\ncharging at 24 A and 234 V, 21 mi\/hr, 27 miles added so far. At
\n5:08 AM<\/strong>: 246 miles, 153 added, and the current has fallen
\nto 12 A at 239 V even though the dial is still set to 24.<\/p>\n
Four separate facts fall out of that pair, and only one of them is the charge
\nrate.<\/p>\n
1. How big the battery actually is<\/h2>\n
At 5:08 the car reads 246 miles with 30 minutes left at 10 mi\/hr, so a 251 mi × 242 Wh = 60.7 kWh<\/strong><\/p>\n It left the factory with 75 kWh. That is 19% gone at 105,000 The day before, the car ran Modesto to Livermore, Livermore to the Santa Cruz 251 minus 93 is 158 rated miles consumed to cover 138 actual 158 × 242 Wh = 38.2 kWh over 138 mi = So the honest range on a full pack, driven the way this car actually gets Aerodynamic drag rises with the square<\/em> of speed, and the power to Santa Cruz harbour to San Carlos: up Highway 17 over the summit at Two things in that ledger are worth arguing about.<\/p>\n The climb costs 489 Wh\/mi<\/strong> — two-thirds more than the And coming back down returns 0.19 kWh. About 4% of what the climb The five hard launches cost 0.5 kWh between them<\/strong> — Fifty feet of 10\/4 SOOW, an L14-30 to 14-50 adapter, the car dialled down to Ten-gauge copper is about 1 mΩ per foot, so fifty feet out and back is But look at the two voltage readings. 239 V at 12 A, 125 rated miles added between 10:57 PM and 5:08 AM — six hours That last hour is the 12 A reading. The dial still says 24. Nobody turned The standing advice is to live between 20% and 80–85% and leave 100% for That is why this one went to 100% overnight: to find out whether 251 miles is Measure the thing. The dashboard is an opinion.<\/p>\n Consumption curve fitted to published steady-state measurements and A 2018 Model 3 Long Range, 105,000 miles on it. Two screenshots of the phone app, six hours apart overnight, turn out to measure the battery more honestly than any number the car displays. Here is what they say. At 10:57 PM: 121 miles of range, charging at 24 A and 234 V, 21 mi\/hr, 27 miles added so … <\/p>\n
\nfull charge is about 251 rated miles<\/strong>. Tesla’s rated mile is a
\nfixed 242 Wh, which makes the usable pack:<\/p>\n
\nmiles<\/strong> — noticeably worse than the 8–10% a Model 3 of that age
\nusually shows. Worth knowing, and worth knowing before<\/em> planning a trip
\naround the number on the screen.<\/p>\n2. A rated mile is not a mile<\/h2>\n
\nBoardwalk, then down to the harbour — 138 real miles<\/strong>,
\nstarting full. It plugged in showing 93 miles of range.<\/p>\n
\nmiles<\/strong>. Every real mile cost 1.14 rated ones. In energy:<\/p>\n
\n277 Wh\/mi<\/strong><\/p>\n
\ndriven, is 60.7 kWh ÷ 277 Wh\/mi = 219 miles<\/strong>. The display
\nsays 251. It is not lying; it is quoting the EPA’s 242 Wh\/mi against a pack
\nit has measured. It simply has no idea how you drive.<\/p>\n![\"Energy](\"https:\/\/schindlerengineering.com\/public\/wp-content\/uploads\/2026\/10\/ev-speed-cost.png\")
<\/p>\n3. Speed is the whole story<\/h2>\n
\novercome it with the cube. That one fact dominates everything else on a
\nfreeway drive. Seventy miles an hour costs about 293 Wh\/mi in this car.
\nEighty-five costs 363. Fifteen extra miles an hour is 24% more
\nenergy<\/strong>, and it is the only lever on the list that moves the number
\nthat far.<\/p>\n4. Where a specific 60 miles goes<\/h2>\n
\n1,800 feet, down into Los Gatos, then 85 and 280 north at 70–85. Sixty
\nmiles. Modelled segment by segment:<\/p>\n![\"Segment-by-segment](\"https:\/\/schindlerengineering.com\/public\/wp-content\/uploads\/2026\/10\/ev-energy-ledger.png\")
<\/p>\n
\nfreeway rate, because lifting 4,100 lb of car and driver 1,800 feet takes
\nabout 3 kWh no matter how gently you do it.<\/p>\n
\ncost.<\/strong> This is the part people get wrong. “Regen all the way down the
\nhill” sounds like a refund, and it isn’t one. At 60 mph, drag and rolling
\nresistance are already eating roughly 10.8 kW; gravity on that grade supplies
\nabout 13 kW. Only the surplus<\/em> reaches the motor, and only about 70%
\nof that survives the trip back into the battery. Regen’s real job is not to
\nrefill the pack. It is to stop you spending, and to save the brakes.<\/p>\n
\ntwo rated miles, about 3% of the drive. A full-throttle pull feels expensive and
\nis nearly free, because the kinetic energy you buy is energy you then get to use.
\nThe penalty is just the efficiency of buying it in a hurry. Drive 85 instead of
\n70 and you will spend six times that much without noticing.<\/p>\n5. The cord, and what it quietly told us<\/h2>\n
\n24 A. That is the right setting: 24 A is 80% of a 30 A circuit, which
\nis what continuous load is allowed to draw.<\/p>\n
\n0.1 Ω<\/strong> — 2.4 V of drop at 24 A, 1% of the
\nsupply, 58 W warming the cable. Entirely fine.<\/p>\n
\n234 V at 24 A.<\/strong> Five volts for twelve amps is
\n0.42 Ω of source impedance<\/strong>, and the cord only accounts
\nfor a quarter of it. The other 0.32 Ω is upstream<\/strong> —
\nthe supply itself sagging under load. Two numbers in a screenshot, and the
\nweakest link in the circuit identifies itself without a meter.<\/p>\n6. What the charge actually ran at<\/h2>\n
\neleven minutes — is 20.2 rated miles per hour<\/strong>, or about
\n4.9 kW into the pack. Predicted from first principles: 24 A ×
\n234 V = 5.62 kW of AC, × 92% for the onboard charger =
\n5.2 kW, 21.4 rated mi\/hr<\/strong>. The measured average comes in
\njust under because of the last hour.<\/p>\n
\nit down — the car did, because it was at 98% and tapering, which is what
\nconstant-voltage charging looks like from the outside. Reading that number as
\n“the circuit is weak” would have been exactly wrong.<\/p>\nWhy 85%, and why not yet<\/h2>\n
\ntrips, because lithium cells age faster held at a high state of charge. The
\nexception is calibration. The car does not measure state of charge directly; it
\ninfers it, and that inference drifts. Charging to 100% and letting it rest gives
\nthe BMS the top reference it needs, and a deep discharge gives it the bottom.<\/p>\n
\nreally what is left. Then<\/em> back to 85% for daily use — and the honest
\nplanning number from here is not 251, and not 219 either. It is 85% of
\n60.7 kWh at whatever speed you actually drive<\/strong>, which at 78 mph
\non 280 is about 170 real miles.<\/p>\n
\n
\nanchored against this car’s own two drives; grade energy computed from mass and
\nelevation, regen credited only on the surplus left after drag. The model
\npredicted 158 rated miles for the Modesto run. The car reported 158.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"