One of my clients wanted to get a few questions answered by you experts. He's trying to make a Prius Chat account... and the system refuses him. I hope a moderator will see this and email me for his email address to solve his problem, but meanwhile: Q1. we see stories of people switching back and forth between EV mode and HV mode to improve mileage. Do you know why this is done? And how it's done? Q2. The owner's manual makes some comment about using the nighttime charge timer to "avoid battery degradation" or some such thing. Do you know what this means? Q3. Speaking of nighttime charging, is it a better deal to do this and take the Edison Time of Day plan? We can apparently just stay on our traditional 5-tier energy plan OR choose to switch to a Time of Day plan. But without concrete analysis I don't know which is better. Oh, we have solar as well, so we are in the low tiers. But I am home during the day a lot, as are my wife and small child, so we use a fair amount of energy during the peak times. Well, experts?
On Q2, I believe the basis of the owner's manual comment is keeping the battery as cool as possible. If you charge in the middle of the night, the battery will (presumably) have had time to cool to ambient since the last drive. Likewise, it can cool down to ambient after charging before you drive it the next day.
No expert here, but... 1) EV (battery powered) driving is most efficient at low speeds (city driving). Though you can drive up to 62 mph in EV, you more quickly lose your charge. If you have stretches where you must drive fast and you know you must use some gas on your trip (more than 12 miles) you should choose HV mode to save your battery power for the slower roads. 2) It's a fact of life for batteries, they eventually wear out, not being able to store as much power as they could when they were new. Keeping the battery in the PiP fully charged without using it makes it age faster (the total charge that can be stored drops more rapidly than if the battery didn't sit for long periods fully charged). The timer provides a nice way for the car to fully charge it's battery right before it is used. This helps keep the battery 'like new' longer, meaning it will last longer for the user. 3... I don't have those options in MN
I'm no expert, just an Owner. A1. If you have a mostly level roads, but then slight hills at the end of your drive, you might want to use the HV ICE for the easy flat driving to save just enough EV Battery to get up those hills, so that it's used up when you get to your destination. Practice will determine how many MILES of EV battery you'll need to get up the hills without ICE, if possible. A2. I use the Charge Timer so that I'm at full charge just before I'm ready to drive. This help Li Battery Life. Also I use it to start an hour after I get to work, to give the battery time to cool down, before it starts the charge. A3. If you have Time of Day Power Billing, using the timer to complete the charge before the Rate increases will save $$$.
A2. One thing that others haven't addressed: Heat is detrimental to long battery life. When running in EV the battery generates heat. When charging, the battery generates heat. So, if you time your battery charge for early in the morning, the battery has time to dissipate the heat from the last run, and you are charging during the coolest part of the day which minimizes the charging heat in the battery.
So Cal Edison customers can call 1-800-4EV-INFO to get a personalized study to determine what rate plan may be best for you. There are several options available and the best choice depends on each person's own useage factorsi including time of their use. There. is a generic internet tool on their website www.sce.com/electric-car/residential/fueling-rates.htm to assist. Generally the time of use plans reduce rates during off peak times when you can charge your Prius, however they increase rates duriing peak times, especially in the summer season. If you add solar panels that can have a significant savings duriing peak times. We decided to do just that.
Yes, check with Edison. If you have solar, you are likely on a special rate already, so we don't have enough information to determine which would be more cost effective. Also depends if they have additional costs if you decide to go TOU or EV rate, like installing a new or second meter for example.
In a conversation with an Edison rep, we determined that the best rate for EV charging came with the installation of a separate meter. However, that is pretty expensive by the time replacement or modification is made to the panel by an electrician, even though SCE gives you the meter "free". As was previosly mentioned, the rates can skyrocket for daytime use in the summer on the special EV plan with just a single meter. We could possibly see summer rates in the third tier of over 50 cents per kWH if we needed to run the A/C a lot. For these reasons, we opted for staying with our existing residential plan, and charging the car only at night. You can set the onboard timer with either a start or a finish time. Then you press the timer switch and plug in the charger when you are done with the car for the day, and it waits until the time you have set to automatically charge the car. Because I have a pretty set routine of leaving home at 6:00 am daily, I set a finish time of 5:50 am. This allows me to "set it and forget it." At SCE's suggestion, I had an electrician come out and check my panel, etc to determine what it would cost to upgrade for a second meter, and also determine if I had an existing circuit that would handle the charging of my car. It took him about ten minutes, and there was no charge for the inspection.
Examples: During the week, I commute on a freeway about 40 miles each way. For that, I will use Hybrid Mode (gas + electric). As I leave home and drive the mile to the freeway, I'll drive in electric-only mode -- EV When I go out to lunch, I'll just use electricity -- EV On weekends, I just drive about our small island town, and I'll do that all electrically -- EV A fully-charged car will go about 14 miles on battery, up to about 50 MPH. So if you're driving about on city streets and small highways, you can drive all-electric. Many people will commute all-electric and some of these people may drive 30 miles a day, yey buy gas once every month or two. Over time, scientifically-inclined members here will concoct mileage-enhancing schemes, but what I wrote above is pretty much what I'll do.
Biscuit boy if I wanted to know these things I would just ask. No his name is CD. I'LL be the 'just drive it' kinda girl.
A3: Generally, if you have PV, it is not worth it to go with a second meter for EV charging. This will be even more true for the PiP since it has a smaller battery than an EV like the Nissan Leaf. We have PV too and do not use a second meter for Leaf charging. The PiP will probably use less electricity than the Leaf - depending on your driving and charging patterns. Our PiP will arrive soon, and even with both of those cars plugging in, we will not pursue the second meter since we have plenty of PV power for the cars.
