What my car’s built-in solar panels did for me today

[Scoutsie]

A kind of neat but limited-use feature that a Toyota Prius has had for a while is a built-in roof solar panel. The sole purpose of this solar panel is to power fans that circulate the air in the car in warm weather so it feels closer to ambient temperature inside. Today in Boston, the forecast was for a high of 94 degrees F. The thermostat in the car registered 99 (we were in the closest neighboring suburb at Costco when I checked).

I guess nowadays this feature is only offered in the Prius Prime and it can supplement the hybrid system and also help power the AC, not just this one fan. Doing a little bit of reading/Googling, I guess the output is about 100W of this particular solar roof (specifically on the Prii of 2010-2016 or whenever they stopped having that feature for both the standard-ass hybrid and the All-New George Foreman Grill plug-in hybrid versions) for use during peak sun hours to power that recirculating fan. The later versions do a bit more apparently and I don’t know as much, only what I’ve gleaned off of Prius Chat.

Anyhow, I guess this feature on a Prius, which is small, can add maybe about 3-4 mpg a day saved in peak sunlight. On a cloudy day, this is null and void. I know we’ve had a couple of solar panel discussions in the past, but hey, let’s have another one! Throw your thoughts out there. I’d love to hear from someone who’s an engineer about these kinds of things.

 

[Chavannigans]

I dig it. Every little bit helps over the lifetime of the vehicle.

 

[TreeKiller]

I like it. My coworkers dd Fisker Ocean has the solar roof which purportedly adds up to 2,000 miles of range per year here in AZ if the vehicle is parked outside all day. That's about 8 miles per work day. That's not nothing.

 

[SpaceEVDriver]

My truck is at 13% State of Charge right now. This time of day is peak demand charge where I pay $19.585 / kW for the highest 1-hour kW usage of the month (during this time). If I tell my truck to charge, it will draw 19.2 kW. That’s $376.03 for one charge, more than my normal monthly bill. On off-peak times, I pay $0.05943/kWh or $0.03495/kWh in winter’s super-off-peak.

Or I can charge my truck using solar during this super-expensive time. For the cost of a few solar panels and an auxiliary battery to buffer the charge.

And as I’ve said in a bunch of other threads, 600W-1000W of solar gives me 50+ miles of extra range while camping (or about 10-20% of my normal range). Some people have said that’s not enough to justify bringing solar along. But the last time I dragged 5- or 10-gallons of gasoline with me, it also didn’t add much range in %. A 5-gallon jerry can will only add 20% or so to the tank, assuming a 25-gallon tank. To me there’s no range benefit between bringing a “solar jerry can” and bringing a gas jerry can. Except I don’t have to deal with the spillage, fumes, smell, fire danger, etc. of gasoline.

 

[TreeKiller]

My truck is at 13% State of Charge right now. This time of day is peak demand charge where I pay $19.585 / kW for the highest 1-hour kW usage of the month (during this time). If I tell my truck to charge, it will draw 19.2 kW. That’s $376.03 for one charge, more than my normal monthly bill. On off-peak times, I pay $0.05943/kWh or $0.03495/kWh in winter’s super-off-peak.

Or I can charge my truck using solar during this super-expensive time. For the cost of a few solar panels and an auxiliary battery to buffer the charge.

And as I’ve said in a bunch of other threads, 600W-1000W of solar gives me 50+ miles of extra range while camping (or about 10-20% of my normal range). Some people have said that’s not enough to justify bringing solar along. But the last time I dragged 5- or 10-gallons of gasoline with me, it also didn’t add much range in %. A 5-gallon jerry can will only add 20% or so to the tank, assuming a 25-gallon tank. To me there’s no range benefit between bringing a “solar jerry can” and bringing a gas jerry can. Except I don’t have to deal with the spillage, fumes, smell, fire danger, etc. of gasoline.

Sounds like you're with APS and on the same plan I'm on with 4-7pm being peak demand. Tangent but your comment just made me chuckle. Last night I had to be the nitpickey husband because I "caught" my wife overriding our HVAC automation which supercools until 3:59pm allowing the HVAC to remain completely off until 7pm without the house becoming uncomfortably warm. I got home from the office around 5pm and immediately noticed one unit was running and my brain went to that peak demand charge and we reminisced on that first summer month we owned the house where we got that shocking (haha) $800 bill.

Yeah, don't want one of those again.

 

[SpaceEVDriver]

Sounds like you're with APS and on the same plan I'm on with 4-7pm being peak demand. Tangent but your comment just made me chuckle. Last night I had to be the nitpickey husband because I "caught" my wife overriding our HVAC automation which supercools until 3:59pm allowing the HVAC to remain completely off until 7pm without the house becoming uncomfortably warm. I got home from the office around 5pm and immediately noticed one unit was running and my brain went to that peak demand charge and we reminisced on that first summer month we owned the house where we got that shocking (haha) $800 bill.

Yeah, don't want one of those again.

Yeah, it's a huge incentive to avoid using the grid at that time, which is obviously the point. But a mistake or two can be super expensive. Hoping to be given PTO with our new solar system by the end of the week. Then I won't have to worry about it.

 

[cyure]

Yeah, it's a huge incentive to avoid using the grid at that time, which is obviously the point. But a mistake or two can be super expensive. Hoping to be given PTO with our new solar system by the end of the week. Then I won't have to worry about it.

I have never even paid attention. To how much I pay for a kw. I’m going to have to look. Our energy provider is a co-op. We even get a rebate once a year.

 

[dreamweaver]

Yeah, it's a huge incentive to avoid using the grid at that time, which is obviously the point. But a mistake or two can be super expensive. Hoping to be given PTO with our new solar system by the end of the week. Then I won't have to worry about it.

Congratulations on your soon to be PTO. It is a great feeling to not have to depend on a utility company. Years ago we install a whole house solar power system with battery backup that handles all our power needs with some extra daily that I sell back to our utility. In 2027 when our Traveler EV arrives that extra will be going to charging.

 

[SpaceEVDriver]

Congratulations on your soon to be PTO. It is a great feeling to not have to depend on a utility company. Years ago we install a whole house solar power system with battery backup that handles all our power needs with some extra daily that I sell back to our utility. In 2027 when our Traveler EV arrives that extra will be going to charging.

We had it on our previous house too, and it was great. I grew up off-grid, so solar’s been part of my lexicon since I got a solar panel for Christmas when I was 8 years old—yes, I’m a nerd, if you couldn’t tell.

This time I’m going to add a generator plug on the inverter’s generator input so I can use the Lightning as a backup if necessary. With a bit of load management, I can get around 80-130 hours from the Lightning before I have to recharge. But the solar will recharge me during the day so I can run indefinitely off-grid if I have to. And with the Lightning’s 7.2 kW output, I could power most of our needs when we don’t have solar.

 

[oldgeeksguide]

My truck is at 13% State of Charge right now. This time of day is peak demand charge where I pay $19.585 / kW for the highest 1-hour kW usage of the month (during this time). If I tell my truck to charge, it will draw 19.2 kW. That’s $376.03 for one charge, more than my normal monthly bill. On off-peak times, I pay $0.05943/kWh or $0.03495/kWh in winter’s super-off-peak.

Or I can charge my truck using solar during this super-expensive time. For the cost of a few solar panels and an auxiliary battery to buffer the charge.

And as I’ve said in a bunch of other threads, 600W-1000W of solar gives me 50+ miles of extra range while camping (or about 10-20% of my normal range). Some people have said that’s not enough to justify bringing solar along. But the last time I dragged 5- or 10-gallons of gasoline with me, it also didn’t add much range in %. A 5-gallon jerry can will only add 20% or so to the tank, assuming a 25-gallon tank. To me there’s no range benefit between bringing a “solar jerry can” and bringing a gas jerry can. Except I don’t have to deal with the spillage, fumes, smell, fire danger, etc. of gasoline.

$19 per kWh? That’s crazy! At that price, it seems like it would incentivize folks to run generators on a hot afternoon, which seems like a bad idea.

 

[TreeKiller]

$19 per kWh? That’s crazy! At that price, it seems like it would incentivize folks to run generators on a hot afternoon, which seems like a bad idea.

Is is crazy, but it is only from 4-7pm M-F and the tradeoff is extremely cheap electricity at all other times. So if you can structure your household to use minimal electricity for 3 hours per day 5 days a week, you can save some money. It's tough since that is the hottest time of day and those are peak dinner making hours, for example, but it can be done. And it's why I supercool for example. If the interior temp is 70 degrees at 4pm, it will stay comfortable so the HVACs remain off until power is cheap again at 7pm.

One thing that I still need to do is put a high capacity smart plug on my beer vending machine in the garage so that the compressor doesn't run from 4-7pm lol.

 

[SpaceEVDriver]

$19 per kWh? That’s crazy! At that price, it seems like it would incentivize folks to run generators on a hot afternoon, which seems like a bad idea.

Is is crazy, but it is only from 4-7pm M-F and the tradeoff is extremely cheap electricity at all other times. So if you can structure your household to use minimal electricity for 3 hours per day 5 days a week, you can save some money. It's tough since that is the hottest time of day and those are peak dinner making hours, for example, but it can be done. And it's why I supercool for example. If the interior temp is 70 degrees at 4pm, it will stay comfortable so the HVACs remain off until power is cheap again at 7pm.

One thing that I still need to do is put a high capacity smart plug on my beer vending machine in the garage so that the compressor doesn't run from 4-7pm lol.

And it’s only for the peak 1 hour demand during the 4-7PM for the month. So if your peak demand on 1 July hits 20 kW and you draw that for an hour (20 kWh), then you’ll pay $19*20 = $380 for that 20 kWh. But for the rest of the month you could draw 19 kWh every hour during the peak demand charge and not pay $19/kWh on those kWh. You’d pay $0.14227/kWh for all the other kWh you use during the 4-7PM timeframe. You only pay $0.05943/kWh for the rest of the day, though, so that would be a silly thing to do.

One of the cheapest ways to address the peak demand charge is to install a battery and inverter to do peak shaving. You don’t even need solar to reduce the cost of your electric bill by quite a lot.

Note also, that this is a voluntary plan for most customers; there are two other general plans and a fourth plan for people with an EV (the EV plan is really not worth it, though).

 

[dreamweaver]

We had it on our previous house too, and it was great. I grew up off-grid, so solar’s been part of my lexicon since I got a solar panel for Christmas when I was 8 years old—yes, I’m a nerd, if you couldn’t tell.

This time I’m going to add a generator plug on the inverter’s generator input so I can use the Lightning as a backup if necessary. With a bit of load management, I can get around 80-130 hours from the Lightning before I have to recharge. But the solar will recharge me during the day so I can run indefinitely off-grid if I have to. And with the Lightning’s 7.2 kW output, I could power most of our needs when we don’t have solar.

Sounds like a solid plan.