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Discussion Starter #1 (Edited)
hey experts,

Tesla recently upgraded thier Supercharger to a new rate of 120 kW, which means you can add three hours of driving to a pack in "just over 20 minutes."

How does DC quick charging work?

Usually in all electric cars, there is some device that converts AC power from the outlet into DC which is used to charge the battery. Right?

Now when you take a Tesla Model S to one of their Superchargers, or you take the Nissan Leaf to the Chademo Quick Charge point, there is direct DC current flowing to the battery which charges the battery at a higher voltage and quickening the charge.
Please correct my understanding.

Also will any car having a Lithium Ion Battery pack support DC Fast charging?
Why cant a Leaf use a Tesla Supercharger? Is there a port connector difference?

Also will constant usage of DC Fast charging affect the life of a Lithium Ion Battery Pack?

Id appreciate any answers!
 

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Quick charging means charging with a high-power charger.
Leaf and Tesla have Lithium Ion battery packs.

Leaf cannot use tesla's Supercharger because it has a different connector and a different battery and a different internal connections that don't support 120 kW (only 60kW).

Constant usage of DC fast charging degrades battery a bit faster than lower power charging but according to Elon difference is small. As almost nobody will do it (as few live next to a supercharger) tesla offers 'no question asked' battery warranty for 8 years. Even to those that that will supercharge every day.

Again according to Elon the main factor eating battery life is average state of charge. If you charge to 100% every day, the battery will degrade much faster than if you only charged to 70%. And charge to 100% those few times you actually need that extra charge/range.
 

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How does DC quick charging work?

Usually in all electric cars, there is some device that converts AC power from the outlet into DC which is used to charge the battery. Right?
Yes, so "DC quick charging" has this charger outside of the car, because due to its higher power it would be too heavy and too expensive to carry on every car all the time while it's only needed occasionally. But in principle, it's a similar charger, just bigger.

Also will any car having a Lithium Ion Battery pack support DC Fast charging?
Practically all electric vehicles now use different variants of lithium ion batteries; LiCoO2, LiMnO2, LiFePO4 etc. Most li-ion batteries can be charged fully or almost fully in 20 to 30 minutes. It makes a big difference whether you need to charge from 0% to 100% or, for example, from 10% to 90%.

Why cant a Leaf use a Tesla Supercharger? Is there a port connector difference?
Yes, and it's not just about the power connector; quick charging needs communication with the car battery management system (BMS); the car needs to be able to shut down the charger and command a charging current limitation.

It's sad that standardization is not going well enough, but I understand Tesla had to come up with their own solution because the usual standards didn't provide enough power.

Also will constant usage of DC Fast charging affect the life of a Lithium Ion Battery Pack?
Actually there's not enough data published yet. It seems to be a consensus that if it affects the life at all, the effect is not that severe, especially as quick charging should not be a daily operation.

Battery technology evolves and battery sizes increase, so in the near future we probably start seeing more and more powerful quick charging systems. It will be in the 500 kW - 1 MW range sooner than most people may think.
 

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Don't kid yourself; Tesla (also) creates their own standards because they like a culture of exclusivity around their products: smaller, svelter connectors; charging stations no one else can use, etc.

The iPod of cars. Hell, if I drove one I'd like it too.
 

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Yeah that might be true but at the same time could you see the firestorm swirling around Tesla if one of their superchargers were involved with an electric vehicle fire, and the EV in question wasn't a Tesla?

Just in my opinion, 120 kW isn't anything to play around with, and certainly isn't anything you should just go plugging into any EV. Tesla has a heating and cooling system for their batteries that not all electric vehicles have.

Not trying to sound like I'm defending Tesla, but think about what would happen if something went wrong. If they could make a regular charging station available at their supercharging stations for other EVs then they would be helping the EV community, which is good but at the same time they would be helping their competition, or atleast their customers.

But in any case, I'm fairly certain higher currents (which are needed for faster charging) will create more losses within the batteries. So it would seem to me that only well cooled batteries would be able to be charged quickly. Most driving doesn't discharge the batteries faster than they can charge, so the cooling system in every EV probably isn't up to the task. Temperature also affects lifetime of the lithium ion batteries as well, so it doesn't just strictly apply to current or voltage.
Just my thoughts
 

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Discussion Starter #6
Thanks for the replies! This is interesting stuff!!
Tesla is going the Apple way. But they have their reasons, as mentioned above.

I'm booking the Mahindra e20 (www.mahindrae2o.com/specifications.htm)
here in India in a month's time and they have fast charging stations too.

I shall use them sparingly!

My first car will be an electric car and am so looking forward to this journey!
 

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Tesla looks the best so far, but we don't know many details.

SAE sucks, no Can Bus and only 90KW.

ChadeMo is better than SAE, uses Can Bus.

The batteries can absorb the power just fine.

Nucleus
 
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