Tesla “Battery Swap” doesn’t work already.

So they’re going to demonstrate the process for swapping the battery. Is there anyone who doesn’t believe they can swap batteries?

The bigger problem is one of cost and practicality. Let’s say you want to set up a battery-swap station in a major population center. And let’s assume you want to be able to service a modest 100 cars per day (in LA a gas station might need to service ten times that in a day).

So you need to have room to store 100 fully-charged batteries. And you need the equipment and facility to charge discharged batteries that just came out of the cars. And you’re going to need heavy equipment to handle and manage the ~400 pound batteries themselves.

Now, consider the cost of the batteries…it seems that Tesla doesn’t really want to say what they cost – articles about Tesla frequently refer to them as costing “tens of thousands of dollars.” I’ve seen prices that indicate Tesla might be selling extra batteries at a considerable loss, possibly to obfuscate the true cost as a PR move. Battery cost is something that Tesla *really* doesn’t want to talk about:

http://online.barrons.com/article/SB50001424052748…

Musk hung up on Barron’s when they wanted to discuss battery cost. Just flat-out hung up on them.

So, anyway, let’s assume for now that a battery pack costs ~$25,000. If you want to have 100 of them on hand for swapping at such a station, your inventory cost is a $2.5 million. Read that again. Two point five million dollars in battery inventory alone.

Now let’s look at some handling issues. These are ~400 pound batteries. You’re not just going to have one guy carrying them around. Or even 2 or 3 guys. You’re going to have forklifts running around inside some kind of underground bunker (because you’ll be replacing the batteries from under the car) that stores all the inventory and charging equipment. We’ll assume the forklifts are electric too, so no need to worry about extra ventilation in your battery bunker. A hundred 400 pound batteries is 40,000 pounds of material that you’re going to be carrying around each day.

Now consider the storage space needed for all the charged batteries…and the racks and chargers to charge them on. That bunker’s gonna be big. What is the land and construction cost going to be for this facility? Especially in an area like LA?

And then…what does the battery swap cost the consumer? After you factor in the $2.5 million inventory cost, the facility cost, the labor and equipment cost, the cost of the electricity to recharge everything, and the lifespan of a battery (which are all going to be doing full cycles every day, granted that you’re in a swap-system now)…and I don’t know. The battery swap facility has to at least break even, if it’s a Tesla-owned facility. Has to make a reasonable profit if it’s a 3rd-party kind of thing. So…$100 a swap? $50? $250? Dunno. Probably can’t know until you actually get a good handle on the facility cost and the lifespan of batteries that are in that kind of constant-use cycle.

Finally, let’s just simply look at time. How long does it take to do the swap, considering that you have to get the car over a limited number of service bays to drop it out from underneath the car and onto a forklift, carry that battery to a charging rack and plug it in, pick up a charged battery from that rack, bring it back to the car and lift it up and install it. Let’s assume that’s ~15 minutes per car, which I have a feeling may be a bit optimistic, but for now it’ll work. On the face of it, you can say “well, at 4 changes per hour, you can do 96 swaps on a single bay in a day, so no big deal!”

Ummm…no. Reckon gas stations get steady-state traffic throughout all hours of the day? What happens is people will be coming in on their way to work, or on their way home from work. You have to squeeze the vast majority of your 100 battery swaps into a couple hours of the day…let’s say 4 hours to be generous. To do 100 swaps in a 4-hour window, you need 6.25 bays (so, 7 actual bays).

That means you need a lot more land than initially you may have been thinking. And your underground bunker needs to be that much larger to accommodate all those swap bays. And now you need more forklifts, and room to safely maneuver all of them and have space for them to get in and out of the storage and charging areas. And your labor costs went up too.

In the end, demonstrating that you *can* change a battery…even if the process for doing so is kind of nifty…is utterly irrelevant. You need to demonstrate how you’re actually going to make that work in the real world – on a reasonably-sized chunk of land, in a reasonable amount of time for the consumer, and at a reasonable cost.

So…save the swap demonstration. What you need to “demonstrate” is how you’re physically and financially going to make a real-world facility work.

Tom- Denver-CO
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TESLA BATTERY

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