Over day to decide: change my 85D to 90D?

[gway]

This. While I hope it is not the case, there is a good chance that on the long run 90 kWh pack after 8-10 years would have lower capacity than similarly stressed 85 kWh pack.

I've got this impression after reading(ok, more like scanning through) quite a few peer-reviewed li-ion papers. But again, as RiverBrick pointed out "we don't know by what extent TM and Panasonic have solved the" issue.

PS. I by no means a battery expert. But bleeding edge of battery developments interested me enough to spent some time on it, and to go beyond of popular science compilations. In fact some really interesting papers do not catch attention pop-science press.

The 90 kWh battery has partly silicon anode, mostly carbon anode. Silicon anodes provide more power density, but have been problematic in that the anode swells as it charges and shrinks as it discharges, resulting in early failure inside the cell. If the carbon/silicon hybrid chemistry has been figured out - great, and Tesla wouldn't be producing it if lab results weren't good, but there is no real-world pack scale experience over time to prove its reliability.

This is me is my concern re: 85D or 90D. I am likely going to order this week. I don't really "need" the 90 so I was on the fence from a cost/benefit perspective already and now wondering if sticking to the 'tried and true 85' is the smart play at present given the relative 'newness' of the 90? Any thoughts appreciated.

 

[Poison Dart Brew]

I have had the 90D since early September, no problems, and very happy. I make some longer trips, and just spent the weekend in Maine with no superchargers. Glad I had that little extra range.

 

[Beryl]

I went from a 70D to 85D to a final order of 90D. I don't think I'll regret it but I might have had remorse if I'd not gone with the battery with the greatest range.

 

[benf]

A little late to the party, but this is how I made my decision:

The cost of a replacement 90D battery pack is $25k (confirmed in some other thread where someone asked their service center for the cost). That comes out to $277/kwh, which is very reasonable. But if you look at the "upgrade" cost for a new Model S, it's $3,000 for 5kw, or $600/kwh. To me, that is ridiculous.

The 90D upgrade should cost ~$1,500. If it did, I would have upgraded. Or if there was a performance benefit to the 90D, I would have upgraded. But $600/kwh just for 15 miles of range...no thanks.

 

[Screwbal]

I went with the 85... somewhat due to the 90 being new but at the same time it was a money thing. Saving the money there gave me more to spend on the air suspension and upgraded interior which I can appreciate every time I drive the car.

 

[pedriscoll]

I purchased an 85D before the 90 battery was available but for the minimal increase in range I don't think the price difference is worth it. I get 240 miles on daily charging and 265-270 on a range charge for my trips to South Bend from Indy. More than adequate for my needs.