Electric cars a step nearer mainstream?

In message , at 10:35:19 on Fri, 6 Jun 2008, The Natural Philosopher remarked:

Whenever I see one on a bonnet.

So they don't use the same technology as my laptop batteries?

In message , at 10:32:26 on Fri, 6 Jun 2008, The Natural Philosopher remarked:

So does a Jag.

Doesn't seem to worry manufacturers today. Heck, they can't even make two models where the *wheels* are interchangeable, let alone spares like the exhaust pipe.

Agreed, this is were regulation comes in, governments insist that for type approval cars must have swappable motive power packs and that they are of a standard interface and a range of standard sizes. It strikes me as a much more sensible option than wiring carparks with all the expense, maintenace, charging (money) that they would involve.

A snag I can see is the space required to store/charge enough batteries for swapping at a busy supermarket "filling" station. At a guess I suspect your looking at 200 or so "fillups"/hour at such a place for maybe 10 hours so thats space required for around 2000 batteries/day (+/- a lot!). These things aren't small or lightweight...

In message , at 09:43:21 on Fri,

Just in case you misunderstood, these were the same sort of rechargeables that people like Sanyo make for most of the laptop manufacturers today.

The advantage would have been the ability to go into a shop and get a replacement from a limited number of form factors. Most seem to be 11.1 volts, and roughly multiples of 500mAH, after all.

They have pulled the tram line overhead wires down around brum before now.

Its a shame they didn't kill themselves.

I have no worries about idiots like that killing themselves, we take far too many precautions to stop it.

Roland Perry gurgled happily, sounding much like they were saying:

Oh, I'm sure - and I can certainly see the benefits.

It's just the delicious irony of "universal" batteries that don't actually fit _anything_...

"Dave Liquorice" gurgled happily, sounding much like they were saying:

There's standard-standards and non-standard-standards.

Automotive diagnostics are a fine example. The US government required the OBD standard about a decade ago. The EU modified that to require the EOBD standard a few years ago.

But those standards only do the very basic diagnostics - if you use the manufacturer's own tools, you can do far, far more.

Same'll happen with the battery packs. There's the standard packs, which interchange happily into anything and give you mebbe 75% performance/ range/charge time/whatever - or there's the "genuine" packs, which only fit that manufacturer's packs and give you full whack.

See also: Dell/Lexmark inkjet cartridges...

Apart from the small detail of the handling problems inherent in 250kg+ battery packs.

However there are less than 15 BATTERY sizes in GENERAL use for starting.

In dry cells we are down to half a dozen common sizes.

As technology matures, people simply assemble to whatever the brand leaders form factor is.

Whats probably more problematic for hot swapping is that the packs would almost certainly carry a lot of electronics in them.

I went through a hard discussion with another electonic engineer, and we hammered away at each other till something we both felt was sensible was left: it basically was a set of sub packs, each one of which could accept charge from a wide variety of voltages, and also act as current limiter, and under and over voltage limits on a sub pack, all of this monitored via a serial bus going to the main onboard computer, so that 'battery low' 'ageing sub pack' ' over temperature' and so on could be sent to both dashboard displays, the main motorspeed contrllers and cooling fans.

At the total pack level that would require an established probably 6 wire connection system: two for teh charger, two for the real power, and two for a balanced high speed serial interface.

This 6 wire system then would be carried down to each sub-pack. If modules went bad,you would 'recondition' by simply swapping in a new subpack and resetting the main fault codes in te computer flash.

Did you know that there are only abouit 4-5 gearbox manufacturers in the world in general use? dittoop fuel injectyion systems?

If the car manufacturers simply made modularised packs, then each manufacturer would assemble its sub sub packs into sub packs, and the sub packs into a pack suitable in capacity for the vehicle: Mke that relatively simple to swap out and one could rapidly have at very low stock levels, the ability to carry half a dozen different sub sub pack types, or if doing hot swapping, total packs. It would make no sense for manufacturers themselves to make each car pack totally different from every other module: economies of scale would dictate that they might sell a car with e.g. a 30Kwh pack for 'town use' small cheap and light - and a 50, 70, 100, 120KWh pack for 'extended motoring' albeit at a weight and cost penalty. Those would all have to fit the same basic cars.

Lightweight packs with thin skinny wheels and restricted power to teh motors would make the urban eco version, add fat wheels and allow the motors to deliver more, and you have the urban sport ..add more pack and you have the GT..fit skinnier wjeel to that and you have the eco range rep car. All using simply different bolt on wheels, a software change, and a few more modules (and of course go faster stripes)

Its less than ideal for sure, as you would need a trolley jack to swap a pack, or something similar, but there is a lot that is less than ideal about IC engines also.

the AA would anyway be sitting there with big diesel gennies to recharge you at the roadside enough to get to a charging station, at enormous expense, if all else failed..

In message , at 10:13:39 on Fri,

Yes, it was a brave effort but fruitless.

The first portable PC I helped design used U2 batteries. I wonder if you can guess which that was?

The Natural Philosopher gurgled happily, sounding much like they were saying:

For autoboxes, yes. But they're not interchangable between applications. Even within a specific autobox manufacturer's range, there'll be several different basic versions of each particular model, further tailored to specific applications - ratios, bellhousings and other hard fitments, then there's the ECU mappings.

Most manufacturers build their own manual boxes, though.

Yes, but again, they're certainly not a straightforward swap between vehicles.

Well mostly you dont: they are all inside ticked away where spray cant get in.

Almost certainly not exactly the same, no.

At the one hor charge rates the low impedance packs I use require no cooling at all. They even survive being discharged in about 3 minutes to almost flat without cooling...

The donsiode is that just about all teh sfaety electronics - whch can get bit hot is removed, and some of the chemistries invlved are pretty flammable. However the automotive battery is between the two really.

It probably needs to be operated on average at something like a 4 hour to discharge rate, and peak discharges in the half hour rate. On a 50Kwh pack that equates to an average sort of 12.5Kw - about 16bhp average

Charged at a one hour rate one might expect to see maybe 5KW of lost energy.that WOULD need cooling, nut thats no big deal if you are pulling

Worst case is pulling that 120bhp: there you might see 10-15Kw of heat lost in very worst cases. More than the fins could cope with, but well within the range of a fan assisted setup.

In message , at 12:04:39 on Fri, 6 Jun 2008, The Natural Philosopher remarked:

Yes, that's true. I can't see why there are more than about four, but that's another question.

Not true. There are dozens of different "button" cells, and several specialist 9v cells for cameras etc. Whenever you want better than lower-quartile performance.

I'm not sure that I agree that's a problem, unless you mean the collateral damage done if you receive a battery pack with broken electronics. These exchangeable packs will have to come with some sort of "no quibble" refund if the pack you get turns out to be a lemon. Plus a free of charge (hoho) and rapid tow to the nearest replacement station.

Doesn't surprise me. Lucas used to do most of the in-car electrics a generation ago. Whatever happened to them?

See above. Hmm they could sell replacement batteries branded as "AA cells", that has a certain historic resonance.

Its not becuse..

Exactly.

The cars should be *able* to recharge in about an hour without becoming too inefficient on the recharge. Most people spend nearly that or more in the supermarket. And most people do not drive 200 miles to go to a supermarket. Esseentially I see the real way this all works as being one overwhelmingly where domestic recharging is carried out, at very modest rates, on cheap rate overnight: in urban situations that implies managed facilities pupose built. Park your car, plug in and go home.

On long hauls you have motorway fast recharge points,where one hour will, at a price, refill your 'tank'.

Forsm with ther own car parks, hotels and the like might choose to equipe them with similar low charge rate facilities or even if they feel its worth it, high rate ones.

I would envisage a simple 240v connector for low rate charge and a 415v

The loser is the person who parks in the street overnight always. Arguably this is a really good way to make sure they dont. Electric cars would need to be parked long term, where they could be charged. If thats not on a residential street near you, tough, but it makes the streets a deal safer anyway.

`Or more likely full diagnostics but *less* whack.

Thst is a bit of a one, that is.

Either fast charge in an hopur, hot swap a 250kg plus pack, or simply take another car and drive away a la magwitches stagecoach idea.

Personally, if someone gave me the option of buying a drive/train/drive or a drive/coach/drive fully integrated system, so I could park my car at a station, catch something else, and then pickup a vehicle at the other end for the last 5 miles, it would be a winner for most business trips > 100 miles that I used to do.

In message , at 12:13:39 on Fri, 6 Jun 2008, The Natural Philosopher remarked:

An awful lot are somewhere that water can get in.

I am not sure even that is true.

No, because the compuuter maps are tailored to the engine, but the sensors are pretty similar in type size and performance.

I think there are only about 5 major Li-ion manufactures out there right now as well.

An intelligent vibrator?

No, more tht if manufacture A decides to implement some fancy charge sensing that menufacture B does not, then uyou might get a warning on te dashboard 'non brande pack installed'

Manufacturers love monopolies.

But teh pronciples of revrese engineering parts so they DO work in all cases has kept the likes of Unipart going for years..and now there is EU legsilation I THINK that mens that manufacturers HAVE to release complete specs on their parts to third party manufacturers in the automotive field.

So it would be a 'hang on while I select on this ccmputer which car you have there..tight, thats it, the pack now talks ford ecobollox for you sir'

Hah. they probably would, at that. ;-)

The Natural Philosopher gurgled happily, sounding much like they were saying:

It is, but I'm starting to suspect you'd doubt it on principle.

True - but, again, there's standard standards and non-standard standards. Lambda sensors are a fine example. 2, 3, 4 wire versions, and at least two completely different basic technologies - zirconium and titanium - before you even consider different threads.