Not seeing EV savings

The beauty of dual-fuels. Use it to the advantage of your particular needs.

 

how does the harbor come into play?

 

I have 2 meters. One for the house, another for the barn. The house is billed residential, the barn commercial (because it's across the street on it's own plot and doesn't have a certificate of occupancy). Power through national grid.

House usually uses 500-800kwh at $0.1771. they do offer time of use billing if you have an electric car with a 1 year trial option where if you end up paying more than you would have under the flat rate they'll let you go back to it and give you a refund of the difference. We don't use enough even with charging the prime every day to change to that yet.

The barn has a $20 monthly connection fee. whether we use 5 or 200 kwh there's still $20 added into the bill. In winter with heating water troughs it gets up to maybe 300kwh and that ends up being about $0.239/kwh. But in summer just running lights it uses almost nothing so the cost would look something like $1+ per kwh.

What I'm getting at is the cost to charge may not be as simple as dividing your power bill by what you pay a month. If you're being charged the $20 connection fee anyway, that's not necessarily related to the cost of driving the car on electric vs gas. Gas is easier to account for - you wouldn't buy it if you weren't driving a gas powered car. The entire cost of the fill up is attributed to owning the car.

Of course with only a 25mile EV range and 2-5 hours to recharge and how efficient the Prime is in HV mode, splitting hairs over fractions of pennies saved per mile wouldn't make much of a difference to your budget. For many people the difference might not be noticeable one way or the other.

 

i agree. if there are fixed costs already on your bill, i would ignore them and only use the variable costs that change with kwh used

 

So doing some aggressive rounding in your favor, $3.58/gal of gas is your breakeven point. If gas prices is higher than this, it's worth plugging in - If gas is less than that, don't bother plugging in.

I'm using the assumption that you'll get 25 miles on 6.5KWh = 3.85miles/Kwh. This number is located in one of your MID menu options. Also assuming 50mpg; though the Primes official EPA is 53mpg. As stated, rounding in your favor and easier to do the numbers in my head. Last assumption, if your numbers are wrong - mine will also be wrong. Garbage in, Garbage out (GIGO) - old computer programming terminology. You kids call them apps now.

 

That would be true if the EV is the only thing being powered from this utility service, and the service would be discontinued if one elects to not charge the EV there.

But if this electric service is shared with anything else, then the cost figure to use is just the incremental cost of the energy for the EV. Any base account charges, that would be paid regardless of EV plugging in or not, needs to be excluded from this cost calculation.

Note that your particular utility has just a single per-kwh charge that covers everything except the fixed account charge. OP lives on the opposite coast, where most electric bills are far different, many different elements (energy, transportation, local distribution, special project and program surcharges, etc.) are listed separately even though they are charged per-kwh, so the bill is inherently more complex and opaque.

 

See post #45

 

You like me are a Prime candidate for off grid solar

 

Yes, you are paying too much. But, is part of your electric bill a base rate for "delivery and service" to your house? Ours is $17.00/month for that, but the cost per KW delivered here in NY is now $.19/KW after the basic monthly charge. (Doesn't matter to me because I have solar panels on my roof ) That said, the municipal chargers in town are free.

 

I just received the very first electric bill from the utility after our community solar farm started its operation. The billed total was $7.56 this month, far less than our usual ~$200/mo. This is after 100% of the usage was credited by the community solar.

Aggregated Net Energy Billing
Carryover 0 kWh
New Credits 994.13206 kWh
Allocated 863 kWh
Remaining 131.13206 kWh

Total Standard Offer Charges Due $0.00
Distribution Minimum Charge $7.48
Stranded Costs Minimum Charge $0.08

Apparently, there is a minimal charge for connecting to the grid that amounts to $7.56/mo. This charge has not appeared on my bill before. With regular use and payment, this minimum charge must have been waived. Apparently, this means if I had the solar panel on my own roof and produced more kWh of electricity than consumed, this amount would have been charged. Since our utility does not pay for the extra kWh generated for the Net metered customers, the cost-saving for the solar panel would be less by this amount.

 

Not necessarily, as "full charge" is vaguely defined for the Prius Prime. Once it starts permanently showing "--" on the MFD, you no longer know the actual charge—it could be anywhere in the region ~ −10–+10% if not even further away from the actual 0%. 6.5 kWh is on the low side for 120-V charging, meaning that either there was some extra charge in the battery or some battery degradation has occurred.

 

For OP's 22 PP, it is probably true that the average "full-charge" using an L1 EVSE @120v is likely to be higher than 6.5kWh. It is likely to be around 6.8kWh average like mine was for the first 6 mo. In his local, his winter months charge could have been substantially higher than that due to the battery heater function. If he used climate preconditioning, it could be even higher. Here is the record of my monthly average for the "full charge". Note that I have included both full charge meaning -- EV range to 100% as well as partial charge extrapolated to 100% charge. Also, I turned off the battery heater function in Jan. Notice the large drop from 7.22kWh/full charge in Dec to 6.59kWh/full charge in Jan. This is presumably due to not using the battery heater function.



In my 2017 PP when it was 3 years old, the average full charge was right around 6.5kWh. Both my 20 and 21 PP had higher full charge kWh for the first 6 months than 2017 PP which explains why I was able to get a longer EV range out of 21 PP when I got it in July last year. But the difference was not statistically significant. So, it may be just that the way I drive has improved over time.

Those are the numbers from the "full-charge" kWh in three different year models in the first 6 mo after purchase.

 

Doesn't turning off the battery-heater function reduce the battery cycle life?

 

It may or may not. I wouldn't know it since I can't make a comparison. But the fact this function is an operator selectable option from the menu, I think it is not an "essential" part of the battery management as the top buffer of the traction battery which we can't change.

 

It will substantially decrease the battery cycle life if you don't charge it at optimal temperature and a lot more so at cold temperatures. This is a well-known fact about lithium-ion batteries.

I think the physical reason is that a lower temperature slows down the diffusion of lithium ions inside the anode carbon host material, which speeds up lithium-metal plating (piling up of lithium) on anode's surface, gradually degrading the battery by building up a barrier at anode's surface.

 

Level 1 charging means more electricity used as the longer time adds more charger overhead to the total.

There is risk of damage charging most Li-ion chemistries when the cell temperature is at 32F/0C or lower. Heating the battery up above that point is a good idea, but it isn't the sole strategy to avoiding damage.

The PiP doesn't have a battery heater, and hasn't seemed to suffer from premature battery capacity loss from freezing charging. When really cold, the system just charges at a much slower rate until the normal heat from the process gets the cells warm enough for regular charge rates.

 

If it is that critical to have the battery heater, then it should not be the owner selectable option. The manual makes repeated warnings against keeping the battery full for a long time and make clear suggestion to use scheduling to charge the traction battery such that the time the car sit with a full charge (albeit it is only ~80%) is minimal. Yet, there is not a single warning about charging the traction battery in a cold climate nor any suggestion to use the battery heater during cold days charging sessions. This is also true about the battery cooler function which is even less important since the default is OFF and you really have to be paying attention to the MID to even turn it on. So, my reasoning is that the car really does not need those functions for Toyota to make sure that the battery last 10yr/15Kmile covered by the warranty.

Either way, I will not likely to know the difference since I can't make a comparison. And I am not likely to keep the car that long.

I think what @Trollbait commented is the reason enough that PP does not need to rely on the battery heater function to protect its battery. If Pip didn't need it, why would PP have to have it?