OT: Driving electric cars in winter

[Mr Macaw]

On Sun, 21 Feb 2016 12:33:00 -0000, Davey wrote:=

t-stop-systems/

The first comment immediately points out the author of the article is a = f****it:

"How does losing half of its charge acceptance translate into losing hal= f of the fuel mileage efficiency gains? Won=E2=80=99t the engine still s= hut-off and stop using fuel? Won=E2=80=99t the problem be with running e= lectrical systems with the engine off and then re-starting the engine (s= ince the battery isn=E2=80=99t accepting enough charge)?"

And I do many short journeys, delivering goods, in a non-start-stop car,= switching off the engine every stop. So I actually start the engine to = drive literally 200 yards. The battery does not die. There is no appar= ent problem. And yes that can be with headlights and wipers and demiste= r on.

-- =

Bills travel through the mail at twice the speed of cheques.

[Mr Macaw]

Except they don't slow down charging, not if the alternator can provide enough current. Normally the battery is not taking the alternator's full capacity. Try this: Start your car, now switch on headlights, wipers, etc, etc, note the tone of the engine change. The alternator is providing more current and thus putting a bigger load on the engine. If the alternator was already maxed out charging the battery after you started your car, there would be no change in engine pitch when you turned stuff on.

[Clive George]

I think everybody agrees if you fix the gear ratio, maximum acceleration is when the engine is running at peak torque.

What most people are saying is that if you choose the gear ratio for maximum acceleration, it will be set so the engine is at maximum BHP.

[dennis]

They normally specify that it has to be a glass mat battery, so yes.

[Mr Macaw]

How often do you notice your car turning the engine off? Because my non-start-stop car gets switched off a lot when I do delivery runs and I just use normal batteries. Starting an engine that's just been running doesn't require much cranking.

[Dave Plowman (News)]

Depends on how big the alternator is. They are far larger than was once the norm. 150 amp isn't unusual - and the actual power consumption of the car hasn't gone up that much.

[Dave Plowman (News)]

Do wonder how accurate it is - and how long ago it was written. I'd guess if the batteries were knackered after a couple of weeks, we'd have heard about it. ;-) Don't most UK cars have at least a three year warrenty?

[Mr Macaw]

The ones I've seen with a sticker in the back window are 5 or 7 years. But I doubt that covers tyres, brake pads, exhaust, battery, etc. They'll be "consumables". It'll only cover the engine failing, the gearbox failing, the bodywork rusting, etc.

[Dave Plowman (News)]

Then you've not been following this thread.

***********************

**********************

That seems perfectly clear to me.

*********************

*********************

The entry of the red herring.

*********************

***********

And finally turnip who never reads or understands anything. And given he claims to be some form of engineer, seems to have invented some form of magical gearbox too which can magic up more torque at one point in an engine's rev band while not doing so at others.

[Davey]

Yes, I would say that most battery warranties I have seen are three years, or maybe even two. There may be exceptions, but I have only shopped for a bog standard car battery.

[Dave Plowman (News)]

The three year new car warranty on my BMW covered the battery. Not a 'stop start' model, though. But I'd have expected to see stuff in the press if they had a short life.

[Mr Macaw]

I've never even looked at the warranty as I've never known a battery I've bought last less than 5 years.

[bert]

In article , NY writes

one of the most dazzling lights I find are those revolving amber things on tractors. At night it's impossible to see past them to overtake.

[Mr Macaw]

What is the ratio of brightness of your full beam to their flashing light?

[Tim Lamb]

In message , bert writes

You mean we haven't pulled over to let you by??

ISTR that tungsten filament headlights were legally restricted to 55W and 65W main beam BICBW:-) Heaven knows what this represents in led output.

[Mr Macaw]

Anyone with common sense would take it to mean 55W and 65W equivalent output (about 5.5W and 6.5W of LED electricity draw). But the law is pedantically stupid and probably allows 55W and 65W input.

[NY]

I don't think tractor drivers are taught to abide by that courtesy any more :-( I've followed tractors, both running "light" and towing big trailers, for many many miles, during which time they have driven past one layby after another (any of which would be plenty long enough for tractor and trailer), but the drivers very rarely pull over.

Part of the problem is that tractors now are making long journeys between fields in one location and barns or grain silos many miles away, whereas before they made shorter journeys between the fields and buildings of the same farm.

Going back to the earlier comment "one of the most dazzling lights I find are those revolving amber things on tractors", I actually find that many emergency vehicles' lights are dangerously bright. When the vehicle is moving and you need to keep out of its way, that's fine. But when a police car is parked beside the road, because he's stopped someone for speeding, the lights should be turned down in number and intensity because all they need to communicate to other road users is "take care not to run into the back of me", for which hazard lights are deemed sufficient for other vehicles, as opposed to "pull over and let me past - I'm in a hurry to get to an incident".

I find it very difficult to see the road beyond a police car when it has

*very* bright blue and red lights imprinting after-images on my retina. It's OK if the road is virtually closed and you are crawling past, looking for a policeman to signal whether or not it's safe to pass. But when the road is open and traffic could be passing vehicles that are off the road in a layby at up to 60 mph, retina-searing blue lights are overkill.

[Dave Plowman (News)]

Typical of legislators that they use 'power' in, rather than 'power' out for this sort of thing.

[charles]

All these light are bright enough to be seen in daylight. They should have an "after dark" setting.

[Mr Macaw]

They were equal back then. But it only takes a bit of common sense to realise that it's the brightness that matters, not the power input. The legislation is for brightness, not economy.