Existing Home Electric Versus Second EV Meter - Economics

Hi guys,

I just bought my first EV. A leaf.

I am deciding between using my existing home electrical system as is, versus having a second electric meter for the EV only which supplies electricity at a reduced cost of 5 cents per KWH.

My town has an incentive for EV owners and said you can install a second electric meter, they charge $300 for the meter and you install it with your own electrician at your own cost.

I do about 15,000 miles per year, 55 mile round trip to work 5 days per week, plus weekend use.

I am just wondering is it an economically sound decision versus plug n play as is on the existing electric system.

MOD NOTE: Please don't put your titles in all caps. -drees

Not sure of your location/utility...

Do you have overhead or underground service currently?

Does the 2nd meter have to be on a separate service or can it be downstream of your existing meter (and then subtractive billing used to determine car usage)?

If the 2nd meter can be downstream, it tends not to cost so much for installation. But if you need a new service and your existing service is underground, that would be a pretty expensive installation....

Hi,

The supply from the street is overhead.
After my panel the supply to the garage in the rear garden is about 150 feet long, under ground. The existing line to the garage is 15 amp and the garage has a 110v supply line.

I don't know yet whether I can have the 2nd EV meter within the existing home electrical supply or if it needs a deprecate meter and panel from the street supply as if its a new home almost! That would be totally counter productive to whatever incentives they are trying to do.

Say I can do it within my own system, at $300 for the meter plus the electricians install fees is it worth it for a 15,000 mile commute on 5 cents per KWH charge?

Really appreciate the help

You don't say what your power costs WITHOUT the utility's "separate EV metering" offer. Four miles per KWh from its battery is a reasonably good figure for a LEAF's energy economy, which is about 3.6 miles/KWh from the wall. So, those 15000 miles you plan to drive will require about 4167 KWh. Assuming your normal utility rate was 12.2 cents/KWh (the national average), and you charge your LEAF exclusively at your home, the utility's deal would be worth (15000 / 3.6) * (12.2 - 5), or $300/year. Assuming the utility doesn't rescind its offer in the meanwhile, it'll take about three years for you to recover your costs.

I don't often make decisions purely on economic basis, but I would do so in this case. You'll derive no peripheral benefit whatsoever from having that meter; it's just a means to qualify for the lower rate. Hmm.. The old balky Blink EVSE that I was issued as part of the (since concluded) EV Project was instrumented to measure and report the energy it delivered, and I suspect other EVSEs are as well. Shame the utility couldn't be persuaded to accept an EVSE's readings; if you were going to buy one anyway, you wouldn't need the extra meter.

We could get Time Of Use metering for our whole house, with no second meter. This would mean trying to use most of our power off-peak, but because of my schedule and my housemate's habits, it wouldn't be all that hard. Naturally, my HM, having raised the issue of higher electric bills, vetoed the TOU plan...

MA DOE is discussing TOU rates, and they may roll it out in a year or so, but could require a sub-meter, too early to say. I've suggested EVSEs with embedded production meters, but no idea if that idea will fly.

If the OP's current municipal utility's rate is close to the $0.16/kWh National Grid is at in the state (varies all the time) he might save $400/year, but the install might cost $1500-2000 all inclusive.

Keep in mind that this isn't just a benefit for this car, it is a benefit for any plug in vehicle or vehicles you ever have in that house.
If you are not planning on staying in the house long, it may not be worth it.

Besides financial, a second meter gives you an easy way to monitor power use of your EVs.

Your avatar doesn't show where you are. But for example - the average contractor around here in So Cal wanted to rape us for $1,000 to bust out the stucco & install a meter socket. I'd be dead of old age before recapturing that kind of expense. On the other hand, our PV array is large enough that So Cal Edison has to pay us at least $100/yr for our surplus juice. That eventually won't go to such waste (giving juice back to edision) once we replace the hybrid Lexus with a 2nd plug in car.

I live in SoCal and we have the option of a single or adding a second EV only meter downstream from the first. The second EV only meter costs significantly less than using a single meter if you use the basic, tier-base plan. Since I had the option to use a TOU plan for the single meter, I went that direction and it costs me about $40/month to operate the Leaf (40 mile daily commute and 50 miles pet weekend). Plus, the single meter plan allows me to add solar cells to the roof and SCE will offset the electricity generated.

So you need to figure out which plan works best for you and your driving habits since one size does not fit all.

If your utility allows subtractive metering, it is a relatively simple and inexpensive task to add separate EV metering. If they do not, it can be much more expensive... (Ironically, LADWP, where I live does allow it for water, but not for electricity... I opted to stick with a single meter since it would never pay back for me.)

Eire32 said:

The supply from the street is overhead.
After my panel the supply to the garage in the rear garden is about 150 feet long, under ground. The existing line to the garage is 15 amp and the garage has a 110v supply line.

Click to expand...

Given this scenario, I would say you are faced with a fairly expensive upgrade to put a Level 2 EVSE into your garage. This is because you will need to pull (likely bury) a new wire from the house to the garage if you want to keep your existing supply for your lights.

As such, if you can get the utility to put new service and an EV meter ON THE GARAGE, then you may come out cheaper both up-front AND for your electricity rate. (But I doubt that is what they are offering.)

It would be good to know what they are offering to do for the $300.

RegGuheert said:

Eire32 said:

The supply from the street is overhead.
After my panel the supply to the garage in the rear garden is about 150 feet long, under ground. The existing line to the garage is 15 amp and the garage has a 110v supply line.

Click to expand...

Given this scenario, I would say you are faced with a fairly expensive upgrade to put a Level 2 EVSE into your garage. This is because you will need to pull (likely bury) a new wire from the house to the garage if you want to keep your existing supply for your lights.

As such, if you can get the utility to put new service and an EV meter ON THE GARAGE, then you may come out cheaper both up-front AND for your electricity rate. (But I doubt that is what they are offering.)

It would be good to know what they are offering to do for the $300.

Click to expand...

Also, be sure and pin them down on that $0.05 rate. I'll bet there's a monthly meter fee and probably distribution charges added also. Total may be a lot more than 5c/kWh.

Alright guys I have more info

So it is a sub-meter that is installed, somewhere downstream, within the existing electrical system.
It does NOT need to be a separate electrical supply.

The sub-meter costs $300 once off, plus your electrician charge is extra pending the many variables.

Only the EV charger can be on this sub-meter. If you charge the car during peak hours then you pay the normal peak rate of 14.3-17.0 cents per KWH.

However, the whole idea is that if you charge the EV off peak ie after 10pm then you get a 5.5 cents per KWH rate.

So, with this all in mind now, what do you all think? Is it economically worthwhile.
Round trip to work is 54 miles, 5 days per week, I will also use if for weekends, Id say about 15,000 miles per year total.

Secondly, Although the leaf charger needs a 40 amp double pull, if I am going to do this install id rather run a sufficient ampage line such that if I get something other than a Nissan leaf in a few years that I dont need to reinstall all over again. The town electrician suggested running a 100 amp line for now, which always allows stepping up to another EV in years to come.
Do you think a 100 Amp line is sufficient or where is this all going?

Lastly, why cant the 110v cable that comes with the Nissan leaf be connected to a 220v connector and wired to the 220v line to the garage? Surely this is the cable they have in Europe....... As it would mean not having to get an EVSE Level 2 at $600 plus extra costs.

Any help greatly appreciated

I bought and installed a second meter in my garage just for power usage information on the car, the meter (rebuilt) was $26 and the base was $10, total with shipping was $55

my utility (Duke power) offers no programs in my area for night rate, electric car usage or anything worthwhile in my area

Eire32 said:

Lastly, why cant the 110v cable that comes with the Nissan leaf be connected to a 220v connector and wired to the 220v line to the garage? Surely this is the cable they have in Europe....... As it would mean not having to get an EVSE Level 2 at $600 plus extra costs.

Any help greatly appreciated

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the 120 cable is designed for 120, hooking it to 240 without having it modified will most likely result in it's electronics being damaged and rendering it non-functional

Running new Power just to the Garage from the street, New Meter just for your EV 100Amp should be good enough, I can't see home charging getting past that.

My "Guess @ EV only Power @ .055 Per KwH" 20KwH per night 6 days a week is somewhere in the $30.00 range per month + $25 meter charge + Delivery charge + tax + Junk Fees + Fuel/Wholesale adj rate.

Just adding keeping the power at your normal rates .15 would run you ~$82 / month. + tax + Junk Fees + Fuel/Wholesale adj rate.

You would need to pull a 220v 100Amp line to the garage, (I would put it in a PVC Pipe, and trench it in, then pull the line thru it.) A sub-box feed next to the meter, 2nd sub-box in garage.
This all is going to be very costly with long cost recover time. (You would need to do this if you go with EV rate, or Normal Rate, to get a 220v charger into the garage.)

Honestly I don't see much of a buy back both options are going to come at about the same price.

Can you charge @ work?
Do you need to worry about cold, keeping the battery warm @ night if Eire (PA) is where you are.. It get cold there...

Eire32 said:

Secondly, Although the leaf charger needs a 40 amp double pull, if I am going to do this install id rather run a sufficient ampage line such that if I get something other than a Nissan leaf in a few years that I dont need to reinstall all over again. The town electrician suggested running a 100 amp line for now, which always allows stepping up to another EV in years to come.
Do you think a 100 Amp line is sufficient or where is this all going?

Click to expand...

I agree that using 100A wiring to your garage makes sense. You'll just use a 40A breaker for now with the 6kW EVSE.

Eire32 said:

Lastly, why cant the 110v cable that comes with the Nissan leaf be connected to a 220v connector and wired to the 220v line to the garage? Surely this is the cable they have in Europe....... As it would mean not having to get an EVSE Level 2 at $600 plus extra costs.

Click to expand...

It's not the same cable used in Europe. If you plug it into 240V, it will be destroyed. The good news is that you can pay to have it upgraded to work with either 120V or 240V at EVSEUpgrade.com for about half the cost of a cheap wall-mounted unit.

Do you have other options besides the garage? Can you mount it on the side of the house and charge in the driveway? Does the utility company have a time of use rate that you can apply to your existing meter, and charge at night?

bbrowncods said:

Do you have other options besides the garage? Can you mount it on the side of the house and charge in the driveway? Does the utility company have a time of use rate that you can apply to your existing meter, and charge at night?

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Nope, the driveway and garage are in the rear about 150 feet from the home.
The garage currently has a 110v supply line for lights, garage door opener and sockets.

I am hoping that the line to the garage is up to spec for a 40amp 220v supply for a level 2 EVSE that can also contain the sub-meter along the way.

Can you run a 110v line in this case to the garage and have a 220v on the same line, or do they need to be two separate lines for each?

Eire32 said:

I am hoping that the line to the garage is up to spec for a 40amp 220v supply for a level 2 EVSE that can also contain the sub-meter along the way.

Click to expand...

That is extremely unlikely. Even it you somehow lucked out and the buried cable was 8 AWG, you would lose your lights, garage door opener and outlets if your repurposed it for the EVSE. That's why I previously stated that this would be an expensive install.

Eire32 said:

Can you run a 110v line in this case to the garage and have a 220v on the same line, or do they need to be two separate lines for each?

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If your chose to go with the utility's meter, then they must be separate. Otherwise, you could bury a nice high-current cable with three wires and ground and put a subpanel in your garage. Then you have a lot of flexibility.

BTW, if you ALREADY have a subpanel in your garage, you may have some very cheap options available. But from what you have described so far, it sounds like you only have a single 120V circuit out there.