The Regen Instant Consumption (Negative mi/kWh)

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The irony is the EPA didn't get anywhere near the correct figure in any case :) To go back to the original question, the negative consumption means the battery is supplying negative power, or put another way, we are charging the battery at this power. If you could go down hill for 100km, and you saw -12kWh/100km, then you would put back 12kWh into the battery (minus losses).

If you are cruising for 2 minutes (say 2km) at 12kWh/100km, then go downhill for 2 minutes (also 2k.) at -12kWh/100km, you have effectively travelled for 4 minutes without using any power. You have got back what you took out.
 
vader said:
The irony is the EPA didn't get anywhere near the correct figure in any case :)
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My understanding is that manufacturers do their own testing according to a specified protocol, then pin their own number on things based on the result. Now why MINI chose to be so conservative is another question.
 
CuriousGeorge said:
My understanding is that manufacturers do their own testing according to a specified protocol, then pin their own number on things based on the result. Now why MINI chose to be so conservative is another question.
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Remember, the company also conservatively stated the F56 MINI Cooper SE takes 6.9 seconds to get to 60 mph. Perhaps BMW/MINI doesn't want to overstate performance figures to prevent complaints by litigious owners whose feet are too heavy (decreasing range) or whose feet are too light (decreasing acceleration). That said, I've found the SE's artificially limited top speed is as specified.
 
CuriousGeorge said:
My understanding is that manufacturers do their own testing according to a specified protocol, then pin their own number on things based on the result. Now why MINI chose to be so conservative is another question.
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I believe it was the SAE J1634 2-cycle test for the Cooper SE. What I find most fascinating is the specific energy of 159 Wh/kg, which would put it in NMC 622 territory for prismatic.
 
CuriousGeorge said:
My understanding is that manufacturers do their own testing according to a specified protocol, then pin their own number on things based on the result
Click to expand...
I found the test document ages ago, and what happens is MINI provide the rolling parameters and the EPA uses those to set up the test. They do freeway and city cycles, average them to get the average distance to go from 100 to 0%, then apply a fudge factor - common for all cars that to the 2 cycle test, of 0.7 . This is the dodgy part. The SE actually averaged 157miles in the test. This is not far off the real world ideal maximum. They got 110 by multiplying by 0.7 . This is why the value is surprisingly about 40% low. For the MINI, the real "fudge factor" is around 0.95 . Basically, do a real test then cripple it with an arbitrary fudge. WLTP does not use the fudge factor, which is why it is far more accurate.
 
Ssbg58 said:
If the unit was kWh/mi, negative values makes sense (can we switch that?).
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The units do make more sense if you switch away from mi/kWh, and the SE can be switched but the only other choices are km/kWh or kWh/100km. kWh/100km is the best choice for getting a sense of performance, but doesn't mesh well with non-metric countries (the US).

e-consumption.webp
 
vader said:
To go back to the original question, the negative consumption means the battery is supplying negative power, or put another way, we are charging the battery at this power. If you could go down hill for 100km, and you saw -12kWh/100km, then you would put back 12kWh into the battery (minus losses).

If you are cruising for 2 minutes (say 2km) at 12kWh/100km, then go downhill for 2 minutes (also 2k.) at -12kWh/100km, you have effectively travelled for 4 minutes without using any power. You have got back what you took out.
Click to expand...
That was not the original question, sort of. The confusion on my end was from the unit of measure I had selected - mi/kWh; Negative kWh/per distance is self explanatory. Negative mi/kWh indicates what distance it would take to recoup 1 kWh as poster number 3 explains.

Potato, tomato, but one is natural and self explanatory, while the other, at least for my brain was mystery.
 
vader said:
I found the test document ages ago, and what happens is MINI provide the rolling parameters and the EPA uses those to set up the test. They do freeway and city cycles, average them to get the average distance to go from 100 to 0%, then apply a fudge factor - common for all cars that to the 2 cycle test, of 0.7 . This is the dodgy part. The SE actually averaged 157miles in the test. This is not far off the real world ideal maximum. They got 110 by multiplying by 0.7 . This is why the value is surprisingly about 40% low. For the MINI, the real "fudge factor" is around 0.95 . Basically, do a real test then cripple it with an arbitrary fudge. WLTP does not use the fudge factor, which is why it is far more accurate.
Click to expand...

Not to forget derail the thread, but I have found the 114mi EPA range to be spot on for highway driving (70mph), which here in the states is really what people care amount when talking Range numbers.
Tom Malogny’s range test also got 114mi IIRC.

The fudge factor may be fairly accurate based on this, but I’d need other data points for other vehicles to say for certain.


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Just over 3.1 miles per (gross, supplied) kWh on both summer and winter tires.
 
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Did the winter tire swap today. The F1s aren't yet at the wear bars, but the sipes are all gone and they now look like Formula 1 rain tires from the early-aughts, basically slicks with a few straight circumferential grooves. They've been sticking well enough, even in much cooler weather than the compound should be able to handle, so I'll try to get a few more months out of them next spring/summer. But I'll likely end up with a new set next year – around here they're about 40% cheaper than the Michelin PS5, and nobody has been able to confirm that those would last 40% longer.
 
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