Response to Robert Llewellyn's Ran-tastic rant about Top Gear

Poor old Robert's been sucked in by the electric vehicle hype and he needs to be called on his latest rant. Here are the facts.

Sorry Robert!

The Tesla Roadster isn't as cheap to run as you think.

Watch Robert's rant here: http://www.youtube.com/watch?v=LPi8EhT_fYA

Category:

Science & Technology

Tags:

• llewtube
• tesla
• roadster
• scrapheap
• electric
• vehicles
• EV

[WXIIIR]

P.S. I forgot to say that the lithium ion batteries in 2008 (date of the vid) really did only around 400 charges but FULL charges, not partial. Your everyday car has a flooded lead acid battery in it that only handles like 15/30 full charge/discharge cycles, but it lasts you some years using it everyday with partial charges doesn't it? Learn something more about how batteries behave and you will realize that your math is completely wrong.

[xjet]

@WXIIIR Actually, I use lithium batteries almost every day -- and in applications that are not too dissimilar to EV use. I was just remarking the other day that the packs I'm presently using have about 200 cycles on them (partial cycles -- I seldom discharge below about 45%) and are already showing signs of reduced capacity and increased internal resistance. These are "state of the art" packs purchased about 18 months ago. There have been no major changes to cells since then.

[WXIIIR]

@xjet and how much do you think they can take up to the point where they will only store 50% of the original capacity? Are you saying that lithium batteries are less durable than lead acid? I use 2x20ah 12v SLA batteries on my electric bicycle and i only use them to half capacity every time they have around 200 partial charges and still hold around 80 to 90% of the original capacity. Also my cell phone uses lithium, 5 years charging every day it lasts 2~3 days (originally was around 5).

[xjet]

@WXIIIR Lithium cells work very well with low charge and discharge rates but when you start trying to push current in and pull it out quickly, you get a much lower cycle-life. That's why your mobile phone works so well with a lithium battery but higher-drain devices (like EVs) are not so good. LiFePO4 looks like the best battery technology right now for cycle-life. Even in high drain/recharge use they have cycle-lives in excess of 1000 and sometimes 2000 cycles.

[WXIIIR]

@xjet Just remembered something. Do you do fast charging? On the cell phone example charging takes around 30min (bigger the battery longer the time) and on the electric bike a full charge would take 10hours (but only around 6 because i only use half capacity). Fast charging affects batteries very much, equalization, maintenance and topping charges are required for good battery life (if you also have a state of the art charger and plug the batteries regularly it takes care of that for you)

[xjet]

@WXIIIR yes, as I said -- charge rate (and discharge rate) are important factors. The problem with EVs is that to be viable as anything other than a commuter vehicle, there has to be some form of quick-charge capability. Li-Ion as we currently know it is not going to cut it. New battery technology will be the answer -- and there are plenty who say "in 5 years we will...." but right now, nothing.

[xjet]

@wingpilot87 Thanks for your valuable feedback. I think you caps-lock key needs attention though. It's now two years since I posted that video -- and still we *still* don't see any affordable electric vehicles on sale in high-street car dealerships. Yet I guess you're right, I must be lying. Mea culpa.

[xjet]

@cmusty It's not about when "electric vehicles are a majority" -- it's about when electric vehicles are even practical. If they *were* practical right now, with oil prices soaring, why aren't people using them? Simple -- because they're *not* yet practical. Not rocket-science.

[FeelinGipper]

You are the man, Bruce!

[WXIIIR]

@chappy0061 I didn't even talked about conversion. A guy that lives near me converted a fiat 127 in his garage and put a 15hp brushless motor and lead acid batteries, it reaches 130km/h, has around 120km of range on 50% charge, if it had lithium instead of lead it would have around 600km range on half charge with the same weight (around 800kg). Electric production cars aren't better yet because brands don't want them to. If you do your own EV (even if its a bike) and some math you will confirm

[chappy0061]

@WXIIIR The current workshops who convert petrol cars into electric ones do so using the existing inefficient running gear and driveline. Most of them also still rely on lead acid batteries.

This results in lousy acceleration and lousy range, for a stupid price.

Not practical.

[WXIIIR]

@xjet Agreed, LiFePO4 is a very good technology. Nowadays EV's have a high drain for sure, i didn't factored that so you are absolutely right. But it's stupid though, because they don't need to, and shouldn't have so high drain (but unfortunately they do). What is the point in sticking a 100hp(ish) electric motor in an electric car (like prius or leaf)? I did the math once and nowadays electric cars consume almost the same amount of energy as fossil fuel cars because of being poorly engineered.