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TomT
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Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: California, now Georgia
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Re: Low battery warning not early enough

Sun Jun 26, 2011 11:50 am

Intuitively, I would say yes, though I have nothing scientific to back up that statement nor any idea of just how much slower would be optimum...
91040 wrote:If 38 mph is the sweet spot for a flat road, does that sweet spot become a lower speed as the grade increases?
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

edatoakrun
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Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Low battery warning not early enough

Sun Jun 26, 2011 12:34 pm

mogur wrote:Intuitively, I would say yes, though I have nothing scientific to back up that statement nor any idea of just how much slower would be optimum...
91040 wrote:If 38 mph is the sweet spot for a flat road, does that sweet spot become a lower speed as the grade increases?
Notice the chart has rpm and torque on the 2 axis's. Extreme torque and rpm conditions, both low and high, are less efficient, so optimum-range speed is probably quite a bit lower than 38 uphill, and higher than 38 downhill.

Using climate control (energy used is a function of drive time) will also increase the optimum-range speed, and higher drag conditions (windows open) will lower it.

The very broad 95% efficiency area in the middle of the graph probably reflects the experience we've all had, of getting consistently good range at speeds between 30-45 mph, as long as you can limit power use (no steep grades) to two "bubbles" or less.
no condition is permanent

JRP3
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Joined: Sat Feb 26, 2011 12:04 pm
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Re: Low battery warning not early enough

Sun Jun 26, 2011 1:14 pm

Some simple testing could be done, drive the same trip, a distance of a few miles at 38mph, 30mph and 20mph and see how many watt hours it takes to recharge the pack for each trip. Use a kill-a-watt meter if the car or charger doesn't give an accurate figure. Obviously you'd need a route that would allow you to easily hold those speeds or close to it.

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