Featured Review of hydrogen

Well, the Tesla lets you completely skip gasoline. The only real reason left to stop at a gas station is for the window squegee, and maybe the air pump.

What exactly is puzzling about the i3-REx design?

If the trucks are successful, maybe VW and Diamler will go back to hydrogen cars then.

It might work out for trucks, but past examples of buses ended up being more costly than BEV buses. Without a more compact and less energy intensive storage solution, which would mean upgrading all current hydrogen stations, I don't see hydrogen cars being popular with the masses.

Because the poster I was replying to would be more focused on range. It was also getting late, so I skipped bringing up other BEVs.

The fact is that very few car buyers actually consider a car's weight. They might think about it if that weight has a noticeable impact on performance, and then they may not make the connection. Tesla and others have shown that the extra weight doesn't have to impact performance. The Rav4 Prime is about 1000 pounds heavier than the ICE model, 600 more than the hybrid, and is the fastest Toyota in the line up.

We should address hydrogen's energy density. It holds more energy by weight, but it has a pretty lousy physical density. So little of it fits in a given space. This is why we have to expend so much energy compressing or liquidfying it. Why it costs more per kg to ship. And why the cars lose so much usable space to the tanks.

 

Several things make Bob's 2014 i3-REx a niche car. Like the Prime, it has seating for 4, but even less cargo area. It has enough initial range to go about 75 miles from home and back. That's using it's full battery range and full gasoline tank. Realistically, it's usable for city use and a predictable commute but regional travel requires that you make sure that there is an OPEN gas station within an hour's drive.

I just found this buried in the I3 wiki page: but BMW had locked out the tank's last half-gallon of capacity in the American market to meet California's ZEV requirements for vehicles with range extender, as the car had more gasoline-powered range than all-electric range, which would affect its status as a zero-emissions vehicle (ZEV) in California. That explains the extra small gas range. They were trying to qualify for a specific legal designation.

In short, it was not designed to be optimal for the driver. It was designed to earn a desirable label in the California and European markets.

Many of the I3 design decisions make more sense when viewed in this light.

 

yes and there are a couple of things here. 1 - Are long range bevs heavier than fuel cell vehicles? 2 - Does that extra weight matter? The answer to the first is no. yes 350 mile range is not 402 miles, but take a model 3, use only rwd, and make the battery 430 miles and it would still be lighter than a mirai if slightly heavier than a clarity. Tesla isn't going to build one because of their perceived market. They want to give people a reason to spend a lot more for a model S. On the second question does the extra weight matter. I would agree not much. Although the roughly 600 lb lighter weight of the 250 mile range rwd lets it handle better on the same tires in dry conditions when pushed than the 350 mile awd model. That longer range model does accelerate better but the 250 mile range model's 5.3 second 0-60 is faster than I accelerate 95% of the time.

I am sure if the rav4 prime was designed from the bottom up to be a phev it would loose weight, but ... it wouldn't really matter much for most buyers. It would mainly help in off road performance.

The i3-rex is going to be discontinued as it was really made to comply to a wierd california regulation. Still buying it used as bob did made it a great value and he has driving cycles that make it worthwhile.

i3 was an experiment, but I expect in the next 5 years bmw will be selling a higher percentage of cars with plugs.

 

There's actually a trial in progress right now to evaluate this. AC Transit in Oakland, California, actually has at least 13 fuel cell buses, some of which have been running since 2005. Actually, to Lee Jay's point, they are Fuel Cell hybrids, with a large battery that gets charged by the fuel cell when the fuel cell power isn't needed to help propel the bus.

They've recently bought some electric buses (and, in fact, most future purchases will be electric), and are planning to do a bus-to-bus comparison of costs on the same bus routes.

I don't think the fuel cell buses are going to come out too well in this competition because apparently they already cost twice as much to run as an equivalent diesel bus

 

Like the Prius Prime, it was designed for the home market. Things are closer together in Europe, and being small has an advantage with the narrower roads. The i3 was also about showing off BMW's carbon fiber prowess as it was about being an EV.

CARB hobbled it, dangerously so. The most damaging thing they required was not letting the range extender come on until the battery was almost discharged. This left the car seriously underpowered in some situations. Unfortunately, BMW probably couldn't afford to have it be just a PHEV for the ZEV program.

As it is intended to be used, and how it works in Europe, is how I picture EREVs should be designed. I even thought the Volt would work this way when announced. The range extender isn't sized to provide full power to the car. This means a cheaper and smaller one is needed. When you know you'll be going beyond the car's EV range, you turn on the extender while there is still plenty of energy in the battery, and it steadily charges the battery.

I think the REx has been cancelled in Europe too. Batteries have simply gotten cheap enough to not warrant a range extender in a car like the i3. This also means carbon fiber is needed less for cutting weight. The i3 now has a larger battery option. I think the range is over 100 miles.

That's how all fuel cell vehicles work. The change in power output is also slow when decreasing. Call for less power, and the excess electricity made by the fuel cell while it is reducing output goes into the battery.

 

Bob, I believe that you are misinterpreting the post. It's not about affordability or efficiency. It's about practicality. If you run down the battery you are left with only a 600 CC engine to move the car. The assumption is that you may need more than that to reliably accelerate or to climb an incline. Running the ICE in parallel with the battery should give you the ability to use the battery at full power longer.

 

Didn't claim it was, but the public charging network is still in the early stages and non-Superchargers can be unreliable, and then some people are unwilling to make the ICE/hybrid to BEV jump directly.

But many owners have run into trouble. Enough to get a class action lawsuit against BMW going.

 

I agreed with everything you said up until this point. Using carbon fiber made sense when battery packs were big and expensive as they were for bmw in 2013 when it first came out. But unlike the EV1 BMW made a serious effort selling it, and is using the knowledge to make better plug-ins.

The i3 battery pack went from 22 kwh to 33 kwh to 42 kwh and this fit in the same space and likely cost bmw less for the big pack than the initial pack cost them. It did add weight, making the weight shaving of the original i3's carbon fiber not matter as much for range or acceleration. The i3 was made to look different like the gen 2 prius, but less expensive cars that look conventional like the tesla model 3 and chevy bolt have been outselling it. They needed to get rid of the carbon fiber cost.

This year bmw will start selling the ix3 with a big battery pack and steel unibody. It's an electrified version of their x3 small SUV. They aren't going to sell it in the US though, but will in Europe as well as china. BMW probably didn't think it would sell well in the US with the model Y and rav4 prime competing with it.

Next year the designed to be electric i4 and ix will coming out. The i4 will have a 80 kwh - 550 kg battery pack. It looks like the 3/4 series but supposedly was designed all the way to be electric. The price is only slightly higher than the outgoing i3. Between the 330e phev and the i4, bmw should be selling more 3 series sedans with a plug than without one. The ix is the size of the x5 but the suv also will be designed to be a bev. Car and driver does disparage the "angry squirrel" grill that both these have like the new 3 series. The ix does use a lot of carbon fiber to lower weight but it still will be a very heavy expensive SUV.

This is relevant to the hydrogen discussion because these are likely to appeal to the green sedan and suv enthusiast that doesn't want to buy a tesla or vw. That doesn't leave much room for fuel cells in either segment outside of korea and japan where all three manufacturers have trouble selling.

 

If it works well enough as is... why did you do the mods in post #107? I was interpreting the mod to run the ICE at 75% as being 75% remaining in the battery. What did I get wrong there?

Dan

 

I wasn't nit picking. It's just that it contradicted the line in the post above "With respect, we'll have to agree to disagree. There is no way 'charging' a battery from a vehicle ICE is efficient or affordable. With Prius Prime experience, it never made economic sense."

But your circumstances make sense. High prices at public charging points are the reason that I've only tried it once. It's less expensive to drive the last 10 miles on gasoline than it is to stop and charge my car for 45 minutes.

 

My Prius Prime experience is that it sometimes makes a lot of sense, and I do it occasionally. It makes sense when it helps to eliminate a warmup cycle or when it helps load the engine more heavily for higher engine efficiency.

I've averaged 72MPG round-trip using charge mode.

 

So much depends on location. I travel the I-5 north - south corridor frequently. Last Wednesday I drove to San Diego from the SF bay area. At the Tejon ranch there is a 24 station supercharger. At 1:25 pm there were 19 chargers in use. To be fair this is around 299 miles from San Francisco and 260 miles from San Jose. It's one of the most direct routes from Silicon Valley to The LA basin. It's also a few miles north of the notorious "Grapevine" pass through the mountain range north of Los Angeles. Today on our return trip at about 2:30 that same station was full. Again, to be fair, a few other stations visible from the freeway were lightly used.

 

Never used a supercharger outside of California, but with one exception have not visited one or passed one to be seen empty in my last 2 years with our Model 3 except in the wee hours of the morning when gas stations are also often empty or closed. Estimate unique location sample size of 40-60 including a few urban supercharging stations.

 

The first hydrogen bus in the Netherlands explodes on its first evening in depot, destroying it, another bus, and the depot.

 

Couldn't have been the hydrogen as the cause. We all know that it harmlessly dissipates rapidly with a leak.

 

And it does. Except when in an enclosed building.