No second meter :(

[TimeHorse]

I'd also like to add that for the 2 or so of you like me in Virginia, Dominion is petitioning the State Corporation Commission to allow them to set up a new Schedule EV rider that would allow your EV to be charged at a different rate than your household. Currently, you can have multiple meters on your home in Virginia, but they'd all have to be billed the same rate. This proposal would add an allowance for a sub-meter that would be a TOU optimized for charging between 01:00 and 05:00. I will be posting more details on my blog as more information becomes available. And just to update my previous post, it looks like $0.056 to $0.061 per kWh (depending on the EV plan selected) as opposed to my typical average of $0.09133 per kWh, after taxes and fuel, etc. riders.

Though I should point out that goes down to $0.048 to $0.053 per kWh if the LEAF had a 6.7kW charger!!!

 

[garygid]

Reduced cost at 6.6 kW charging because all the charging fits into the 1-5 am window?

 

[ERG4ALL]

When we had our PV system installed we had a 200 Amp service from the utiltiy. The issue was that you cannot have more than a 20% PV feed into the panel. The reason is that the buss bars are rated at 200 Amp. It is conceivable that if you were at 100% capacity and the PV system was generating at max. then the busses would have to handle a 240 Amp current which may overheat the buss bars. To be properly hooked up the installing company recommended (and it turns out we were set up exactly right) that the PV input to your main panel be at the opposite end of the buss bars from your utility feed. Thus, the utility brought in 200A at the bottom of the panel and the PV 40A breaker was at the top of the bus bar. That way the entire load will not travel the entire length of the buss bar before current is used. This seems a little far fetched but the regs. often call for the worst case to be safe.

 

[TimeHorse]

Reduced cost at 6.6 kW charging because all the charging fits into the 1-5 am window?

My scenario consists of the following:

80% charge (19.2 kWh) of battery used on a daily basis, average (75 mi round-trip to work [hypermiling many days, no doubt])
50% of weekday charge (40% of total; 9.6 kWh) on Saturday and Sunday (ignoring holidays)

Thus, to finish charging by 5am under 6.7 kW, I start charging at 02:08:03 on weekdays and 03:34:01 on weekend, both within the 4 hours super-off-peak proposed by Dominion Virginia.

With the 3.3kW charger, I still have weekends in super-off-peak, starting at 02:05:27 but now some of the charging is pushed into Off-peak, at 23:10:54 the previous day, though I avoid any intermediate rates. Under Schedule 1EV, there's 3.261 cents per kWh increase in summer (6 months) and 2.771 cents per kWh increase in winter (6 months); under the EV-only Schedule EV it's a 3.265 cents per kWh increase, year round.

Of course, as I said, all that adds up to is about $50 annual savings with a 6.7kW charger, but there's more than that since there's also the convenience of getting home at 16:00 and in a pinch being able to charge most of my car by 19:00. (Though I'd hate to pay those electric rates!)

 

[wsbca]

Reduced cost at 6.6 kW charging because all the charging fits into the 1-5 am window?

My scenario consists of the following:

80% charge (19.2 kWh) of battery used on a daily basis, average (75 mi round-trip to work [hypermiling many days, no doubt])
50% of weekday charge (40% of total; 9.6 kWh) on Saturday and Sunday (ignoring holidays)

It doesn't change your bottom line by very much ($10/year?), but in the interest of accuracy, it's probably going to take you about 23 kWh from the wall to recharge after driving 75 miles (ie 3.25 wall to wheels - might be a bit better than that, but it's not going to be the 3.9 implied by your figures). On the flip side, the "3.3" kW charger pulls ~3.77 from the wall, which "counts" as that much in the 3.25 figure. So it might take you 6:10 to recharge instead of 5:50.

 

[TimeHorse]

Reduced cost at 6.6 kW charging because all the charging fits into the 1-5 am window?

My scenario consists of the following:

80% charge (19.2 kWh) of battery used on a daily basis, average (75 mi round-trip to work [hypermiling many days, no doubt])
50% of weekday charge (40% of total; 9.6 kWh) on Saturday and Sunday (ignoring holidays)

It doesn't change your bottom line by very much ($10/year?), but in the interest of accuracy, it's probably going to take you about 23 kWh from the wall to recharge after driving 75 miles (ie 3.25 wall to wheels - might be a bit better than that, but it's not going to be the 3.9 implied by your figures). On the flip side, the "3.3" kW charger pulls ~3.77 from the wall, which "counts" as that much in the 3.25 figure. So it might take you 6:10 to recharge instead of 5:50.

Well, I'd be happy to try and compute that but I've got all my calculations in a Google Spreadsheet (a very large Google Spreadsheet that takes a few minutes to update but sure, I can redo the calculation with 95% weekdays, which represents about 23 kWh on a 24 kWh battery; I know you're actually trying to represent loss in the circuits charging the battery (meter to battery) as well as on-the-road efficiency (battery to distance) but by just saying my daily battery usage is nearer to 95% of the capacity I think by your estimates we'd be better in line.

Now, I type that one change from 80% to 95% into my Google Spreadsheet and voilà:

Working

And typically then it just locks up. I could try to reload it but then I'd have a 25% chance of not getting a blank screen as a result. Bugger this google! Those maths are easy, of course. The problem is summing the kWh for a given month, looking up the hour-by-hour charge for the EV usage, including the 5 W base load of the CS-100, that comes to about $2 per year then all the riders and taxes and arrrrgggggg why won't this bloody thing load! :evil: :roll:

 

[planet4ever]

Well, I'd be happy to try and compute that but I've got all my calculations in a Google Spreadsheet (a very large Google Spreadsheet that takes a few minutes to update

I guess I'm just old-fashioned. I never feel like my footing is very firm when I'm walking on "the cloud". Whenever I can I use an Open Office Calc spreadsheet on my own computer. I refuse to pay Micro$oft the big bucks for Excel. Why should I when Open Office, like Google, is free? It's compatible with Excel, too.

Ray

 

[TimeHorse]

I guess I'm just old-fashioned. I never feel like my footing is very firm when I'm walking on "the cloud". Whenever I can I use an Open Office Calc spreadsheet on my own computer. I refuse to pay Micro$oft the big bucks for Excel. Why should I when Open Office, like Google, is free? It's compatible with Excel, too.

Ray

And Google Docs speaks Open Office, though that doesn't mean my QUERY formula will come through; what I really need is a cloud database.

 

[JimK]

When we had our PV system installed we had a 200 Amp service from the utiltiy. The issue was that you cannot have more than a 20% PV feed into the panel. The reason is that the buss bars are rated at 200 Amp. It is conceivable that if you were at 100% capacity and the PV system was generating at max. then the busses would have to handle a 240 Amp current which may overheat the buss bars. To be properly hooked up the installing company recommended (and it turns out we were set up exactly right) that the PV input to your main panel be at the opposite end of the buss bars from your utility feed. Thus, the utility brought in 200A at the bottom of the panel and the PV 40A breaker was at the top of the bus bar. That way the entire load will not travel the entire length of the buss bar before current is used. This seems a little far fetched but the regs. often call for the worst case to be safe.

The PV current is subtractive not additive! If you were drawing the full 200 amps from your service and the PV system was providing 40 amps the buss current is 160 amps. However if the PV system was the first circuit on the buss the service would see 160A and the buss after the PV breaker could see the full 200A. If the PV was the last breaker on the buss the maximum buss current would be 160A.

 

[garygid]

Sorry, 200 amps in at one place (main breaker) and 40 in at another place (PV generation) COULD allow 240 amps out at one spot on the bus. However, since the loads are "small", and distributed along the buss, this "worst-case" does not happen.

In any case, the typical electrical codes only allow over-rating the buss by 20% for PV generation.

 

[ERG4ALL]

JimK Wrote:

The PV current is subtractive not additive!

Thank you garygid:

Sorry, 200 amps in at one place (main breaker) and 40 in at another place (PV generation) COULD allow 240 amps out at one spot on the bus.

 

[TimeHorse]

It doesn't change your bottom line by very much ($10/year?), but in the interest of accuracy, it's probably going to take you about 23 kWh from the wall to recharge after driving 75 miles (ie 3.25 wall to wheels - might be a bit better than that, but it's not going to be the 3.9 implied by your figures). On the flip side, the "3.3" kW charger pulls ~3.77 from the wall, which "counts" as that much in the 3.25 figure. So it might take you 6:10 to recharge instead of 5:50.

Fair points. For my new simulation, I will change my parameters to 95% battery (about 23 kWh) per day, 47.5% each weekend day. Then, I will figure a 3 1/3 mi/kWh for my average fuel efficiency which has the rather nice consequence of coming to exactly 23,792.94 miles per year (no way I could lease at 15k miles with that number!); which, coincidently, I was quite surprised to find came to the exact same number at I computed for current ICE miles per year. The ICE is computed as 16 gallons per week with 52.1775 weeks per year in the Gregorian calendar for a total of 834.84 gallons per year. Multiply that by my estimated ICE average fuel efficiency of 28.5 mpg (about 8.25 l/100km) and Bob's your uncle, you get 23,792.94 miles once more.

Of course, these are gross averages, but my preliminary results show with these numbers:

• $650+ under the base household Schedule 1
• $530- under a separate TOU Meter under Schedule 1T
• $565+ under a separate TOU Meter under Schedule 1S
• $450+ under a separate TOU Meter under Schedule EV
• $420+ under an EV household Meter under Schedule 1EV

I think that represents about $100 per year more, but I will go with that for the sake of your suggested accuracy.

Now, with the 6.7kW charger, those costs go to

• $650+ under the base household Schedule 1 (no TOU)
• $530- under a separate TOU Meter under Schedule 1T (no Super-Off-Peak)
• $565+ under a separate TOU Meter under Schedule 1S (no Super-Off-Peak)
• $370- under a separate TOU Meter under Schedule EV (same as it was under the old simulation)
• $345- under an EV household Meter under Schedule 1EV (same as it was under the old simulation)

Which means $75 - $80 savings per year under the 6.7kW charger since the charge now fits in the 4 hour Super-Off-Peak window. Again small but it does add up.

 

[wwhitney]

Well, there is a UL-listed dual meter adapter made by E.J. Brooks Utility. See http://www.brooksutility.com/catalog/product-detail.asp?ID=570 The UL certification can be verified at http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=PKAX.E142236 That page only lists one of the model numbers for the adapter, so I'm not clear if the other configurations are also UL listed. I also have no idea on pricing or availability, I have not contacted the company.

Update: contrary to their web page, this UL-listed dual meter adapter made by Brooks Utility is a series meter adapter, not a parallel meter adapter. So it is used for putting two meters in series to check their accuracy, not for separately metering two loads. As far as I know, there are no UL-listed parallel dual meter adapters.

Cheers, Wayne

 

[TimeHorse]

Well, there is a UL-listed dual meter adapter made by E.J. Brooks Utility. See http://www.brooksutility.com/catalog/product-detail.asp?ID=570 The UL certification can be verified at http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=PKAX.E142236 That page only lists one of the model numbers for the adapter, so I'm not clear if the other configurations are also UL listed. I also have no idea on pricing or availability, I have not contacted the company.

Update: contrary to their web page, this UL-listed dual meter adapter made by Brooks Utility is a series meter adapter, not a parallel meter adapter. So it is used for putting two meters in series to check their accuracy, not for separately metering two loads. As far as I know, there are no UL-listed parallel dual meter adapters.

Cheers, Wayne

Most dual and tri meters I've heard about, and I'll probably get a Tri meter under the Dom VA Power program, basically have the mains going to the first meter, then branching to the second and third meters, where the other 2 meters are subtracted from the readout of the first meter on the display, or in the case of a smart meter, in the X.25 signal they send back to the PU. Of course, I'm not a power engineer, so what do I know?

 

[scubasandy]

We're in Phoenix, Az and I am about to get my charger installed free (plus $700 out of pocket because we need a new circuit box). I called SRP, our electric company and she said after I get the permits from the city (Scottsdale), they can come out and install a second meter free, BUT there would be a $28 turn on fee and a $20 monthly service fee for the new account.

Seems to me (without doing the math) that would counteract any cost savings of going to a time-of day usage plan. Especially in Phoenix where our biggest cost in AC in the summer between 4-7pm.

Just an FYI for anyone thinking a second meter will save money due to the decreased energy costs.

Susan (newbie, no LEAF yet)

 

[TimeHorse]

We're in Phoenix, Az and I am about to get my charger installed free (plus $700 out of pocket because we need a new circuit box). I called SRP, our electric company and she said after I get the permits from the city (Scottsdale), they can come out and install a second meter free, BUT there would be a $28 turn on fee and a $20 monthly service fee for the new account.

Seems to me (without doing the math) that would counteract any cost savings of going to a time-of day usage plan. Especially in Phoenix where our biggest cost in AC in the summer between 4-7pm.

Just an FYI for anyone thinking a second meter will save money due to the decreased energy costs.

Susan (newbie, no LEAF yet)

Thanks, Susan!

I can't remember if I mentioned this before, but I do know if the old TOU programs under Dominion Virginia Power could have been used it would have been a $7 monthly fee, and with my estimated 75 mi per work day, I still would have made out better with it. But we can't dual meter under those old plans. Instead, they're trying to introduce (State Corporation Commission willing) 2 new EV rate pilot programs. The Dual-Meter version (no doubt inspired in part by my inquires), known as Schedule EV, would be $2.40 per month service IIRC and has a super-off-peak rate that is mighty fine! So in this case, it's well worth it to the tune of about $200 per year savings, or about 33% off the standard Schedule 1.

One of these days I'm gonna update my blog about this...

 

[ERG4ALL]

We're in Phoenix, Az and I am about to get my charger installed free (plus $700 out of pocket because we need a new circuit box). I called SRP, our electric company and she said after I get the permits from the city (Scottsdale), they can come out and install a second meter free, BUT there would be a $28 turn on fee and a $20 monthly service fee for the new account.

When you say a "new account" is that in addition to your existing account, or will you have two accounts? Up here in Show Low we have Navapache Electric Coop service. When we went solar we had an extra meter installed on the output of our PV array plus a different meter put on our service pole but we still have only one account. It's just now a solar account. We generate more electricity than we use but we still get a monthly bill of $27.05 to cover all the fixed costs (e.g. meter reading, accounting billing, etc.). I am fine with that because if I were to be off grid I wouldn't have gotten the subsidy from NEC and I still would have to contend with batteries and all the attendant maintenance. Thus, if you're only paying $20 per month, that sounds like a bargain.

 

[TimeHorse]

When you say a "new account" is that in addition to your existing account, or will you have two accounts?

If Dominion's plan is any indication, it will be 1 account, 1 bill, but the bill will be the combined cost for 2 independent services. This is useful because certain utility taxes in Virginia diminish with higher total Joules (kWh) used, so by combining them you're more likely to reach a lower utility tax bracket.