Tesla Model 3

[Longsnowsm]

In the past the VAWT's had problems with high winds tearing things.I just saw a startup on an investment show talking about a VAWT they have designed and patented that can furl out of the high winds to preserve itself. I thought that looked promising, but they are still a startup looking for investment to buy the equipment to be able to mass produce them. I hope they are able to get these produced.

I have always like the VAWT's because think they should generate power more consistently at lower wind speeds and aren't as sensitive to the clean air requirement.

I will be watching for more of these to hit the market and see what people are saying. A little time and maturity in the market will go a long way.

[freebeard]

Looking around, it appears I started a wind power thread in march.

ecomodder.com/forum/showthread.php/bernoulli-wind-wall-40111.html

I'll drop a post about horizontal VAWT there. You are welcome.

[redpoint5]

Originally Posted by Longsnowsm

I have an off grid homestead. I presently have my solar system sized for specific loads and needs. My objective is to keep the KWH as low as possible in the EV so that I will be able to Level 1 charge the car off of my power system without breaking stuff or having to add a lot more to capacity to my home power build.

L1 charging is less efficient than L2 generally speaking. Not sure what the losses look like from batteries, but from the grid you spend less time running pumps and fans and whatnot by quickly charging the EV rather than prolonging the charging session.

[JSH]

Originally Posted by redpoint5

L1 charging is less efficient than L2 generally speaking. Not sure what the losses look like from batteries, but from the grid you spend less time running pumps and fans and whatnot by quickly charging the EV rather than prolonging the charging session.

That is what I have found in my charging experiments.

L1 was much less efficient than L2.

Charging at 110V adding about 15 kWh and stopping 80% charging losses were 18 - 19%. Charging on 220V, adding 15 kWh and stopping at 80 had 7% charging losses.

Charging at lower SoC is more efficient than at high Soc.

When I was charging to 100% and adding 12 kWh on Level 2 losses were 19%
When I charged to 100% and added 34 kWh on L2 losses were 11.4%
When I charged to 80% and added 33 kWh on L2 the losses were only 6%

[redpoint5]

I rough estimated 20% losses L1 charging the Prius plug-in, and 10% was what others had reported for L2 charging. I had no way to measure L2 efficiency at the time, but my converted Leaf EVSE cut charging time in half.

[Longsnowsm]

The real challenge there is all about load and being able to provide that on the power I produce. For example for the last few days it has been cloudy overcast and almost nothing was generated. Winter is pretty rough so I would probably have to stick with L1 during the winter and only on days when I am actually getting some sun.

During summers or good sun days and my batteries are topped off then I could probably deal with L2 charging. I think I will have to be flexible. I did have a 50amp outlet put in where I plan to be parking the car in anticipation of being able to L2 charge, but I think I will have to adjust to condition of my batteries and what kind of sunshine I am getting or expecting. It will be a learning experience.

[JSH]

Lots of chargers are flexible. My Wallbox Pulsar is 240V but adjustable from 2 to 48 amps with the app. (It also has a switch in the back that sets a maximum amperage based on the circuit - mine is set to 24 amps)

[Longsnowsm]

I was looking at the settings online for the Tesla and it appears you can set the amperage in the car down to like 5amp I think. So the answer may be to just throttle the amount pulled in those settings to get the best efficiency at 240 for less loss. Thanks for mentioning the 240v being more efficient and setting the amperage on the EVSE. That looks like the way to make this possible to keep loads down. Thanks for mentioning it guys. This is helpful.

[hayden55]

The higher the voltage the less heat loss and resistance and losses in the wire (for the same energy transferred). Thats how they come up with home electrical wire ratings for the most part. Electric current carrying capacity in the heat of the local environment vs the point at which the wire will get too hot and i assume they more or less care about fires over efficiency. So they got their ratings and then added a safety factor to make them idiot proof, at least we all hope. Some idiots are too good! I do my best at that some times.
So if you could compare
120v charging at 25A vs 240v charging at 12.5A you should lose less energy from the transfer with the 240.
Ideal would be like charging at 1000v but 3A as it would have very small losses. For the most part it just leads to less heat production in the entire electrical system that will be charging the car so more of it goes in the battery.
So if yall can use 240 and charge as slowly as you need to (ie: 8 hour parking every night could be better spent charging for 8 hours instead of 3)
this is why automotive engineers hate 12v systems but we are stuck with them over going to higher voltages because of pita factor.

[redpoint5]

It's not the higher voltage that is mostly responsible for reducing the charging losses, it's completing the charge sooner.