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IMHO hydrogen fuel cell technology is more practical. No charging time means that you can travel any range without delays as long as you have hydrogen fuel stat

by Gonzih 13y ago

IMHO hydrogen fuel cell technology is more practical. No charging time means that you can travel any range without delays as long as you have hydrogen fuel stations on your way. That kind of technology gives you more freedom I guess. You feel less limited by your vehicle. And as far as I know charging li-ion batteries is still very slow, they will go flat at some point, faster you are charging them faster they become flat and they are very heavy.

XorNot 13y ago
Charging time is overblown. You can charge a modern battery to 80% in about 5 minutes. That's about how long it takes to fill my car with gas at the moment. You're not going to be refueling a hydrogen fueled car that quick - it's a volatile, extremely high pressure, extremely cold gas. The safety considerations are substantial.
- Gonzih 13y ago
  Ok, what about durability of batteries compared with durability of fuel cell? I'm just curious because I think that batteries are less durable right now than fuel cells.
  - stonemetal 13y ago
    http://www1.eere.energy.gov/hydrogenandfuelcells/durability_group.html http://www1.eere.energy.gov/hydrogenandfuelcells/durability_... DOE targets 5k hrs of operation for fuel cells used in transportation. I haven't been able to find an hours of operation for batteries. Wikipedia gins up some numbers to claim 10 to 20 years life expectancy. On the whole it seems batteries are in the lead at this point, but both are near the expected baseline for automobiles. http://en.wikipedia.org/wiki/Electric_vehicle_battery http://en.wikipedia.org/wiki/Electric_vehicle_battery
- walshemj 13y ago
  At what amperage and voltage and how much did it cost to upgrade the charging station connection to the grid. And how do you cool the battery during such a fast charge? what % of the energy is lost in heat from the chemical reaction - even Tesla has to obey the laws of thermo dynamics. Thinking about it from a thermofluids angle You could I suppose have a complex system of heat exchangers built in to the the battery pack and hook the car up to a water connection and flush chilled water (or better some non conductive fluid) through whilst charging but water and high voltage and amps are not the best of friends. Now where did i put my steam tables :-)
  - marvin 13y ago
    Tesla's supercharging stations charge at 135kW 400V DC, recharging >50% of a 85kWH battery in 30 minutes. The power is delivered from a large (>300kWH) battery pack installed in the charging station, which is continously trickle-charged from the grid. There will also be swap stations implemented, swapping out the entire 85kWH battery pack in 2 minutes. This is largely a solved problem, both from the sides of technology and deployment. It's just that public perception hasn't caught up yet. Give it 5 years and just about everyone will want one of these cars. For everyday use you won't even need the quick-charge capability.
    - sucramb 13y ago
      > Give it 5 years and just about everyone will want one of these cars. They sold a batch of MiEV / IOn for $15.000 here and so far everybody is very enthusiastic about them. I think 5 years is a tad optimistic but I give it less then 10 years.
CamperBob2 13y ago
Ever try to move a large quantity of compressed gas from one place to another in a hurry? It's never as simple as "no charging time." In my opinion, any alternative-fuel technology that doesn't involve swappable power modules -- whether they're batteries, fuel cells, fusion reactors, or whatever -- is bullshit. Tesla has at least taken some steps in the right direction.

by Gonzih 13y ago

XorNot 13y ago

Charging time is overblown. You can charge a modern battery to 80% in about 5 minutes. That's about how long it takes to fill my car with gas at the moment. You're not going to be refueling a hydrogen fueled car that quick - it's a volatile, extremely high pressure, extremely cold gas. The safety considerations are substantial.

Gonzih 13y ago
Ok, what about durability of batteries compared with durability of fuel cell? I'm just curious because I think that batteries are less durable right now than fuel cells.
- stonemetal 13y ago
  http://www1.eere.energy.gov/hydrogenandfuelcells/durability_group.html http://www1.eere.energy.gov/hydrogenandfuelcells/durability_... DOE targets 5k hrs of operation for fuel cells used in transportation. I haven't been able to find an hours of operation for batteries. Wikipedia gins up some numbers to claim 10 to 20 years life expectancy. On the whole it seems batteries are in the lead at this point, but both are near the expected baseline for automobiles. http://en.wikipedia.org/wiki/Electric_vehicle_battery http://en.wikipedia.org/wiki/Electric_vehicle_battery
walshemj 13y ago
At what amperage and voltage and how much did it cost to upgrade the charging station connection to the grid. And how do you cool the battery during such a fast charge? what % of the energy is lost in heat from the chemical reaction - even Tesla has to obey the laws of thermo dynamics. Thinking about it from a thermofluids angle You could I suppose have a complex system of heat exchangers built in to the the battery pack and hook the car up to a water connection and flush chilled water (or better some non conductive fluid) through whilst charging but water and high voltage and amps are not the best of friends. Now where did i put my steam tables :-)
- marvin 13y ago
  Tesla's supercharging stations charge at 135kW 400V DC, recharging >50% of a 85kWH battery in 30 minutes. The power is delivered from a large (>300kWH) battery pack installed in the charging station, which is continously trickle-charged from the grid. There will also be swap stations implemented, swapping out the entire 85kWH battery pack in 2 minutes. This is largely a solved problem, both from the sides of technology and deployment. It's just that public perception hasn't caught up yet. Give it 5 years and just about everyone will want one of these cars. For everyday use you won't even need the quick-charge capability.
  - sucramb 13y ago
    > Give it 5 years and just about everyone will want one of these cars. They sold a batch of MiEV / IOn for $15.000 here and so far everybody is very enthusiastic about them. I think 5 years is a tad optimistic but I give it less then 10 years.

CamperBob2 13y ago

Ever try to move a large quantity of compressed gas from one place to another in a hurry? It's never as simple as "no charging time." In my opinion, any alternative-fuel technology that doesn't involve swappable power modules -- whether they're batteries, fuel cells, fusion reactors, or whatever -- is bullshit. Tesla has at least taken some steps in the right direction.