Cybertruck 48V Auxiliary Battery vs. 12V & 16V

Recently, Caresoft did a video with the Autoline Network Youtube channel regarding Tesla’s design evolution, in this video they also discuss & compare various low voltage batteries i.e. auxiliary batteries from various vehicles. So let’s discuss the interesting insights shared there.

12V Ford Bronco:

The Ford Bronco battery is a lead-acid 23kg(50 pounds) battery, we can find similar batteries in almost all ICE vehicles worldwide although the current delivery capacity may vary, as being an ICE vehicle the battery has to perform high current demanding operations like cranking up the engine and also it has to be capable of cold-starting the vehicle. The advantage & why they have been used since the beginning is that they are cheap, reliable, allow for deep discharge, and can dump huge amounts of current compared to similar lithium-ion batteries. 

Despite these advantages, the weight of the battery is very significant and it is a tedious task getting the battery replaced from a user’s perspective. From an engineering standpoint, the structural requirements for sustaining its weight on the vehicle are also demanding and can add to the total weight of the overall low-voltage system.

12V 2021 Tesla Model Y battery:

Even though it is a lead-acid battery, In comparison with the ICE vehicle 12V battery, the model Y battery is almost half the weight(12.8kg ~28 pounds) as it has the role of keeping the electronic system running and has no engine cranking duties. But the weight is still not insignificant.

16V 2022 Model Y battery:

Tesla replaced the lead-acid battery with a 1.8kg(~4 pounds) Li-ion battery and hence managed to get 10 kg (~20 pounds) of weight out of the vehicle, which helped in improving the range and overall efficiency of the vehicle.

The battery unit itself comes with its individual battery management system(BMS) for its 4 pouch cells connected in series for monitoring and maintaining individual cell parameters.

Also, the battery has LIN communication terminals for communicating with the front controller which controls all the low-voltage components 

The operating voltage of the 16V battery is 15.5 to 15.8V and the capacity is 6.9Ah which is less compared to its lead-acid counterparts with 45Ah capacity and hence can’t be used to jumpstart other vehicles.

The battery has 5 terminals( positive terminal, negative terminal, LIN communication & 2 terminals for electronic connector position assurance(ECPA)) Vs. just the positive & negative of the lead acid battery.

Cybertruck 48V battery:

The Cybertruck comes with a 48V low-voltage battery (2.2 kg/4.8 pounds) and 48V low-voltage architecture.

The main advantage of a higher low-voltage system (pun intended) is that the current requirement of the overall circuit drops due to higher voltage which leads to lesser wire gauge requirement of the wiring harness which ultimately helps in weight and cost reduction overall.

The operating voltage is 41 to 42V from initial impressions & the battery has a similar construction to the 16V li-ion battery although more details are yet to be found out.

Cybertruck Battery Pack Structural Analysis

The Cybertruck battery pack uses Tesla’s 2nd generation 4680 form factor cells and the battery pack also is a structural element of the vehicle. The seats are directly attached to the battery pack which makes it easier to assemble the vehicles and also minimizes the necessity of having another layer of sheet metal between the battery pack and the vehicle interior.

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