[Wrestling with a springy hose clamp]

In a production line they often come fitted with a plastic clip with a loop in that you pull off, similar to your nut concept. Not unsual to hear them called grenade clips.

https://www.mubea.com/sites/default/files/styles/max_500/public/2019-05/06_raumspar_federbandschelle_mit_handy-clip.jpg?itok=0DAg2_-W

[Where did you get yours from]

My surname has always got shortened to Pants since primary school. A conversation at uni ended up with me announcing 'Superpants to the rescue', ever since then it has been a nickname.

[Brake cleaner sprayer]

I've got the cheaper wurth one- had it about 6 months and so far so good!

 

[Shed Cladding]

I've now built three sheds where I have used fencing feather edge boards. They are fairly reasonably priced if bought from a specialist fencing supplier- The one I use is quoting £1.69 per board at 1.8m x 22mm x 125mm.  With a 25mm overlap that comes out at less that £10/sqm. If you go this route I would recommend using a membrane behind it.

This the latest shed project during the build

[Inter leaf plastic shim material]

If it's thin a wad punch works pretty well- No snagging then!

 

[Her Majesty Queen Elizabeth II]

My only royal story involves Land Rover products:

About 15 years ago Mark and I were travelling down to South Wales to meet some of the forum members for an off-roading weekend. We were in Mark's Disco that he had at the time, with him driving as we headed down the M4. As we came close to the windsor junction we noticed two identical Range Rovers in the nearside lane in close successsion, as we slowly passed them I looked out the window casually and had to do a double take as I realised the women in the rear of one of these vehicles looking closely at us was the Queen.

We joked at the time about what she was saying to the others in the car- maybe 'Oh look one's subjects are going orrffff roading"

RIP Ma'am

[Body work]

Slighty more difficult would be to fill using solid rivets if you can get to both sides. These can then be filled flat and then painted- The way aircraft are put together (all though they may mill them flat).

 

[Open sided grommets]

Index marine do a range of glands for larger connectors- useful on boats for aerial connections etc- I used them on miltary vehicles in the past succesfully.

Index marine

[Soldering station recommendations]

Watching this with interest- I've been contemplating options soledering myself. I had a job where I needed to de-solder a load of 2.5sqmm wire. My 15W Antex was way underpowered, and a cheapy 50W iron had a terrible tip that refused to tin. In the past I had an oppurtuniy to borrow a metcal from work whenever I needed a good iron, but no longer work at that company so not an option. The secondhand Weller stations seem overpriced for secondhand to me. Might well therefore try the atten one from Maplin unless you might have a metcal available @Ed Poore?

[JLR Q2 Losses]

8 hours ago, elbekko said:

Answers to the points below:

Couple of thoughts on that post (and yes, I am a big proponent of hydrogen fuel cell vehicles):

• It doesn't have to come from fossil fuels. Just like electricity can be cheaply produced from fossil fuels, doesn't mean that's always going to be the case, so I'd say that's a pretty disingenuous argument.

  • I agree that Hydrogen does not have to be extracted from fossil fuels, there are technically viable alternatives, however as it stands today the vast majority is extracted from them and therefore right now battery electric vehicles are considerably greener, (having a lower carbon footprint). If left purely to the free market, I cannot see how we would increase the proportion of green hydrogen as we have a combination of vested interests (oil companies) and higher costs for the green production. The only way I can see the proportion of green hydrogen increasing significantly is If our governments were to work together and bring in legislation to require it, or there were overwhelmingly beneficial incentives (noting that this has been what kick-started the big solar and wind power schemes).

  •  

• Generation inefficiency really doesn't matter because it's easily transportable. Nobody says you have to use local (excess or not) power. There are vast swathes of the earth with lots of water and nearly free power: solar, wind, geothermal. Line transmission makes these nonviable to connect to the grid, but hydrogen you can just chuck on a boat.

  •  I agree that in areas where green electricity production is easier and there is not local demand for the electricity (North Africa for instance), Hydrogen production could be a way of storing and transporting that energy. Bear in mind that the volumetric energy density is significantly lower than that for liquid fuels and therefore to move the same amount of energy, larger tanker volumes would be needed for Hydrogen. The efficiency of the conversion is still important though as it would translate to the installation cost of the project.

    I believe that the best use for this hydrogen is to offset that used in the chemical industry (fertiliser production etc) as this would offset the need for the use of hydrogen obtain from fossil fuels where it is essential to use hydrogen for its chemical properties.

• All the downsides you list for fuel cells, except for the purity of the hydrogen, are valid for BEVs too. Lithium-Ion batteries need a bunch of thermal management, both heating and cooling.

  • It’s true that batteries need thermal management, and therefore the battery used in a FCEV will also need this. What a fuel cell brings is additional ‘Balance of Plant’. This is not a technical barrier in any way, however it is very easy to miss the complexity of a fuel cell system if you only focus on the fuel cell stack.

You also handily didn't list the upsides of hydrogen fuel cell vehicles:

• Weight. Weight is a huge factor in efficiency, and being able to avoid having a 1 tonne battery is big.

  • See notes under last point

• There is already a bunch of hydrogen infrastructure around. Pipelines already run across Belgium, and I wouldn't be surprised if that's already the case in other countries too:

  • I didn’t mention infrastructure particularly as I believe it is ‘swings and roundabouts’ when you compare it with electricity infrastructure. I don’t see there being many major technical challenges in the Hydrogen infrastructure, as illustrated by your example of existing pipelines. BEVs will need grid, and especially local distribution upgrades, but this can mostly be staggered over time. This is likely to be a more distributed task though. Hydrogen infrastructure arguably needs bigger up-front investment (pipelines can’t easily be built piecemeal). Either way we will have some technical challenges and some big investments to be made.

• Refuelling time remains a big one. Charging a huge battery quickly is just limited by the laws of physics. Charging a 150 kWh battery in 5 minutes with a 600V charger would take 3000A continuous (!). Even at 10kV that's still 180A. Totally ignoring here the massive amount of heat the battery would need to dissipate while charging.

  • In the US (I have never found directly equivalent UK figures, but our mean mileage is less), 97% of travel (by road) is below 150 miles per day (when vehicle is in use). For BEVs, it is expected that the vast majority of charging will be carried out at home, typically overnight and so the refuelling time is not as big an issue as you would first expect. There will need to be fast chargers on the motorway and trunk road network to service those vehicles that genuinely do need to do high mileage, but again whilst this will need investment, either FCEV or BEV would need similar numbers of service station upgrades.

    On the weight point, if the mileage needed isn’t that high, then batteries don’t need to be heavy- the vast majority for passenger cars won’t be anything like 1 tonne, more like the 3-400kgof a leaf. At this, the weight saving advantage starts falling away (struggling to find mass of FCEV parts), but it is still there.

    This leaves some special applications where Hydrogen does make more sense because of the refuelling time or convieniece- very long distance vehicles, vehicles operating away from practical charging infrastructure (military/ agriculture) or ones where the machine does not sit idle overnight (mining etc).

 

[JLR Q2 Losses]

For the equivalency:

1kg approx. equivalent to 2.8kg petrol (approximately 1 gallon)

https://afdc.energy.gov/fuels/hydrogen_basics.html

[JLR Q2 Losses]

Good points- I'll have to look out the energy density equivalents.

On the return to gas, you are right that getting it to a gas isn't the challenge, what I should have added there is that the gas would then need compressing to a level which it could be transferred to the vehicle- again adding complexity and another (energy efficiency) loss.

 

[JLR Q2 Losses]

I've recently seen a couple of press releases that may be of interest. The first is a serious attempt at Lithium carbonate extraction in the UK, with a pilot plant running:

https://britishlithium.co.uk/first-lithium-carbonate-produced/

It's worth noting that the vast bulk of Lithium ion batteries don't use metallic Lithium, and compounds such as carbonates may be used directly.

 

Secondly Veolia, one of the biggest waste management/ recycling companies has announce the construction of a UK dismantling/ recycling plant:

https://www.veolia.co.uk/press-releases/veolia-announces-its-first-electric-vehicle-battery-recycling-plant-uk

[JLR Q2 Losses]

As I promised, I've finally written up my thoughts and observations on Hydrogen use as a fuel. Apologies it's taken ages to get round to this- Christmas kind of got in the way!

As an opening point, Fuel Cell Electric Vehicles (FCEV)s are Battery Electric Vehicles with additional components, and a reduced sized battery pack. The battery is necessary to start the fuel cell stack and to take account of the short duration variations in power needed by a vehicle- a finite time exists to ramp up power from the fuel cell stack as it's output is related to the gas flow in, both H2 and air.

In my opinion, Hydrogen is not a viable or sensible solution for personal transportation, or for many of the other areas where we currently use liquid fuels (petrol, diesel, fuel oils) or natural gas. There are use cases where it does make some sense, but I see these as only a very small proportion of the total. There is a good analogy of Hydrogen being touted as the 'Swiss Army Knife' of solutions. Much like the Swiss Army Knife it COULD be used as an energy carrier for lots of these tasks, but it probably SHOULDN'T for most of them as there is a better option available. See the link for an illustration;

https://www.linkedin.com/pulse/clean-hydrogen-ladder-v40-michael-liebreich/

There are a significant number of challenges which have to be overcome with Hydrogen;

Efficiency & Green Hydrogen

Many hydrogen proponents start the conversation with something along the lines of "IF we use excess electricity to hydrolyse water then the solution is green". Whilst this is true, the electrolysis of water is highly inefficient- Peak efficiency is around 50%, and due to the electrochemistry of the reaction can't get significantly better than this. The conversion efficiency in the fuel cell back to electricity is in the range of 40-60% if a Proton Exchange Membrane (PEM) cell is used (currently the only practical cell for automotive use).

If we ignore all the other losses in managing and distributing the gas, the best efficiency from electricity in to useful power at the wheel is around 25%. Once the distribution and any other losses are included, the efficiency will be less than 20%

If we compare this with an BEV- transmission and distribution losses will be less than 10% and the efficiency of charging batteries and then delivering power from battery, through inverter, motor and drivetrain to wheel will be around 90%, we will see an overall efficiency of around 80%. (Numbers are all approximate due to difficulty of pulling accurate figures together that compare directly- there are studies that attempt this though).

If we use green hydrogen, and the only factor in play is commercial, this efficiency difference alone would be enough to stop FCEVs in their tracks as they would be some 4-5x the cost to run per mile than a BEV! With the exception of very limited uses where paying a premium for increased range (and/or reduced fuelling/ charging) would be justifiable, for example some military vehicles or agricultural vehicles, this cost difference would be prohibitive.

Greenwashing

Whilst we could generate Hydrogen from green electricity, more than 95% of current production comes from 'reforming' of methane, and so as of today, FCEVs are not green. Worse still, there is a strong lobby from the oil companies to keep using petrochemicals as feedstocks for hydrogen. Understandably they want to keep using their reserves as we reduce our dependence on other liquid fuels. Until recently this lobbying has been at a low level, but since COP26 it is becoming more visible. I have seen Youtube ads, and recently the Sunday Times magazine carried a double page advert from Aramco advocating hydrogen related to this campaign:

https://www.aramco.com/en/campaigns/powered-by-how/blue-hydrogen

I can't see a solution where the green hydrogen would be economically viable against Hydrogen from the oil companies (due to the inefficiencies discussed above), and they have a second advantage- that they already own a distribution network that could be transitioned to supply of Hydrogen.

Thirdly there are unfair comparisons being made- if you compare Hydrogen against existing fuels (petrol/ diesel), as is commonly done, you get a very different picture to comparing against electricity

Up until now, I have illustrated the best case scenario for green Hydrogen- i.e. made with excess green electricity. Unfortunately we are not in a position of having significant excess green electricity supplies, we currently use it all in offsetting our generation by other fuels. It will be another 20 or more years before we truly do have excess green electricity that we could seriously consider using for Hydrogen production (generalisation!- We may see limited scale peak levelling schemes in a shorter timescale- that would be a whole other discussion)

https://gridwatch.co.uk/

There are also a number of technical challenges to also be addressed;

Storage and distribution

Storage of hydrogen and it's distribution is difficult. It can either be moved as a compressed gas, or as a liquid. Both have significant challenges. Hydrogen is a gas with a very low density, and so to compress it to usable levels requires a lot of energy, even when compressed heavily, it's density remains low. There are absorption methods that help increase the gas that can be stored in a cylinder, but even with implementing these we end up with sizeable storage tanks.

If we look at commercial cylinders, a 50 litre nominal cylinder only holds 1kg of gas!!!

https://specialty.airliquide.co.uk/product/hydrogen-5-0-501/?industry=oil-and-gas

Whilst a lot can be done to reduce this mass, it nevertheless remains a significant part of the vehicle mass, less than batteries but not insignificant like a petrol tank.

As a liquid, the fill density will be much higher, but then you have to maintain the temperature below -253C, put a lot of energy in to liquify, and live with constant losses with the gas boiling off (again detracting from efficiency). I'm not aware of any practical applications on vehicle using liquid fuel, so you would also have the complexity of converting from a liquid and back to gas at a fuelling station.

Technical Complexity

It's easy to think of just the fuel cell stack itself, which in reality is quite simple, but there is a lot of complexity around this;

Water management is needed to both stop the membranes fully drying out as they warm up, but also remove the generated excess water safely (without causing isolation issues when running at 100s volts).

Temperature needs control- freezing of the water would also be detrimental as would overheating.

Air is needed in large volumes, so powerful external blowers are needed. This comes with air management and filtration needed to avoid bringing in dust or particulate contamination.

A level of cell balancing and management is needed, similar to that used with Lithium ion cells.

Pipework and valves are needed for the H2 gas supply.

All of this needs careful control to balance the gas flow with the electrical load.

There are now well integrated solutions to much of this, but there is a level of complexity to these systems that is often not thought about.

Rare Metals

Whilst fuel cells do not use rare earth metals, the PEM type used in vehicles do however use platinum, another metal where supply is limited and expensive.

Life & poisoning

As fuel cells are reacting two chemicals together with aid of a catalyst, there are mechanisms for the catalyst to be 'poisoned'. The presence of a number of chemicals particularly Sulphur containing ones, such as Hydrogen Sulphide and Sulphur Dioxide as well as Carbon Monoxide and Sodium Chloride can reduce the effectiveness of the cell significantly, reducing it's life.

https://www.technology.matthey.com/article/57/4/259-271/

https://www.hydrogen.energy.gov/pdfs/progress05/vii_i_4_uribe.pdf

This means the hydrogen used must be very pure, but even with this in place there is a very real risk of atmospheric pollutants making their way into the cell mixed in with the feed air, and subsequently shortened lifetimes.

Other uses

In my opinion, the best uses for any hydrogen generated from electricity in schemes using excess electricity is in displacing fossil derived hydrogen as chemical feedstocks in industrial processes such as the manufacture of fertilisers. Whilst there would still be an efficiency hit in the electrolyser, we don't get the second hit when converted back to electricity. Secondly these processes need hydrogen, there is no other viable alternative, and so eliminating the use of methane would bring additional benefits- no carbon capture needed for example.

Much of what I have written has been summarised as a graphic known as the 'hydrogen ladder' which can be found at the first link above. This neatly ranks the uses of hydrogen from 'Unavoidable' there is a clear benefit (such as the chemical feedstocks above), down to where they are 'Uncompetitive'. Overall I think this is a well thought out and presented graphic, I'm sure there are some use that could change position a little, but I believe the overall ranking is sound.

[JLR Q2 Losses]

Thanks everyone!

5 hours ago, missingsid said:

Bah your biased!!!

 

 

 

 

Actually good info and eager to see the next installment.

Yup- I will be!!!!

Having had the oppurtunity to work on such a wide range of vehicles and system types has exposed me to the real engineering challanges and hopefully that means I have been able to pick up useful information to share!

[JLR Q2 Losses]

Thanks Guys- No problem- might be a few days before hydrogen.

[JLR Q2 Losses]

I have been meaning to write a proper reply to some of these EV questions that crop up from time to time but hadn't got round to it before, but finally got round to it! 
Full disclosure- I have been working as an Engineer in the EV field since 2008 and have contributed to a really wide range of projects from the first EV homologated in Europe, to vehicles ranging from motorbikes to trains, on BEVs, hybrids and fuel cells, and from sedate last mile travel to Formula E. I'm now working for a supplier of cutting-edge EV motors and inverters.

Part 1 EVs

Batteries
Most people don't realise li-ion is a very broad term; it covers around 20 distinct battery chemistries. The cells used in EVs are NOT the same as those used in laptops and mobile devices (they are more closely related to power tool cells). The ones chosen for EVs (e.g. NMC) are typically those which are safer and have superior cycle and calendar life. Compare this with mobile phones where the energy density is the prime driver to make the product smaller and lighter, but this can be traded off against life.

Resale values
Whilst this was a barrier in the early days of production, now we have 10s of thousands of EVs on the road, there is good evidence that the batteries are lasting the design life of the vehicle with only minor levels of range reduction. Resale values in EVs, on average are in fact higher at present than ICE, retaining 48.9% of their value after three years or 36,000 miles compared to 40% for ICE. Whilst this may be buoyed slightly by current availability issues with new cars, the picture here looks very good.
https://www.carwow.co.uk/blog/do-electric-cars-depreciate#gref

Cost
In my opinion we don't need any breakthroughs in fundamental battery technology for personal transportation to reach mass EV adoption- the technical solutions are all mature enough today. Although there will continue to be developments as efficiency (as measured by range vs cost) will become a dominant factor for consumers in the next five years as every car manufacturer introduces a wider selection of vehicles into their range. The major barrier is still cost- this is slowly reducing and is less of a problem the more expensive the vehicle, hence the greater initial adoption at the premium end of the market, but any breakthroughs that reduce battery cost will have significant effects. This is why solid-state cells are of such interest as they offer big potential cost savings as the number of process steps in manufacturing a cell are reduced.

For a good background on batteries, I would highly recommend this document:
https://warwick.ac.uk/fac/sci/wmg/business/automotive_batteries_101_wmg-apc.pdf
I use this when training new staff at work.

Lifecycle
The Hummer vs Prius lifecycle analysis, and variations on a theme including the Jeep wrangler have been around since 2007 when a marketing company publicised a 'report' on a lifecycle analysis. This was debunked shortly after as it had made non-comparable assumptions between the two cars. Full details here in a contemporary report:
https://pacinst.org/wp-content/uploads/2013/02/hummer_vs_prius3.pdf

The reality is that all car makers do carry out Lifecycle analysis on EVs and whilst there is some variation in their conclusions, they do show significant benefit over ICE vehicles in lifecycle cost. This is improving continuously as the mix of electricity on the grid improves, the efficiency of the vehicle improves, the mass goes down and manufacturing processes are improved.

In some areas, there are significant benefits over ICEs, transmissions become significantly similar- we no longer need massively complex automatic transmissions- a simple reduction gear box, or at most two-speed gearbox is required. The motor is hugely simpler than an engine. The aftertreatment needed for the exhaust, which is now highly complex, also goes, and we therefore remove the need for platinum in this area. We do have to add an inverter, but these are becoming commoditised and simpler. The only major difference is really around the battery.

The industry is working hard both to reduce the need for rare earth metals in cells and to make sure the whole supply chain is as green and ethical as possible, including the recycling, but I am fully admit this is the area where there is furthest to go. 

Having said that it is very easy to overlook the ills of the petrochemical industry- they are both normalised now and socialised across the population- Some easy examples would be the countless wars fought where oil or gas was at least part of the reason (Gulf war, Russia's annexation of Crimea), the environmental disasters (Exxon Valdez, Niger Delta, Deepwater Horizon) and the massive energy costs of refining oil (90% efficiency = approx. 5kWh/ gallon).
https://publications.anl.gov/anlpubs/2011/01/69026.pdfWhen you look at all these other social downsides, fixing the problem of ethical mining of a relatively modest amount of lithium and rare earth metals looks like a much easier 'problem' to fix. Personally I would like to see us try and become less reliant on imports of suspect provenance when we have at least Lithium and Cobalt here in the UK and could invest in world class processing to go with it.
https://www2.bgs.ac.uk/mineralsuk/statistics/rawMaterialsForALowCarbonFuture.html#RMP
https://www2.bgs.ac.uk/mineralsuk/download/briefing_papers/batteryRawMaterial.pdf

Charging
The industry has been pretty good at getting a common charging port and protocol implemented- this started out back in 2009 when Mennekes, one of the connector manufacturers proposed an interface- we used it on the Smart ED as the first customer, and this soon became adopted as the low current (up to 32A, 3 phase) solution. The average daily mileage in the UK is around 25 miles (and this has only changed by relatively small amount over the preceding 40 years, so can be seen as relatively stable). For most people, topping this up on a domestic charge point would take no more than a few hours, and the standard charge port is adequate for average daily needs.

The high-power DC charging situation is a little more complicated, but for new cars in Europe there is a widely adopted standard- it only becomes a challenge with the very fastest charging for nominal 800V vehicles where the charge points are currently limited, but this really only is a concern for anyone who can afford a Ferrari or similar!

The use of fast chargers is largely limited to the fast trunk network, therefore whilst a lot of investment will be needed for these, they are relatively limited in number and so the challenges of bringing in a supply reasonably practical. The bulk of the charging for personal vehicles is likely to be at home or local at lower rates, and then the biggest challenge is the local grid infrastructure update. This will be needed anyway in the coming decades as we are reliant on cabling dating back to the 1930s in some cases. Interestingly in this area some of the electricity companies are installing telematics at substations and joints in networks using current sensors which then enable proactive replacement on the most heavily stressed areas of the grid first (as people connect EVs, heat-pumps and solar generation).

For part two i'll cover Hydrogen
 

[Ideas Welcome]

Super Sculpey- Widely used in making props, puppets and the such like.

I'd usually buy this sort of thing from Tiranti

https://www.tiranti.co.uk/Products/003d0011001a00100002

 

[Thoughts on wiring repairs]

The third option would be to put a coonector in where you make the splice- It will obviously take up space but might offer you some easier flexability to upgrade.

In this instance i would however probably solder, but it would need to be sleeved with adhesive lined heatshrink and well supported to ensure that vibration won't affect the joint.

 

[Secret Life of Components]

His career is very varied- If you get a chance to visit, the arcades in Southwold and London are well worth a visit.

My first exposure was when I was about 5, although I never relaised it until a couple of years ago. He illustrated a book 'making a car' which was one of my favourites. It was only when it turned up when clearing out books from my parents loft. I distinctly remember being fascinated by a page about putting the instrument panel together- which is one of the things i've ended up doing in my professional career.

Definately have a delve on his website, and if you can lay your hands on a copy, his book 'Almost Everything There is to Know' is fantastic. Amazon link Hadn't realised how much it is going for now!

 

[Secret Life of Components]

Indeed- Some great things happening!!!

 

[Secret Life of Components]

I'm sure that many members here have good memories of Tim Hunkin and his series 'Secret Life of Machines'. Personally Tim has been an inspiration, definately shaping my attitude to engineering, and as a result of an article he wrote I ended up working in the Exploratorium in San Fransisco.

Tim is releasing a new series, starting next week on youtube 'The Secret Life of Components'. If anyone hasn't seen the original machines series- I'd recommenc checking them out too.

SLOC

[Where do you buy metal stock ?]

When I was in Surrey, a lot of what I needed came from the local scrapyards, which meant it was cheap!

More recently I've used Ringwood Precision who have an online store. Similar to ebay prices, but I have always had good service.

[Off Road Engineering- Youtube]

No problem!

I worked with Ianto very early on in his career, probably more than 15 years ago! There is definately a lot of 'opinion' out there in youtubeland, so I thought it was well worth sharing here to cut through some of the rubbish!!

 

[Off Road Engineering- Youtube]

A friend of mine from my days working at Pinzgauer, who then went on to lecturing At Harpur Adams has recently started a new Youtube channel, covering engineering of off road vehicles. Hopefully this might be of some use to the members here.

Youtube Off Road Engineering