500 mile Cybertruck is a must

[charliemagpie]

Ok.. thats interesting. So we have scope to add a total 340KW for 760 miles.

Filling that @ .50c per kw will add up.

But 1200km range. That would be enough to win over the fence sitters.

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[Bill906]

I was actually thinking the same thing, that a add-on pack could be slid into the bed and would cost you about 4" (100mm). On the surface area of the bed you could fit another 130kWh of pack, or another 300miles of range and weigh 477kg. You would you have to split it into 8 parts to make it small enough to move by hand though.

Would this add-on pack be something the user could connect and remove? If yes, you'd need high power/voltage connections., coolant connections, low voltage communication connections to tell the vehicle computer the pack is there, its state of charge, it's temp etc. I'd think there'd need to be some high power regulation circuits between removable pack and main pack. Otherwise, what would happen if one pack was fully charged and the other was near depleted? These high voltage/energy packs aren't like 12V car batteries where you can just throw jumper cables between them and go.

 

[JBee]

Ok.. thats interesting. So we have scope to add a total 340KW for 760 miles.

Filling that @ .50c per kw will add up.

But 1200km range. That would be enough to win over the fence sitters.

From your own home solar setup that would work out to $24 a fill. With that much range you should make it there and back.

 

[JBee]

Would this add-on pack be something the user could connect and remove? If yes, you'd need high power/voltage connections., coolant connections, low voltage communication connections to tell the vehicle computer the pack is there, its state of charge, it's temp etc. I'd think there'd need to be some high power regulation circuits between removable pack and main pack. Otherwise, what would happen if one pack was fully charged and the other was near depleted? These high voltage/energy packs aren't like 12V car batteries where you can just throw jumper cables between them and go.

Well the weight of the pack alone sort of excludes that. As for the connectivity to the main pack, it need not power the motors directly and have enough to do peak load, rather it need only to discharge as fast as normal cruise to extend range, and at most at 40% of the main pack if at all if used for peak.

 

[Crissa]

Would this add-on pack be something the user could connect and remove? If yes, you'd need high power/voltage connections., coolant connections, low voltage communication connections to tell the vehicle computer the pack is there, its state of charge, it's temp etc. I'd think there'd need to be some high power regulation circuits between removable pack and main pack. Otherwise, what would happen if one pack was fully charged and the other was near depleted? These high voltage/energy packs aren't like 12V car batteries where you can just throw jumper cables between them and go.

Any add-on pack would have to have a draw-down through a voltage regulator. Which means that once you can do that, you can accept input from solar or any generator.

And we already have 'high voltage dc with low voltages communications' it's called a Tesla connector, and every Supercharger has one.

-Crissa

 

[JBee]

Any add-on pack would have to have a draw-down through a voltage regulator.

Why?
You can add as many battery strings as you want at the right string voltage.

 

[Crissa]

Why?
You can add as many battery strings as you want at the right string voltage.

...Because you need the right voltage? Duh? You said it right there in your sentence.

What the right voltage is varies by what the other battery's voltage is. Otherwise you don't draw down the extended pack. And as packs age they become mis-matches. So the extended pack needs to be adjusted to a compatible but slightly higher voltage. Just like how an MPPT solar controller works. Or a USB battery.

-Crissa

 

[JBee]

...Because you need the right voltage? Duh? You said it right there in your sentence.

What the right voltage is varies by what the other battery's voltage is. Otherwise you don't draw down the extended pack. And as packs age they become mis-matches. So the extended pack needs to be adjusted to a compatible but slightly higher voltage. Just like how an MPPT solar controller works. Or a USB battery.

-Crissa

Yeah I said it. "Right string voltage".
As in use the same string voltage as your main pack. Only thing you need to do is only allow it to connect at the same SoC. No DC voltage regulator required. As previously mentioned a pack this size wouldn't be DIY install because if its mass. So you wouldn't do it often and could just use the BMS to close the relay to connect when they match. From there on in the extender pack will simply behave as part of the pack.

 

[Macgyverfever]

Yeah I said it. "Right string voltage".
As in use the same string voltage as your main pack. Only thing you need to do is only allow it connect it at the same SoC. No DC voltage regulator required. As previously mentioned a pack this size wouldn't be DIY install because if its mass. So you wouldn't do it often and could just use the BMS to close the relay to connect when they match. From there on in the extender pack will simply behave as part of the pack.

Yep was looking for BMS somewhere in there

 

[Crissa]

Yeah I said it. "Right string voltage".
As in use the same string voltage as your main pack. Only thing you need to do is only allow it connect it at the same SoC. No DC voltage regulator required. As previously mentioned a pack this size wouldn't be DIY install because if its mass. So you wouldn't do it often and could just use the BMS to close the relay to connect when they match. From there on in the extender pack will simply behave as part of the pack.

I'm sorry, that doesn't work. If you don't control the voltage, you cannot control which pack how much power is being drawn from.

-Crissa

 

[JBee]

I'm sorry, that doesn't work. If you don't control the voltage, you cannot control which pack how much power is being drawn from.

-Crissa

Why would I want too? None of the Tesla built in packs do that.

Maybe we aren't talking about the same thing. I was talking about a 360kWh double stacked 4680 pack "and" 130kWh in the bed, for a grand total of 490kWh.

Even with 1000kW of quad plaid motors we are still only looking at 2C. Plaid is ruuning at 10C in comparison. No cooling required. No regulator either...by that do you mean voltage converter? If so swichmode?

I'd still like to see a DC input for solar on the CT. Even just for a few kWs.

 

[charliemagpie]

So there was a fair bit of chatter when the CT was revealed that there was going to be enough height in the floor for a double high stacked battery pack

In fact going by the CT floor surface area available I calculate that you will only get around 170kWh in one layer of batteries, between the wheels under the cabin. That's around 380miles of range according to ABRP

after Musks twitter announcement today .. maybe 500 miles is it.

Just Maybe !! the second pack will be 80% air ... that would assist flotation?

 

[Macgyverfever]

after Musks twitter announcement today .. maybe 500 miles is it.

Just Maybe !! the second pack will be 80% air ... that would assist flotation?

Regardless, I'll take it!

 

[JBee]

after Musks twitter announcement today .. maybe 500 miles is it.

Just Maybe !! the second pack will be 80% air ... that would assist flotation?

Well air lithium packs would help with flotation.

I'm not sure the first one will be 500miles, I'm sort of expecting a 400mile QM first, at a price point to capture both DM and TM customers. Say $64k?

 

[charliemagpie]

Nahh,,, Youve just designed a racing Donkey !

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