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Lucid Production Week Event

Easyrider949

Member
Joined
Sep 22, 2021
Messages
5
Tom55data is making an incorrect assumption. The EPA includes charging losses in its MPGe numbers. The numbers above assume that 100% of the energy provided to the car ended up in the battery. We know this is physically impossible. Battery cells charge at a slightly higher voltage than they discharge. This means that the energy into the battery is always more than the energy stored in the battery. This is often referred to as battery efficiency. Secondly, there are losses in the charging circuit. I am not sure how the EPA charges the car but I assume they are using a level 2 AC charger to represent typical home charging. During charging, the Lucid "Wunderbox" has to both boost voltage and convert AC to DC to charge the battery. This circuit will have losses that contribute to the charging efficiency. In addition, all wiring will have small resistive losses that contribute to the charging efficiency.

Battery efficiency and charging circuit efficiency vary with state of charge. They are less efficient at a lower state of charge than a higher state of charge. The EPA is charging from zero to 100% so the low efficiency at low state of charge is included in the overall charging loss.

Assuming an average battery efficiency of 95% and a "Wunderbox" (including wiring losses) efficiency of 90%, you get 112.7 kWhr capacity battery for the case shown above.

The idea that a 924V architecture implies a larger battery capacity is non-sense. The voltage tells us how may cells need to be stacked in series to reach 924 volts. Typical cell voltages are around 3.6 volts depending on chemistry. This voltage can vary between 3.2 and 4.2 volts depending on temperature, state of charge and if the battery is being charged. I have no idea what what condition 924V refers to.

Battery cells are connected in series to increase voltage and connected in parallel to increase current. At 3.6 volts per cell, we need 257 cells in series to reach 924V. Since a module has 300 cells, reaching 924V is not a problem. The more interesting question is how to create a balanced module or pair of modules between series and parallel combinations that add up to 924V.

Since power is equal to current times voltage, higer voltge architecture allows charging or discharging at a lower current. It is the current that damages the cells when the battery is charged to quickly. Hence, the Lucid can charge quickly without cell damage due to its higher voltage.
Thank you for your detail information, that was interesting.
 

CADreamer

New Member
Joined
Oct 4, 2021
Messages
2
Anyone have any idea how many of the Dream reservation holders were invited to the Casa Grande event or how they decided who to invite? Were non dream reservation holders (outside of media/VIPs) invited? I have been asking my sales rep to be able to get an opportunity to do a test drive before I confirmed my order, so was a be peeved to not have the opportunity as a Dream edition reservation holder. Granted, While I initially reserved in Sept. 2020 (9/2/2020), I cancelled and didn't place my current reservation until Jan. 2021, and my sales rep said that only the earliest reservation holders were invited.
 

hmp10

Expert Member
Founding Member
Joined
Mar 7, 2020
Messages
741
They invited 20, all Dream buyers, is my understanding.
 
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