saving money at the pump

[Howard LewisParticipant @howardlewis46836]

Driving technique greatly affects energy consunption, whetehr it enters th vehicle via hose or a cable.

In all caes (Of electric, hybrid, or fuel injected engines) lifting off the throttle early (aided by looking, and reacting, well ahead) cuts off the fuel to the power unit.

Harsh acceleration consumes fuel rapidly, since the prime mover is required to deliver maximum power, which consumes energy.

Similarly, higher driving speeds consume more energy. Air resistance increases as the cube of speed, so driving at 60 mph, uses a lot less than doing 70 mph.

My little naturally aspirated 1 litre, low emission, petrol fuelled car returned over 70 mpg keeping below 60 mph for most of the time, aided by the 50 mph speed limits on M5, between Devon and East Anglia.

(When I drive to the west midlands, or to the west country, my journeys would be longer in duration because of the need to recharge en route, so an EV is not suitable for those journeys).

It may not be WHAT you drive, but HOW you drive that affects fuel or energy consunption.

Now we need to pray for fine weather to dry the laundry, rather than the tumble drier. But never mind the loss of crops and agricultural land. We can import, so that the emissions are elsewhere!

Bring on net zero?

Howard

[duncan webster 1Participant @duncanwebster1]

[Dave HalfordParticipant @davehalford22513]

Has anyone compared the insurance costs?

Purely comparing insurance groups and towing weights (I tow) a Merc EQC comes out higher than the jeep 6.4 litre SRT cost new is roughly comparable

Range seems to halve when towing EV, an IC drops nearly a quarter.

[not done it yetParticipant @notdoneityet]

I just love the claim that the grid needs lots of copper to up grade it.

Just an unsubstantiated guess, IMO.

Is that for conductors, transformers or what?

Maybe he is unaware that many transmission lines are not copper, but Aluminium?

Maybe he is unaware that the voltages of upgrades may be substantially higher than at present?

Maybe he is unaware that HVDC transmission is more efficient than HVAC?

Let’s have some clear facts, not uncorroborated guesses!

Thread is about rising cost of fossil fuels.  Replacing those fuels with electrical energy is so much more energy efficient – nothing to do with insurance, either (my car is more to insure than my old diesel – but not if one considers the difference in performance, for instance).

As I said at the outset, bite the bullet and pay more for the fuel – or change to a far more efficient drive system.  Electric drives win every time.  Nobody would choose to drive their lathe and mill by an ICE, would they?  Even if they were to use a fossil-fuelled generator, the efficient drive is still by an electric motor.

[John HaineParticipant @johnhaine32865]

PEDANT ALERT!

I’m sure that tongues are slightly in cheeks but…

For the avoidance of doubt, when you charge a battery by feeding electrons into one terminal, exactly as many flow out of the other! Otherwise the charger would accumulate a very high positive voltage…

[Robert Atkinson 2Participant @robertatkinson2]

[Dave HalfordParticipant @davehalford22513]

[duncan webster 1Participant @duncanwebster1]

High voltage dc transmission does not imply dc generation. It gets away from capacitance losses,  and according to a cable engineer I knew, is the only way to go for long distance underground and underwater cables

[Robert Atkinson 2Participant @robertatkinson2]

Underground is less of an issue than underwater as the larger size of thicker insulation and thus less capacitance is not such an issue. But it’a a bit of a niche case. I don’t see DC for primary distribution in the near future.

[NealebParticipant @nealeb]

This thread started off talking about saving money at the pump and a recent post talked about reducing fuel/energy consumption by gentle acceleration and avoiding braking. Broadly speaking, sound advice but I think that it is a bit more complicated than that. Most obvious issue is that EVs recover quite a lot of the vehicle’s kinetic energy when “braking”, which explains why I keep seeing my own EV deliver more miles per kWh in town than when driving at steady speed, in contrast to IC cars which throw away all that KE in heating the brakes (or engine frictional losses, or whatever). The other point which has puzzled me for a long while now, as someone who thinks more about efficient than fast driving, is just what is the most economical rate of acceleration? Slow acceleration and waste fuel spending too long at inefficient speeds and at the other extreme rapid energy-wasting acceleration. So where’s the sweet spot in the middle to save most money at the pump? I don’t know, for example, whether my EV is more effective at recuperation when braking harder or more gently, although I suspect that there is a difference.

Given that there are so many variables associated with actual vehicle use outside our control (thus making all this nonsense about publishing “real-world” fuel economy numbers just that – nonsense) I’m not even sure how, as scientists and engineers, we can actually find the sweet spot. Would anyone like to suggest an answer to what seems an insoluble problem?

[blowlampParticipant @blowlamp]

[Wink HackmanParticipant @winkhackman25989]

[Robert Atkinson 2Participant @robertatkinson2]

[Mark RandParticipant @markrand96270]

[Russell EberhardtParticipant @russelleberhardt48058]

[not done it yetParticipant @notdoneityet]

[NealebParticipant @nealeb]

…and a look at Zapmap in preparation for a trip from Devon to Scotland later this year suggests that recharging prices on the motorway are pretty much in line with prices elsewhere, unlike fossil fuel prices. Still puts the per-mile cost roughly on a par with what I used to pay for diesel but as 75-80% of my miles allow me to charge at home, overall costs are way down. Especially as the EV is so much more economical round-town than a big diesel that was still warming up by the time I was home.

As for electrons (now consider to be my friends), I assume that 1mm/sec is an average drift rate and they buzz around a bit in all directions? I understand that they might give a wave to other particles on the way but I’m uncertain about the principle of that.

[VicParticipant @vic]

[VicParticipant @vic]

[not done it yetParticipant @notdoneityet]

Vic,

Two good posts for those who appear to know somlittle about Aluminium replacing copper.  They have been making HV conductors with aluminium strands surrounding a steel hawser (for strength) for decades!

Also a good one re the price of fossil extract.🙂🙂

[VicParticipant @vic]

[Robert Atkinson 2Participant @robertatkinson2]

And the reason aluminium wasn’t used in the 90s was because of all the issues they had with the stuff they used in the 70’s.

[howardbParticipant @howardb]

We have a 400 volt 3P + N overhead line across our land in France which supplies us and the rest of the ville.

A few years ago our little ville of about 15 houses got rewired, the feed in cable was supported with an additional concrete post on our land as the source of the supply came from a different direction etc.

The cotton reel with the cable on it was dumped on our land adjacent to the road so I had a look at the ID label. It read  that the cable was 70 Sq mm and AL.

The four cables were pvc insulated with three twisted around the  central cable.

The only odd effect I have noticed subsequently is that during hot weather the lowest part of the “droop loop” across our land is a good 12 inches lower than when it’s cold over the  driveway.

It’s not a problem for us with our vehicles and trailers, except if we have a delivery with a 7.5 tonne box van when the top of the van body and cable comes a bit close. I always advise the driver of this – the reaction is the usual french shrug.

 

[NealebParticipant @nealeb]

I used to live in a village in Hampshire where half the village had pretty good broadband – this was soon after it was introduced – and our end, the newer end, didn’t. I was told that it was down to the use of aluminium BT cables for the newer houses which were fine for speech but couldn’t handle the broadband signals. We also had problems with the odd wire break which meant the BT engineer coming out and swapping to another core. Don’t know what they were going to do when they had worked their way through all four cores…

[Robert Atkinson 2Participant @robertatkinson2]

The high thermal expansion coefficient of aluminium, about 30% higher than copper, is an issue. It causes work hardening and fatigue. It is also an issue in motors and transformers as it much higher than iron or steel. High motor efficiency is dependent on small clearances and low resistance. Aluminium is poorer than copper in both respects as you have to allow for expansion / differential movment. Additionally resistance is about 50% higher increasing heating or needing thicker conductors.

Robert

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