Smart Car of America Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
312 Posts
Discussion Starter #1
OK so I know there are a few of you on here that have solar setup at your house that allows you to charge your ED's at no charge. I have been interested in solar for a long time but have not done the research yet and have questioned the ROI time to get set up. I have always wanted to slowly build a system and add to it as I go but not sure where to start.

With the purchase of my ED I am wanting to see what it would take to setup a system that would charge the car every day. I do not understand the math involved in calculating this out and how to determine what panels and equipment I would need. Can you guys help explain this in layman's terms? What kind of expense would a setup like this cost? Also being in the NW where it is cloudy and rainy a majority of the time in the winter, would I be able to get enough juice to charge the car each day?

For the calculation purposes I would say in a worse case scenario that I would be at 20% SOC in the dead of winter when I get home each day.
 

·
Premium Member
Joined
·
1,790 Posts
As far as I know the Pacific Northwest doesn't get much sun during this time of the year. So unless someone gave you many solar cells for a vast area of sqft, the mAh produced would only amount up to a trickle charge in the great scheme of things. It's just cost prohibitive.
Perhaps some one could correct me on this...
 

·
Registered
Joined
·
312 Posts
Discussion Starter #3
Yeah that is what I have thought. That is why I really didn't dig too deep into the idea.
 

·
Registered
Joined
·
465 Posts
You would need a 10kW system to charge your car everyday and a 20kWh battery bank to store the electricity until you charge. You're looking at about 15,000 to 20,000 dollars if you do all the work yourself and use lead acid batteries.

I did complete study on what I needed about two years ago when I put the deposit on my ED. If you lived in florida or some sunny place like that you could easily cut down to 5kW or less.
 

·
Registered
Joined
·
271 Posts
A lot of the calculation depends on what you are paying per kilowatt. I have heard that rates are less expensive in the Pacific Northwest because off abundant hydro generating capacity.
 

·
Registered
Joined
·
646 Posts
This is a futile effort, unless your solar is subsidized substantially, in which case you would still charge from a 110v or 240v home charger and just use the solar panels to feed your local electric grid to offset the cost.

Instead, just plug in, pay the electric bill, and rejoice that it s 1/5th of what your gasoline bill would have been.
 

·
Registered
Joined
·
515 Posts

·
Registered
Joined
·
527 Posts
I'm lazy.

I pay Bullfrog Power - Canada's 100% green energy provider for 100% renewable electricity that I use to charge my Smart ED.

While this is more expensive than using my local grid, it does support renewable energy expansion, and provides a small amount of feel goodness to boot.

I am using my buying power to promote something I believe in.

My property is covered in massive mature trees, so no option for solar (I've really looked).
http://www.bullfrogpower.com/
 

·
Registered
Joined
·
37 Posts
Solarcity free installation are all over the place now, though i donot have experience with them, just a pointer
 

·
Registered
Joined
·
271 Posts
PluggedSolar Can Make Electric Vehicles - Tesla, Leaf, Honda Fit, Smart Fortwo and More - Save on Fuel Cost Forever

it all depends on your location

I have a 5 KW system now and with my Volt and Smart ED my average bill is 90.00 a month.....my bill use to be between 250 and 350 a month

I plan on adding a smaller plug in model like above to reduce my bill further
as this will be on top of my new Smart ED carport as soon as it get city approval
Is your existing system a single inverter or is it micro inverter based?

I read the sales information on that system and at $2000 and 1.7kW it costs $1.18 per Watt. Today you can buy panels for $0.75 per Watt and micro inverters are $150 each. It also appears those panels only generate 9.71 Watts per sq ft compared to 18 Watts per sq ft in the market place so if you are tight on roof area this may not be the best option in the long run. It might be more cost effective to add more panels and micro inverters to your existing system. The sales information for that system calls it "breakthrough technology" when in fact is is the same technology being installed on rooftops every day by Solar City and others.

Also read your net metering agreement with SCE carefully. You may need to get SCE's permission to add capacicity.
 

·
Registered
Joined
·
271 Posts
This is a futile effort, unless your solar is subsidized substantially, in which case you would still charge from a 110v or 240v home charger and just use the solar panels to feed your local electric grid to offset the cost.

Instead, just plug in, pay the electric bill, and rejoice that it s 1/5th of what your gasoline bill would have been.
I assume what you mean is futile is the effort and expense of installing a battery based PV (photo voltaic) system versus a gridtie PV system.

In some rate scenarios, using a gridtie system, you can generate electricity during the day and get credit at $0.25 per kW and then at night charge your car at $0.11 per kW.

It may seem crazy but in 10 months using a similar TOU rate plan from SCE (Southern California Edison) I use more kWatts of energy than I generate but my bill will net out to zero $ because I shifted my consumption to the cheaper time frames.
 

·
Registered
Joined
·
2,773 Posts

·
Registered
Joined
·
646 Posts
you don't need to be on TOU when you have solar, because you are always in Tier 1 or have a negative bill. Unless you bought a really underpowered system.
 

·
Registered
Joined
·
271 Posts
you don't need to be on TOU when you have solar, because you are always in Tier 1 or have a negative bill. Unless you bought a really underpowered system.
I agree, one doesn't need to be on TOU when you have solar. I was curious about how jzchen approached this since he seems to have a lot of knowledge of solar systems that readers of this forum might benefit from. He also appears to be in SCE territory like I am. Others in PG&E and SDG&E or different states or countries may have different rate structures.

In my mind an under powered system is one that leaves you with a bill at the end of the yearly true up. Being in Tier One with my utility is, in my mind leaving money on the table. On the other hand it is suboptimal to buy so much capacity to significantly over generate. The utilities in California only pay you for that net generation at a wholesale rate of $0.04 per kiloWatt. at the time of the annual true up. That means the ROI for the extra capacity is much lower.

It can be advantageous to be on TOU when you have an electric car or cars whose charging is a large portion of your consumption. It doesn't work for everybody but in my case I only charge my cars at night during the super off peak rates and generate during the day when I get credit at the high rates. I think I am in the sweet spot of net metering, because I will use more power than I generate but will have a negative dollar balance. At true up my net consumption is eliminated by my negative balance and I don't pay anything. The key to getting the most out of TOU rates is load shifting, but there is an enhancement that solar can add because most of what is generated can be at higher rates.
 

·
Registered
Joined
·
210 Posts
solar is one of the greatest benefits anyone could ever imagine. the thing is, why would people begin to worry whether it sia good investment or not. By far, it is one of the best benefits. My family has an 8kW system on the roof, running the whole house, a swimspa, and my car. Literally in summer, we make money back cuz the sun is higher, and in winter time due to the heat and now the space heaters come out, my family is only paying 30$ a month for simply charging the car. The ROI is actually very splendid, but why worry about it when it provides such a luxury and freedom to electricity???

My dad owns a solar company and we do deal with Oregon, so if you are serious and want more information on solar, feel free to shoot me a PM or email me at [email protected]
 

·
Registered
Joined
·
2,773 Posts
I agree, one doesn't need to be on TOU when you have solar. I was curious about how jzchen approached this since he seems to have a lot of knowledge of solar systems that readers of this forum might benefit from. He also appears to be in SCE territory like I am. Others in PG&E and SDG&E or different states or countries may have different rate structures.

In my mind an under powered system is one that leaves you with a bill at the end of the yearly true up. Being in Tier One with my utility is, in my mind leaving money on the table. On the other hand it is suboptimal to buy so much capacity to significantly over generate. The utilities in California only pay you for that net generation at a wholesale rate of $0.04 per kiloWatt. at the time of the annual true up. That means the ROI for the extra capacity is much lower.

It can be advantageous to be on TOU when you have an electric car or cars whose charging is a large portion of your consumption. It doesn't work for everybody but in my case I only charge my cars at night during the super off peak rates and generate during the day when I get credit at the high rates. I think I am in the sweet spot of net metering, because I will use more power than I generate but will have a negative dollar balance. At true up my net consumption is eliminated by my negative balance and I don't pay anything. The key to getting the most out of TOU rates is load shifting, but there is an enhancement that solar can add because most of what is generated can be at higher rates.
This is difficult for me to give enlightenment on because our system was just installed towards the end of this May. I spent months researching and debating, and still ended up with a company that I wasn't really happy with in the end.

In searching for a system I got quotes from a few sources. I tried to compare apples to apples because a couple would try to tier shave and one tried to completely zero my bill. I ended up going with one that gave me a system with the inverters and panels that I wanted. Some companies wouldn't sell me SolarEdge with SunPower SPR-327 panels that I wanted. (Back in November they didn't have the X series yet.) My goal was to squeeze as much out of the south facing roof as possible. SunPower panels were the most efficient I could find. As a perspective a proposal I received of 40 Aleo panels, each with the same sq. area as a SunPower panel, would product a tiny bit more output overall than the 28 SPR-327s that I have. (One or two competing salesmen wondered if they could even fit 40 on the roof's eastern, western, and southern portions!) I couldn't get all 28 panels on the South facing roof. I only got 18. 10 are East facing per my request, although West facing probably would have been better.

Tier shaving is probably most cost effective. Our bill went up to over $500/month in the hot summer months and my father and I were arguing over when to open and close windows. I asked for advice on the forums, and the consensus was that I just suck it up and follow his lead. To make a long story short I still felt nervous about such a high electricity bill that I wouldn't be able to sustain living here after my parents pass the responsibilities to me, so I went ahead with the install, although at times I seriously thought of just letting go of the $1000 deposit and cancelling.

The companies are well aware of the math involved in calculating the cost effectiveness of solar. Give a few a call and they can definitely steer you in a direction that you find reasonable. A few notes to keep in mind is that performance tends to degrade over time, (less so with SunPower Panels,) and each different panel and inverter will come with different warranties. One reason I chose SunPower and SolarEdge is because I could line up the 25 yr warranties by upgrading the inverter warranty to 25 yrs, the optimizer warranties are already 25 yrs, as are the SunPower panels. Some solar installers tend to embellish the monetary benifits of solar by fixing output over time and projecting the future rate hikes of electric utility company. I also found one that also included how much you have to earn, before taxes, to cover your future electricity bill! I'm honestly not sure how accurate these forward looking statements are. They seem more prediction, so take it with a grain of salt. They also have fancy ways of predicting the output of your system, which I did find scientific, like the how the tilt of your roof effects output, or whether surrounding trees would possibly hinder production. (I got to see what is called a "solar eye" which measures light availability at a specific spot by looking around and factoring your latitude.)

We hit Tier 4 on the DOMESTIC rate, for those with SCE, which is @ $0.31 per kilowatt hour. Tier 1 is $0.13 per kilowatt hour and our allotment is 426 kWh. Tier 2 is $0.16 per kWh and our allotment is 128 kWh. Tier 3 is $0.27 per kWh and our allotment is 298 kWh. I calculated our average cost to be $0.25 per kilowatt hour over a 1 year span before purchasing our system. Even after solar, (partially because my wife bought a C-MAX Energi plug in hybrid at the end of June,) this August we hit Tier 4, but then again I am not trying to follow TOU, we just plug in as soon as the car gets home.
 
1 - 17 of 17 Posts
Top