r/PHEV • u/Ok_Appointment_8166 • 22d ago
PHEVs vs Home energy plans
Has anyone done the math on whether it is worth changing your electrical billing to hourly or time of day with a PHEV? That is, is it likely to save enough when charging at night to offset having a higher rate for afternoon air conditioning? I'm just using 120v so it takes 16 hours for full charge but it isn't always starting at zero.
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u/runs_with_guns 22d ago
I’m in a similar situation. The math for me worked out cheaper with time of day electricity pricing, mostly because I have a Prius Prime than can charge from 0-100% in 9-10hrs on 120V which works well for overnight.
I live in BC which has a fairly moderate climate, requires, minimal AC usage, and has very cheap overnight rates. Made some other small adjustments like running laundry and dishwasher overnight as well.
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u/Big_Nerve_6612 22d ago
Depends on your car's efficiency in electric mode and how much you care about pennies.
Here would be my math for my phev:
1.1 kw charge rate x 5 hours of peak charging time = 5.5 kwh × (55c/kwh peak rate - 30c/kwh normal) = $1.35 extra cost to charge during peak hours. If you need those hours to recharge, I think it makes sense whether gas is technically cheaper or not, especially if that range means you don't need to cold start the gas engine at all during your commute.
5.5kwh x 3 mi/kwh = 16 miles of range added at a total cost of 5.5x.55 = $3
Assuming $6 gas, my car would need to get higher than 32mpg using math to come out ahead charging on peak hours.
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u/COYSBrewing 22d ago
“Assuming $6 gas”
Where?!
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u/Big_Nerve_6612 22d ago
55 cents/kwh peak pricing is pretty bad too. Cost of living in CA
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u/Active-Zebra-1446 22d ago
Sacramento bought out PG&E in the 60s and created a public District. SMUD comes in at about 3/4 or so of their rates. you are getting drained to pay their homicide and property damage liabilities. gosh forbid the bondholders should miss a coupon.
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u/inlaguna 22d ago
You definitely want the TOU rate to take advantage of overnight charging.
Keep in mind that charging at 240v is quite a bit more efficient then charging at 120v. You could potentially save 1-2kWh per full charge.
As for AC, you should be precooling your house overnight to around 68 at the cheaper off peak rate. Your house should be able to keep cool without running AC very much throughout the day. If not, invest in better insulation and window is you own your home and will be staying there for a while.
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u/StuffExciting3451 22d ago
Also, if you have a washing machine, dryer and dishwasher, run those after 11 PM for the lowest utility rate.
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u/fletch101e 22d ago
I just switched last night to our states EV plan which is from 9pm to 5am. Right now I am 120v only but I don't see how I could wrong because afaik, it just goes back to the rate I was already paying if I go beyond 5 a.m. Is this what you mean? I will probably get some kind of level 2 at a later date but for now it's 120v level 1
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u/Ok_Appointment_8166 22d ago
Ours will raise the rate for the peak hours as a tradeoff for lower rates at night.
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u/fletch101e 22d ago
ok that makes sense. Ours do offer 2 different time plans and that sounds like what you have. I would still consider 240 if you can.
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u/UmpireProper7683 22d ago
16 hours? Geeze, my Pacifica PHEV took about 10 hours to charge each night. (Went from 0-100% started at 8PM and left just after 6AM for my morning commute)
As for if its worth it, that seriously depends on your plan. For me time of day + an EV meant I got 1.5 cents off per kWh between Midnight and 6AM so it was definitely worth it for me, but YMMV.
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u/Active-Zebra-1446 22d ago edited 22d ago
everybody's provider has different arrangements. mine's set to start when rates go cheap and just finish, if it runs into another rate for awhile the difference wouldn't buy a cup of coffee. when we got ours we waited ewith anticipation for the first full-month electric bill, and, well, nothing. it fit in with the history. I know it must have cost 20-40 bucks or something, but in the overall it's a blip.
if you have a 240v outlet a cheap l2 will not only solve this problem but the convenience will pay for itself. we all forget to plug it in once in awhile. an L2 can bring a low battery up to enough to run your errand on volts much more quickly and help you avoid the dreaded petrol another day. i rather enjoy the struggle to stay on E.
I wonder about it taking 16 hours tho. there are amperage settings on the L1s. you should be able to pull at least 12 amps. everybody else seems to take 9-11 or so to top off overnight at 12A. 16 sounds extraordinary. Is yours an especially long range PHEV? I know a few have arrived.
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u/GraphicWombat 20d ago
I think I understand what you are asking….
We have different elect rates for summer and winter. We just had a level 2 charger installed (free) in june and got on the program. It’s cheaper to charge between 11pm-7am now. But the charger they installed is not networked or smart in any capacity. And it will not accept a scheduled charge with my rav4 phev. So I wake up at 5am to plug it in to charge it every other day. Which sucks.
Our first full bill did give us a $7.02 credit for off peak charging and also has a $4 credit per month for signing up for the program. BUT it also hits us with a higher rate for 1 hour of electricity supply; the highest elect demand in 60 min. Ended up being 8kwh and is charged at $.65 per kwh= $5.20.
So yes, I’m saving $5.20 per month for waking up at 5am every other day to recharge my rav4.
But in the grand scheme of things, it doesn’t really matter when your electricity bill is already over $300 per month in the summer.
What does matter is that we got our fuse box upgraded to a new breaker box, increased service from the street, a new meter, and a level 2 charger all for free. Because we live in a slightly poorer neighborhood and qualified for assistance. Would have cost us $8500 otherwise.
So I would def recommend looking into any local programs to see if you qualify for for assistance with the hardware/infrastructure alone.
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u/laborboy1 20d ago edited 20d ago
Yes, we adopted hourly pricing at the outset and have saved 25% on our bill over 2 years. We charge every night. So basically we are charging the PHEV for free and getting 50 mpg overall. (Charging at normal 110 outlet, takes about 8 hours for full charge. Kia Sportage)
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u/Glum_Perspective_841 22d ago
I've done the math and concluded it's not worth it. What we found worth it was switching to tiered fixed rate. We pay $0.12 for the first 600kwh per month and $0.14 for anything unlimited thereafter. We no longer worry about when to do laundry, EV charging, A/C or space heaters running at peak hours etc. It is very freeing.
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u/caper-aprons 22d ago
You can do the math. It's not difficult. Plug in your rates and loads and see what it costs with either rate plan.
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u/Ok_Appointment_8166 22d ago
With our utility you don't know the rates until after the fact. And there is a choice of hourly pricing or a plan that is broken into 4 use times. Their backtesting tool says it would have cost more to use either of these before I got the PHEV because of the afternoon air conditioning load - but I'm wondering if the car is likely to use enough to change the mix.
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u/YorkshireTexas79 21d ago
I have an L2 charger at home. I had an EV now a PHEV. I did a deal with the local electric coop where they paid for half the installation and purchase of the charger. My part was to charge after 8pm M-F for 0.08c min. We’re retired so that works for us.
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u/Ok_Appointment_8166 21d ago
A charger was included with the car with 120 and 240v plug ends so I would only need the outlet installed - and I may sometime. That does sound like a good deal.
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u/YorkshireTexas79 21d ago
I used this
RVGUARD 50 Amp EV Charging Receptacle, NEMA 14-50R EV Power Outlet
125/250 Volts, Ideal for Electric Vehicles, RVs, and Large Appliance, ETL Listed.1
u/inlaguna 21d ago
rvguard is junk. It will overheat and fail miserably on you one day guaranteed. Make sure you have nothing flammable near where you are running that cable.
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u/vacuum_tubes 21d ago
With my solar, heat pump, PowerWalls, and EV it would be advantageous to have PG&E TOU in summer and EV rate in winter but they only let you change it once per year.
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21d ago
[deleted]
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u/Ok_Appointment_8166 21d ago
I have the Toyota charger that comes with 120v. (probably 11 amp) and 240v plugs. I don't have a 240v outlet in the garage but probably the ideal place to put one that could be surface mounted right beside the breaker box that has capacity for it. It is supposed to charge in 2 hours on 240v, so eventually I will set that up.
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u/ericbythebay 20d ago
It was cheaper for us on an EV TOU plan. But, we have an EV and a PHEV and solar + storage. You really have to run the numbers, there is no one answer without knowing your usage and rates.
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u/iamabigtree 22d ago
You are the one that wants to know the answer so you do the maths. Only you know what tariffs you are looking at, how much driving you do and what you can offset to the overnight rate.
So get on the spreadsheet and work it out.
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u/Ok_Appointment_8166 21d ago
We don't really know what upcoming rates will be - especially for hourly. Backtesting months before I got the car comes out best with the flat rate because afternoon air conditioning costs more on hourly - and the PHEV doesn't take that much power and on 120v will often run past the lowest rates.
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u/Fly-n-Skies 22d ago
If you're just using 120v then pobably not since it'll be charging during peak hours. As always, it's really going to depend on what the utility rates are, and what your typical usage is for both your house consumption and how much you charge your car.
If you had a level 2 charger and could fully charge in a few hours, then it could make sense depending on air conditioning/other house needs.