"Range Remaining" algorithm?

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jennrod12

Well-known member
Joined
Feb 11, 2012
Messages
234
Location
Santa Clara, CA
As I understand it, the "range remaining" adjusts to the type of driving you are doing. Any idea how often it adjusts?

I usually drive around town and am used to seeing 50-60 miles of range remaining after driving for a while. When I jumped on the freeway a couple of times, I was shocked to see "range remaining" of about 35 miles after driving only about four miles. I think my brain took that to mean that every four miles I drove would deplete the range remaining by 20 miles, leaving only about 7 miles of real range remaining, but now I realize that it was probably adjusting and I could have actually driven about 35 more miles at freeway speeds.

I'd like to better understand how it makes these calculations, is that documented anywhere?

Thanks,

Jenn
 
The Range Remaining (RR) calculation is probably a trade secret. After all the bad-mouthing the Leaf's GOM was getting, I happen to think our i-MiEV's algorithm is pretty good.

The update rate can be pretty fast - turn on the heater and watch it lose 10 miles almost immediately, although that could simply be (initially) a fixed subtractive element in the algorithm rather than a coulomb counting over time calculation.

Recognize that, as presently implemented, the RR calculation can't possibly anticipate jumping from city streets to the Interstate, nor the huge 5-mile hill you're about to climb. In the future, I envision sufficient RR sophistication to include, for example, GPS-entered route with speed and altitude to be considered.

It's been fun thinking about all the variables that could enter into this model... actual measured performance over time in addition to all the BMS fixed, variable, and rate functions.

I think the RR's little brain is constantly churning, and it's fun to watch the RR climb in response to careful driving. It's a game to drive into town, and then come back with a larger number for RR than one left with.
 
Just when I thought I could predict RR, what should happen but a full charge resulting in a RR=98 http://myimiev.com/forum/viewtopic.php?p=1285#p1285 picture shows RR=96, despite my having driven the car not too conservatively the night before. My wife, a featherfoot, probably put on 40 miles earlier that day, most of it non-highway. Pity I didn't record the RR and number of bars before I started charging. Still trying to get a feel for how far back in time the RR algorithm reaches. At the other end, I've had mine down (once) to one flashing bar and RR=7. Anyone able to predict what their RR will be after a full charge?
 
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