Miles/kWh

[biffo]

Yeah, he’s addictive! It’s all about day-to-day practicality

 

[Les burrows]

Yeah, he’s addictive! It’s all about day-to-day practicality

Yeh I have to agree and the savings on an ice car is amazing as the guy rightly said
Les

 

[tonymc]

Best I havemanaged so far, some cross country accross A&B roads, 120 miles and still 49% remaining.

 

[Petriix]

This is my best long journey so far. It says 4.7 miles per kWh, but that's nonsense. We used 56% (it had already charged up by 1% by the time I took the photo) to cover 146.8 miles which is just over 27kWh at almost 5.4 miles per kWh.

We charged up to 86% while we had some lunch, then I put my foot down a bit on the second leg. In the end we covered 210 miles using 84%. That's 250 miles total range and around 5.1 miles per kWh. With the aircon off and going a little slower I think 300 miles might be possible.

 

[Les burrows]

This is my best long journey so far. It says 4.7 miles per kWh, but that's nonsense. We used 56% (it had already charged up by 1% by the time I took the photo) to cover 146.8 miles which is just over 27kWh at almost 5.4 miles per kWh.

View attachment 4218

We charged up to 86% while we had some lunch, then I put my foot down a bit on the second leg. In the end we covered 210 miles using 84%. That's 250 miles total range and around 5.1 miles per kWh. With the aircon off and going a little slower I think 300 miles might be possible.

View attachment 4219

Hi Petriix have you got a picture of the accumulated miles screen after your 5560 or so miles I posted one of mine in #217 after 3700 there about so would be interesting to yours with more mileage
Les

 

[Adee]

This is my best long journey so far. It says 4.7 miles per kWh, but that's nonsense. We used 56% (it had already charged up by 1% by the time I took the photo) to cover 146.8 miles which is just over 27kWh at almost 5.4 miles per kWh.

View attachment 4218

We charged up to 86% while we had some lunch, then I put my foot down a bit on the second leg. In the end we covered 210 miles using 84%. That's 250 miles total range and around 5.1 miles per kWh. With the aircon off and going a little slower I think 300 miles might be possible.

View attachment 4219

That's pretty remarkable, Petriix. I'd love to hear of someone exceeding 300miles on a "full tank"!
I wonder if anyone has logged a journey mileage starting from full charge and running the battery down to 1-2%. This is probably the most certain way of ensuring the battery charge indicator is accurate. I don't have the bottle I'm afraid.

 

[Adee]

That's pretty remarkable, Petriix. I'd love to hear of someone exceeding 300miles on a "full tank"!
I wonder if anyone has logged a journey mileage starting from full charge and running the battery down to 1-2%. This is probably the most certain way of ensuring the battery charge indicator is accurate. I don't have the bottle I'm afraid.

I have been trying to keep logs for some of my journeys. I have attached a graph of one set of data where I recorded the actual mileage at various stopping points vs the battery charge used to that point. You can see how linear it is (which surprised me!). You can also see that it extrapolates to 250miles (using a least squares curve fit) when there is no charge remaining. The data only goes up to 42% battery depletion as I obviously must have decided to recharge it at that stage.
I generally drive in a fairly sedate way, but this is still pretty comforting! It suggests that the fuel consumption meter should be showing around 5miles/kWhr, but I can never get above 4.6.

 

[Petriix]

Hi Petriix have you got a picture of the accumulated miles screen after your 5560 or so miles I posted one of mine in #217 after 3700 there about so would be interesting to yours with more mileage
Les

I don't have a photo of it but it's showing 3.8 miles per kWh. As measured meter to wheel it's doing more like 3.4 miles per kWh so charging losses are around 12% on average; I do slow charge a lot from surplus solar so losses are likely higher from this. But I suspect that the reported 3.8 miles per kWh figure is significantly under what I'm actually achieving battery to wheel.

 

[Johnny 5 is alive]

Has anyone noticed that their 1st 50% achieves far better mileage than their 2nd 50%?
I know petrols and diesels have pretty inaccurate gauges, my Kia Cee'd used to go from 1/4 full to empty in a blink! But I expected electric car gauges to be much more linear.
Quite often I've managed to get between 120 & 130 miles from the 1st 50%, leading me to think I might hit the magic 250-mile range mark,only to see the last few % deplete much quicker.
I have a theory: as the battery voltage is lower towards the end of its capacity, to achieve the same wattage requires more amps, thus depleting the remaining capacity quicker. But I'm no electro genius, I'd be interested to hear any more convincing theories! ?

 

[Petriix]

Has anyone noticed that their 1st 50% achieves far better mileage than their 2nd 50%?
I know petrols and diesels have pretty inaccurate gauges, my Kia Cee'd used to go from 1/4 full to empty in a blink! But I expected electric car gauges to be much more linear.
Quite often I've managed to get between 120 & 130 miles from the 1st 50%, leading me to think I might hit the magic 250-mile range mark,only to see the last few % deplete much quicker.
I have a theory: as the battery voltage is lower towards the end of its capacity, to achieve the same wattage requires more amps, thus depleting the remaining capacity quicker. But I'm no electro genius, I'd be interested to hear any more convincing theories! ?

I've not noticed that. I monitor it pretty closely while I drive and it seems pretty linear to me. The battery percentage should be a reasonably close approximation of the usable energy remaining so voltage and amperage shouldn't affect it (unless their algorithm for calculating it is wrong).

 

[Adee]

Has anyone noticed that their 1st 50% achieves far better mileage than their 2nd 50%?
I know petrols and diesels have pretty inaccurate gauges, my Kia Cee'd used to go from 1/4 full to empty in a blink! But I expected electric car gauges to be much more linear.
Quite often I've managed to get between 120 & 130 miles from the 1st 50%, leading me to think I might hit the magic 250-mile range mark,only to see the last few % deplete much quicker.
I have a theory: as the battery voltage is lower towards the end of its capacity, to achieve the same wattage requires more amps, thus depleting the remaining capacity quicker. But I'm no electro genius, I'd be interested to hear any more convincing theories! ?

Wouldn't be surprised, Johnny5. I still struggle to understand how the car can deduces its actual charge at any given time. It does appear to be reasonably accurate though, I think.
If you look at my graph a couple of entries back, you can see how linear the charge depletion seems to be over the first 45% and in this case it did extrapolate to 250miles on a full battery charge. But I need to take it further to see if the slope changes. Just haven't had chance to do that yet.
Your argument sounds plausible to me BTW.

 

[Johnny 5 is alive]

Wouldn't be surprised, Johnny5. I still struggle to understand how the car can deduces its actual charge at any given time. It does appear to be reasonably accurate though, I think.
If you look at my graph a couple of entries back, you can see how linear the charge depletion seems to be over the first 45% and in this case it did extrapolate to 250miles on a full battery charge. But I need to take it further to see if the slope changes. Just haven't had chance to do that yet.
Your argument sounds plausible to me BTW.

When my paralysed friend and I set a world record in 2004 (well that's how they described it, but it was actually a world first) it was made possible by the advent of lithium polymer cells, and the first thing we noticed about them was the much more linear voltage decay over capacity during discharge. Previous cells such as nickel metal hydride and especially nickel cadmium "held on" to their voltage for anything up to 80% of the duration and in some cases (especially in cold weather) the voltage under load could actually be seen to INCREASE at around 20-30% discharge as the electrolyte warmed up and allowed more efficient ion transfer.
This is also why digital devices such as laptops and mobile phones display the battery percentage so accurately from full to empty.
So I guess this is how the 5 "knows" the remaining battery percentage as it is almost directly proportional to the nominal battery voltage at any given time, certainly in other applications.

 

[Adee]

When my paralysed friend and I set a world record in 2004 (well that's how they described it, but it was actually a world first) it was made possible by the advent of lithium polymer cells, and the first thing we noticed about them was the much more linear voltage decay over capacity during discharge. Previous cells such as nickel metal hydride and especially nickel cadmium "held on" to their voltage for anything up to 80% of the duration and in some cases (especially in cold weather) the voltage under load could actually be seen to INCREASE at around 20-30% discharge as the electrolyte warmed up and allowed more efficient ion transfer.
This is also why digital devices such as laptops and mobile phones display the battery percentage so accurately from full to empty.
So I guess this is how the 5 "knows" the remaining battery percentage as it is almost directly proportional to the nominal battery voltage at any given time, certainly in other applications.

Well I never knew that! Presumably, then, the voltage drops linearly between its maximum fully charged value and some other value which must still be quite high even close to zero charge? If this weren't the case the battery voltage would be down around, say, 100V at 20% charge, 50V at 10% charge etc and the car wouldn't work at all?

Obviously we have to know what the world record was in now!

 

[Johnny 5 is alive]

Well I never knew that! Presumably, then, the voltage drops linearly between its maximum fully charged value and some other value which must still be quite high even close to zero charge? If this weren't the case the battery voltage would be down around, say, 100V at 20% charge, 50V at 10% charge etc and the car wouldn't work at all?

Obviously we have to know what the world record was in now!

Fully charged each lithium cell is 4.2v, nominal is 3.7v and most protection software does not allow any cell to fall below 3v. The reason for this is that below a certain voltage (which varies with composition and type but usually around 2.8v) the cell can become non-recoverable. (Ask me how I know this ?)
So the capacity is only useful between 4.2v and 3v per cell and the percentage is most likely to be measured between these values.
I'm dying to know what happens to an MG5 when it actually gets to zero HV voltage - yesterday I got home with 3% and at 5% it told me that the A/C was "restricted"! I'm assuming all drive would be lost but the systems would still work from the normal car battery? I don't really want to try it, although surely at some point it will happen to someone on here and we will get a full report!

The record attempt wasn't particularly exciting (actually July 2006 not 2004 as mentioned above, my memory isn't what it used to be ?) but the full length DVD documentary they made of it is a nice memory to have, especially as my late father features in it ?

 

[Adee]

Fully charged each lithium cell is 4.2v, nominal is 3.7v and most protection software does not allow any cell to fall below 3v. The reason for this is that below a certain voltage (which varies with composition and type but usually around 2.8v) the cell can become non-recoverable. (Ask me how I know this ?)
So the capacity is only useful between 4.2v and 3v per cell and the percentage is most likely to be measured between these values.
I'm dying to know what happens to an MG5 when it actually gets to zero HV voltage - yesterday I got home with 3% and at 5% it told me that the A/C was "restricted"! I'm assuming all drive would be lost but the systems would still work from the normal car battery? I don't really want to try it, although surely at some point it will happen to someone on here and we will get a full report!

The record attempt wasn't particularly exciting (actually July 2006 not 2004 as mentioned above, my memory isn't what it used to be ?) but the full length DVD documentary they made of it is a nice memory to have, especially as my late father features in it ?

Ahh so you're not actually Johnny 5 then??
Quite an impressive achievement to be able to look back on.
So you needed two pilots....one for the aircraft and one for the boat ( I presume the boat didn't have to be battery powered as well!!).

3V to 4.2V ought to allow for a reasonable degree of resolution/accuracy in battery charge computation. Given the linearity I saw over the range 100% charge - 55% charge, I'm starting to believe that this technology is becoming pretty dependable.

Thanks for sharing!

 

[Petriix]

Well I never knew that! Presumably, then, the voltage drops linearly between its maximum fully charged value and some other value which must still be quite high even close to zero charge? If this weren't the case the battery voltage would be down around, say, 100V at 20% charge, 50V at 10% charge etc and the car wouldn't work at all?

Obviously we have to know what the world record was in now!

It's not quite a linear drop. You can monitor it on the power screen. It goes faster in the first and last part of the voltage range and slower in the middle. This is accounted for in the calculation.

 

[m4rmite]

5 weeks of ownership and 865 miles later, it had 2.5 miles on it when i got it.

4.3 miles/kWh average and 95% of that is driving through brum centre traffic each work day.
Normally driving in eco and kers 3.
Not too shabby.

 

[5teep]

That's where the EV excels, stop start town traffic.

 

[Les burrows]

View attachment 4343
5 weeks of ownership and 865 miles later, it had 2.5 miles on it when i got it.

4.3 miles/kWh average and 95% of that is driving through brum centre traffic each work day.
Normally driving in eco and kers 3.
Not too shabby.

Hi m4rmite,indeed not shabby at all, this is the kind of picture I like “ie” the accumulated total screen, as a think this is the best way to see what the car is actually returning.
I myself posted my cars same screen in this thread #217 and this is the screen that tells you the correct figures in my opinion, in my view it’s quite easy to get numbers of 5-6 mpkh and over in the right conditions and over a short distance of 20-50 miles and these pictures don’t mean very much to me, keep it up and send us another when you have notched up around 4-5000 miles with the kind of driving you say you do in a city environment.

To hit the figures that MG quoted 214-276 miles for the MG5 you will need to be constantly returning around the 4.35 mark for 214miles
And around the 5.6 mark for the 276 figure from the 48.8 kw useable battery I think the figures was
Les

 

[5teep]

I suspect I am going to be near the top of the high mileage list. Will be 3 weeks on Tuesday since picking my company car up and I'm quite happy with my 3.9mkwh. My driving is mostly A roads and B roads.
My range seems to be pretty consistently 200 miles.