3 ms·

Two miles per day is still not nothing. It's energy that requires zero infrastructure, no new charging stations, no tax incentives, no panels on anyone's house

Two miles per day is still not nothing. It's energy that requires zero infrastructure, no new charging stations, no tax incentives, no panels on anyone's house for their HOA to get stompy about. But it's not just about range. Long-term parking of EVs is problematic because if a lead-acid goes kaput after sitting unattended for a year, you're only out $100. But if that's your traction pack, it totals the car. Solar charge makes long-term parking feasible, and enables telematics modems to stay awake, etc.

jerf 7y ago
"Two miles per day is still not nothing." I didn't say it was nothing, I said it was below the noise floor, which is a much more interesting way of putting it. It's not worth putting a big solar panel on the car and pretending it's going to do anything if the effect of the solar panel is literally swamped by whether or not you had coffee this morning and its effects on whether or not you have a lead foot this morning. Since "literally" has been devalued, let me highlight that I mean it in its original sense; it doesn't take that much of a commute before that will be the case. Or any number of other things that will just swamp this signal, like whether you had to use the electric heater or AC and how much of it you needed, whether you got stuck behind a semi doing 65 for a good portion of your commute or were cruising by yourself at 80 in the left lane, whether the wind was blowing against or with you today, and so on. It's not zero, but it's lost in the noise. "Solar charge makes long-term parking feasible, and enables telematics modems to stay awake, etc." https://forums.tesla.com/forum/forums/how-much-battery-charge-does-your-model-s-lose-day https://forums.tesla.com/forum/forums/how-much-battery-charg... suggests drain can vary in the 1-10 mile/day range just sitting there. This wouldn't even cover that entire range, with the optimistic assumptions on how much solar this is producing. YMMV depending on a lot of exact conditions, but it's certainly not the obvious win you'd hope where the solar can overpower normal drain by a clear order of magnitude. (I'm not loving trying to compare two amounts of energy loss in terms of "miles" here, though they're probably roughly comparable.) It makes me wonder if they've got some other optimistic assumptions in there we weren't thinking of in terms of the car not draining very fast, or even if the number was generated simply by dividing the amount of power it generates by how much power/mile is necessary. Arguing in favor of the latter is that marketers like the bigger numbers, and especially the positive numbers rather than negatives. That post suggests it is likely to be the case that many real customers will at best notice that this solar panel slows down battery drain from just sitting there, but due to cloudy days, winter sun, etc. is not actually capable of overcoming it!

jerf 7y ago

"Two miles per day is still not nothing." I didn't say it was nothing, I said it was below the noise floor, which is a much more interesting way of putting it. It's not worth putting a big solar panel on the car and pretending it's going to do anything if the effect of the solar panel is literally swamped by whether or not you had coffee this morning and its effects on whether or not you have a lead foot this morning. Since "literally" has been devalued, let me highlight that I mean it in its original sense; it doesn't take that much of a commute before that will be the case. Or any number of other things that will just swamp this signal, like whether you had to use the electric heater or AC and how much of it you needed, whether you got stuck behind a semi doing 65 for a good portion of your commute or were cruising by yourself at 80 in the left lane, whether the wind was blowing against or with you today, and so on. It's not zero, but it's lost in the noise. "Solar charge makes long-term parking feasible, and enables telematics modems to stay awake, etc." https://forums.tesla.com/forum/forums/how-much-battery-charge-does-your-model-s-lose-day https://forums.tesla.com/forum/forums/how-much-battery-charg... suggests drain can vary in the 1-10 mile/day range just sitting there. This wouldn't even cover that entire range, with the optimistic assumptions on how much solar this is producing. YMMV depending on a lot of exact conditions, but it's certainly not the obvious win you'd hope where the solar can overpower normal drain by a clear order of magnitude. (I'm not loving trying to compare two amounts of energy loss in terms of "miles" here, though they're probably roughly comparable.) It makes me wonder if they've got some other optimistic assumptions in there we weren't thinking of in terms of the car not draining very fast, or even if the number was generated simply by dividing the amount of power it generates by how much power/mile is necessary. Arguing in favor of the latter is that marketers like the bigger numbers, and especially the positive numbers rather than negatives. That post suggests it is likely to be the case that many real customers will at best notice that this solar panel slows down battery drain from just sitting there, but due to cloudy days, winter sun, etc. is not actually capable of overcoming it!