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Imiev measured data

Posted: Fri, 01 Nov 2013, 03:44
by Monkeyboy
Nice work Cometboy,

with patience and good timing significant efficiencies can be achieved. I drive during off peak, sheltered (from winds)roads mostly 70 and 80km/h and brake with a double tap for max regen. Still trying to beat that 132 without turtle ;-)

Imiev measured data

Posted: Fri, 01 Nov 2013, 04:56
by carnut1100
Well on my way to work there is a sstretch of over a kilometre where if I nudge it into N it will coast along at around 70-75 kmh or I have to hold the throttl just so in D.
Free coasting will always be more efficient way of using kinetic energy than regen.
Regen in turn is more efficient than wasting that energy as heat in your brakes.
If there is a good reason not to coast in N then I will quit doing so....

Imiev measured data

Posted: Fri, 01 Nov 2013, 05:24
by acmotor
We should discuss this further.
IMHO In an ICE manual, placing the gearbox in neutral removes the mechanical load of the ICE engine and some of the gearbox geartrain load. That may allow you to take your foot of the accelerator pedal to cruise and may minimiser fuel consumption.
Using neutral to coast is a historical hangover from ICEs I think.

However in a single radio permanently engaged emotor system in an EV the driving technique is different. All control is Via the accelerator pedal. Neutral does not mechanically disengage the motor. It just tells the motor controller to back out. This is not intended by the manufacturer nor does it reduce energy consumption. The emotor itself can cruise with less power consumption that the car radio when appropriate.

kurt's commemt about vehicle dynamics is also very valid.

Imiev measured data

Posted: Fri, 01 Nov 2013, 11:42
by carnut1100
The reason I was doing it is that I could take my foot off the pedal and coast along for 1.5km without having to tweak the pedal into the perfect spot.
Mine being a 2010 doesn't have the C position on the shifter or I would just use that.
Basically by putting it in N I can eensure that no power is being consumed by the motor and no kinetic energy is being eaten by trying to regen.
Vehicle dynamics I hear you, but I was only doing it on gentle slopes with no sharp bends.

Granny driving to work and back I got a charge of 160 wh/km.
Two trips to town and back pushing it hard, full throttle up hills etc pretty much as leadfoot as possible got me 210.

Imiev measured data

Posted: Fri, 01 Nov 2013, 16:16
by acmotor
I hear what you are saying however putting the vehicle in neutral to cruise is technically bad for the controller when using a pmac motor since it is a passive generator and the controller must deal with the generated emf, with a full battery in particular this is an issue. As mentioned mitsi have probably done their best to deal with this situation but pmac emotor and vfd wise it is bad practice.
You need to practice steady foot driving...at all times to get the best range from an EV IMHO.

Imiev measured data

Posted: Fri, 01 Nov 2013, 19:01
by CometBoy
Would agree certainly not a good practise...

Have you looked at the CAN interfaced Cruise Control units that are fairly cheap and effective? Might make life easier for you?

Something like this is suitable for your i (I think?) Others might comment on these??

http://www.waeco.com/en/4374.php

I have been happy with the Waeco products in the past.

I have also entertained the idea of adding cruise but to try and avoid speeding fines that have happened in the MightyBoy from time to time. Speeding does seem a by-product of driving an EV?

Bruce

Imiev measured data

Posted: Fri, 01 Nov 2013, 19:31
by offgridQLD
Most phones or sat nav units can warn you if you are going over the speed limit to.

Im an the fence about cruise control on the Imiev. With all trips under 2hrs I wouldn't and not much of that is usually don't on roads with open space to use it effectively.

That said i do find the Imievs throttle is so light (as in very little resistance) and it moves that freely that you can get almost like a cramp in your ankle trying to lock your foot in one position and avoid movement on the longer trips 100km. So perhaps it would come in handy.

Kurt

Imiev measured data

Posted: Fri, 01 Nov 2013, 19:49
by carnut1100
I've looked at that Waeco unit.
Perhaps down the track a little.

I can certainly hold the throttle at zero, was just trying to maximise the coasting distance.
Won't do it again....

Biggest gain for cruise for me is that my commute is along quiet country roads where the speed limit has been dropped to 70 the whole way....roads which in past times I was quite comfortable zooming in a sports coupe a lot quicker than that!
EVs being so smooth it certainly takes concentration to stay under 70 on such roads!

Imiev measured data

Posted: Fri, 01 Nov 2013, 23:31
by acmotor
I have looked at the waeco CAN based cruise control for the imiev about a year ago. I went as far as emailing waeco to confirm suitability but chickened out at at the $650 price and a concern at not being able to set up the 'try hard' settings so they would be more relaxed for EV use.
Particularly in undulating terrain I imagined cruise control trying too hard to maintain an exact speed and wasting power.
Try yourself to hold an exact speed in hills and look at the power meter!

I'm waiting now for someone else to try a wwaeco CC. Image

Imiev measured data

Posted: Mon, 04 Nov 2013, 19:58
by offgridQLD
There was a update over the weekend for Canion app. Could be just luck but it's been more stable for me (no dropouts) But to soon to tell for sure. They have added averages for each screen. It's a nice feature. After logging 100km of driving some of graphs visually can be hard to guess the average. Now there is a line across the graph indicting the average and the number is listed up top.

For example my average throttle position over the 102 km trip was 30%. There were a few other small changes and features added.

One thing I noted when driving home was the average speed that I had been listing from my trips that was always kind of low from what i would have expected. Part of the reason might be that when your stopped at the lights the average speed starts going down so its time based over the distance not just the average of the true motion speed above Zero.

I manages 95whr - km on my trip home funny enough I went faster then I usually do but was able to maintain more momentum, as in got lucky with lights and traffic flow.

also on the trip up I used around 12kwh and I put the car on solar charge sat morning. I went out kayaking for the day and just let it do its thing. Came back at 4pm and the house battery's were on float and the Imiev was full. I usually like to split it over 2 days but on a nice day when I am out it wasn't a issue. Inching closer to adding the additional 4kw of pv so it should be a walk in the park with 8kw total.

Kurt

Imiev measured data

Posted: Tue, 05 Nov 2013, 05:04
by acmotor
yes, I got the canion 109 (now 110) update too. Good news you say about the lack of dropouts now. That was putting me off buying the upmarket BTCAN.

Keep us posted Kurt with your logged info. It is amazing just how energy frugal the iMiEV is !

Great news about your off grid system. True zero emissions. Direct action.

edit: version number is increasing daily !

Imiev measured data

Posted: Tue, 05 Nov 2013, 16:49
by carnut1100
I wish I could get numbers like that....:-(

Imiev measured data

Posted: Tue, 05 Nov 2013, 16:51
by offgridQLD
I think your doing ok for your location considering temps and terrain.

Kurt

Imiev measured data

Posted: Thu, 07 Nov 2013, 13:23
by carnut1100
Been house sitting at a friend's place, no hills.
Current charge I've done 99km, have three bars left and RR says 26km remaining....looks like it's the hills!

Imiev measured data

Posted: Thu, 07 Nov 2013, 13:31
by offgridQLD
Yep, when you have real time logging you can see the difference in Whr-km. It might be sitting at say 100wh km at 90kmh and then you go up a steep climb and your using 200 - 400 whr. You can see it just by looking at the imiev gauge look where the needle is to climb a good hill, 2nd line - 30kw or so? Yet on the flat its easy to keep it in the green.

Imiev measured data

Posted: Thu, 07 Nov 2013, 14:00
by Johny
carnut1100 wrote: Been house sitting at a friend's place, no hills.
Current charge I've done 99km, have three bars left and RR says 26km remaining....looks like it's the hills!
That's good news!

Imiev measured data

Posted: Thu, 07 Nov 2013, 23:49
by Monkeyboy
Nice work, that's an efficient drive.

Imiev measured data

Posted: Fri, 08 Nov 2013, 02:40
by offgridQLD
yep I think as things warm up a little down in the deep south he will get even better numbers.

What tyre pressure are you running?

I run 40psi all round.

Kurt

Imiev measured data

Posted: Fri, 08 Nov 2013, 02:49
by Monkeyboy
Did my PB with 40 PSI, but run 36 normally.

Imiev measured data

Posted: Fri, 08 Nov 2013, 05:09
by carnut1100
41 psi.

Yeah, that run coincided with a 28 degree day which might have helped....

Imiev measured data

Posted: Fri, 08 Nov 2013, 12:49
by Johny
offgridQLD wrote: yep I think as things warm up a little down in the deep south he will get even better numbers.
Funny you should say that Kurt. At 25 degrees yesterday I broke the 90km total estimated range (at 80% DOD, 12kw/h pack) on my daily commute. It's normally around 80km. The iMiev is no doubt more level WRT temperature - taking the pack circulating air from the cabin but it's an indication. (The Vogue weighs 1080kg - same as iMiev.)

Imiev measured data

Posted: Fri, 08 Nov 2013, 16:12
by carnut1100
Well I got a bit cheeky last night....knew I was pushing it but I didn't get a chance to charge up.
Giving one of my colleagues a drive didn't help either, but I've made another EV convert....the one giving me the most stick about the car is now seriously thinking of selling his Falcon and tracking doan an ex lease 2010 from the mainland!

Anyhow, turtle came on when I was about 5 km from home....all good until the last steep pinch to my house when it just said no.......
Little brother to the rescue, tow the last few hundred metres and put it on charge.

18.6 kWh from properly empty to fill.

Big thimg though is I got my best ever consumption so far, 150 Wh/km, including two trips up my Hill....
RR meter was showing 119km when I got in this morning and I got it up to 122km for a bit on the way to work.

Imiev measured data

Posted: Fri, 08 Nov 2013, 16:37
by Johny
I wonder whether the pack cells were not well balanced when you got the car. With each charge they get closer to full balance and therefore full pack capacity. Higher temperatures would be helping too.

Imiev measured data

Posted: Fri, 08 Nov 2013, 20:30
by carnut1100
I hope you're right!
When I picked it up the RR was showing 92 off a full charge.

It was serviced just before I got it and they said a battery test was dome with a full drain and charge.......I'm still chasing the Test results from the workshop, doesn't help that the electrician is on holidays....

Back to cold, wet and drizzly....looking forward to what numbers I can pull come summer!

Imiev measured data

Posted: Sat, 09 Nov 2013, 03:22
by offgridQLD
So you have used 100% of your battery's accessible capacity. Turtled and then driven until shutdown and it took 18.6 kWh to refill .

Given that the battery is 16kwh this makes charging about 86% efficient plug to battery. I think the Imiev isn't going to let you use 100% of the capacity but very close if you add all the numbers up I would say perhaps 85% efficacy or so might be more like the number.

Remembering that charging from empty or a low SOC is always a little more efficient that partial charging in the upper range. So 85% or so is about as good as it gets.

I suspected the charging was a little less efficient than most first thought.

On a side note (and you most likely already know) I consider the turtle to be like the oil pressure light on a ice car. You don't really want to see it and every time you do its not doing great things for the battery. My rule and its a common one is 80% DOD or 2 bars on your fuel gauge should be a limit you try and work to get a good life from the pack.

Kurt