Running on empty.... - Renault Z.E. Forum
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post #1 of 15 (permalink) Old 04-02-2014, 11:16 AM Thread Starter
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Running on empty....

I went on my longest trip today from Glasgow to the seaside at Ayr - a round trip of just under 70m. I took it easy and light-footed it all the way and the first time I was willing not to recharge enroute.

The suggested range was slightly pessimistic, but I was showing 3m range when I has 2.75 to go then the range zeroed (well, --.-- what you get at the end of a full charge). I was expecting limited functionality as I was on the last mile - the orange battery was lit and the alarm was chirruping away every 20sec, but all seemed normal and I was still 1 octet away from the bottom of the scale.

I was running on 'reserve' but how long before I get the limited speed talked about in the manual. Anyone know?
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post #2 of 15 (permalink) Old 04-02-2014, 11:44 AM
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RE: Running on empty....

Quote:
Originally Posted by Buzby
.. I was showing 3m range when I has 2.75 to go then the range zeroed (well, --.-- what you get at the end of a full charge). I was expecting limited functionality as I was on the last mile - the orange battery was lit and the alarm was chirruping away every 20sec, but all seemed normal and I was still 1 octet away from the bottom of the scale.

I was running on 'reserve' but how long before I get the limited speed talked about in the manual. Anyone know?
Hmm...

That's not the behaviour of mine. My SOC meter will get to the top of the last octal and then the battery alarm sounds briefly and the light comes on. At that point you have around 10 miles, driving style dependent. I have never run the battery down to restricted power, but going on the SOC as a Godly indication, I do not get the 'continuous' sound until it is almost at the bottom of that octal. Mine usually goes '--' at 4 miles showing (I guess it is a quantity of charge, rather than miles, then).

It is very annoying not to turn that off. A couple of times I know full well that I have X miles left and can make the intended journey, but the range guess is blank and the beeping continuous.

I would estimate that the SOC needle hits the bottom of the octal with 2 miles (of my 'normal' 10mi/octal driving) left.

So to hazard an estimation, top of final octal and first beep indicates 2.5kWh remaining, blank gauge and continuous bleeping indicates 1kWh remaining, and as needle just hits rock-bottom there is 0.5kWh remaining. The rest depends on your own miles/kWh.

Once chap here has reported running into power limiting. I don't know he was paying much attention to exactly what the gauges were saying at the time. If there is more below that rock-bottom SOC position then I don't know what it is, but that does account for the full 22 kWh from full so I don't think I would really want to try unless I was put in that position. The continuous beeping is plenty enough to dissuade me from testing it out just for the sake of it!!!

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post #3 of 15 (permalink) Old 04-02-2014, 02:04 PM Thread Starter
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RE: Running on empty....

Thanks to the cars connectivity, I now know what was left in the car battery, thanks to the hourly emails the car sends me (isn't it nice to be loved?)

"Welcome Buzby,

The battery level of your vehicle (VF1LZBZ*********) is still low:

Battery level: 2%
Estimated Range: 3.1 mile
Checked on: 02/04/2014 15:45

These values may be slightly different from the current information in your vehicle.

See you soon on the Renault Portal.
The Renault Team"

So, I still had 3m (estimated) left - but I agree, once warned, you should be able to acknowledge it and silence the racket. It would seem reasonable to assume that the limiting of travel must cut in at 1% before you roll to a halt.

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post #4 of 15 (permalink) Old 04-03-2014, 04:49 AM Thread Starter
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RE: Running on empty....

Addendum:

Just noticed my estimated range following this deep discharge has made the distance available increase considerably. On accepting the car, in the last year it had barely driven 58 miles (going by the service book). The estimated range was usually 38-45 miles, and really on a par what I got from the Twizy (and it's smaller battery). This steadily increased over the last month, and seemed to settle at 64.0 miles.

Whether due to increased usage, slightly higher temperatures, or the deep discharge of the last long run, the estimated range has now increased to 76.4, which is more like it. In reality, my mileage for the run to Ayr (via Kilmarnock) was actually 78 miles between charges, so the estimated range is playing catch-up.

I doubt I'll ever make it to the Renault-suggested triple digit goal - perhaps I'll need divine intervention, a following wind and done serious slipstream work!
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post #5 of 15 (permalink) Old 04-03-2014, 05:00 AM
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RE: Running on empty....

Don't give up, Busby. Through the hot spell last year I was achieving a genuine 100+ over 7 or 8 recharges. And having noted comments from others, Donald especially, regarding driving style and range I believe that if I swap poodling around on very minor roads at low speeds to driving at middling speeds, say 50-60 on decent B or A roads I might do even better. If I ever get my car back in my hands I'll check it out.
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post #6 of 15 (permalink) Old 04-03-2014, 05:11 AM
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RE: Running on empty....

I've very rarely looked at the range estimator, let alone use it.

I have the power gauge showing all the time, and drive in the knowledge of the SOC needle because you should adjust your driving style according to the SOC meter, not the guesstimated range. That range estimate will tell you nothing about how you should drive to complete your trip on the charge you have because it can only work on how you've driven before and not how you need to drive to cover the remaining miles.

Stay below 18kW and you should get 10 miles per octal. If you need 12 miles per octal, you need to be aiming to hold back to 12kW or so for most of the time.
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post #7 of 15 (permalink) Old 04-03-2014, 12:11 PM Thread Starter
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RE: Running on empty....

The mechanics of range guestimator I'm used to - the the Vectrix had one with visions of grandeur before it (say) suggested 12 miles left, then decremented 1m apparently every 20 seconds irrespective of load. On the Fluence, it seems to be far better tuned and I was pleasantly surprised at how close it was.

Still, I look forward to pushing the envelope further and agree medium-speed driving does indeed appear to aid range. I'm really hoping you get your pride and joy back soonest William!
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post #8 of 15 (permalink) Old 04-03-2014, 12:23 PM
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RE: Running on empty....

I always reset my distance reading every time I do a full charge, which also resets the range readout, usually to 66 or 67 miles, which seems to the the default value. Most of the time, that value then improves as I drive fairly gently.

I'm guessing that left to its own devices, the Fluence ZE probably works on the basis of the last 150 miles or so for range/consumption calculations - at least I think that's roughly what most car trip computers etc do.
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post #9 of 15 (permalink) Old 04-03-2014, 03:09 PM
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RE: Running on empty....

ElectricDave, yes the guessometer does look back over something like 150 miles or so. By now you should have noticed the guessed range rising as ambient temperature does likewise - reassuring after the doom and gloom of the winter.

If you want to feel smug just remember those poor Leafie owners don't have the benefit of our accurate battery meter, which is what I use mostly, always aiming to charge when down to a quarter then there's never a fear of range anxiety. Of course, when you've allowed it to go down to 11 and then you find you can't charge...

P.S. Rumour has it that my missing car might finally be travelling in the direction of someone who can fiddle with it. I began to think it had been hijacked.
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post #10 of 15 (permalink) Old 04-03-2014, 05:29 PM Thread Starter
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RE: Running on empty....

I trust this will form the basis of the ebook best seller 'Confessions of a Fluence Owner'...... ?
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