EV's in Winter - Extremes of Range - Renault Z.E. Forum
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post #1 of 44 (permalink) Old 02-08-2014, 03:54 AM Thread Starter
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EV's in Winter - Extremes of Range

I've now been enjoying EV motoring for a whole year so it's time to recap. Through the milder months I was able to achieve 65-105 miles per charge, the 105 figure being the average during the hottest period of 2013.

Now we are in winter and the story is rather different. As Autumn progressed range dropped to the 80's and then the 70's. Once I needed heat in the car a more dramatic drop took place culminating in one charge representing ...only 43 miles. To achieve that figure I was not drivinga bove 50mph but did set the heat to 22 degrees as I had an elderly passenger to keep warm. That's really an effective 15 miles return journey plus some leeway. Worrying that maybe the battery itself was suffering the following miles were driven trying my hardest to keep the draw of power from the battery below 12kw and resorting to 2 sweaters instead of heat. Range this time was back to 74 miles - I reckon that's reassuring.

For the technical detail:
Miles driven 59
Remaining range 15 (just under 1/4 of battery)
m/kwh 4.63
kw consumed 16
charge type: 10A cable
time to complete charge 6h 38m
calculated charge rate 2.41kw

Can anyone beat that for winter driving? Incidentally, keeping consumption down below 12kw is pretty well impossible when pulling out of junctions or going uphill with other cars behind. However, on the move keeping below 12kw does not mean crawling along, just means using a light right foot.
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post #2 of 44 (permalink) Old 02-08-2014, 06:02 AM
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RE: EV's in Winter - Extremes of Range

Thanks William. Good useful post, esp for non owners.

Do you use the preheat? How does that compare on range?
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post #3 of 44 (permalink) Old 02-08-2014, 06:33 AM Thread Starter
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RE: EV's in Winter - Extremes of Range

GrumpyCabbie, I've never used the preheat but it must help especially for those trying to commute to work in the morning. If they're making an early start they might even get the preheat at offpeak rate. Although I charge on offpeak my earliest use of the car is much later so the preheat would be at full price, whereas the electricity in the battery was cut price! Mean or wot?

I reckon for those who like heat that early morning preheat could save between 1/8 and 1/4 of the battery, and on damp or frosty mornings the benefit is clear.
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post #4 of 44 (permalink) Old 02-08-2014, 06:38 AM
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RE: EV's in Winter - Extremes of Range

Useful stuff. Thanks for sharing.

I tend to set the car at 19 degrees, but that said the comfortable temperature for me seems to vary wildly between different cars. One manufacturer's idea of 19 is another's idea of 17 - or at least that's what it feels like.

I do hope that setting the dial down to 19 degrees means at least one extra mile.
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post #5 of 44 (permalink) Old 02-08-2014, 12:12 PM
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RE: EV's in Winter - Extremes of Range

On my regular commute, the upper figures I am achieving one battery's worth-equivalent is 80 to 85 miles, which is with the 19C-to-feet setting. I would say 65 to 75mi is more the norm, though.

I am tending to drive faster because I have to do a full charge every night anyway, due to the heating requirements, and also to stay in the outside lane to avoid the debris of the crumbling carriageways in the 'truck' lanes. I have already had one heavy windscreen strike from a lump of tarmac while being in the inside lane too much this winter. I have therefore been upping my speed. Interestingly, I have found that if you build your power demands up gradually, the range suffers relatively less than if you attempted the same speeds in summer. i.e. driving at 52ish in winter sees ~25% less range than doing so in summer. However, driving up at motorway speeds, 70ish, there is little range difference (not counting the extra cab heating demand on top).

I am going to experiment with this a little more to understand. I think it is because if you get the cells to heat up, by higher loads, then they work more efficiently and 'more summer-like', I guess.

At motorway speeds with 19C set, I am currently routinely getting 55 to 60 mi range (in fact, this is exactly as the Fluence sales brochure suggests is typical for these conditions - credit to Renault for accurate literature and an accurate range gauge).

With rain and a few 'extra' fast accels en route, traffic depending, that can drop below 50 miles range. I've little doubt I could make that drop to 40mi range if I really pushed the car hard, but efficient driving is programmed into my right foot and I always tend to hesitate less rather than drive faster so I will usually get the best of of cars at whatever average speeds I am covering.

Pre-heating saves a relatively fixed quantity of energy: From 0 and frosty, turning the heater on consumes +1 to 1.5kWh on top of any driving and heating. From 0 and not frosty, more 0.75 to 1kWh. From ~5ish is ~0.5kWh. I don't think there is any benefit in preheating much above 5C because punching the 'demist' button puts enough 'tepid' air into the cabin space within a minute that, IMHO, you don't really get enough time to get to feel cold before the car gets warm enough! All preheating really does above 5C is waste a couple of kWh of juice from the wall in the 30 mins before the set time.

If you have the battery range, you will save 10 to 20p by not using pre-heating but simply de-icing with some warm water. When it is 0 or less and frosty, the heater will run up to 3.7kW (actually more than the max charging current) and will hold that for at least 15 minutes in the preceeding half hour before the set time. So you end up actually burning more electricity than just defrosting. Of course, the benefit is that you save 1.5kWh of range of the battery, though at a cost of 2 to 2.5kWh of preheating. Of course, preheating avoids the hassle of defrosting the car and if that's worth spending an extra kWh then you should use it, and I do indeed use preheat because 10p extra doesn't register on my worries in life. I have far bigger things to get worried about!

You will note above that I have mentioned figures from 40mi range to 85mi range. There is quite some variability possible in winter. As mentioned, you might like to try driving a bit quicker if you have the range to do so because it doesn't make such a big noticeable difference than it does in summer. You might be surprised at how little difference it makes.
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post #6 of 44 (permalink) Old 02-09-2014, 11:24 AM
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RE: EV's in Winter - Extremes of Range

First - I'm glad to be back! I thought these forums had died of spam and only checked back on the off-chance.

Anyway, I've been racking up a few miles on my Fluence and every day my decision to take the plunge has been vindicated.

I've got another car (petrol) and I use the Fluence for every journey I feel confident it can make range-wise and use the petrol car for everything else. In December, I only used the petrol car for two airport runs and the Fluence for absolutely everything else. In January, I didn't use the petrol car until the 21st, when I used it for a longish distance work trip. I'm easily doing at least half of my miles in the Fluence.

In the recent cold weather, my range has been about 75-76 miles where I've done longish trips- that's with a gentle right foot and sparing use of heat/aircon/lights.

It goes down quite a bit on weeks when I only do local journeys, but for those periods I regard range as unimportant anyway, given the ease of topping up, and don't really monitor it closely.

My longest regular run (from Ely, Cambs) is to King's Lynn - about 28 miles each way. Yesterday I went to Bury St Edmunds for the first time (ca 30 miles each way).

I'm building up for a first attempt at Peterborough and back, only a little further on a directish back-road route, but much further by the main A roads.

So far I haven't used public charging points at all.
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post #7 of 44 (permalink) Old 02-09-2014, 11:46 AM
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RE: EV's in Winter - Extremes of Range

Any comments on what the car is like to live with when viewed from the driving seat, i.e. in terms of ride and handling, noise levels, overall comfort, brakes, throttle response and the like? I do get the feeling when reading EV reviews generally that the writer forgets a lot of people buy cars for how they feel, regardless of power source.

I honestly believe that the 'it runs on cheap electricity!' line isn't as big a draw as people think.
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post #8 of 44 (permalink) Old 02-09-2014, 12:23 PM
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RE: EV's in Winter - Extremes of Range

Maybe start a new thread, for 'driving experience'?
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post #9 of 44 (permalink) Old 02-09-2014, 12:53 PM
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RE: EV's in Winter - Extremes of Range

Fair point. And good idea.
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post #10 of 44 (permalink) Old 02-09-2014, 12:55 PM
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RE: EV's in Winter - Extremes of Range

Yeah, what's it like to drive having only 95 bhp on tap? Is it a snail for overtaking or does the instant torque make up for it?
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