Rob
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Post by Rob on Feb 9, 2017 20:47:57 GMT
Just reading something on the 18650 cells used in the Tesla Model S (they have a new cell for the Model 3). Suggestion is they won't last more than say 8 years... If that was true for even a few thousand of the cells that's not good for future owners. Expect even shorter life for hot climates.
And how labour intensive will it be to replace 7104 cells in the battery packs at a main dealer. And getting the cells transported in high numbers might be an issue - they're Lithium Ion after all.
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Post by lygonos on Feb 9, 2017 21:56:27 GMT
There is no metallic Lithium in a Li-ion battery. You likely have one next to your genitals in your mobile phone.
For longevity, temperature control is vital as well as not over and undercharging the cells - Tesla have liquid cooling for their battery packs and will likely last 10+ years/200,000 miles fairly readily.
Nissan LEAFs have been found to struggle in hot areas like Arizona as they do not have the same active temperature control.
Once a battery pack degrades, the usual disposal is to use it as static storage. They can be used to store energy at recharging stations so that when they are unoccupied the batteries can be topped up to enable sustained high output during busy spells.
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Post by Hofmeister on Feb 9, 2017 22:21:08 GMT
Ironically, the plant used for recycling the infamous exploding Samsung Galaxy li-ion batteries, has just caught fire.
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Rob
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Post by Rob on Feb 9, 2017 23:31:54 GMT
Apparently the Tesla's will limit charging when batteries are cold. Sounds fair enough. So they won't even do regenerative braking until the batteries warm up.
Whilst I can see the logic of more cells in battery packs to provide the necessary charge, etc. 7104 batteries a little bigger than AA's is not what I expected. But a battery life of only 10 years is crap. Well no it's not but the biggest 'single' cost in the Tesla is the batteries.
And I'd seen the news about the Samsung factory fire - ironic indeed.
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Post by lygonos on Feb 9, 2017 23:45:01 GMT
Who knows what the life expectancy will be - ultimately it will depend on what level of degradation a user will tolerate. There are a number of battery degradation charts on the web - this is a typical one (owners self-reporting the state of charge compared to new) ![]()  Even at 100,000+ miles the batteries generally manage 90-95% original storage so lifespan will be as long as the life of the car in some cases. Presumably in 10 years time there will be independent battery specialists who can repair or exchange battery packs? What I doubt there will be is a countrywide hydrogen network. |
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Rob
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Post by Rob on Feb 9, 2017 23:54:34 GMT
The Model S uses standard Li-Ion cells. And a lot of them. So probably no reason why anybody couldn't swap out faulty cells. Presumably there is intelligence in each battery pack to isolate faulty cells.
I just wouldn't want to be the one replacing all 7104 batteries/cells :-)
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Deleted
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Post by Deleted on Feb 22, 2017 10:36:14 GMT
I was waiting at some traffic lights this morning when a white Tesla Model S P90D pulled up alongside me to my right. When the lights went green, this thing took off in a manner I've never seen a car do on a public road. It was staggering, the speed at which it pulled away from me. Only ever seen such acceleration from a high powered motorbike, but this was of course in total slience. Awesome. The car got to the next set of red lights much more quickly than me. :-)
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Post by commerdriver on Feb 22, 2017 11:27:10 GMT
I was waiting at some traffic lights this morning when a white Tesla Model S P90D pulled up alongside me to my right. When the lights went green, this thing took off in a manner I've never seen a car do on a public road. It was staggering, the speed at which it pulled away from me. Only ever seen such acceleration from a high powered motorbike, but this was of course in total slience. Awesome. The car got to the next set of red lights much more quickly than me. :-) They kind of do that, even hybrids which usually move off in electric mode, can leave pretty much anything behind from a standing start. Somebody technical will be along soon to explain probably |
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Post by Deleted on Feb 22, 2017 11:34:17 GMT
I realised they were capable of such feats, I'd just not witnessed someone applying the right foot so dramatically before. I'd actually seen this geezer pull out of his drive, and then saw him arrive at his office almost next door to mine 5 miles later, so I expect he's quite happy to boot it every time as his daily commute is so low he's not bothered about range.
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Post by Hofmeister on Feb 22, 2017 14:49:14 GMT
I was waiting at some traffic lights this morning when a white Tesla Model S P90D pulled up alongside me to my right. When the lights went green, this thing took off in a manner I've never seen a car do on a public road. It was staggering, the speed at which it pulled away from me. Only ever seen such acceleration from a high powered motorbike, but this was of course in total slience. Awesome. The car got to the next set of red lights much more quickly than me. :-) They kind of do that, even hybrids which usually move off in electric mode, can leave pretty much anything behind from a standing start. Somebody technical will be along soon to explain probably Its because all the torque is available at anything above 0 revs. Electric motors have very flat torque curves, you get it all all the time. You'll never beat a leccy car off the lights tho they usually get caught by IC cars (of equivalent BHP per ton) at around the 60 mph mark. |
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Deleted
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Post by Deleted on Feb 24, 2017 22:31:52 GMT
It's about 45mph with a Toyota hybrid but in town the lights to lights race is huge fun vs a 535d. They just don't get going until a hybrid is braking for the next lights.
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WDB
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Post by WDB on Feb 25, 2017 7:06:08 GMT
Speaking of braking, do all hybrids (and full electrics) do the regenerative braking thing and slow down abruptly when you lift off the 'throttle'? With a Tesla, not only do you get the retardation, you show brake lights without touching the other pedal.
Tesla lets you turn this feature off, so that the car drives more like a petrol car on the overrun, but until you do - or adapt your driving style to always pressing one pedal or the other - it makes for rather jerky progress and some bewildered drivers behind. I followed a Model S the other day that was doing this, and if I hadn't driven and researched the S myself, I'd have blamed the driver for lack of acceleration sense.
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Deleted
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Post by Deleted on Feb 25, 2017 18:07:02 GMT
I've only driven a Toyota Auris hybrid, drive that on an autobahn when the batteries are drained the top speed reduces, back off the throttle and it's like hitting a brick wall, it grabs as much energy as it can and throws it at the batteries.
Not sure what the brake lights are up to, the retardation is definitely stronger than just backing off with an IC engine
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Rob
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Post by Rob on Feb 25, 2017 18:11:29 GMT
The Mercedes B250 electric/hybrid lets you vary brake regeneration with paddles on the steering column/wheel.
I would imagine the Tesla ranges quoted can only be achieved with some regeneration via brakes in the real world.
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Post by lygonos on Feb 26, 2017 0:21:28 GMT
I would imagine the Tesla ranges quoted can only be achieved with some regeneration via brakes in the real world.
Regeneration is better than friction brakes but is far from 100% efficient (~50% at best I believe) at converting kinetic to electrical energy - the best mileage is gained through coasting rather than regen (other than hypermiling techniques like being right up the arse of a lorry to reduce drag). The biggest range reducers are the speed being driven at and starting with a very cold battery (Merc use Tesla batteries which have active heating/cooling so they can be warmed through while charging to mitigate this).
It's best not to fully charge or near discharge Li-ion batteries - the B250e for example normally charges to ~78% of nominal capacity (it has a 36kWh battery pack but normally uses 28kWh for driving - using the 'range extender' button while charging allows the battery to fill to 89% (32kWh) but is meant for occasional use as it may accelerate battery degradation.
NEDC range is 124miles normally, and 142miles using range extender - real world is 80-100 and 95-120ish respectively going by owner reports.
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