings on gas and service never caught up with the Leaf's depreciation, and after 3 years and 60000 miles all together I spent about the same amount on the Leaf as I would have on the premium gas thirsty 20mpg car it replaced, that is if I were to sell either today. The looming out of pocket battery replacement in a couple of years will surely eat all the future savings too.

 

[Eire32]

I decided to lease for those reasons!

 

[hill]

So it's all finally hooked up!

12kwh used off peak to refill battery from 45% full. A 45 mile round trip is costing 60 cents. Incredible!

I ended up getting an electrical supply and account just for the car.

Fees involved.
$1,000 electrician
$35 permit
$300 smart meter
$0 electrical drop from the power co
$340 EVSE upgrade.
Process took 3 days.

Let me know if you guys would like more info!

Sadly, it'd take me decades to recover the $1,300+
to make matters worse, many utilities (seeing this as a profit loss) are tagging on fees just to have the 2nd meter ... so it really really takes for ever just to recoup the investment. Still ... here's to hoping it works out for you.

.

 

[Valdemar]

I decided to lease for those reasons!

Leases weren't as good 3 years ago, and 20k mile/year ones even more so. I suppose it's not fair to compare a used car and a new Leaf in my case, and even if not as good as I had hoped overall it worked out well enough, so I have no regrets.

 

[Eire32]

So in my case, to put in a 240 volt line on my existing home service would have been
More expensive $1850 electrical fee v $1,000
Put more strain on my existing 200 amp service
Maximum amps would have been 40 amps on the line
Put a trench in my garden at more cost and hassle
So it's capacity would always have been limited
The drop was also free. The smart meter was a once off fee of $300. The fee per month is about $5 for the line.

So this is specific to my case.

My other car is a 4.2L V8 AWD, it would cost $500 or more per month on gas.

So in my case it's great. Plus, should I ever up it to a Tesla or if cars in future need a 100 amp line I have that capacity right now. I would have had to pay $4,000 to up my home service to 400 amps. So it was the most cost effective solution in my case.

Plus, having 100 amps just for an EV in future and a reduced off peak service fee is a major plus.

 

[Valdemar]

Curious why you think you'd need to up your service to 400A for a future Tesla. Did you perform a total load calculation?

 

[johnrhansen]

I don't get around much, but I don't ever remember seeing anything in between 200 amp and 400 amp services.

 

[Eire32]

Yes, I did a load calculation as did the electrician.

If I did a 240 volt line from my existing 200 amp panel like I said the max amps run would be 40 amps, not future proof!

Teslas need more than the 30 amps needed for the leaf. They are already up to 85amps so I think 100 amps should suffice.

 

[Eire32]

I don't get around much, but I don't ever remember seeing anything in between 200 amp and 400 amp services.

Neither did I until last week. 400 amp service exists. We have our own town plant, that may help!