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tdscanuck t1_iyenymu wrote

You can just plug them in. The problem is that a normal wall outlet doesn't provide nearly enough power to charge a car battery in a reasonable time. You need a lot more current, which means a dedicated circuit and special wiring.

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Spiritual_Jaguar4685 t1_iyeobqg wrote

In a sense, you can just plug in electric cars. The issue is that most "residential" electrical circuits don't give enough energy to charge an EV in a reasonable amount of time. As far as I know, most EVs can be plugged into a standard US wall plug but it will take north of a day to charge the batteries. So not exactly convenient.

So the chargers aren't just devices you plug into an existing receptacle like a laptop charger, they are special dedicated circuits that directly run back to your home's main electrical distribution panel to give more powerful energy directly to your battery. Even so, these kinds of charges might need an hour or two to recharge your batteries.

Special 'high-energy' charging stations use levels of electricity that your home doesn't even have, they require dedicated transformers and gear on a more commercial or industrial scale and can charge your batteries in 15 or 20 minutes.

EDIT - so to be clear, all these different sources of electricity require various equipment to make them "receivable" by the car. It would be like your cell phone have a powerbrick built into it with a USB-C and USB-Micro connector, a 2 prong and 3 prong 120V receptacle, and a NEMA plug, with all the various transformers required to charge the battery properly. That's clearly a dumb way of designing a portable product and we have various power cords, multi-adapters, and power bricks built into the wires we use to charge, and not into the cell phone itself. Same-same with EVs.

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mousicle t1_iyeoq6r wrote

You would have to build in 4 different kinds of plugs, normal plugs, big dryer plugs, level 2 charging plugs and fast charging plugs. Instead of having 4 differnt plugs it's easire to have one socket and have the different plugs at the place you charge. A lot of cars do come with an adapater so you can just plug into a normal outlet though that you carry with your car.

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TehWildMan_ t1_iyepqj0 wrote

A typical US household outlet can only be used for 1500 watts continuously, and that's sometimes complicated by the fact there may be other devices on that same circuit that are also drawing electricity.

1.5kw isn't a very fast charging speed for electric vehicle batteries, especially for vehicles driven every day or close to that.

A household EV charger is just a special connecter wired up to a power source rated for a higher current at 230v.

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Taco__Bandito t1_iyeqspe wrote

It’s super easy to do yourself with some basic electrical knowledge. Trickle charge is the only way to charge an EV without permanent damage due to the nature of high capacity batteries and the conversions that take place.

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Carlos-In-Charge t1_iyeraxe wrote

Imagine regular electrical outlets delivering electricity the way a garden hose delivers water. It’ll eventually get you enough. A fire hose delivers more water with more power because the hose is bigger and the pump is stronger. Charging a car is similar to a job that needs a fire hose to complete efficiently.

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5L1Mu5L1M t1_iyet00u wrote

Well you could just built in the charger into the car

And just pull out the wire to plug into an outlet like those irons with retractable cords

But now your stuck with one type of outlet

You have 120v which is the one you plug in your phone to charge

Then you have the 240v that dryers plug in

Then you got the various different charging standards at charge stations that do the fast charging in different way

Like CCS and CHAdemo and of course Tesla

So for the sake of portability, modularity, and cost

We keep the charging on the outside

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coherent-rambling t1_iyeq8hu wrote

You actually do just plug them in - the charging components are all in the car. The fancy Level 2 home wall charger is just a glorified extension cord with circuitry that tells the charger in the car the maximum amount of power it's allowed to draw. This is an important safety feature.

When you plug in a normal cord, whether that's 120v in North America or 240v in other countries, the car will only charge at whatever rate the normal sockets in that country are rated for. The standard North American socket can provide 1.5 kilowatts, so cars delivered to North America will not attempt to charge faster than that on a standard cord.

When you want more power, you need a nonstandard circuit. Again talking about North America, we've got two different common 240v plugs: a 7.2 kW plug for electric clothes driers, and a 12 kW plug for electric stoves. How does the car know which of those you're plugged into? It doesn't. And what if you want even more power, so you get a hard-wired connection that could be as much as 20 kW? Now you can't just make assumptions about how much power the car can use without tripping breakers, you have to tell it what's available. Rather than trusting end users to always punch in the right values, we get licensed electricians to install a fancy extension cord that does this automatically.

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Taco__Bandito t1_iyet1rr wrote

American homes receive two 120v feeds making a total of 240v..

You do not charge an EV with 120v at home. That’s insane. 240v is the trickle charge which is the only real way to charge an EV without permanent damage to the battery.

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coherent-rambling t1_iyevuaa wrote

You'd be silly to charge your EV with 120v at home, but it's not going to damage the battery, it's just slow. Most EV's actually come with a 120v cord, called a Level 1 charger, so you can do this in a pinch (and so the manufacturer can be assured that every buyer will be able to go home with a charging solution right away).

Your implication that 120v charging could cause permanent damage is completely bullshit; batteries can be damaged by excessive charge rates but not by slow charges.

Nor is 240v a trickle charge. Trickle charging is typically considered just enough to offset self-discharge, which even 1.5 kW Level 1 chargers can exceed. Level 2 240v charging is a "normal" charge, and is generally around 0.1C (a 10-hour charge), which is very safe for most battery chemistries. Level 3 DC fast-charging is the fast option, and the only one that really causes extra wear and tear.

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Taco__Bandito t1_iyf7okb wrote

I didn’t realize 120v was even an option. I didn’t mean that 120v would damage it, I meant the rapid charging will.

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Taco__Bandito t1_iyeqknl wrote

A wall outlet is 120v. Yet EVs mostly use 480v induction motors.

Batteries are also direct current and power supplied in the grid is AC so you need to convert it either at the source (EV charger, or increasingly so the cars have an inverter built in)

Some EVs use AC induction motors so the conversion happens twice in some cars, losing a lot of energy as heat.

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