Fremont polices Tesla in high speed felony chase ran out of battery power! - Page 1
Forum section: electronics / general

author: MT
author_rank: Super Contributor
timestamp: September 26, 2019, 02:19:02 am
content: “I’ve got to try to find a charging station for the Tesla so I can make it back to the city,” Hartman said.https://www.mercurynews.com/2019/09/24/fremont-police-tesla-runs-low-on-juice-during-high-speed-chase/

author: james_s
author_rank: Super Contributor
timestamp: September 26, 2019, 02:30:10 am
content: Seems like an odd choice of vehicle for a police cruiser. Fragile, very expensive to repair, high purchase price. I suppose they probably just stole it (asset forfeiture) from an accused drug dealer though.

author: windsmurf
author_rank: Frequent Contributor
timestamp: September 26, 2019, 02:38:44 am
content: Fremont is where Teslas are made. Most likely it was donated by Tesla to the city PD.EDIT:Nevermind... they bought it used.https://www.digitaltrends.com/cars/tesla-model-s-police-car-hits-the-streets-in-fremont-california/

author: floobydust
author_rank: Super Contributor
timestamp: September 26, 2019, 02:42:47 am
content: Tesla Model S 85, 0-60MPH around 3.2 seconds and quarter mile time of 11.7 sec 113.7MPH- is very fast.Dodge Charger police package... 5.7L engine 0-60MPH in 6.0 seconds and quarter mile time of 14.6 sec 97MPH."Fremont Police Department bought a single used 2014 TESLA Model S 85 in January 2018 for $61,478.50 (including taxes and fees) to replace a 2007 Dodge Charger that was being retired in their fleet."It's supposed to have payback on maintenance compared to internal combustion engine.edit:GM has high-speed pursuit detection in their ECM firmware. I wonder if Tesla has it?If you're full throttle most of the time for several minutes, or extended high speeds >120MPH, it dials back engine power, to give the police a chance to catch you. Feature disabled for police interceptors.There are production automobiles faster and more nimble than what the cops drive.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 26, 2019, 02:47:24 am
content: How long before someone develops some sort of grappling hook or something to attach itself to the target car and then allow the cop car to be pulled by the target car so it would be the target car that runs out of power first. (Would make an interesting Mythbusters build!)

author: james_s
author_rank: Super Contributor
timestamp: September 26, 2019, 02:49:52 am
content: It may come out ahead in terms of engine maintenance, however I bet it will be damaged in some sort of collision sooner or later which will be exceptionally expensive to repair. Pursuit vehicles very often have to ram or pitman maneuver the vehicle they're chasing.

author: amyk
author_rank: Super Contributor
timestamp: September 26, 2019, 02:50:04 am
content: Quote from: floobydust on September 26, 2019, 02:42:47 amThe Charger may not be as quick off the line and in the 1/4 mile, but it will travel far longer on a tank of gas than a charge of the Tesla.

author: floobydust
author_rank: Super Contributor
timestamp: September 26, 2019, 02:54:01 am
content: Car runs out of gasoline... either the gasoline tank or the batteries might be low - it's just misfortune to be unprepared for a chase?

author: wraper
author_rank: Unknown
timestamp: September 26, 2019, 03:02:42 am
content: Quote from: james_s on September 26, 2019, 02:30:10 amNothing wrong with Tesla, stupid police. Started pursuit with almost empty battery. If you forget to fill gasoline car, result will be exactly the same.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 26, 2019, 03:29:28 am
content: Quote from: wraper on September 26, 2019, 03:02:42 amExcept it takes 20 minutes to charge a Tesla just to halfway even with a supercharger whereas with a gas car you just grab a jerrycan and dump it in less than a minute. So if you are running the Tesla a lot, odds are you will run out of juice due to the amount of charge time.

author: magic
author_rank: Super Contributor
timestamp: September 26, 2019, 06:52:46 am
content: Another falls for the hypeQuote from: NiHaoMike on September 26, 2019, 02:47:24 amI estimate one year before a bystander gets killed in an accident involving that contraption.

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 26, 2019, 07:21:32 am
content: Quote from: NiHaoMike on September 26, 2019, 02:47:24 amWoefully complicated contraptions in high tension situations are a terrific idea that can only go right.

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2019, 10:20:22 am
content: Quote from: floobydust on September 26, 2019, 02:42:47 amThat seems like an odd story. It is way more likely the cooling system isn't adequate to run the engine at full power for more than a few minutes.

author: TERRA Operative
author_rank: Super Contributor
timestamp: September 26, 2019, 10:52:56 am
content: The grappling hook idea was already done in one of the Fast and Furious movies, but they added EMP capabilities to it too.

author: tom66
author_rank: Super Contributor
timestamp: September 26, 2019, 11:04:48 am
content: I don't see news stories when the Dodge Chargers run out of fuel...?

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2019, 12:23:40 pm
content: Quote from: wraper on September 26, 2019, 03:02:42 amBut you can fill-up a gasoline car in less than 5 minutes and catch up again. A police car will have much less delays due to red lights and being slowed down by traffic.

author: dr.diesel
author_rank: Super Contributor
timestamp: September 26, 2019, 12:35:06 pm
content: You can't outrun the Motorola, as the old saying goes, these people rarely get away for long.Too bad the story doesn't bother to cover if the suspect was ever caught.

author: floobydust
author_rank: Super Contributor
timestamp: September 26, 2019, 12:36:59 pm
content: Quote from: nctnico on September 26, 2019, 10:20:22 amuh a friend disassembled the firmware in a GM ECU, long ago. When hacking something was for fun and learning.We got stumped on the safety routines.There was a full-throttle event counter and integrator to detect if a vehicle is being driven in a malicious manner. You would not go on/off hard throttle 20 times in a few minutes or stay full throttle for a minute while picking up groceries and beer.The code would set a latch and progressively retard ignition timing and disable power-enrichment fuel, putting it into "granny mode" as I called it. The engine would get increasingly weaker. There was also vehicle speed limiting code. Not all cars can drive the Autobahn before aerodynamics and handling crap out.I thought it was police associations lobbying car makers or Congress for this, to lessen high speed chase carnage. The Corvette code was likely different I'll have to investigate, as it is a performance car that could be driven on a race track.In a high speed chase, engines don't overheat because they are getting plenty of airflow.Most of the heat is from the exhaust manifolds, so a chassis dyno without a big fan will quickly have exhaust glowing orange hot and then an engine (exterior) can overheat and roast exhaust valves.Tesla would have routines to limit thermals on the battery pack, electric motor and drive, to protect the car. I wonder if police car applications were considered, or if this high speed chase triggered code to fake a dead battery?

author: Siwastaja
author_rank: Super Contributor
timestamp: September 26, 2019, 12:46:15 pm
content: I remember seeing news of police cars running out of fuel during chases, maybe decades ago, more than once. They are very small news (if at all), won't make headlines. Tesla, OTOH, makes headlines.Whether fueling takes 3 or 30 minutes is irrelevant. Both are way too long during a high-speed chase.In any case, high-speed chases are an overemphasized part of police work of getting the criminals caught. Methods that do not risk the bystanders are / should be preferred whenever possible.

author: wraper
author_rank: Unknown
timestamp: September 26, 2019, 12:58:00 pm
content: Quote from: nctnico on September 26, 2019, 12:23:40 pmLOL, as if criminal will wait even 30 seconds for police to catch up and care about traffic lights.

author: tom66
author_rank: Super Contributor
timestamp: September 26, 2019, 01:13:09 pm
content: Quote from: nctnico on September 26, 2019, 12:23:40 pmI suspect that any cop in a high speed chase that pulls over for even a minute is no longer going to be in that chase.I also wouldn't be surprised one bit if a Tesla has better range than say a Dodge Charger when it is hammered. EVs generally are more efficient than gasoline vehicles under high loads, especially because much braking energy can be recovered by regeneration.

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2019, 01:25:15 pm
content: Quote from: wraper on September 26, 2019, 12:58:00 pmBut other cars will block the road while waiting for a traffic light. Same for crossing traffic.

author: wraper
author_rank: Unknown
timestamp: September 26, 2019, 02:12:09 pm
content: Quote from: nctnico on September 26, 2019, 01:25:15 pmIn very select cases when there is no way to move around at all. Also if stuck in traffic, criminals usually just leave a car and run.

author: MT
author_rank: Super Contributor
timestamp: September 26, 2019, 02:12:55 pm
content: Quote from: wraper on September 26, 2019, 03:02:42 amConcur police stupid choosing Tesla as police car.

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2019, 04:23:57 pm
content: Quote from: wraper on September 26, 2019, 02:12:09 pmOnly if the police are chasing them. So filling up in 5 minutes is not a problem. Catch them at the next traffic light. And as someone else noted: nobody can outrun 'Motorola'....

author: nctnico
author_rank: Super Contributor
timestamp: September 26, 2019, 04:29:18 pm
content: Quote from: tom66 on September 26, 2019, 01:13:09 pmDon't think so. ICE engines are the most efficient near maximum load versus RPM (this is not maximum power output). Or more precisely: when run at near full throttle. Besides that the Tesla has a serious weight disadvantage especially when needing to go through some fast corners; the regeneration tops out at 60kW so the rest of the energy will be burned by the brakes. Remember kinetic energy goes up square versus speed so any extra weight is a killer.

author: tom66
author_rank: Super Contributor
timestamp: September 26, 2019, 07:06:17 pm
content: Engines are more efficient at high loads? That is not really correct. At around peak torque optimum efficiency is achieved, but this is far away from the "flooring it" type of driving that a police chase ensues, with the engine operating near to maximum rpm.An electric vehicle will suffer a fall in efficiency at maximum power, but the decrease will be from around 90% to 60% (depending on resistive losses due to I^2 * R) whereas a gasoline engine will fall from a best-case efficiency of 25% to less than 10%. The relative drop is far higher for the ICE.I have gathered some data from my Golf GTE's powertrain, comparing fuel input to power output, that demonstrates this.The benefit an ICE has is that liquid fuel is easily stored so a police car might have extended fuel tanks, also the engine can generally get much hotter without risking catastrophic failure (just tends to shorten its lifespan somewhat.)

author: duak
author_rank: Super Contributor
timestamp: September 27, 2019, 04:19:11 am
content: I've been helping a neighbor out with his race car, a 1960 Austin-Healey Sprite with a 1.3 litre engine. Event by event, we've been making it reliable by breaking then finding and replacing the weak links. On the first day of a two day event, we got it to where it was fast and about as bulletproof as it was going to get. I didn't come to the track until the afternoon of the 2nd day. When I got there, it was barely running and wouldn't even complete one lap. The owner figured it was ignition and was making some new ignition cables. I went over the symptoms and what he had done and then checked the fuel level with a stick. Drier than a popcorn fart. Even though we'd filled it up the previous day, because it had never lasted that long before we didn't think it would use all the fuel. We figured it used up more than five gallons (Imperial) to go less than 40 miles for warm-up, qualification and one race. Less than eight miles per gallon to put out maybe 75 HP at its peak?.It's said that speed costs money - how fast can you afford to go?

author: benst
author_rank: Regular Contributor
timestamp: September 27, 2019, 11:01:58 am
content: It looks like the original news article describing this was a bit of click bait. Here is an official response from the Fremont Police Department:https://www.facebook.com/FremontPoliceDepartment/photos/a.210771958992325/2452175384851960/?type=3&theaterBen

author: james_s
author_rank: Super Contributor
timestamp: September 27, 2019, 06:21:53 pm
content: Let's not turn this into yet another general EV vs ICE threads please. This seems to happen in every single thread that has anything to do with EVs.

author: wraper
author_rank: Unknown
timestamp: September 27, 2019, 06:42:51 pm
content: Quote from: james_s on September 27, 2019, 06:21:53 pmYou don't need to turn it into such. It already is such in the nutshell meaning from post one and clickbait news source it originated with. Some car ran out of charge/fuel, it's sure news worthy of global prominence.