Alex on Autos: The truth about EVs and Solar

[azjohn]

I have been following him for a while, I never knew he is off grid.

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[Crissa]

Good data, but...

...Damn this guy is super-inefficient. His car is poor efficiency, his everything is inefficient - before we get to his water and heat!

Yeah, he could be worse, but geez. And who charges all 15k miles at home? I can only manage about 8k from home. (And he never gets into the inefficiency of changing the solar from DC to AC (up to -50%) to a DC charger (~-16%))

And his panels are... inefficient. They're on-ground, in a forest, which isn't his fault, so they're the best he can do. But most people have full sun. And while most houses have only so much roof... they often have accessory buildings, pergola, etc.

A solar panel that's up four feet from the ground doesn't stop grass from growing, animals from grazing. One at 10' would allow full patio use.

Panels being cheap means putting panels everywhere is a thing you can do. As long as the power*time/cost fits your use.

I used solar panels for blackout curtains, which then charged all my devices. The blackout curtains were something I had to have, so it would have been wasted sunlight anyhow.

-Crissa

 

[Cybercarlson]

@Crissa
You made some very valid points and I value your post very much.

But at this point I have to object:

And he never gets into the inefficiency of changing the solar from DC to AC (up to -50%)

If it would be so inefficient, how would you ever run your AC home grid from it ???
My converter sits right at the panel and has a rated efficiency that is much higher:

Hoymiles MI-600
Efficiency CEC Peak efficiency 96.7% 96.7% 96.7% CEC weighted efficiency 96.5% 96.5% 96.5% Norminal MPPT efficiency 99.8%

Granted there are minimal losses in the wire (since it is 220V AC starting 60cm behind each panel),
I do not lose any thing close to your stated "up to -50%"
Actually it is something like 5% at the most in the first step and a bit more at the AC to DC (BEV internal charger) side I think.

What might I have misunderstood?
Please help me out here...

btw. I am a big supporter of DC to AC right at the module.
It is much safer than the deadly and dangerous high DC currents in the most widly used PV Systems.
A side benefit is mppt and rapid shutdown for each single module.
I am surprised that the TESLA still uses the old school system with all its shortcummings and the many wooden houses in the USA. ?‍???

 

[Pappy]

Maybe this is the place for my thoughts; Speaking in terms of Grid reliability and those cost associated with failure as seen most recently in Texas. What if; assume for a second that ICE vehicles give way to the battery powered vehicles in the future. What happens to the Grid when everybody gets off work at 5pm, travels home and plugs in their baby????

 

[Crissa]

If it would be so inefficient, how would you ever run your AC home grid from it ???
My converter sits right at the panel and has a rated efficiency that is much higher:

Inverter. Not the MPPT voltage tracker.

Inverters become very inefficient at low power uses. That's why many grid-tied systems are using many micro-inverters instead of a single inverter.

If you're putting it into a battery, you want to stay to that MPPT efficiency level, and not throw an on inverter and charger to get back to battery DC on top of it.

-Crissa

 

[Bill906]

Maybe this is the place for my thoughts; Speaking in terms of Grid reliability and those cost associated with failure as seen most recently in Texas. What if; assume for a second that ICE vehicles give way to the battery powered vehicles in the future. What happens to the Grid when everybody gets off work at 5pm, travels home and plugs in their baby????

https://www.cybertruckownersclub.co...anned-can-the-grid-handle-electric-cars.2426/

 

[ldjessee]

Maybe this is the place for my thoughts; Speaking in terms of Grid reliability and those cost associated with failure as seen most recently in Texas. What if; assume for a second that ICE vehicles give way to the battery powered vehicles in the future. What happens to the Grid when everybody gets off work at 5pm, travels home and plugs in their baby????

Most of the EVs, especially newer ones, let you plug it in, but set the time when it will charge.
And, given the huge drop in rate and usage of electricity at night, I am sure many power companies will be happy to sell power at night when the grid is under utilized compared to during the day.

This is something that is bandied about a lot, adjusting for this would not be as big a deal as many think it is.

There are many videos from many different views. I have compared a few different perspectives and it looks like that by the time we even get to 50% conversion to EVs the grid could grow to compensate for the 100% conversion in the same time frame.

 

[Cybercarlson]

@Crissa

Inverter. Not the MPPT voltage tracker.

Inverters become very inefficient at low power uses. That's why many grid-tied systems are using many micro-inverters instead of a single inverter.

If you're putting it into a battery, you want to stay to that MPPT efficiency level, and not throw an on inverter and charger to get back to battery DC on top of it.

-Crissa

I am sorry to have been misunderstood.

My system is based on micro-inverters with integrated MPPT for each module.
I do not use a battery (total cost inefficient and we have practically no power outages where I live ).
The BEV will only be charged (>2kW-11kW) during peak PV production times, with Surpluspower that would normaly go into the grid (no Netmetering avilable in Germany).

IMHO this will be the way PV systems will evolve for safety, plugandplay, efficiency, controlability and scaleability reasons.
If you like to look at your app, to monitor your system, you will be very happy to have this controll at the module level. It makes maintanance and trouble shooting much easyer.

Even if you put your Solar DC direct in you EV the voltage has to be transformed, granted with less loses than inverting AC-DC.

People thinking of getting a PV system should inform them selve about micro-inverters, there have been a lot of innovations and cost reductions in this area.

Most of the PV Install companys will not give you those new informations.
They like to install what they know and makes profit for them.........
reminding me of ICE Car salespeople that do not tell you the truth about BEV......
We are all human after all.

 

[Pappy]

Most of the EVs, especially newer ones, let you plug it in, but set the time when it will charge.
And, given the huge drop in rate and usage of electricity at night, I am sure many power companies will be happy to sell power at night when the grid is under utilized compared to during the day.

This is something that is bandied about a lot, adjusting for this would not be as big a deal as many think it is.

There are many videos from many different views. I have compared a few different perspectives and it looks like that by the time we even get to 50% conversion to EVs the grid could grow to compensate for the 100% conversion in the same time frame.

Thank you, my power company offers and I currently use the reduced TOU rate. Monthly average is at .18 per kWh? I’ve not researched others to see how my rate compares.

 

[Pappy]

@Crissa


I am sorry to have been misunderstood.

My system is based on micro-inverters with integrated MPPT for each module.
I do not use a battery (total cost inefficient and we have practically no power outages where I live ).
The BEV will only be charged (>2kW-11kW) during peak PV production times, with Surpluspower that would normaly go into the grid (no Netmetering avilable in Germany).

IMHO this will be the way PV systems will evolve for safety, plugandplay, efficiency, controlability and scaleability reasons.
If you like to look at your app, to monitor your system, you will be very happy to have this controll at the module level. It makes maintanance and trouble shooting much easyer.

Even if you put your Solar DC direct in you EV the voltage has to be transformed, granted with less loses than inverting AC-DC.

People thinking of getting a PV system should inform them selve about micro-inverters, there have been a lot of innovations and cost reductions in this area.

Most of the PV Install companys will not give you those new informations.
They like to install what they know and makes profit for them.........
reminding me of ICE Car salespeople that do not tell you the truth about BEV......
We are all human after all.

I am very interested in a PV system and was quoted panels with micro inverters. The single most important issue to me was; “I was told that I would not have power if the grid was down”. That in itself killed the deal. I want power if/when the grid fails. I want to be responsible for my own power reliability. Any advice would be greatly appreciated and I feel this is important to the success of all CT owners.

 

[Crissa]

I am sorry to have been misunderstood.

My system is based on micro-inverters with integrated MPPT for each module.
I do not use a battery (total cost inefficient and we have practically no power outages where I live ).

No, no, your system is safer and more efficient to have the microinverters and controllers for each panel segment! But it's also more costly up front than a single inverter.

But if you were charging a battery, you generally want to do it as directly as possible, with as little conversion as possible.

Solar-tied EV storage can use the DC charging port to take out as well as put in stored energy. Bypassing the AC charger is more efficient, assuming you use a higher voltage from you panel segments, and in that case, micro MPPT controllers, so each follows their own output level.

It's very different from what we do today, which is why vehicle storage for the grid and buildings has not taken off.

-Crissa

 

[Luke42]

Maybe this is the place for my thoughts; Speaking in terms of Grid reliability and those cost associated with failure as seen most recently in Texas. What if; assume for a second that ICE vehicles give way to the battery powered vehicles in the future. What happens to the Grid when everybody gets off work at 5pm, travels home and plugs in their baby????

This question is best answered by examining what electric utility folks call the Duck Curve. The Duck Curve is the graph showing how demand for electricity varies throughout the day.

The simple answer is just to program the cars to postpone charging until later at night, so they'll all be ready to go in the morning.

General information about how electric demand varies throughout the day:
https://en.wikipedia.org/wiki/Duck_curve
(Example is from California.)

Texas duck curve example:
https://pv-magazine-usa.com/2018/07/24/texas-power-grid-begging-for-solar-power/
(From 2018, note that the bottom of the graph is not 0MW. Definitely from a source with a point-of-view, but they seem to care enough to use actual data and present it clearly.)