GOM mystery solved

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vader

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So for a while I suspected that the GOM algorithm was faulty, and now I think I have cracked it. I went up the coast last weekend - 120ish km of freeway driving. There was a few roadworks where the speed lowered to 80kph, which helped the economy. I kept a reasonably careful eye on the consumption which was around 14.5kWh/100km. When I got home and recharged, the GOM read 190km - acually the largest reading I have ever seen. My theory is that the GOM only takes into account the energy *used*, not the energy regenerated. A freeway trip regens very little, so you use close to your average consumption. Around town, you regen significantly more, but also use significantly more (always accelerating, slowing etc).

So on the freeway, I used 14.5ish, which translates to around 200km range - 190 is pretty close. Around town, your consumption may be around 18kWh/100km *but*you regen say 6 kWh/100km. Total use from the battery is actuallyon 12kWh/100km. 150km on the GOM translates to around 19kWh100km. Yep, it fits. In the real world, regen is a thing so you may use 19kWh/100km, but you get back say 7kWh/100km, giving a net of 12. This gives around 240km range. Yep, it all fits. I suppose you can't guarantee regen, but you can be quite certain of the used power. When I say used, I mean the power drawn from the battery rather than total drained from the battery (drawn - regen)).

Anyone driving around town with lots of regen will obliterate the GOM, whereas a freeway traveller might get a reasonably accurate figure.
 
Excellent analysis. No recorded data points here, but when I left the DCFC this afternoon with an 86% SOC, the GOM predicted 142 km. I took a “back highway” (55 mph-posted single carriageway) and set the cruise at 90 km/h. As the odometer ticked up, so did the GOM! About 30 km along, the GOM showed 146! It then started to track closely with my often-observed 2 km/%SOC until I hit the autoroute about 40 km from home, with heavy rain and a set speed of 105.
 
Ooh, this is a promising hypothesis!

It always bothered me that the SE includes energy used during climatization as part of it's consumption calculation for a "trip", which further reduces the average it calculates. Not accounting for energy regained by regen braking seems consistent with that philosophy.
 
Without netting the regen, it could be tedious to track and calculate. I wonder if I can get my GOM to reach 50 miles at 100% charge this winter.
 
vader said:
My theory is that the GOM only takes into account the energy *used*, not the energy regenerated.
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That seems like a huge flaw to me, but must have been an intentional decision somewhere. Is this how range estimates work in other EVs? I'm really only familiar with my own car.
 
endquote said:
That seems like a huge flaw to me, but must have been an intentional decision somewhere. Is this how range estimates work in other EVs? I'm really only familiar with my own car.
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The GOM follows the second ABC rule: "Always Be Conservative." ("Always Be Charging" is the first ABC rule of the SE.)
 
That would explain the strangely low efficiency figure reported. It much excuse for it given the car shows negative energy usage on the gauge cluster when under regen so it knows the numbers, they’re just absent from the formula? Annoying if true…
Still doesn’t explain why the GOM continues to show what may be rated range vs learning from your driving habits as ours never improved no matter how I drive it.
I also get 130 miles of range on the highway without much in the way of regen so the ranger situate is just useless.
But good to know I’m. It going crazy re the efficient figure which is definitely lower than battery percentage calculations suggest. Sometimes by a large margin (but less so on the highway as you point out).
 
AndysComputer said:
Still doesn’t explain why the GOM continues to show what may be rated range vs learning from your driving habits as ours never improved no matter how I drive it.
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MINI said from the beginning the GOM doesn't learn, it's always only based on the previous trip. I wouldn't do things that way, but at least they were clear about it.
 
Puppethead said:
MINI said from the beginning the GOM doesn't learn, it's always only based on the previous trip. I wouldn't do things that way, but at least they were clear about it.
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Well Mini we’re giving inaccurate info then as the previous trio has no bearing. I can do a 130 mile highway run it a 170 mile around town run and the range estimate when charged back up to 100% will stay within 108-119 miles which appears to be EPA rated range possibly with an adjustment for temperature.
 
AndysComputer said:
Well Mini we’re giving inaccurate info then as the previous trio has no bearing. I can do a 130 mile highway run it a 170 mile around town run and the range estimate when charged back up to 100% will stay within 108-119 miles which appears to be EPA rated range possibly with an adjustment for temperature.
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Likewise, I've seen the GOM reset to a lower value on the same day just by activating the nav. After a long day driving with the local MINI club, my GOM showed me I had plenty range to make it home after it had "learned" from the day's driving. Activated the navigation to go home, and it instantly dropped low enough to complain I didn't have enough range to get there. (I got home easily, and the GOM eventually agreed as I got closer to home.)
 
Also, mine has never displayed more than 160 km/99 miles on a fresh, 100% charge, never mind the NRCan-rated 183 km or EPA 114 miles.
 
AndysComputer said:
Well Mini we’re giving inaccurate info then as the previous trio has no bearing. I can do a 130 mile highway run it a 170 mile around town run and the range estimate when charged back up to 100% will stay within 108-119 miles which appears to be EPA rated range possibly with an adjustment for temperature.
Click to expand...
This is my point exactly :) On the freeway, you don't regen a lot, so the last trip shows the battery drawn, which is close to the battery drained (ie. drained = drawn - regen). Around town, you may have drawn 18-20kWh/100km (or the imperial equivalent), and regened 6-8kWh/100km - but the GOM ignores the fact that we drew 18, but put back 6, giving a net drain of 12. It sees "18" and calculates 100*28.9/18 = 160.5km range, or almost 100miles on the nose. In reality, you only drained 12kWh/100km, which gives 240km (150mi) range. So your last trip was on the freeway, using 14.5kWh/100km with little to no regen, so range = 200km (124mi), and the GOM says 190km when you recharge. After doing 250km around town, drawing 18, but draining 12, the GOM says 160km range.
 
vader said:
My theory is that the GOM only takes into account the energy *used*, not the energy regenerated.
Click to expand...
Don't SE drivers see the GOM estimate increase when they're using regen braking going down a long hill? I have no local long hill to answer this question.
 
I see the GOM go up all the time in the mountains. Generally road grades tend to not be terribly steep so regen is limited. Instead the car will fall into that the area between power and regen. I have often wondered if the GOM does not understand this “coasting” gray area.
 
MrSnrub said:
So realistically with mixed driving what’s the avg ?
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My GOM has never shown above about 114 miles range, but as someone else pointed out it adjusts itself as you drive. It may take multiple miles for the GOM to drop 1 mile.

I can easily get over 130 miles range with mixed driving in the summer, but only about 100 miles range in severe winter.
 
All local all the time - I get a realistic 150mi summer, 100mi winter. GOM rarely shows over 100mi. Tons of hills so that theory is interesting. I swapped in my winter shoes and efficiency dropped maybe 10%, GOM is exactly the same.
 
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