No 800v for Model 3/Y, but maybe for Cybertruck?

[ajdelange]

Already have in my own way

OK.
Here's 2 more tips then.

1)In doing your calculations be aware that only ;erhaps 70 - 80% of what you collect will wind up going to your loads (IOW each hFSE from the PV array winds up as 0.7 -0.8 hFSE at your load panels. This is because of "round trip loss" as the DC gets changed to AC and back to DC and back to AC and finally back to DC.

2)Given 1) it makes sense to try to charge your vehicles when the sun is shining so the losses associated with going into and out of your Powerwall equivalent is not incurred.

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[ituner-HF]

Have a question for an EE. When charging is voltage or amperage the most important thing? High voltage, same or lower amperage. Will that charge faster than higher amperage, lower voltage? I assume a 400-900V charger isn't going to be available at most utility-connected houses in the USA. This would require either a transformer or higher voltage utility lines. If you're using solar connected to batteries, I presume you could find (maybe?) an inverter that could handle a 400-900V DC input with a high output but you'd also need a very large solar array to charge it.

At home Cybertruck uses the internal AC-DC converter. So vehicle takes in 240VAC and produces ~400VDC to charge the battery pack. 800V packs seem to be a problem not for home charging scenario but for the SuperCharger scenario, which are DC fast chargers: CCS protocol permits any voltage from 200V to 1000V. The protocol is not the issue, the SuperCharger current hardware might be the limitation. BTW, SuperChargers take as input 3phase 480VAC and produce VDC.

 

[ajdelange]

At home Cybertruck uses the internal AC-DC converter. So vehicle takes in 240VAC and produces ~400VDC to charge the battery pack. 800V packs seem to be a problem not for home charging scenario but for the SuperCharger scenario, which are DC fast chargers:

The in-car charger would also have to produce over 800 V to charge an 800V battery in a car with an 800V pack. It would not be a particularly big deal to design this charger. Several OEMs have already done it.

CCS protocol permits any voltage from 200V to 1000V. The protocol is not the issue, the SuperCharger current hardware might be the limitation.

The envelope of the HPC350 class of DCFC is 200 -920 V and 5 - 500A not to exceed 350 kW. Once one has a power supply that will do 200 - 920V for the car he just (conceptually) puts a bunch of them in a cabinet all connected to a common output bus. The early Tesal SC are rumored to have been built exactly this way (using modules from the S) and photos of the cabinet interior certainly supported this notion. So there really is no real difficulty with building a Tesla 920 V supercharger either. The challenge is backward capability with current cars that charge at around 400 V and need well over 500A.

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