Battery Breakthrough?

Battery Breakthrough?

What do you think about this? Sounds to me pretty much like a breakthrough. When could this technology be used in a Tesla EV?


Timo | 2 October 2012

That's actually old news here.

Answer is when it gets out of the lab and into mass production. When that happens is anybody's guess. Soon, I hope.

dgaz | 2 October 2012

I want to ask some questions about the battery but first would like to complain (take note I don't spend much time on forums generally) that this Forum is really confusing to me.

1) I tried to figure out how to start a new thread and couldn't figure that out so here I am.
2) I wanted to search the forum for threads having to do with a particular topic but haven't found a way to do a topic search.
3) Whenever I do look at an established thread it starts with the oldest message (sometimes years ago) and I have to go to the bottom of the page and request the last message - tedious.
4) generally I look at Tesla as a high tech company but I have experienced far friendlier and logial forums on numerous occasions.

Now to the battery questions:

1) It is known that batteries (including LiIon) degrade sitting still and do so faster at higher temperatures. So they will retain capacity better in Alaska than in Phoenix. I have been told by Tesla that the battery is cooled and kept at 70-75 degrees by a dedicated closed cycle cooling system. I've seen nothing about this on the website or on the forum (I can't search!). I'd like to know more about it. In Phoenix the average temperature during the summer over 24 hrs exceeds 75 degrees - does that mean the cooling is operating 24 hours a day? That is OK if at home charging but on the street at an average temperature of well over 95 degrees how many miles are lost per hour due to this active cooling and what is the life expectancy of a cooling system running 24/7 for months at a time over a number of years? AC system do do pretty well in Phoenix - so hopefully this system is really well engineered.

2) It is also known that the life of a battery is degraded if charged too rapidly. The recent "Super Chargers" are obviously charging at a very high rate. Charge rates are described in terms of the capacity (C) of a battery and charge rates of .5C and C are recommended. What is the rate for the Super Charger and how will the total life time cycles be impacted.

3) I understand the source of the batteries is Panasonic. On the Panasonic website I can find no guestimate as to the maximum number of cycles expected under various conditions. However it is generally known that shallow discharges per cycle, e.g 10%, give perhaps ten times the number of cycles of 90% discharges. However, if one thinks about the total miles driven it seems to come out to be about the same total miles of lifetime capability. But all of this assumes temperatures and charge rates are "proper"; how does active cooling and Super Charging play out in these considerations?

4) Once I saw a neat WhitePaper on Tesla's site about all of the really nifty techniques they were using to monitor the individual batteries for temperature and performance for safety and increased life expectancy. I don't know where it is now (and would like to re-read it) but it is dated anyway. Has anything of this nature been published recently? I imagine there is a lot that Tesla knows that I would like to know about when thinking of spending $100K on a car with so much short interest on the stock. I would think some of this info would influence others besides me!

5) Another very interesting tidbit I have been told by Tesla is that many (all?) of the the 7000 or so batteries are being monitored at all times (what parameters beside temperature and voltage?) and in the event a cell fails that in principle that single cell can be replaced. I'd be interested in the practicality of that as it would give me a lot more confidence that a multi-$K battery would not fail to the point of needing a replacement, but at what point - single cell, a block of x-number of cells, etc. - is it economically and practical to replace a few bad cells? I understand that if I treat my battery right it is covered by Warranty, but what I am getting at is the viability of the battery system for Tesla itself. If the batteries are really designed to be highly repairable then the warranty outlays will be much more reasonable.

Sorry to insert this here - maybe someone can move it (or them) to the right location?


Brian H | 2 October 2012

1) Go into the Discussions, and select General, Roadster, Model S, or Model S. On the right, above the two columns, are the options Post New Forum Topic and Back To Forum Home.
2) Search is unavailable except by using a standard search engine and including a site restriction string, such as '' somewhere in the search field. This applies to any engine and any site, of course.
3) If you are tracking a topic, when you open the discussion page the Replies column shows "x new". Clicking that number takes you to the most recent entries.
4) Agreed. The forum is minimalist and primitive, possibly the worst on the web. If not for the topic, and very occasional entries in General etc. from TM, everyone would use exclusively. As it is, it gets at least an order of magnitude more posts than this lame one.


1) One Roadster owner has had his car 4 years and lost only 2% -- in Alaska! But here's the Roadster tech page:
The best summary for Model S I found is here:
2) Various opinions/answers to this have been circulating. The latest appears to be, "use Supercharging as often as you need to; just don't overcharge on Range Mode".
3) Yes, total miles seems to work out the same. In effect, total "cycles" available means full discharge/recharge cycles, or fractional charges adding up to the same.
4)Don't know. Try the site search method above on the entire site, or .
5) Probably at the brick level (11 bricks in a battery).

Brian H | 2 October 2012

typo: "... Model S or Model X"

dgaz | 2 October 2012

Hmmm - for some reason I was not aware of (or forgot) But I tried to log in and have run into trouble getting in. I tried re-registering but nothing is working - even after I received my username and a reset password. Brian - maybe you could contact me directly to straighten this out.

Thanks for your answers - even though they were partial answers. I will follow up on your suggestions.

Timo | 3 October 2012

For battery cooling, think of it like freezer that you never open running at very low setting. The power drain is tiny, a good chest freezer that actually freezes things and not just drop temperature a few degrees use like 150-200kWh per year. I believe the parasitic load from onboard computer systems and other accessories are bigger drain than battery AC. This is at least if the insulation in the battery compartment is a good one (which I believe it is).

It gets more strain when you are driving because using batteries heat them up, but even then the impact is tiny compared to power requirement for simply moving the two ton block of metal at highway speeds.

Brian H | 3 October 2012

Dropping something from room temp to sub-zero and holding it there is different from draining heat generated continuously. But any heat pump is inherently highly efficient.

Here is the contact page:

Registration problems is one of the "options" to ask about.

jerry3 | 6 October 2012


-- cooling is operating 24 hours a day?

Basically, yes. There are a few tricks to make it even more efficient for Roadsters, but the Model S shouldn't require those because the batteries are liquid cooled rather than air cooled.

-- many miles are lost per hour due to this active cooling and what is the life expectancy of a cooling system running 24/7 for months at a time over a number of years?

This has not been a problem for Roadster owners. The Model S is even more efficient because of the heat pumps (the Roadster is air cooled).

-- On the Panasonic website I can find no guestimate as to the maximum number of cycles expected under various conditions. has many threads on these issues.

And it wouldn't really matter if you could because the way a single cell behaves is not all that applicable to an array of many cells.

-- thinking of spending $100K on a car with so much short interest on the stock.

It's generally bad news to bet against Elon Musk. You're best off thinking of the Model S as a $60,000 car with a $30,000 to $40,000 prepayment of fuel.

-- in the event a cell fails that in principle that single cell can be replaced

In the Roadster a "sheet" of cells is replaced, not an individual cell. The replacement mode hasn't been announced for the Model S, but the entire battery can be replaced in under five minutes.

-- does active cooling and Super Charging play out in these considerations

It's charging to 100% and leaving it there that does the damage. A standard mode charge is only to 80% and generally a super charge will be a 50% charge (30% to 80%). As the battery gets fuller the charging rate slows.

ggr | 6 October 2012

Correction to Jerry: the battery in the Roadster is also liquid cooled. The motor and Power Electronics Module are air cooled. On the Model S, everything is liquid cooled.

jerry3 | 7 October 2012

Thanks ggr

up north | 7 October 2012

what would be the ideal constant temp to keep my garage at.

jerry3 | 7 October 2012

If you are comfortable, then the car is comfortable.

Sudre_ | 7 October 2012

If the car is plugged in I don't think it cares what the temp of your garage is.

up north | 8 October 2012

lets go outside the garage. whats the ideal constant temp for the batteries not plugged in.

Brian H | 8 October 2012

Back on topic, yet another approach to "doubling charge speed":

BYT | 23 October 2012

If interested... Donald Sadoway: The missing link to renewable energy, TED Talk on the Liquid Metal Battery... Donald Sadoway is working on a battery miracle -- an inexpensive, incredibly efficient, three-layered battery using “liquid metal."

eliranngr | 27 October 2012

As much as I can see, no one talked or addressed another serious espect of using a battery in any electric vehicle, especially Model S and Model X, and that is its SAR (Specific Absorption Rate) exposure value.
It is well known that not only cellular, WiFi or other means of transition creates radiation that might effect a human tissue in the long term, but so do batteries.
Why isn't the Model S/X batteries SAR value being published along with the vehicles Specs?
Other then that- this is the most amazing revolution since the invention of the wheel itself. Huge LIKE from me.

Timo | 29 October 2012

Batteries don't cause any SAR. SAR is caused by radio frequency electromagnetic field, and there is no "radio frequency" with DC potential difference. Motor emits low power rotating magnetic field, but even that is very far from radio frequencies. In fact ICE engine spark plugs cause far more and stronger radio frequency interference than BEV motor.

danielccc | 6 November 2012

+1 Timo

I'll add that cell phones operate at gigahertz ranges, the same frequency range of microwave ovens. Tissue absorbs energy from radio waves at those frequencies. They literally measure SAR by seeing how much the temperature of a tissue equivalent warms (in the order of one degree). There is an argument as to the biological significance of this. Time will tell.

The car does not generate energy at these frequencies or anywhere near them (except for the cell antenna, and that if minimally well designed should be irradiated outside the cabin).

There have been claims that low frequency fields, like those generated by AC cables and motors, are also bad for health. This might be so at very high power levels, but is doubtful at low levels since we are routinely exposed pretty much everywhere.

Battery current is DC and creates no EMF. It does create a static magnetic field, but that's not even worth discussing.

The motor does generate a low frequency field, though I believe it's substantially shielded. It's not hard, any ferrous metal will do. Has this been a forum topic? I seem to recall something but not clearly.

Jolinar | 6 November 2012

@ eliranngr
Is it really well known? If so, why I don't know anything specific about that?
Can you please give me some reliable source of more information about batteries and SAR?

Timo | 7 November 2012

They literally measure SAR by seeing how much the temperature of a tissue equivalent warms (in the order of one degree)

(about phones) you can get your ear and surrounding tissues to warm up more than that by keeping a wooden block at your ear. Ears are one spot on human head that radiates heat quite effectively, and if that radiation is blocked you start to cumulate heat. I think that many "tissue changes" are caused more by that than that EMF that phone causes. Unfortunately EMF nutjobs probably count those changes to EMF radiation instead of just biological heat cumulation.

There is no evidence that normal electronics and radio traffic we use cause any biological changes that actually has any effect. I think the psychological effect to biology is way higher than physical (just the stress of being always "on alert" by carrying cellphone is one of the modern day problems. You can't actually relax and feel that you have no obligation to be available at all times just because you have a cellphone and not feel guilty when/if you turn it off).