Author Topic: Electric cars  (Read 693306 times)

peteo48

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Re: Electric cars
« Reply #1410 on: February 05, 2020, 05:02:57 PM »
I think range anxiety is a thing although my pal dismisses it (he has a 24 kwh Leaf). My issue is the occasional need to do longer trips into areas where there is no charging infrastructure. You often hear it said that there are now more public charging points than there are petrol stations. Technically it is true but the average filling station will have ten pumps and will only take 5 minutes to fill your car so the comparison is meaningless.

The Tekna Leaf is a lovely car though. If you never did more than, say 50 miles, it would be ideal because you could drive it without compromising on heat, air con and speed. As a second car - a no brainer.

John Ratsey

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Re: Electric cars
« Reply #1411 on: February 05, 2020, 05:48:22 PM »
Even in the dead of night, it rarely drops to less that about 30 Gw, so where is the additional 35 Gw that John talks about going to come from?
The 35 GW was everyone charging for the same 4 hour period. Spread it over 8 hours (11pm to 7am) and the requirement is less formidable. Nonetheless, we need several more big nuclear power stations (or the equivalent output in Small Modular Reactors) as the sun won't be shining and the wind might not be blowing when everyone wants to charge their vehicles. If the SMRs are deemed safe enough to be placed in urban areas then the waste heat can be used to replace all the gas being burned by the central heating boilers.

I am concerned that the 24 kWh battery may not be sufficient for a winter return trip in traffic. I could always connect it up at Mum’s, using the 13A charging cable but a couple of hours on that probably wouldn’t make much difference. I’ll have to give this some thought and a bit more research.
13A = 3kW so potentially 6kWh in 2 hours (more likely 5.5 kWh usable charge). That's almost the difference between the 24 and 30kWh versions of the Leaf and 4 miles/kWh an extra 22 miles. Nonetheless, you might be struggling if the battery loses some capacity but if you are planning to move and reduce the maximum journey distance then that's not a show-stopper. I would trust a battery gauge more than a normal fuel gauge.

Apart from going a bit more slowly and turning the heating off, there's probably not as much scope to stretch the mileage by careful driving as the energy potentially wasted in braking should be put back into the battery.  An EV should handle queuing traffic much better than an IC engine as the bursts of power to move the vehicle forwards are largely recovered when stopping. An IC hybrid is also more efficient in such conditions than a non-hybrid. Do EVs have LED lights by default? A pair of 60W halogen bulbs is a significant power drain (particularly in queuing traffic).
« Last Edit: February 05, 2020, 05:54:01 PM by John Ratsey »
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culzean

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Re: Electric cars
« Reply #1412 on: February 05, 2020, 06:16:54 PM »
I would trust a battery gauge more than a normal fuel gauge.

 Do EVs have LED lights by default? A pair of 60W halogen bulbs is a significant power drain (particularly in queuing traffic).

https://mpoweruk.com/soc.htm

There is a reason the SOC indicator is often called a guessometer,  methods of working out state of charge or battery health are very tricky and not as accurate as people may think.  Using battery terminal voltage may work quite well for a lead acid battery where battery terminal voltage is fairly closely related to state of charge, but for lithium chemistries that does not work so coulomb counting is used, which tries to measure what goes in and what comes out but as battery ages its capacity gets less, so this has to be factored into the algorithm,  and anything that interrupts the measuring can result in large errors.  One source of error is self discharge of battery which can give a higher reading for SOC than actual is the case.  Also keeping Li-Ion battery chemistry in a high state of charge damages it.

I had a good example of coulomb counting going wrong on my electric razor recently when I replaced the Li-ION battery.  I had checked the new battery voltage before installation and it was pretty much fully charged at 3.75volts - but after installation the shaver would not run,  I had to unsolder battery again, connect a bulb across to discharge to 2.85 volts and then reconnect,  after reconnecting the battery I then recharged it and the shaver ran OK and has done so ever since - the fact that the coulomb counting device was not happy meant it stopped the shaver running even with a fully charged battery simply because it had lost track of the battery charge / discharge history.   I had no idea how much charge was in the battery after I discharged it,  which means that the error is now fixed in the coulomb counter, it may say battery is empty and stop razor running when battery is still 30% full for all I know....


I would have thought LED lights all round would be absolutely essential on battery powered cars due to drain of filament lights.
« Last Edit: February 05, 2020, 09:06:49 PM by culzean »
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Jocko

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Re: Electric cars
« Reply #1413 on: February 05, 2020, 06:21:08 PM »
The Tekna has LED headlights but I don't think the lesser models do. They do have LED running lights, front and rear. I am currently looking at insurance costs as buying it as a second car is not that silly an idea. With no Road Tax, it is only the insurance costs and what I use in electricity I need to payout. And when I use the Leaf I won't be burning fuel in the Jazz. It is not as if I need to sell the Jazz to fund the purchase. The Jazz may be going to the great scrapyard in the sky, come its next MOT!

Jocko

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Re: Electric cars
« Reply #1414 on: February 05, 2020, 06:50:59 PM »
AA quoted £307 for insurance but I will phone my insurer since I am adding a second car. A second car won't be that cheap.

peteo48

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Re: Electric cars
« Reply #1415 on: February 05, 2020, 09:29:30 PM »
Of course the important thing Jocko is that you stay around this forum so we can follow your next adventures. We'd miss you if you went.

Jocko

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Re: Electric cars
« Reply #1416 on: February 05, 2020, 10:11:47 PM »
If I still have the Jazz as well, I will still be eligible for the forum!

springswood

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Re: Electric cars
« Reply #1417 on: February 06, 2020, 07:42:43 AM »
Quote
The Jazz may be going to the great scrapyard in the sky, come its next MOT!

I do hope not. But perhaps you could donate it to medical science, see where your amazing fuel economy comes from  ;D.

Also I second what's been said about a couple of hours 3kw charge makes a difference and how one of the big plusses of BEVs is that crawling in traffic doesn't waste juice.

What I wondered is how good is the interior space in the Leaf?
« Last Edit: February 06, 2020, 07:47:18 AM by springswood »
"Indecision is a terrible thing"
Or is it? What do you think?

Jocko

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Re: Electric cars
« Reply #1418 on: February 06, 2020, 10:13:26 AM »
What I wondered is how good is the interior space in the Leaf?
It doesn't have the wonderful magic seats of the Jazz but it is quite roomy (it is a size up from the Jazz). The taxi company, here in Kirkcaldy, seems to find them roomy enough. For 99.9% of my motoring, I only need two front seats, and they were comfortable and roomy enough. The boot is a bit small but all I normally need is room for shopping. I seldom ever have to carry cases and my golfing days are long past.




Insuring it as a second car looks a bit iffy. You can only have NCB on one of the cars you insure. My wife doesn't drive so we cannot split them. That may well be the fly in the ointment regarding having it as a second car.

culzean

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Re: Electric cars
« Reply #1419 on: February 06, 2020, 11:30:57 AM »
So now the government is saying that after a certain date new houses cannot be fitted with gas boilers for heating and hot water.  Not every place is suitable for ground source heatpumps which are the most efficient alternative at around 3.5kw return on 1 kw used to drive the pump,  airsource heatpumps ( reverse cycle airconditioning ) are next with 2 to 2.5kw per 1 Kw of electricity used.  Both these systems have a fairly low flow temperature of around 40degC, which is not really high enough for heating water properly and probably more suited to underfloor heating than conventional convector radiators.  The capital cost of both these systems is high,  with ground source being very high.

So the government banning other sorts of energy is placing more and more and more emphasis on electrical power,  but we are not building any nuclear reactors for reliable base power supply, and keep putting money into unreliable solar and wind.  Using gas to produce electrical power is not near as efficient as burning gas in an efficient condensing gas boiler in your house or building.

With all this extra electricity required I am sure the greenies who want it are gonna have apoplexy when new pylons start appearing on the countryside.  but the fact is that underground cables for very high voltages are prohibitively expensive compared to pylons and need more maintenance - we are going to need those Rolls-Royce local nuclear stations for sure.  It was Edison who wanted to use DC and have a power station in every town ( distributing DC could not be done over any distance back then ) and Tesla who said AC was better ( and he was 100% correct ) because it was easy to raise the voltage with transformers to enable high voltage / low current transmission ( power = volts x amps,  so for any given power as the voltage rises the current drops enabling smaller cables to be used ).
« Last Edit: February 06, 2020, 11:45:29 AM by culzean »
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Jocko

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Re: Electric cars
« Reply #1420 on: February 06, 2020, 11:36:54 AM »
So what would you suggest to stop us burning fossil fuels? Or do you not think that burning fossil fuels is an issue?

guest4871

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Re: Electric cars
« Reply #1421 on: February 06, 2020, 03:16:15 PM »
So what would you suggest to stop us burning fossil fuels? Or do you not think that burning fossil fuels is an issue?

The problem seems to be, by not burning fossil fuels or wood, we are effectively banning fire. Fire has supported the human race for some (let's say) 300,000 years.

Not burning fossil fuels is only a temporary solution anyway as population growth continues unrestrained.

More benefit would probably accrue from population control, reduction in the huge waste we all now generate and heavy restrictions on consumerism and natural resource utilisation - none of which will be politically or economically popular.

Focusing on fossil fuels is probably missing the real problem. And, until you can persuade the US to cooperate, it is probably pointless. We don't know it would work anyway. Scientists used to think the earth was flat and diesel was a good thing and all things nuclear were very bad for humankind.

madasafish

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Re: Electric cars
« Reply #1422 on: February 06, 2020, 06:45:23 PM »
I write  as Renewables are producing 12% of our power and nuclear 13%...Coal is 7%  (Gridwatch)

culzean

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Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

John Ratsey

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Re: Electric cars
« Reply #1424 on: February 06, 2020, 08:48:46 PM »
It was Edison who wanted to use DC and have a power station in every town ( distributing DC could not be done over any distance back then ) and Tesla who said AC was better ( and he was 100% correct ) because it was easy to raise the voltage with transformers to enable high voltage / low current transmission ( power = volts x amps,  so for any given power as the voltage rises the current drops enabling smaller cables to be used ).
However, the long distance power system interconnectors are high voltage (500kV or more) DC to avoid the AC induction losses (there's also the advantage that the AC grids at each end don't have to be synchronised) and the reduction in losses over a long distance more than offset the cost of conversion at each end.

So what would you suggest to stop us burning fossil fuels? Or do you not think that burning fossil fuels is an issue?
Wood fires aren't fossil fuel although they still produce CO2 and other unwanted emissions. Otherwise we'll all have to wrap up during the colder months.
« Last Edit: February 06, 2020, 08:51:26 PM by John Ratsey »
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