Supercharging: 75 vs 85 pack

[SeminoleFSU]

Hey Gang,
Need your help on this one since the folks at Tesla can't tell me for sure. I currently have a 2013 P85 and I've been looking at new inventory 75D and 100D's... We like to roadtrip in our Tesla and one thing we don't want to do is spend any longer on the supercharger than we currently do... We're okay if it's the same, or less.

Trying to determine the 75 vs 85 supercharger experience. Basically we don't want anything slower than the 85 we have today, otherwise I'll go 100... If the 75 is the same speed as the 85 or faster, we'll go 75..

Thoughts?

 

[Kuhz]

75s have a 350V battery hence they top out at 95-98kw on a supercharger. 85 and 100 batteries are 400V and can supercharge up to 115-120kw (on 120kw supercharger). So yes, you will supercharge faster on the 120kw SuCs in the latter cars but you have to decide whether that’s worth the extra 20k (between 75D and 100D)

 

[TexasEV]

The 75 will supercharge slightly slower than a 85 if you’re starting from a low SOC, but honestly I can’t see that be the determining factor for anyone in choosing whether to get a 75 or 100 kWh battery. Do you want the extra range or not? With the extra range you can sometimes skip a supercharger that you would need with a 75, which is a much bigger time saver than comparing supercharging speeds.

 

[BerTX]

Actually, the 75D is slightly more efficient than the 85, so yes, the charging is faster with the bigger battery, but the actual amount of time spent Supercharging on a long trip is only about 5% more. That is an extra 30 minutes on a trip from LA to NYC.

 

[ucmndd]

+1 to Kuhz. Effective supercharging limit for the 75 packs is 100kw. Very rare these days for me to see >95 kw.

Interestingly enough this doesn’t seem to be voltage related as the older 70kwh packs (which are also 350v) can charge considerably faster.

 

[Kuhz]

+1 to Kuhz. Effective supercharging limit for the 75 packs is 100kw. Very rare these days for me to see >95 kw.

Interestingly enough this doesn’t seem to be voltage related as the older 70kwh packs (which are also 350v) can charge considerably faster.

Yes the 350v units seem to be capable of supercharging at full speed (based on that 70D quirk) but throttled back in 75s and 75Ds for some reason. There aren’t that may 70s though

 

[SeminoleFSU]

Thanks for the replies everyone! I was having a hard time trying to quantify how much going forward the 100D vs 75D would impact our charging times for our most common road trip destinations. To do that I went into evtripplanner.com and entered the start/end addresses for a couple of our most common destinations and clicked "route through superchargers." From there it's easy to toggle between 75D w/ 19" tires and P85 w/ 21's.
To my surprise the 75D shaves off time according to his algorithm. That was a head scratcher for me so I started to wonder... I think his math is based on a flat charge rate (no taper) at almost max (theoretical) charge speed for each car type.
If my assumption is correct about it being a rudimentary calculation that doesn't take into consideration charge taper, my next best way to determine what our road trip experience was going to be like from the standpoint of super charging times is to pick the brain of all you smart folks on here...
Struggling to justify the 100 if the road trip experience between my P85 and a new 75D is essentially the same.. or very close to the same.

Hopefully that adds more color in terms of my thought process for all the kind folks responding

 

[zap fizzle]

+1 to Kuhz. Effective supercharging limit for the 75 packs is 100kw. Very rare these days for me to see >95 kw.

Interestingly enough this doesn’t seem to be voltage related as the older 70kwh packs (which are also 350v) can charge considerably faster.

The old 70 pack touches 116kW peak but it tapers away rapidly from 25% SoC.

The 75 tops out at about 96kW, but will sustain over 90kW until 50%.

So, real-world, the 75 is faster than the 70; the 70 only has an advantage when you arrive almost empty and leave pretty soon after starting.

The graphs at Tesla Battery Charging Data from 801 Cars – About A Better Routeplanner probably help make this clearer.

 

[SeminoleFSU]

Thanks guys. I think @TexasEV said it best. The bigger pack enables you to possibly skip less desirable super chargers and that's the biggest time saving. While this isn't a big deal eight now, with the M3 rolling out in droves I think congestion and lines will be more common and that's where the 100 pack will give greater flexibility. Think I'll stick with the 100 for now.
Thanks again everyone!

 

[ucmndd]

Thanks guys. I think @TexasEV said it best. The bigger pack enables you to possibly skip less desirable super chargers and that's the biggest time saving. While this isn't a big deal eight now, with the M3 rolling out in droves I think congestion and lines will be more common and that's where the 100 pack will give greater flexibility. Think I'll stick with the 100 for now.
Thanks again everyone!

I think, practically speaking, there are very few real-world instances where you can completely skip a supercharger with a 100 that you'd need with a 75. Sure you could come up with a few... but this wouldn't be my deciding factor.

That said, one point that hasn't been discussed yet is potential future improvements. As the article that @zap fizzle posted points out, the 100kwh battery is a beast, charging north of 100kw all the way to ~60% SoC. When/if the oft-rumored Supercharger v3 happens, it's reasonable to expect that the 100kwh battery will charge significantly faster than the current supercharger-capped ~120kw at low state of charge.

The 75 is never gonna charge north of 100kw, no matter how fast the new superchargers get.