EVSE 120 VAC Charging Efficiency

[SparkevBlogspot]

Using 10K miles per year, 4mi / kWh and 75% L1 charging efficiency,

No, no! 4mi/kWh includes all inefficiency. If you tack on another 75%, you can drive in even worse conditions, maybe run the AC/heater for a while in stand-still. I had all the windows open with both foster dogs sticking their heads out (sometimes me, too) and ran the AC from time to time and still got 4 mi/kWh. Even going uphill 2000 ft from dog beach to home, I got about 3.5 mi/kWh as described in my efficiency blog post. Since you have go down hill to get up hill, 4 mi/kWh includes the combination of high mi/kWh down hill + low mi/kWh up hill.

Most of the driving my wife and I do is in town with short freeway hops.

Do you ever plan to drive further than 35 miles away from home? How often? If more than 2 times a month, and you don't want to wait 4 hours per public charge, or pay lot more via Blink or eVgo flex plan, you should get eVgo OTG plan. Then your minimum EV energy bill is $15 + how much you use DCFC. Only 2 DCFC will be worst as $15 is spread over only two sessions, but still better than not having the OTG plan. If your solar covers the rest, you'll be getting 183 MPGe. Not as good as Korea with their $8/gal gas, but still pretty good. I updated the public charging blog to describe your situation. For me, not having at least 2 DCFC per month is unthinkable, and I pay $15.

I still come out ahead of the total cost of gasoline to operate our 2002 Honda Accord

If your existing paid off gas car is trouble free, total cost would be far cheaper to continue to operate the gas car. Biggest cost for going with SparkEV lease was insurance. They want much more than basic coverage, and per year cost compared to my old gas car is almost $1000 more per year. I like my now discontinued gas car, so I decided to pay more for SparkEV to save on wearing down the gas car. You can see what torment I went through to arrive at this decision in my first blog post.

http://sparkev.blogspot.com/2015/05/first-of-all.html

 

[MrDRMorgan]

I live in the central valley of California and the closest DC charger (not Tesla) is located about 15 miles to the West. There is a two-station L2 charging station at the transit station in town. Therefore, most of my charging will be done at home. Eventually I will venture out of town and then it will be fun to see how far I can go by using pay-for-power charging stations.

My 2002 Honda Accord is free and clear. Just the gasoline cost for my Honda works out to about $132 per month at $3.50 per gallon.

The monthly cost for the leased Spark EV which includes lease costs, full coverage insurance costs, auto license fee costs and what I would have to pay PG&E for power no longer covered by my PV solar system, works out to be about $126 per month. The monthly Spark EV cost also includes a $2500 rebate from the State and a $3000 rebate from the county in which I live.

My daughter will use the Honda and she will pay for the gas. The overall savings will actually be even better because the Spark EV will replace most of the in-town travel I currently do in my full-sized Chevy pickup truck at 12 mpg.

 

[SparkevBlogspot]

Sorry I jumped the gun. Didn't know about 3K rebate from your county. That will make it little cheaper than continuing with Accord. What county is that?

Something for your neighbors who mostly make short trips to consider is that gas car's catalytic converter may not get fully warmed up; I don't care about emissions, but more build-up can result from cool converter, reducing its life. I don't know if your country requires smog check. EV is well worth little bit of premium when smog check fail anxiety is avoided. I always feel like getting cardiac arrest every two years.

It' looks like you're all in. Seeing how SparkEV may be the first EV under 20K that's more fun and quicker than new gas cars, this might be the start of a revolution. Welcome to the second american revolution!

 

[MrDRMorgan]

I live in Manteca, San Joaquin County, California 95336. The county rebate is an part of an effort to reduce air pollution in the valley. We do have vehicle smog checks every 2 years. My 13-year old Honda has always passed with flying colors as it is a ULEV vehicle and has never even come close to the smog check limits even after 150K miles.

I was looking at NRG EVgo DC charger locations within 100 miles of my home location and it is possible for me to get to DC charge stations that would allow me to have about a 100+ mile one-way range North and West of Manteca. Going South or East is a whole different story.

PS - A friend of mine has one of the discontinued Chinese EV cars and he just leased a 2015 Spark EV 2LT with DC charger. He let me drive the Spark EV and that hooked me for good. It was quite difficult to find a new 2015 Spark EV 2LT with DC charger within 100 miles of here as GM's lease plan cleared the shelves so to speak. I got lucky and found two coming to a nearby Chevy dealer. One had already been spoken for and I grabbed the other one. Both were still in transit but I hope to take delivery this week.

 

[bicycleguy]

You might want to reconsider using time of use (TOU) rates. Now that you have something that can use the low night rate it makes a big difference.

With SCE I plan to sell them solar at peak time rate of $.46 and buy back for the car off peak at $.11. This would also allow you to charge with 240V which has been pointed out is more efficient.

Why do you want to charge on 120V. The Bosche EVSE charger is almost free with the $500 discount GM deal.

 

[MrDRMorgan]

The main purpose of getting the Spark EV, besides having fun with it, is to run around town and eliminate most or all of the gasoline we currently purchase for use in our Honda and especially in my full-size Chevy Truck. Our average daily mileage will be about 20- 25 miles per day which equates to about 5-6 kwh per day and that can easily be handled by charging from 9 pm to 6 am using the provided L1 charger. Also, there is a public L2 charge station about 2 miles from my home should I need to use it and provided it is not too expensive. Having said this, I still may buy the Bosch L2 charger only because it is a good deal and then have it installed later should I need it.

I do not need TOU electric rates since my solar system - under NEM rate plan - currently covers 100% of my daily home power needs plus some. Even with the usage for the Spark EV factored in, I will never get higher than PG&E's tier 1. Most of my power usage comes during the PEAK and PART-PEAK time periods. So, right now I see no reason to switch to a TOU rate schedule.

Here is current PG&E rate information to show what I mean:

Standard Rate Plan E-1
Total Energy Rates ($ per kWh)------Tier 1
Baseline Usage--------------------- $0.16352

TOU Rate Plan E-6
Total Energy Rates $ per kWh)---------PEAK----PART-PEAK---OFF-PEAK
Summer Baseline Usage--------------$0.32306---$0.20779-----$0.13101
Winter Baseline Usage------------------------------$0.15218-----$0.13535

EV TOU Rate Plan
Total Energy Rates $ per kWh)---------PEAK-----PART-PEAK----OFF-PEAK
Summer Usage--------------------------$0.42781----$0.22551-----$0.09992
Winter Usage----------------------------$0.29378----$0.17360-----$0.10281

Eventually, I expect more DC charge stations will be installed closer to me. Right now the closest one is 15 miles away.

 

[bicycleguy]

Sorry, me again. I don't have solar yet so maybe I'm missing something. With one of the TOU plans doesn't PG&E pay you for your solar at the TOU rate? So during the peak on the standard plan they only pay you $.16 for any power you shove on the grid but with TOU they would pay you $.32 or $.42 or $.29 ?

I'm interested because otherwise the solar would make much less sense $wise for me. Without that TOU rate I don't think all these solar companies would be 'volunteering' to put panels on your house for free. I've noticed how given the chance they will put the panels on the house to maximize western sun exposure which occurs at TOU peak rate hours. I've even seen them on the north west where the south west would have been better if only kws mattered.

I really want to power my Spark with the sun. But it would be easier if I can show the wife an economic benefit.

 

[MrDRMorgan]

Bicycleguy - thanks for the question. I hope my explanation below will help you.

The object with PV solar is to generate sufficient kWhs to offset most or, if you are lucky, all of your kWh consumption. Unfortunately peak solar output does not usually occur at the same hour as peak consumption. In my opinion, the TOU rate schedules do not mean much when a PV solar system is considered. If you have an EV, PV solar and a TOU rate schedule, you would charge the EV during off-peak hours and let the PV solar reduce or eliminate the expensive peak and partial-peak power consumption. That is where you will save big time! The electric company will bill you depending on the number of kWhs consumed during each period - peak, part-peak or off-peak.

I have been working for years to find ways to reduce the power consumption in my home and I was able to cut my usage from 6000 kWh per year down to 5000 kWh per year by reducing power consumed by lights, computers, printers, TV / stereo, etc. For the last two years my solar system has produced about 400 kWh more than I consumed. On a hourly basis, if I produce more kWh than I consume, the excess kWh goes into my account. In the evening when my hourly kWh usage exceeds the output of my solar system, I draw from my account in kWh - not $$$. On each anniversary of the startup date of my solar system, PG&E has an account True-Up where I pay for any excess power I consumed over the previous 12-month period or, in my case, PG&E pays me for all excess power I generated BUT they pay me at the wholesale price THEY pay for purchasing power which amounts to about $0.045 per kWh. I believe this holds true regardless of what rate schedule is in effect as long as you are covered by the NEMS rate schedule. Most solar companies will try to size your solar system to cover approximately 80% of your usage so be sure to add in what you expect your EV to consume.

I have a number of spreadsheets I use to analyze my power generation, consumption and costs on a daily and monthly basis and I watch where every kWh goes and when it is used.

I estimate my Spark EV (when I get it next week, hopefully) will require about 183 kWh per month to meet my projected mileage usage needs. When I look at my monthly estimates for what my solar system generates and what my combined consumption for car and home will be, I end up short about 1047 kWh for the True-Up year. However, March Through May I generate more than my combined usage so the excess kWh goes into my account to be drawn down in later months. I actually will not be short on kWh until August and then I will continue to be short going through February of the next year. However, at no time do I ever get out of PG&E's Tier 1 rate for any month and most of my consumption occurs during the peak and off peak periods. If you look at the Tier 1 rate schedules I posted earlier, you see I would have to pay more for each kWh in the E-6 TOU and EV TOU rate schedules than I would on my current E-1 standard rate schedule. Look at a solar system kWh production as income and your home and EV car as kWh expenses.

Having said all of this, you should contact your power company and have them explain how the NEMS rate schedule applies to their TOU rate schedules. The power company should be able to show you how much power you consume for each hour of each day of each month. I know PG&E does this and they have an excellent website which I use daily. You will need to know this to make an informed decision.

 

[SparkieVee]

MrDr, you seem quite well informed. Maybe your electrical usage is a bit outside the norm, but since your total usage is similar to mine I'm guessing that it's not too far out there and a case could be made for TOU rates. Bicycleguy, I'm more in line with your thinking.

I've had my Spark for a year and a half, and I got solar two months ago. I decided to go with a TOU plan from SCE. Here's my thinking:

About 70% of my power generation will be during peak hours (12-6 on my plan). During those hours I'm generally not using all that much. There's the stuff that's on 24/7 (computers, fridge, etc.), but much other usage I can push to non-peak times. In the summer I'm willing to let the house get a couple of degrees warmer until 6 to push more air conditioning usage off-peak. Charging the car can pretty much all be off-peak. SCE gives me credit at the higher rate for the on-peak power that I send to the grid (so far I've sent 70% of what I've generated back to the grid), and then charges me at the lower rate for the off-peak power I use.

My projections are that I will generate 80-90% of the power I need, but due to getting paid at a high rate for power I push to the grid during the day and purchasing at a low rate at night, I'll likely wind up with a credit at the end of the year. SCE won't pay me that credit - they only pay wholesale for KWh that you produce above what you use, not based on the rates they charge you - but it will mean that I have no bill instead of having to pay tier 1 rates for the KWhs I'm short.

I did choose a two-tier rate instead of three-tier because I didn't want to have to worry about reducing usage during the evening hours. With a 3-tier rate (SCE has super-low rates 11pm-8am, mid-tier 8am-2pm and 8pm-11pm, and high rates 2-8pm), it would've been tougher to push all my usage to the lowest rate. Car charging yes, air conditioning not so much. You also need to consider when your solar generates power. Mine faces almost due south, so it's great during mid-day, but would still be split between mid and high rates on a 3-tier plan. If yours faces east, the TOU rates are off from when you're at peak generation, and TOU will likely be a bad deal. Southwest or west is probably ideal for playing with TOU rates, at least if the times are like SCE's.

 

[KingUltra]

I'm also on SCE area.
I have had my 2 Sparks for a full month now.
My electric bill went up from the usual $80 to $180 last month, as the Cars pushed me into Tier 4 rates.

This billing cycle I switched to TOU rates, so I'm doing all the charging after 10 pm.
I did not use much power to go Solar before, so let's see how it goes this month.

 

[MrDRMorgan]

SparkieVee

Good points. I do have a TOU spreadsheet model and I will see what the difference could be. Before EV, it really didn't matter which rate schedule I was on since 100% of my power consumption has been covered from day 1 by the solar system. Now, by adding the EV, my power consumption will exceed what my solar system generates and it may be time to consider a TOU rate schedule. My biggest power hogs in my home are the refrigerator, small freezer in the garage and the AC and furnace. There isn't much more I can do to reduce the power consumed by these appliances or shift the usage times.

We do agree on one point. If you have solar and are operating under the NEMS rate plan, any surplus kWh energy credits you have at True-Up will be paid to you only at the wholesale rate the power company pays to purchase power and not at the standard or TOU rate it was earned. At my last True-Up in March I had a surplus of 431 kWh with a credit value of $50.88. I received payment ( it was applied against my natural gas bill) in the amount of $18.86 ($0.04376 per kWh) and PG&E got to pocket $32.02.

KingUltra

Thanks for you comments. Let me know how things go. I am picking up my Spark EV today an I will be carefully monitoring the power consumption.

 

[bicycleguy]

Here's a snippet of a neighbors bill with solar, no EV with Southern Cal Edison.

The 'Delivery' charges don't change but for 'Generation' he's getting paid $.15 or $.17/kwh and paying only $.06 or $.07/kwh. He used 300kwh off peak that was more than covered by 191 kWh on peak.

Perhaps PG&E doesn't do this?

 

[SparkevBlogspot]

Is he selling at $0.06186/kWh Lvl1 or is it 2X that amount? Bill is very convoluted and unclear exactly what is going on.

Tier1 use in San Diego is $0.17/kWh. I looked up TOU, and their "super low" rate was same as Tier1. So if one's selling at less than half of Tier1 (as the bill seem to suggest), but buying at tier1 rate at night, I don't know if that's any good. I don't know if excess Solar capacity will ever pay for itself when you're buying at twice your selling.

10K miles/yr lease doesn't allow for much driving. At 4 mi/kWh, that's 2500kWh/year. At $0.17/kWh, that's $425/year. That doesn't buy a whole lot of solar.

Of course, you can way over drive the car like some of us do. It's so addictive, is this what Heroin is like? Then you may try to get even more solar by standing in street corner with a sign that read "will work for extra solar panels", just like addicts.

 

[NORTON]

I don't know if excess Solar capacity will ever pay for itself when you're buying at twice your selling.

This is always THE ISSUE.
Until we have nationwide NET METERING home solar will be in the margins.

Do you know who lobbies hard against Net Metering?

Look, I know their side of the story, but that 'Grid' has been up and running for over 100 years. Sure someone has to pay for it and maintain it when it goes down, but encouraging solar use is for the good of everyone.
Kind of like how EV's are good for everyone and the government wants to encourage this green energy technology with tax incentives.

Solar electric needs more encouragement.

 

[MrDRMorgan]

bicycleguy,

Thanks for the data. I have downloaded SCE's TOU-D-T rate schedule for further review.

If I have done my math correctly, the peak L1 cost/credit (generation + distribution) is $0.21425 per kWh. The peak L2 cost/credit is $0.34101 per kWh. Off-peak L1 cost/credit is $0.12239 per kWh and off-peak L2 cost/credit is $0.24915 per kWh.

It looks like his solar system produced 191 kWh more than he consumed during the peak period and in the off-peak period, he consumed 300 kWh more than any additional kWh his solar system might have contributed.

I picked up my Spark EV on Saturday and, when I got home after a 50 mile drive, put it on the charger at 8 amps. I used the car yesterday and put it back on the charger last night to take it to the top - 84 miles. Starting today I will be monitoring mileage vs charging kWh as measured by a Kill-A-Watt EZ power meter at the wall outlet.

 

[MrDRMorgan]

SparkevBlogspot -

I agree. If all you want to do is use PV solar to charge your EV to avoid paying the power company, it isn't worth it. However, as in my case, I will replace most of the transportation use of my 1999 Chevy pickup truck with the Spark EV. At $3.50 per gallon gas, I come out way ahead. Get rid of the truck and it gets even better.

 

[SparkevBlogspot]

If I have done my math correctly, the peak L1 cost/credit (generation + distribution) is $0.21425 per kWh. The peak L2 cost/credit is $0.34101 per kWh. Off-peak L1 cost/credit is $0.12239 per kWh and off-peak L2 cost/credit is $0.24915 per kWh.

Thanks for the clarification. Is he selling to the grid the same price as if he'd be buying or is he selling for less (wholesale price?) Does it show how much less he's selling?

I picked up my Spark EV on Saturday and, when I got home after a 50 mile drive, put it on the charger at 8 amps. I used the car yesterday and put it back on the charger last night to take it to the top - 84 miles. Starting today I will be monitoring mileage vs charging kWh as measured by a Kill-A-Watt EZ power meter at the wall outlet.

Congrats! It won't be 84 miles, depending on how it was driven before you bought it. Mine was 75 or something for first few full charges, and now it routinely hit 90+ miles on full change. Also compare the mi/kWh reported by the car and odometer divided by Kill-A-Watt for efficiency. My car seems very optimistic at 80%.

 

[MrDRMorgan]

SparkevBlogspot -

I believe each month the power company will only use peak kWh credits against peak kWh usage. The same holds true for the off-peak kWh credits and usage. At the annual true-up the total remaining kWh credits, regardless of which period they came from, will be paid out at the wholesale kWh rate the utility pays for power.

Back on the charger tonight. The trip display on my Spark EV shows 4.14 mi / kWh for 136 miles. These miles were a mix of road and freeway - all with the A/C on. I will see what the Kill-A-Watt EZ says tomorrow. Great little car so far. Now my wife wants one of her own.

 

[SparkevBlogspot]

regardless of which period they came from, will be paid out at the wholesale kWh rate the utility pays for power.

What I want to know is how much does it cost to use (buy) and how much does it cost to sell. I don't know where that is in the bill.

The trip display on my Spark EV shows 4.14 mi / kWh for 136 miles. These miles were a mix of road and freeway - all with the A/C on.

Seems kind of low. Mine was showing 4.8 mi/kWh in the beginning with some AC and heat, but 4 mi/kWh according to Kill-A-Watt. Heat and AC only used about 1kW to 2kW.

tomorrow. Great little car so far. Now my wife wants one of her own.

It's like crack cocaine. Everybody wants one once they take a whiff of it... :twisted:

 

[MrDRMorgan]

SparkevBlogspot-

Reading SCE's Schedule TOU-D-T-PTR rate schedule will give you a migraine.

The on-peak period is 12 noon to 6 pm weekdays (M-F) except for holidays.
The off-peak period is everything else.
The PTR period runs from 2 pm to 6 pm and when it is put into effect is determined by SCE and their load demand.

Notice on the bill that there are two levels and mention of a % of baseline. Baseline quantities are determined by SCE and may be different for different areas in their service area. The different levels are based on the baseline. As more power is consumed, the rate per kWh goes up as total kWh consumption crosses the usage limit per level. It looks like this rate schedule only has two levels. Level 1 is 1-130% of the baseline amount. Level 2 is everything over 130% of the baseline amount.

The bill shows, in the on-peak period, he received credit for 149 L1 kWh at a rate of $0.21245 per Kwh (delivery + generation) and an on-peak credit for 42 L2 kWh at a rate of $0.34101 per kWh (delivery + generation). This credit is due to his solar system producing more power than he consumed. Had he produced less than he consumed, the bill would show a charge instead of a credit. The L1 and L2 rates per kWh would still be the same as shown above.

His solar system would be contributing very little at 6 pm when off-peak starts so he would have to pay the going rate for all off-peak power he consumed. The bill shows no off-peak power credits. He paid $0.12239 per kWh for a total of 233 L1 kWh and $0.24915 per kWh for a total of 67 L2 kWh.