Battery Question

Battery Question

Hello All,

Quick question on the battery. I have heard and read that when charging your Tesla, it is best to charge to about 80% (or anything other than 100%) to preserve your battery. My question is, what if you were to get the base battery for the Model 3 (say 40kWh) which gets you the "at least" 215 miles, but this battery can be upgraded (or unlocked) to 55kWh at a price of course...could you charge the 40kWh battery to 100% since it is actually a 55kWh battery? It would be cool if you could.



Octagondd | October 18, 2016

I think it is unknown where in the charge profile they limit the usable kwh. I am not sure if they use Voltage to measure state of charge, or if they use amphours, or a combination of both. My assumption is voltage since measuring amphours is harder. Amphour counters have a hard time counting small amps loads when configured for optimal counting of large amp loads.

If they do use voltage, then it seems they could set the usable kwh wherever they want in the profile. Lithium ion cells in general like to be near 50% state of charge so to me the optimal setup would be to center the usable kwh on 50% and hopefully that means a fuil charge of smaller usable battery would result in the fastest super charge possible by avoiding the 90-100% range.

Calibrotha2000 | October 19, 2016

From what I've heard yes. I hear now with anyone who buys a 60kwh battery they are able to charge to 100% since it's actually got a bigger battery so that would be the case if tesla gave the 3 the same kind of bigger batter that had to be unlocked

jordanrichard | October 19, 2016

Calibrotha200 +1

As for what is the best SOC to go to, per the Charge screen, up to 90% is considered "Daily". So take that for what it is worth.

topher | October 19, 2016

I think the premise is unlikely. Tesla has stopped making 60kWh batteries upgradable to 75. It seems unlikely to me that they will try it once again with the Model ≡. 40kWh would be unexpected for a 215 mile range (50-55 seems far more likely), and they have said that it will have below 60kWh. Not a lot of room there.

Thank you kindly.

leskchan | October 19, 2016

It's more likely than not to have 1 battery pack for Model 3 for 215-mile base model and 255-mile upgrade option. It's cheaper, incremental cost, to manufacturer and stock 1 size than multiple sizes of anything. Same with S and X, autopilot hardware is on all cars, regardless you buy the AutoPilot option or not.

Tesla discontinue 60kWH for X only, mostly because it not in demand. Most X buyers can afford 75.

topher | October 19, 2016

" It's cheaper, incremental cost, to manufacturer and stock 1 size than multiple sizes of anything."

So you are saying that a car which has over thirteen options, amounting to some 1,075,200 different possible configuration is going to say that just one more option is more than they can handle, and just GIVE AWAY $8,500 worth of batteries?

Thank you kindly

dd.micsol | October 19, 2016

New cells will be used. He already hinted that. I'll bet there are 2 sizes of batteries in the end. One controlled by software as a limiter. You'll have your entry level car then anything with a d or p or l will have full battery but might be limited by software.

leskchan | October 19, 2016

@topher Do you math first. $8,500 is not the cost, it's the list price.

Using S60/S75 for math, the price difference is $8,500 for 15kWh more. If you use these number, the per unit cost of $8,500/15kWh = $567/kWh. So the entire battery is $567x75=$42,500. The battery cannot cost $42,500.

Going forward with the Gigafactory, Tesla will bring down battery cost to under $200/kWh in the near term.

Let's use $200/kWh and make some assuming here for Model 3. Let's say 50kWh will get you 250 miles. So this works out to be 50/250=0.20kWh/mile. Then say for 215 miles the battery will be 215x0.2=43kWh. So the difference is 50-43=7kWh or 7kWh x $200.kWh = $1,400 in costs. The list price will be say 3x more or about $4,500 more for the upgrade. More people will opt for the upgrade immediately or eventually. it will all work out.

At buffet restaurant, some will eat 1 plate and others will have 10 plates. It all averages out.

Red Sage ca us | October 19, 2016

leskshan: Please imagine this post as a big, huge, head shaking smiley.

jamilworm | October 19, 2016

@topher "So you are saying that a car which has over thirteen options, amounting to some 1,075,200 different possible configuration is going to say that just one more option is more than they can handle"

That is not out of the questions. Adding one more option would add over 1 million possible configurations for the car. It's not hard to imagine that they could streamline things by eliminating that variable during manufacturing.

Rocky_H | October 20, 2016

But if they are already on the large scale of making many hundreds of thousands of battery packs, the scale is already so big that the production simplification doesn't amount to as much, and they would save quite a lot by NOT giving away any huge quantities of battery cells.

topher | October 20, 2016

"@topher Do you math first. $8,500 is not the cost, it's the list price."

My math is fine. Do your economics. 'Worth' is price. Tesla could sell those batteries for $8,500 or they could include them in a car for free. Difference in Tesla revenues, $8,500 minus the tiny costs of keeping two battery types in stock.

leskchan | October 20, 2016

Not true. It is also maximizing opportunity costs. If you put a bigger battery, more people (not everyone) will opt for the upgrade immediately or eventually. This is true for many products.

XM Radio Antenna - I have it but I don't subscribe.
Theatre Popup - You upgrade to large for $1 more plus 1 refill.
Fountain Drink - S/M/L all you can drink. In the end you drink the same amount.

dd.micsol | October 20, 2016

I'm hoping it is the other way around. you get the mid level car-you get the biggest battery but locked to a certain kw. Entry level is just that-entry level. If you get the D-I won't be surprised if you have to get the medium battery-not the largest but not the smallest-this is why I believe there will be bundling of some sort going on. Just my guess.
Making all cars with bigger batteries is just too costly. If I remember correctly - telsa said the cost is about 85.00/kw-that was before I invested heavily into lithium. Now it's much more expensive to get the raw material. It might cost them more like 105.00kw now. I really don't know though. We're back to-it's completely unknown but we are trying to make educated guesses.

Rocky_H | October 20, 2016

@leskchan, Try some real examples.

(1) XM: You pay for the upgraded stereo, Tesla includes the receiving hardware--exactly what you paid for. A subscription fee would go to XM, not to Tesla, so there is no monetary difference to them whether you sign up for it or not.
(2) Soda
(3) Soda

You're seriously going to try to make an equivalent cost analogy of rechargeable lithium ion batteries (the very thing that makes electric cars so expensive) versus one of the cheapest substances on Earth?

Red Sage ca us | October 20, 2016

Hence, why traditional automobile manufacturers such as Honda tie the majority of options to specific trim level packages. It also shows why thus far Tesla has offered no alternatives for interior carpet, dashboard color, or lining of trunk and frunk. That makes building cars a bit more streamlined, especially at higher volumes.

leskchan | October 20, 2016

No, my Audi has basic equipment, including Sirius radio and AT&T Mobile Hotspot. When free trial was over, I never subscribe.

Tesla includes AP 1 and 2 hardware on all car, no pirce increase for 2.0 either. You don't have to buy the AP option and let the hardware sit there and rust.

You can make the argument that you paid for it as part of the car. That's would be the same for a larger battery pack.