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Why only 72A, 16kW AC charging?

emir-t

Member
Oct 28, 2013
452
553
Istanbul
I know that Tesla thinks for city charging 72A is way more than enough and for roadtrips it offers Superchargers but, in Europe 3-phase plugs are quite common to find. They support 22kW (32A each phase, 96A) easily and you can find more than that too. Even Renault ZOE has 64kW AC charger (96A each phase, 288A).

Prior to Model S refresh we could have dual chargers and 22kW but now, top limit is only 16kW. Even with this setup it doesn't allow larger than 11kW charging without an EVSE. Why all these limitations?

I live in Turkey and we have zero superchargers and zero ChaDeMo. If we could charge at 22kW we gain 110km/h and virtually every hotel, restaurant or industrial area has 3 phase plugs. I could plug in at a restaurant and get 160km juice while only having lunch. For that I need old, dual charger Model S and an expensive cable with a built in EVSE.

I don't think it would be a huge cost item for Tesla to add a very capable three phase charger. Why do you think they have so much limitations?
 

mblakele

Safety Score: 99
Mar 7, 2016
1,786
6,013
SF Bay Area
Have you asked Tesla? Smart companies pay attention to what customers and potential customers ask for.

Speculating, the cost of developing and delivering a high-power three-phase solution may be higher than you think, and (known) demand may not be sufficient. Offering more options has extra costs too.

Today's on-board charger options make sense for most of Tesla's markets, because they expect owners to charge overnight most of the time. For faster charging they expect us to use superchargers. It's sad that there are no superchargers in Turkey today. But there's hope: I see nine sites planned on the 2016 future locations map at Supercharger | Tesla.
 

David99

Active Member
Jan 31, 2014
4,856
7,166
Brea, Orange County
I think the decisions was to save cost and simplify. A single charger vs two is a lot easier in production and you can charge the customer more without any cost to Tesla (it's just a software switch to enable 72 Amp). 10 kW is plenty for home charging, 16 kW is more than plenty.

For road trips DC charging is the way to go. 16 vs 22 kW makes little difference and both are too slow for road trips when 120 kW is available at Superchargers.
 

ggnykk

Active Member
Feb 7, 2016
1,573
806
Earth
I think the decisions was to save cost and simplify. A single charger vs two is a lot easier in production and you can charge the customer more without any cost to Tesla (it's just a software switch to enable 72 Amp). 10 kW is plenty for home charging, 16 kW is more than plenty.

For road trips DC charging is the way to go. 16 vs 22 kW makes little difference and both are too slow for road trips when 120 kW is available at Superchargers.
If emir-t's claim of the ability to charge at 64 kw is true, that's a huge advantage if we can charge at that speed with AC destination charger. That's basically the same as having fast DC charging everywhere.
 

Dudukian

Member
Jul 31, 2016
12
5
76131
It's all about the cost and liability . I have a Chevy Volt that defaults to 8 amps @ 120v. Pretty silly . They also limit the 240v to 16 amps when it should easily take 30 amps .
 

McRat

Well-Known Member
Jan 20, 2016
5,771
6,077
LA
Yes, the lack of support from all EV companies for commercial 3ph or 277vac is really amazing.

Don't they know how commercial buildings are wired? The lights are 277vac 1ph in the US, the power at the panel is 480vac 3ph. This is stepped down to 208vac 3ph so you can have 120vac 1ph for office equipment. Silliness = most office equipment sold today does in fact accept 208vac or higher for euro compatibility.

I'm not sure any American EV's are sold that will accept 277 or 480v. Sure they will accept 208vac 1ph, but that just takes longer to charge than 240.
 
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McRat

Well-Known Member
Jan 20, 2016
5,771
6,077
LA
Why? There wasn't enough of a market demand to justify the extra cost. This was a cost saving move on Tesla's part.

It stops business owners from putting outlets in their parking lot for employee EVSE's.

Your parking lot lights are 277 1ph, EVSE's cannot use it.
 

Lanber

Member
Sep 20, 2015
64
31
Norway
The first poster answered his own question himself.

Turkey has NO superchargers and NO chademo. For a very good reason. For now the % of electric cars is pitiful and not changing anywhere fast.
Get a pre facelift S with duel chargers. Best option.
 

nwdiver

Well-Known Member
Feb 17, 2013
8,342
11,392
United States
This may also have been a result of issues with the HPWCs charging at 80A. The heat generated by charging is the square of the current. So with 72A vs 80A you're only getting ~10% more power but you're generating ~20% more heat for the same size conductor. I remember that with the first generation HPWCs there were A LOT of thermal issues if you charged at ~80A.

Even 72A at 277v is still ~20kW. That's more than enough for destination charging. You'll typically be fully charged in 3 or 4 hours.
 

McRat

Well-Known Member
Jan 20, 2016
5,771
6,077
LA
Fun fact, both the HPWC and onboard charger are compatible with 277v single phase power.

Thank you, I did not know that. Hurray Tesla!

EDIT: I came to the 'no-277' conclusion based on spec sheets from Bosch and Clipper Creek on L2 AC charging. So I wired our business EVSE at 208vac 1ph.
 
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miimura

Well-Known Member
Aug 21, 2013
6,559
6,365
Los Altos, CA
I think it would be particular to the spec of the individual station, and the individual onboard charger. I doubt official J1772 spec allows voltages over 240 AC volts nominal.
In addition, it's only the new North American HPWC that has the load sharing feature and the side handle socket that is compatible with 277VAC single phase.
 

miimura

Well-Known Member
Aug 21, 2013
6,559
6,365
Los Altos, CA
The other benefit of the new 72 amp charger is that it has the junction box function integrated. That means that there are many fewer individual components that have to pass Supercharger current through to the battery pack. If the Norwegian Model S Supercharger fire was caused by the car, it could have been an overheating component under the rear passenger seat where the original junction box was located. The new charger with integrated junction box would likely eliminate the failure mode that caused that loss.
 

nwdiver

Well-Known Member
Feb 17, 2013
8,342
11,392
United States
No, I'm pretty sure it tops out at 250v. Even if a particular EVSE would accept it, the cars that have been built to the J1772 spec might not.

It's worth noting that the voltage difference between 240 and 277 is more than it appears... 240 is L-L (120v-N/G). 277v is one leg of 480v so it's 277v-N/G...

The high spec of 240v is 264v but it would quickly drop under load. If you set up the taps on a Transformer to give you 264 it would be exceeded pretty regularly...
 

Dborn

Confirmed
Aug 26, 2011
2,715
409
Sydney, Australia
I have a Tesla 3 phase wall connector in my garage running 32 amps at 240v per phase. - I get 23-24 kW when I charge with dual chargers. My UMC is also 3 phase capable but Max's out at precisely half the above by design. Standard line voltage in Australia is 240v. 3 phase is used by my ducted air conditioning and private home elevator. I have 4 storey home built on the side of a cliff.
 

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