Also batteries have contactors separating into halves (regular cars have 200V halves).
Really? Which cars? Not Teslas as their packs are pretty much all 350v or 400v, no contactor to split them in half.
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Also batteries have contactors separating into halves (regular cars have 200V halves).
Are not. Before normal charging voltage and current is applied an insulation and current leak test is performed.surface contamination effects are important to consider.
Ahh s**t, it was manual disconnect and/or fuse, not contactor that operated all the time.Really? Which cars? Not Teslas as their packs are pretty much all 350v or 400v, no contactor to split them in half.
Also I wouldn't agree on "all conductors" are exposed. Chademo, while mated, actually is sealed (I think IP66).
Actually, we have problems with ChaDeMo plugs in my country. We have a lot of bad weather and due to dew forming on
the plug, charging sessions often do not start. I've been in that situation many times. I literally have to clean/wipe the plug.
I like your thinking. But as these babies are going to be saving the fleet manager so much cash, they're going to be doing double or triple shifts. No downtime.I think I figured out why Tesla is offering a million mile warranty. I believe it is so they can use the semi battery for arbitrage and to move excess energy between locations customers.
The warranty overcomes the potential customer objection of battery degradation.
Customer buys truck. Customer signs long term PPA. Tesla buys, sells and moves energy as a secondary business to keeping the truck adequately powered. This is at no additional cost beyond software development and needing V2G in the semi and charger.
This is a debugged remake of Musk's original solarcity grand strategy.
And this is the reason why there is no bedI like your thinking. But as these babies are going to be saving the fleet manager so much cash, they're going to be doing double or triple shifts. No downtime.
I like your thinking. But as these babies are going to be saving the fleet manager so much cash, they're going to be doing double or triple shifts. No downtime.
Any meaningful battery that is going to be plugged in longer than needed for its next scheduled duty, on a connection with menaingful throughput rating, of course can support grid fluctuations.I'm going to guess that the utilization rate of non-OTR semi is 20% at most. Lowering the cost of running a semi a bit does not mean that McDonald's starts accepting deliveries at 1 am.
Musk/Solarcity has probably wanted to consolidate powerpacks for grid services since the beginning. That has proved impractical for a variety of reasons. But with Tesla semi they have giant batteries paid for by commercial customers. Many of these batteries are going to be plugged in for 12 hours weekdays and all weekend.
Tesla has such patent. I believe it would cause problems during winter.Maybe for quick charging special drive over stations could be developed that are hydraulically actuated with big matching pins and sockets? No human interaction with the couplers at all and huge power transmission.
And if a battery is never needed to be more than a given SOC, it's just needlessly big which constitutes a waste of resources.
If you can accept a 10 minute charge stop on days when you run higher on consumption, that takes away need for the reserve you mentioned. To be used only a few times per year, on cold days or with unusually strong head winds.The key word here is "never". A fleets battery capacity is going to be sized to the highest energy utilization day plus some reserve. That leaves on average substantial extra capacity, especially considering seasonality. Trucks running for Walmart in snow states are going to have substantial extra capacity in summer. Tesla solar dedicated to charging is also going to have excess. Than there are weekends.
The key is scheduling and routing software for truck management to meet the customers requirement.
Tesla has such patent. I believe it would cause problems during winter.
I think that would be an easy fix compared to manhandling huge cables and sockets. It's possible to also have the receivers built into the front or sides. Special covered plugs through the front bumpers could be a solution as long as they retract into a position that could be driven over or beside when done.
Reading all these posts about the infrastructure required to run trucks it's easy to see the costs of operation parallelling or exceeding current petroleum powered equipment.
And this is just for trucks, they can travel to charging stations, imagine remote stationed equipment where you have to take the energy to them...
I think that would be an easy fix compared to manhandling huge cables and sockets. It's possible to also have the receivers built into the front or sides. Special covered plugs through the front bumpers could be a solution as long as they retract into a position that could be driven over or beside when done.
Reading all these posts about the infrastructure required to run trucks it's easy to see the costs of operation parallelling or exceeding current petroleum powered equipment. And this is just for trucks, they can travel to charging stations, imagine remote stationed equipment where you have to take the energy to them...
Explain, as I'm tired of listening for that BS. I even asked for professional opinion from my dad to be sure.
Socket on the side is easier to manually clean from snow and ice when needed. Charging snake could handle heavy cables:
800 V is safe when everything goes as planned. If not, it is much more dangerous than 400 V. So it should be avoided if possible:
1 MW charger 400 V -> 2.5 kA.
Copper cable 5 cm wide 1 cm thick (easier to bend in one direction). For 1 m cable resistance = 16.78 / (0.01 * 0.05) = 33560 nΩ
Power loss P=I*I*R = 2.5 * 2.5 * 33.560 = 210 W
+ & - cables, length 3 m -> 1260 W power loss. About 0.1 % of total power. Cooling is needed.
1 m would weight 0.05 * 0.01 * 8960 = 4.48 kg + & - cables, length 3 m -> 27 kg Spring support would be enough.
Tesla semi has separate circuit for each battery. So split cable to four separate cables with separate plugs. Spring support is not needed.
Thanks for the calculations. I ran 250 mcm welding cable in a 4 pack/1.6kWh/mile scenario (1.28 MW charger) and get about 2.1kW of loss for a 3 meter cable. So liquid cooling would be reasonable. Insulated cable weight of 82 lbs/ 27kg of which half would be inherterly supported by the station.
Regarding the voltage discussion. Higher voltage is typically more dangerous, but we need to look at the system as a whole.
The only way to be exposed to the potential is to make contact with both cables (a double fault). If the megacharger has shielded cables and guard/ shield rings on the connectors, it will know instantly if there is leakage from either of the main conductors (a single fault). So it can shutdown at the first sign of trouble, long before people are exposed.
Current electronics also check for wiring faults to chassis. As long as the vehicle blows its pyro fuse (crash case) and opens the contactors, pack voltage is not a concern. Unless the pack is breached, in which case each {max safe fire fighting voltage} section would need pyro fused.
Edit: early submit click.