SigmundA

71 ms·

841.
by SigmundA 5y ago
"Never" is bold statement, bottom line current battery technology is lighter than current fuel cell technology in production vehicles while being simpler and more cost effective. Please let me know when that situation changes I am
842.
by SigmundA 5y ago
Diesel exhaust temps are around 600c SOFC operate 600c-1000c. Heat recovery turbines use either organic Rankine cycle (steam turbine) or Brayton where the fuel cell replaces or is along side the combustion chamber in a gas turbine. Comparin
843.
by SigmundA 5y ago
This is physically impossible perpetual motion.
844.
by SigmundA 5y ago
Uses hydrogen (H2) not water (H2O), again H2 has to be split from O with energy somehow.
845.
by SigmundA 5y ago
So now how much does a hydrogen fuel cell semi weigh whats its range? How much does it cost? Where do you fill it up? Current hydrogen fuel cell vehicles weight more than an equivalent battery powered car not not even looking at cost and po
846.
by SigmundA 5y ago
https://cleantechnica.com/2020/02/19/bloombergnef-lithium-io...
847.
by SigmundA 5y ago
Tesla is claiming "under 2kwh/mile" for their semi. At 2kwh/mile your looking at a megawatt for 500 miles range which is close to an 8 hour drive. There will need to be stall where a semi can park for 8 hours using a cha
848.
by SigmundA 5y ago
That makes no sense, it's takes much more power to split hydrogen from water than you get out of it. Where does the power come from to split the water?
849.
by SigmundA 5y ago
Lithium batteries have tripled in energy density since 2010 while the price has dropped about 90% I believe. I was pretty skeptical when Tesla announced the Semi but the trend lines are there if not on Elons over promise timeline. I agree i
850.
by SigmundA 5y ago
Seem pretty relevant to look at the final weight, cost and performance of a vehicle when claiming fuel cells are superior to batteries due to hydrogens weight. Bottom line your example hydrogen fuel cell car weighs with a smaller motor more
851.
by SigmundA 5y ago
Single moving part and generator and power control. None of that is free in terms of complexity, weight and cost. This is on top of whats needed for the fuel cell, plus you will probably need a buffer battery to fully utilize. Makes more se
852.
by SigmundA 5y ago
Yes with 10,000 psi hydrogen lines from trailer to tractor and expensive tanks on the trailer. AFAIK the Tesla semi has all batteries in the tractor. He is most certainly not my god.
853.
by SigmundA 5y ago
A large truck will not be able to use a CCS charger even at 800v for under an hour. The Tesla semi look to be using a special connector with 4 parallel DC connections while a CCS2 is only a single pair. Your going to need a Megawatt for rea
854.
by SigmundA 5y ago
Not sure why you say that, its very critical in Europe and still a concern in the US.
855.
by SigmundA 5y ago
The Mirai has a 1.6 kwh battery pack because the fuel cell cannot output the needed power for acceleration and to allow regenerative braking. It runs on the electric motor alone just like a Tesla. But yeah so add the buffer battery in your
856.
by SigmundA 5y ago
Long wheelbase sleepers are very difficult to maneuver, they are pretty specialized and you won't see them in Europe do to length restrictions.
857.
by SigmundA 5y ago
Mirai: 1,850 kg Model 3 (Long-Range Dual-Motor): 1,847kg I am going to guess it's all the structure needed to protect the 10,000 psi hydrogen tanks.
858.
by SigmundA 5y ago
Heat conversion is going to mean more equipment (heat recovery turbine?). SOHCS run at what 1000c? Don't see that being practical for vehicle use any time soon.
859.
by SigmundA 5y ago
So where are the hydrogen semis? $/mile hydrogen is far behind diesels and batteries at this point.
860.
by SigmundA 5y ago
Trucks have length limits and more constrained in Europe which is why you still see many cab overs there. The US loosened length limits in the 70's allowing for long nose trucks which help with aero dynamics and safety.
861.
by SigmundA 5y ago
You won't get 75Wh to the wheel with 2kg and the hydrogen tanks and fuel cells have weight.
862.
by SigmundA 5y ago
SpaceX does not use hydrogen in its rocket engines. https://en.wikipedia.org/wiki/SpaceX_rocket_engines
863.
by SigmundA 5y ago
There are no hydrogen trucks on the road either, time will tell which one is viable. Physics tells me which one will be more likely no need for a argumentum ab auctoritate .
864.
by SigmundA 5y ago
I don't see a lot of extra room on a truck for safe liquid hydrogen tanks 5 times the size of diesel tanks.
865.
by SigmundA 5y ago
Look at volume instead of weight. Hydrogen is only 8 MJ/L in liquid form vs 38MJ/L for Diesel. Think of the space needed in the vehicle. Next creating liquid hydrogen is a very energy intensive process compared to refining diesel.
866.
by SigmundA 5y ago
Not the biggest Elon fan but I do believe he is right about Hydrogen [1]. Hydrogen is not sitting around somewhere to be pumped out of the ground it must be split from something else like water which is very energy intensive. It is very low
867.
by SigmundA 5y ago
They seemed to be referencing fuel cells not combustion engines.
868.
by SigmundA 5y ago
Again here in FL dragging sandy bottom is pretty common and most of the time no big deal, maybe scuffing your skeg. Many times what happens is you're out of the channel on a plane no problem, then you slow down come off a plane and oop
869.
by SigmundA 5y ago
How much does it cost to replace the foils should you tear them off? Because honestly on a pleasure boat say in Florida where I am your not going to hit a log but you will drag bottom at some point due to shallow waters and tides. Most outb
870.
by SigmundA 5y ago
Only if you remember to retract them.

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