Electric vehicles-Conversions

[CitroJim]

LDV built a great range of vehicles, builder's trucks, school and police minibuses, ambulances etc.

I drove a very late LDV Van made just before it all folded... Best van I've ever driven. Knocked a lot of spots off the Trannies and Merc. Sprinters of the time...

[Mandrake]

Wife has just told me that Glasgow City Council and all it's arms length companies have had EV for a few years now. She drives a diesel VW van all kitted out in Police colours. EV's she say have basically been a flop. They tried them and they have now sat around or been sold. They need vehicles that can drive 24hrs a day...........non stop.

Sounds like somebody in the council didn't think through the use case of the vehicle before buying them! Do they truly need to run every vehicle 24 hours a day ? If so electric is clearly not suitable for that. If it's just an 8-10 hour day that they need to do without stopping to charge then current EV's may not have the range for that, but that will change in the future.

By the way the two Ion's I drove one of which I bought were both from the Inverclyde council - and according to the guy I was talking to they replaced their 5 year old Ion's with, yep, brand new Ion's.... so I don't know what their use case was but it seemed to be useful to them in some way!

She also said that there are loads of charge points around Glasgow which mostly sit unused day and night.

As an experiment I drove into Glasgow today and parked in Cambridge Street car park - there are 8 EV charging spots, 4 were taken when I arrived at 8:20, checking online now at 10:20 I can see that all 8 are currently in use! As my car is probably topped up by now (it was only down to 70% so I didn't really need to charge at all) I'm going to be a good citizen and walk down at lunch time to move it to a standard parking spot to free up a charger! I didn't anticipate all 8 slots filling up so quickly...

You actually don't want high utilisation of EV charging spots - because if people find they are always full when they arrive they can't use them. Something like 50% utilisation is what you want - enough for the installations to be worthwhile, but not so much that you can never get into one when you need it and have a reasonably good chance of finding an available charging spot. I know if I thought the spaces would all be tied up most of the time it would put me right off any journey where I might need to charge away from home.

[Mandrake]

So I went back to move my car and sure enough all the EV spaces were full:



The ones that were there when I first arrived were all still there. From left to right we have a Zoe, Kia Soul, Mitsubishi Outlander, BMW i3 (?), my Ion, and then three more Zoe's!

So apparently Zoe's are popular around here, at least among people that like to or need to get free charging.

[CitroJim]

Never realised the Kia Soul was an EV Simon... One of my neighbours has one - ugly brutes aren't they - the Soul not my neighbours - and I'm sure hers is an ICE powered-one...

Or it is just an ICE one wrongly parked?

[Mandrake]

Yes it is an ugly brute.

There may well be an ICE version of the Kia Soul as well (I think there may be) but the one I saw was definitely an EV and was plugged in.

The Outlander and BMW i3 are both plug in hybrids not pure EV's, however I think the Soul is a pure BEV, as are the Zoe and Ion of course.

[CitroJim]

I must go and check now Simon

[demag]

The Soul looks good with some innovative ideas and a good range. I see Citroen have announced an electric Berlingo with a 100 mile range. Too late to the party me thinks and let's hope they've sorted the turbo problem.

Sent from my Wileyfox Swift using Tapatalk

[Mandrake]

The Soul looks good with some innovative ideas and a good range. I see Citroen have announced an electric Berlingo with a 100 mile range. Too late to the party me thinks and let's hope they've sorted the turbo problem.

Late to the party indeed. And a 24kWh battery in a mid sized van will not give 100 mile range in the real world. Expect about 70-80 if you're lucky. If it doesn't use a heat pump for the heater knock another 10-15 miles off that in the winter. Already obsolete at launch...

I was also reading that this is just the Citroen version of the BEV Peugeot Partner which has been out for about a year already!!

[Mandrake]

Interesting article on the Tesla battery pack, which although based on the standard Panasonic 18650 cylindrical cell format, is using a custom chemistry that has much greater cycle life than regular 18650 cells:

https://electrek.co/2017/03/22/tesla-ba ... breakdown/

Quite a startling difference - the standard version of the cell is down to about 70% of original capacity after only 500 cycles, this is also typical of the batteries found in cell phones etc. The Tesla version of the cell in the same form factor holds 95% of its capacity after 500 cycles and about 85% after 3000 cycles!

To put this into perspective, if we consider a mid-range Tesla that can do 230 miles on a charge, 500 cycles is 115,000 miles with a negligible 5% loss in range, and 3000 cycles is 690,000 miles with a noticeable but still acceptable 15% loss in range - which almost certainly will outlast the mechanical life of the car! By comparison, my Ion battery has already lost 17% of its raw capacity in 28,000 miles. (Although the range isn't impacted yet as the lost capacity is in the "hidden" spare capacity that is not normally used)

Then add the advanced liquid heating/cooling system for the cells in the pack that keeps the cell temperatures in the Goldilocks range so they don't run too cold or get overheated, and you have the recipe for a very long lasting battery.

I think 10 years from now history will show that the Tesla battery packs vastly outlasted anything else on the market and that fears of capacity loss with mileage were unfounded, and this may cause them to hold their value a lot better than other EV's with less sophisticated battery systems like the early 1st gen Leaf with its notoriously high capacity loss with mileage. If you can buy a Tesla with a largely aluminium rust free body at 10 years old and 100k miles and still have 95% of the original battery range why wouldn't you ?

[CitroJim]

Interesting stuff Simon, now correct me if I'm wrong but isn't an 18650 cell about the size of an AA cell? If so then I'm utterly staggered they form the basis of a traction battery...

Presumably wired in series-parallel to obtain the requisite voltage/capacity?

[Mandrake]

It's a bit bigger than a AA, its 65mm long and 18mm in diameter, hence the number. Typical capacity is around 2.6Ah:

https://www.sparkfun.com/products/12895

The Tesla battery pack is an interesting configuration, and different to most other EV's.

For example the pack on the Ion consists of 88 large rectangular 3.7v 46Ah cells all in series, broken down into groups of 4 or 8 cells in series with an ECU to monitor and balance each group of 4 or 8. But overall, every cell in the entire pack is in series, so a single failed open circuit cell would take the whole pack out of action.

The Tesla pack has a parallel series configuration. I don't remember the exact numbers off hand so these are approximate - there are about 16 modules connected in series to get the full pack voltage, each module has its own battery management system. Within the module you have a series parallel configuration. A group of about 8 individual cells are connected directly in parallel with each other via fused link wires that are spot welded to the bus bars. This means every single cell has its own individual fuse in event of a fault. Each group of 8 parallel cells acts as one bigger cell from the point of view of battery management, and are inherently balanced between each other as the terminal voltages are identical in a parallel group. Within a module there are several (6 ?) such groups of paralleled cells connected in series with each other to achieve an overall module voltage of about 24 volts.

You can see some pictures here, and you can see the little welded fuse wires on each individual cell in the 3rd picture:

http://qnovo.blogspot.co.uk/2014/11/31.html

Very clever system - for a start, a cell that fails in such a way to blow the fuse (internal short) would burn out its own little fuse wire and the other 7 cells of that parallel group would keep functioning albeit at slightly reduced capacity. If a single cell fails in a fully series configuration like the Ion the whole pack stops working!

As for total number of cells, in the 60kWh pack there are roughly 6,900 cells.

[RichardW]

If you can buy a Tesla with a largely aluminium rust free body at 10 years old and 100k miles and still have 95% of the original battery range why wouldn't you ?

No room in the back for bikes / building crap / camping gear

[Mandrake]

If you can buy a Tesla with a largely aluminium rust free body at 10 years old and 100k miles and still have 95% of the original battery range why wouldn't you ?

No room in the back for bikes / building crap / camping gear

Uh,

Have you looked in the boot of a Model S ? It has the biggest boot of any hatchback I've ever seen. It's simply massive. And don't forget you have a decent sized boot under the front bonnet as well.

Or if you need more you could go for the Model X which is a crossover SUV. Lack of boot space is not something you would accuse the Model S/X of.

[Peter.N.]

This thread is becoming more and more interesting, if all the links are factual I might be able to afford one that still works in 10 years time.

Peter

[white exec]

It is extraordinary that the battery packs consist of this huge number of very small cells, almost like filling the space with rack upon rack of double-length C-size - although in a different class of performance. Does mean, though, that the physical/chemical/electrical strain on any one cell is massively reduced, to a level where they stand a chance of surviving.