Someone check my math.

If you have a 100 kWh battery and a 100 kW connection, you can charge in nominally one hour.

If you have a 100 kWh battery and want to charge in 5 minutes, you'll need a 1200 kW connection.

<sigh>  This probably isn't quite how it works.  It's out of my field of expertise.

It's nice that they can build a battery that can accept a charge that fast.  

Hook

Edited August 8, 2025Aug 8 by LHookins

You're not wrong, Larry. In a lab, maybe. Real world conditions, nah. Not yet, at least.

Why isn't more research being put into the Toyota Mirai experiment? From what I understand it is an electric vehicle but instead of the energy being supplied by batteries it uses a fuel cell that uses hydrogen to generate the energy needed. No charging times, no fire risks, simply very similar to how we currently refuel our ICE vehicles. Not to mention the absence of rare earth minerals and the associated recycling needed to make BEVs truly viable.

Marketing blurb from Toyota follows but take away the brand and the concept makes a lot of sense:

Overview of Toyota's Hydrogen Engine Technology

Toyota has been a pioneer in hydrogen technology, focusing on fuel cell vehicles and hydrogen combustion engines. Their commitment to hydrogen is part of a broader strategy to achieve carbon neutrality.

Hydrogen Fuel Cell Vehicles

• Toyota Mirai: The Mirai is Toyota's flagship hydrogen fuel cell vehicle. It generates electricity by combining hydrogen from its fuel tank with oxygen from the air, producing only water vapor as a by-product.

• Fueling Process: Hydrogen is pumped into carbon-fiber-reinforced tanks at specialized stations. The Mirai offers a range of about 400 miles on a full tank.

Hydrogen Combustion Engines

• Prototype Development: Toyota is also developing hydrogen combustion engines, such as the Corolla Cross Hydrogen Concept. This engine uses hydrogen instead of gasoline, leveraging existing internal combustion technology.

• Performance Enhancements: In motorsport applications, Toyota has tested hydrogen combustion engines, achieving significant improvements in power and efficiency.

Future Directions

• Multi-Pathway Strategy: Toyota believes in a diverse approach to zero-emission vehicles, combining hydrogen fuel cells, hydrogen combustion, and battery electric technologies to meet varying market needs.

• Infrastructure Investment: The company is investing in hydrogen production and refueling infrastructure to support the growth of hydrogen-powered vehicles.

Toyota's advancements in hydrogen technology aim to provide sustainable mobility solutions while reducing carbon emissions.

 

For the record, we have a 2020 RAV4 hybrid. Hasn't missed a beat since we bought it, 970+kms of range. Very happy with it.

Watashiwa  Nihonjin des when it comes to cars indeed.

3 hours ago, LHookins said:

If you have a 100 kWh battery and want to charge in 5 minutes, you'll need a 1200 kW connection.

1 hour ago, speedyTC said:

You're not wrong, Larry. In a lab, maybe. Real world conditions, nah. Not yet, at least.

My biggest question:  Where are you going to find a 1200 kW charger? 😄 

My understanding is that the cars don't charge linearly so I can't guess what the proper number should be.  I've heard that it takes the same amount to time to charge from 20 to 80 percent as it does from 80 to 100 percent.  Are the power requirements the same throughout the range?  Is that "5 minutes" for 0-100% or 20-80%?  

To get optimum recharge time, the battery has to be in a narrow temperature range, so you might need to heat or cool it depending on ambient temperature (taking even more time and power).  Doesn't charging heat the battery, and to get the 5 minute recharge time they had to make the battery able to withstand the heat generated by charging that fast?

Hydrogen is one of these things that sound good, but it seems to have something of a bad reputation.  I'm not sure why.

Hook

 

48 minutes ago, LHookins said:

Hydrogen is one of these things that sound good, but it seems to have something of a bad reputation.  I'm not sure why.

Combustibility concerns, perhaps? Quote from Wiki:

Hydrogen Combustibility

Flammability Characteristics

• Hydrogen is highly flammable and has a flammability range of 4% to 75% when mixed with air.
• Ignition can occur at a volumetric ratio of hydrogen to air as low as 4%.
• It possesses the highest rating of four on the NFPA 704 flammability scale.

Combustion Properties

• Hydrogen burns with a pale blue flame and produces only water as a byproduct, making it cleaner than conventional fuels.
• The energy required to ignite hydrogen is lower than that for many other fuels, meaning it can ignite easily from a small spark.

Safety Considerations

• Hydrogen is colorless, odorless, and tasteless, which makes leaks difficult to detect without proper sensors.
• In confined spaces, hydrogen can accumulate and reach flammable concentrations, posing explosion risks.
• Proper handling, storage, and safety protocols are essential to mitigate risks associated with hydrogen combustion.

Hydrogen's properties make it a potent fuel, but they also require careful management to ensure safety.

 

I'm certain that issues such as these can be overcome fairly easily once the decision (and funds) to go ahead with this tech are made available. Once again it all boils down to that bottom line and shareholders. 

4 hours ago, speedyTC said:

Why isn't more research being put into the Toyota Mirai experiment? From what I understand it is an electric vehicle but instead of the energy being supplied by batteries it uses a fuel cell that uses hydrogen to generate the energy needed.

 

Too many negatives with hydrogen and BEV is miles ahead. 96% of hydrogen is manufactured from fossil fuels, then you need complex filling stations that have cryogenically cooled hydrogen, of which there are a miniscule number, cryogenically cooled tanker vehicles to transport it around, specially designed storage tanks to store the hydrogen, as hydrogen molecules are so small they can leak with ease, then there's the volatility.

its the fact that BEV's are lightyears ahead in development with fewer drawbacks and that there are 2.7 million BEV chargers world-wide.

 

Edited August 8, 2025Aug 8 by martin-w

6 hours ago, LHookins said:

If you have a 100 kWh battery and want to charge in 5 minutes, you'll need a 1200 kW connection.

 

Yep, more juice is required for faster charging. There are a number of strategies used though. One of them is batteries. Many fast chargers have banks of batteries to manage the demand, taking the strain off the grid, if required. There are a number of other strategies, too. 

4 hours ago, martin-w said:

Many fast chargers have banks of batteries to manage the demand, taking the strain off the grid

Thanks, Martin.  That makes sense.

I'm trying to imagine the economics of building a fast charging station.  If someone is going to invest that much in a fast charger, how much more will a customer be paying for a 5 minute charge than for a "normal" one?

We already heard one story about a guy who stopped at a dealership on a trip to charge his car and got hit with a three figure bill.  Turns out the dealer never wanted to put in the charging station, had to pay something like $90k to get it installed, so he was setting really high prices.  I can't verify the accuracy of this story, but I can imagine this being normal for a 5 minute charge.

Hook

7 hours ago, speedyTC said:

Hydrogen is colorless, odorless, and tasteless, which makes leaks difficult to detect without proper sensors.

Simple enough to add "stinkum" like they do with stove gas. 🙂

 

Quote

"Stinkum" commonly refers to the odorant added to natural gas to make leaks detectable. Natural gas is naturally odorless, colorless, and tasteless. To ensure safety, companies add chemicals like mercaptans (like ethyl mercaptan) to give it a distinctive, rotten-egg smell, making leaks easily noticeable. This allows people to detect leaks before they become dangerous. 

Lubrication will still be needed between the piston rings and cylinder walls, so the exhaust gas won't quite be pure H2O, and there may be other contaminants.  Probably won't be enough to matter, not like gasoline exhaust.  If we could recapture the water, I wouldn't drink it.  😄 

Hook

10 hours ago, LHookins said:

Hydrogen is one of these things that sound good, but it seems to have something of a bad reputation.  I'm not sure why.

Hindenburg anyone?

1 hour ago, LHookins said:

Lubrication will still be needed between the piston rings and cylinder walls, so the exhaust gas won't quite be pure H2O, and there may be other contaminants.  Probably won't be enough to matter, not like gasoline exhaust.  If we could recapture the water, I wouldn't drink it.

I understand the Mirai is a fuel cell EV. Same technology as the one used in the Apollo capsules for generating both electricity and drinking water (although the astronauts had to deal with a bit of remaining H2 dissolved in the water). Lubrication would be needed if you're burning hydrogen using a conventional combustion engine cycle (the typical suck-squeeze-bang-blow cycle). Feasible, but you already mentioned some drawbacks.

Edited August 8, 2025Aug 8 by Luis Hernandez

4 hours ago, LHookins said:

I'm trying to imagine the economics of building a fast charging station.  If someone is going to invest that much in a fast charger, how much more will a customer be paying for a 5 minute charge than for a "normal" one?

 

It would have to be a reasonable price or nobody would use them.

In reality, the vast majority of BEV drivers, most of the time, charge slowly over night at home while they sleep.

Toyota hasn't given up on hydrogen, they are still investing in it for commercial vehicles but they have shifted more to EV's like everyone else.

 

Edited August 8, 2025Aug 8 by martin-w

This presentation is based on our Aussie reality but most, if not all, points made do apply to the rest of the world as well. It's a precis of the presentation and I have not yet found a link to the actual speech.

It's an interesting and balanced view of the state of the auto industry today by an engineer and journo and not some paid-for nobody.

"In reality, the vast majority of BEV drivers, most of the time, charge slowly over night at home while they sleep."
If you have a garage or driveway that allows a charging cable to be run from the premises. It's a first world assumption and has to be taken in context. Chances are that these folks live in suburbs and are relatively well off at least in the US and Australia. Europe, however, is an entirely different kettle of fish with space and population density being deciding factors.

Battery tech is still evolving and at a relatively slow pace. As Cadogan mentions in his presentation BEVs should be a part of the solution (along with other technologies including the current fossil fuel option) and not seen or relied upon as the miracle solution. I mentioned in my earlier post that funding is paramount to developing viable solutions. Of course there are problems with hydrogen, as there are with battery tech but funding and research can overcome them.

It has to be a holistic approach.

Edited August 9, 2025Aug 9 by speedyTC

4 hours ago, speedyTC said:

If you have a garage or driveway that allows a charging cable to be run from the premises. It's a first world assumption and has to be taken in context. Chances are that these folks live in suburbs and are relatively well off at least in the US and Australia. Europe, however, is an entirely different kettle of fish with space and population density being deciding factors.

 

As I said, most charge (currently) at home. When BEV adoption is even higher, and perhaps compulsory whether we like it or not, no offsteet parking is something that will need addressing. From what I've read, its something like 10% of car owners in the US and more like 30% in the UK have no off street parking. About the same as UK in Australia. Later in your post you talk about technological progress, funding and research, well, this is already applying to the ability to charge for those without off road charging. There are multiple technologies in development and some in use. Lampposts being used for chargers, charging points at the kerb etc. I saw an interesting system the other day, namely a channel across the path housing the cable with a flexible gasket filling the Channel, leading to a charging point flush with the kerb. 

 

4 hours ago, speedyTC said:

Battery tech is still evolving and at a relatively slow pace. 

 

Utterly wrong. 

"Electric vehicle (EV) battery technology is undergoing rapid advancements, with a focus on increased energy density, faster charging times, and improved safety. Solid-state batteries, silicon anodes, and lithium-sulfur batteries are among the emerging technologies showing promise for the future of EVs. "

We can elaborate on the above, if you like.

 

5 hours ago, speedyTC said:

Of course there are problems with hydrogen, as there are with battery tech but funding and research can overcome them.

 

No amount of funding or research is going to eliminate the requirement for as many hydrogen filling stations as we have petrol stations, now. Or the fact that the volatile hydrogen requires complex cryogenic cooling to be stored. Or the fact that the cryogenically cooled hydrogen would require transportation around various countries, to the filling stations, in a super cool liquid form. Or the fact that by the time the hydrogen gets in the tank its only 45% efficient.

There are currently 16 hydrogen filling stations in the UK, compared with 82,000 electric charging stations. 59 in the US and 70,000 electric charging stations. And those stations have multiple ports.

And as I said... 96%of hydrogen is derived from fossil fuels. 

As I said... BEV's are lightyears ahead in development. Hydrogen can't catch up for domestic cars but it still has a role for other forms of transport.

https://medium.com/enrique-dans/physics-wins-hydrogen-cars-lose-475974e343dc

On 8/7/2025 at 7:18 AM, Matthew Kane said:

Steve Jobs tried extremely hard to keep Apple products made in California but lost that initiative long ago.

For what it's worth, it looks like Apple manufacturing is coming back to the US.  It won't just be in California, though, far as I know.

I have an automatic blood pressure machine made in China.  My cardiologist was impressed with it.  I'm not surprised that Chinese can make some very good products.

Hook

7 hours ago, martin-w said:

And as I said... 96%of hydrogen is derived from fossil fuels.

And only 15% of American electricity is derived from wind (10%) and solar (5%).  Another 5% from hydro rounds out the renewables.

Fossil fuels comprise 60%, with 40% natural gas and 20% coal.  We get another 20% from nuclear.

These numbers are rounded (because I can), and come from:

https://www.eia.gov/tools/faqs/faq.php?id=427&t=3

I suppose we could run our cars on natural gas and cut out all the middlemen, which would be more efficient, but then what would we do with all the excess petroleum?  And what would quickly replace the electricity generation, which powers your heat and air conditioning and AI datacenters?  Also, we'd run out of natural gas at some point.

Maybe we could just keep things as they are now, and rely on innovation to keep increasing efficiency of petroleum based cars, which has worked fairly well so far.  All the excess CO2 being produced will increase crop yields and make forests grow faster and spread out.  Maybe trees will start growing in Iceland again, and the UK can revive it's wine industry.

😁

Or, I guess we can all buy Chinese EVs and just live with the fact that they are powered 60% by fossil fuels.

<ahem>  Sorry 'bout that. 🙂 

Hook

Not pushing one form of propulsion over another, Martin. Just saying that much more is needed to be done but in an organised and scientific way rather than be driven by profit and lobbies as both fossil fuel and electric proponents tend to do.