50 million batteries - range extender update

[Tinker71]

With the recent news that batteries are not the limiting factor on the CT ramp I think we can expect the Range Extender any time. That is assuming it uses 4680 batteries. I really want to see the hackability of that connection.

Did anyone recall from the tear downs if this was identified?

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[mongo]

With the recent news that batteries are not the limiting factor on the CT ramp I think we can expect the Range Extender any time. That is assuming it uses 4680 batteries. I really want to see the hackability of that connection.

Did anyone recall from the tear downs if this was identified?

4680 production seems to be keeping pace with Cybertruck production, but I don't think that means acceleration of range extender deliveries.

Teardowns did not show any connection points (one review mislabeled the port called out in the service manual as the inductive charging port).

I suspect installation will require modification of the pack penthouse to add the additional power connections needed. Though it is possible they instead just loop current HV and coolant lines through it.

 

[Tinker71]

4680 production seems to be keeping pace with Cybertruck production, but I don't think that means acceleration of range extender deliveries.

Teardowns did not show any connection points (one review mislabeled the port called out in the service manual as the inductive charging port).

I suspect installation will require modification of the pack penthouse to add the additional power connections needed. Though it is possible they instead just loop current HV and coolant lines through it.

Maybe the induction charger connection is the place to hack. I am thinking a 2000 watt fuel cell that allows the waste heat to heat the cabin/battery. Removable off course. That would increase the winter range a bit and prevent getting stranded as long as the fuel cell had fuel.

 

[Tinker71]

Maybe the induction charger connection is the place to hack. I am thinking a 2000 watt fuel cell that allows the waste heat to heat the cabin/battery. Removable off course. That would increase the winter range a bit and prevent getting stranded as long as the fuel cell had fuel.

What else would delay range extender? @ $16000 it is a high margin adder. I can't recall the exact size but ~45kWhr x $100 cost = $4500. There is the box/BMS/cooling, but I bet they can build it for $8000.

 

[Speedr]

It was. Sandy Monroe called it out, as did someone on here with the diagram from the Service Manual.

I'm fine with it coming out a little later, with the hope that they have special batteries that really increase the energy density.

 

[Tinker71]

It was. Sandy Monroe called it out, as did someone on here with the diagram from the Service Manual.

I'm fine with it coming out a little later, with the hope that they have special batteries that really increase the energy density.

That is the catch in my mind. Will they match voltage/cell capacity ? ... ie truly integrate into the pack or is it stand alone capacity that recharges the main pack. The later means it is more hackable.

If the range extender uses different cells and just charges the main pack through a DC converter then voltage would not matter as much. Otherwise if the cells are different the BMS would need to compensate for the difference. Usually through wasting the difference.

Then again, charging one battery to charge another is also wasteful. But the price per kWhr is coming down, so it mostly the wasted weight.

 

[mongo]

That is the catch in my mind. Will they match voltage/cell capacity ? ... ie truly integrate into the pack or is it stand alone capacity that recharges the main pack. The later means it is more hackable.

If the range extender uses different cells and just charges the main pack through a DC converter then voltage would not matter as much. Otherwise if the cells are different the BMS would need to compensate for the difference. Usually through wasting the difference.

Then again, charging one battery to charge another is also wasteful. But the price per kWhr is coming down, so it mostly the wasted weight.

I really expect it will be direct connection and the same chemistry to match voltage vs SOC. Anything else is a waste of parts and less efficient.

 

[Tinker71]

I really expect it will be direct connection and the same chemistry to match voltage vs SOC. Anything else is a waste of parts and less efficient.

You are probably right. I haven't studied the split pack architecture but they will essentially be adding to each parallel string if not mistaken. That is potentially a lot of connections, and given the separation and potential age difference in cells the BMS will need to continually compensate.

 

[mongo]

You are probably right. I haven't studied the split pack architecture but they will essentially be adding to each parallel string if not mistaken. That is potentially a lot of connections, and given the separation and potential age difference in cells the BMS will need to continually compensate.

They can either run 2 HV lines and add a series/parallel switch to the extender or 4 HV lines and no switch. Guessing they go with two HV and two contactors.
BMS impact is minimal because each pack (main and extender) balances independently so they only need to track their own cell groups. The parallel connection forces main and extender to track the same overall voltage. They'll be providing different amounts of power from the start, so differential aging is a non-issue.

 

[TyPope]

I say they just tap into where the DC connection point is and use the extender as an extender. As you chew through your 123kwh pack, the 45kwh extender will charge as you drive. Let's face it. Even those who want the extender would want the option to remove it to be able to use the whole bed on occasion.

I'd like to have a connection point available for DIY solar charging/battery maintenance. I can see using the L-Track to mount a solar panel that would normally be covered by the tonneau cover in a way that the panel is just barely under the cover when closed.

Perhaps it would just be around 500w but that would probably counter phantom drain and the weight penalty.

I think I could get 4-5 hours of sunlight on it during workdays. That probably isn't enough to power my whole 84-mile commute but would cover at least half of it. Kidding. I'd be lucky to get 7 miles a day with it, and more like 4.

 

[Tinker71]

I'd be lucky to get 7 miles a day with it, and more like 4.

5 miles per day is 1800 miles per year. If that was an ICE truck that is the equivalent to 120 gallons per year. Probably a 2 year payback. I could see 1000 + watt arrays that fold out and track a little. I can't wait for people to hack this.

 

[mongo]

5 miles per day is 1800 miles per year. If that was an ICE truck that is the equivalent to 120 gallons per year. Probably a 2 year payback. I could see 1000 + watt arrays that fold out and track a little. I can't wait for people to hack this.

5 miles per day @ 380 Wh/mile = 1.9 kWh
With losses, say 2.5 kWh
8 hours of sun: 300 W solar
20% efficient 1kW/m² (optimistic) = 1.5 m² of panel 16.2 sqft, so that can fit in the bed
2.5 kWh * $0.19 * 365 = $173/yr
400W 12V system on Amazon: $600
+inverter
+battery

Using it as a 48V maintainer might work better.

 

[rrolsbe]

That is the catch in my mind. Will they match voltage/cell capacity ? ... ie truly integrate into the pack or is it stand alone capacity that recharges the main pack. The later means it is more hackable.

If the range extender uses different cells and just charges the main pack through a DC converter then voltage would not matter as much. Otherwise if the cells are different the BMS would need to compensate for the difference. Usually through wasting the difference.

Then again, charging one battery to charge another is also wasteful. But the price per kWhr is coming down, so it mostly the wasted weight.

Since the HV battery has two 400V sections that can be configured in a serial or parallel configuration, have the tear downs confirmed if there is one or two BMS's? There could be two BMS's implemented on a single large board so it might be hard to confirm such.

 

[Crissa]

I would assume the range extender will be set up like the main pack; 800v but splittable in voltage, and usable in serial with the main pack for long range consumption.

-Crissa

 

[mongo]

Since the HV battery has two 400V sections that can be configured in a serial or parallel configuration, have the tear downs confirmed if there is one or two BMS's? There could be two BMS's implemented on a single large board so it might be hard to confirm such.

There are 4 BMB, one per 200V module. Along with the High Voltage Controller that oversees everything and runs the series/parallel switch.

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