Range Remaining; Energy Gauge; Trip Meter. What do you use?

[JoeS]

RobertC, you've pointed out a number of the variables the poor RR algorithm has to deal with. We each have our preferences in using the instruments available, and for you the RR gauge appears to be superfluous. Your call.

For example, in all my previous lead-acid EVs I have relied heavily on a Trip Meter, usually unintentionally 'calibrated' by rolling to a stop somewhere (once!). Since the Trip Meter in the iMiEV is inconvenient, I've supplemented it with a GPS which not only shows me my trip distance at a glance, but for longer trips I program it to give me the Distance To Go (DTG) which I, in turn, bounce off the RR gauge. If the DTG is larger than RR, that's a signal to slow down (unless I'm at the top of a monster hill)! Having four instruments simultaneously visible (RR, Trip, DTG, Fuel) gives me a warm fuzzy feeling.

For me, the granularity of the RR gauge is far better than the Fuel Gauge and despite driving in hilly areas at speeds varying between 25mph and >65mph, I nevertheless find the RR display very useful, even when alternating the car between my own leadfoot and my wife's featherfoot. To each his/her own.

In adapting to the seeming vagaries of the RR gauge we are all doing what we're supposed to: paying attention to our limited energy resource.

Incidentally, and further supporting your argument, I defy anyone to be able to predict exactly what their RR will be after a full charge.

...I can make my RR meter say anything I want...

When you get over 103miles take a photograph and post it to become a new record holder on that Max RR thread. :roll:

 

[Don]

Now this morning I have a fully charged battery. What is my range? If I repeat the same trip as last night, driving the same speed with the AC on, it's about 50 miles.
But I had no intention of driving on the highway at 70 mph today. Today I had to drive on local roads.
What is my range? Not 50 miles.
If I drive conservatively and don't use much AC, my range is more like 60 or 70 or 80 miles.

It still works, even if you begin with only 50 RR miles, driving conservatively on local roads and not using any A/C, the meter will continue to update it's prediction, mile after mile, getting more and more accurate as you go based on what you're doing in real time - Many times, you'll see the number increase as you drive

We don't have a lot of hills around here, but I have noticed that sometimes on a long, uphill freeway on-ramp, I can use 2 or 3 miles off the meter just getting up to freeway speed . . . . but then on a long down-ramp using the 'B' mode, I usually get back 1 or 2 of those miles as I slow down to the stoplight

I find it extremely useful, but I guess not everyone looks at it the same way. Different strokes for different folks, as they say

Don

 

[Llecentaur]

I have been following the RR discussion carefully.

In general I find it usefull.

However, there is one aspect I do not explain, maybe someone has an explanation.

Several times, it has happened that I arrived home (always after a climb) and sometimes see RR 70km with 8 bars remaining. This happens after hypermiling and in May temperatures. Then simple Math would say that the 100% range would be ~140km.

Now I have never seen the RR after full charge higher than 117 km.

Does this mean hat while driving it guesstimates with lower history of data than once fully charged.

One advantage I see is that it tends to be pessimistic when I am hypermiling. But I must admit it is confusing.

 

[Don]

I have been following the RR discussion carefully.

In general I find it usefull.

However, there is one aspect I do not explain, maybe someone has an explanation.

Several times, it has happened that I arrived home (always after a climb) and sometimes see RR 70km with 8 bars remaining. This happens after hypermiling and in May temperatures. Then simple Math would say that the 100% range would be ~140km.

Now I have never seen the RR after full charge higher than 117 km.

Does this mean hat while driving it guesstimates with lower history of data than once fully charged.

One advantage I see is that it tends to be pessimistic when I am hypermiling. But I must admit it is confusing.

You can't double the RR number at the mid-point and say it should be the max range - Way too many variables. If you consistently drove 40 to 50 Kmh, your max might be 175 Km . . . . who knows? There are documented cases of people who have driven over 100 miles on a charge

You say that getting home requires a climb and the best you ever see after a charge is 117 Km . . . . correct?

What do you think you would see if your trip home was on level ground, instead of climbing? 125 Km or so? What would it be if your trip home was downhill instead of climbing? 140 Km? The best documented RR after a recharge so far is 103 miles . . . . 165 Kms

The meter algorithm isn't perfect and since it's basis for the calculation is only the last 25 Kms you drove, it's never going to be exactly right . . . . but the way it appears to work makes sense to me . . . . which in itself is a bit scary :lol:

Don

 

[peterdambier]

I have come a long way to Energy Gauge reliable and Trip Meter for guessing.

Sometimes Karin and me are going long distance after careful and mostly too optimistic planning.

I am given some 18 kilometers for free in one direction but the way home needs 4 bars. The other direction is more "normal" and suggests me up to 164 Hyper Milling kilometers.

Far away from home I am suggested some 120 kilometers and I know my next socket is 111 kilomters away. Careful driving should get me there but I have seen from previous to stops for charging that I need more than guessed. It is mostly highway and it is uphill. I got there but the turtle was giving me a fit.

The 4 sockets were blocked by 8 motor homes. Next day it took me another 12 kilometers with the turtle nagging until I found another socket. The way back home I shared 2 sockets with an electric bbq 400V/32A from the city hall. I had to cross those 111 kilometers again and missed a turn that took me another 8 kilometers until I noticed. Turtle complaning again ...

So I learned 111 kilometers no more. Let us see, optimistic 160 kilometers, that is 16 bars and 2 of them belong to the turtle. That is 120 kilometers. Yes, I have driven 120 kilometers.

I have seen other times. This winter my real range came down to mostly reliable 80 kilometers and I would not do that every day. Looking at the Energy Gauge tells me what is in the battery and the Trip Meter tells my where I am. RR shows what my brain is guessing except my brain knows where I want to go and RR does not. Of coarse I could calculate but my stomach knows better.

 

[Zelenec]

Now I have never seen the RR after full charge higher than 117 km.

Try to charge somewhere after at least 20km of slow downhill drive. Your RR should show you min. 160km after full charge.