The battery is a 75kW battery. Unless you’re running electricity along a 500 foot run I’m going with negligible.
He's talking about the on-board charger losses (probably 95% efficient at best) & the heat losses in the battery to charge it. These are accounted for in MPGe; it is a "wall-to-wheel" measurement (MPGe), which is different than battery to wheel (what the car displays). You can calculate this stuff yourself if you have a separately metered home charger.
ok, Alan, since you Disagreed with my post, you want to at least own it and show what is disagreeable? Perhaps post your math to show the solar payoff? (I have SCE and have run their numbers numerous times, and as a finance guy, they don't pan out unless the OP is a big user of electrons -- pool, spa, big family, et al. But in which case, OP would routinely be in Tier 3...)
I thought about responding earlier but didn't bother. I told him to "consider solar if it's possible for you" - not to just get it blindly. I told him to do the calculations for his situation.
356kWh is a lot per month. I was routinely below that in my house before getting electric vehicles. It doesn't keep the lights on, if they're incandescent. But if every single light is LED and you get rid of your vampire drains, and throw the breaker on your AC when you're not using it (they often use 40W when not being used 8 months of the year), then you can easily use a lot less than this.
Anyway, that means he's routinely in Tier 2. Let's say he's at 800kWh per month without EV (that sounded like what he was saying!) To me that is a fantastic amount of power but it is what I interpreted. A 4kW system can be had for under 10k these days, pretty easily. I think if you run these numbers I think you'll find it will pay off in less than 10 years, though it can be difficult to determine because there is regulation risk. Even if the payoff is less than 10 years, it may not make sense for him - for whatever reason!
You do have to account for the CONVENIENCE of charging at home worry free, too, that's why I recommended 8kW. He may be charging at work but it's convenient to be able to top up at home for optimal battery health and for complete flexibility - it is not hard to drive 250 miles in a weekend. Do you really want to fiddle around with it and leave your battery at 10% for 24 hours when you don't need to? That could be costly (we don't know, but Tesla recommends you leave your car plugged in and they don't allow you to charge to less than 50% without manual intervention).
I'll let you do the math, I don't really care; I have solar (not enough, even though I am not an energy hog, which is why I recommend 8kW), I am in San Diego, so the rules are different, but it has saved me money for 6 years. I had zero electricity bills for 5 years (actually, negative) (now the rules have changed and it's not as good) and last year I asked for a check for $1400 from SDG&E for my generation credits & other incentives. Still, it has not yet paid off. But it's not far off. And solar is a lot cheaper & better now than when I bought it 6 years ago. And there is "psychological" benefit.
Everyone's situation is different.
EDIT: I'll add that people don't buy Teslas ONLY to save a ton of money on fueling costs. They are luxury cars. If you wanted to save money on transportation costs (and help the environment to some extent) you'd buy a Prius. That gives you $0.06/mi with today's gas prices. A Tesla in San Diego run at a home without solar is going to run a pretty penny and is probably not going to be cheaper. Without solar, from SDG&E, you can pay $192 per year ($16/mo) to get a nighttime rate of something around 10 cents per kWh. But your rates on your AC use during the day are going to go way up from what they were with net metering. This excellent rate for an AWD Tesla is $0.034/mi (10/290). For 12k miles/yr, add $0.016/mi for the flat fee and you're at $0.05/mi.
So, if you have a nice luxurious Tesla, just make it easy for yourself to charge it without thinking about the cost, if you can. If you're in Southern California solar it is an ideal place for solar, so assuming your roof is good, and like 10 other things are good, just get it. And get a LOT to insulate yourself from rate (regulation) risk because it's annoying to spend $15k on an array and then still be paying electric bills (though it's actually probably more "optimal" to be in that situation). Also, if you have a LOT of solar, swap out your gas furnace for a heat pump when it needs to be replaced. You'll save a few hundred a year on natural gas. $15-20k for solar shouldn't be a problem if you're buying a Tesla and it will make the experience better.
