A boom. Then a bust. And now, a new equilibrium?

The title of this post could very well apply to my enthusiasm for blogging (although it really is meant to reflect the state of the battery industry). 

The last time I made regular posts (I’m not counting the one-off posts in the last couple of years) was in May 2012.  In the meantime, a lot has happened in the world of batteries.  But I have not been writing about them.  Early last year, I noticed that I was unable to even access this site and it was auto forwarding to a different website (and no, the website it was directing to was not really that exciting!).  Apparently one of the widgets (like Digg, or equivalent) had been compromised and was taking over the site.  Welcome to the problem of monetization on the web and the unsavory practices it promotes.   

I had a personal reason for the lack of activity on this blog.  We had a kid in August 2012 and my weekends were spent trying to design a battery-powered diaper-changing robot rather than writing.  But the timing coincided with the precipitous drop in cleantech after the boom in the 1^st decade of this century.   All of cleantech was taking a beating; deal flow was nonexistent; and the whole startup scene in cleantech appeared to be dying.  

I was fully expecting battery startups to collapse and the whole sector to take a beating.   Some of this did happen: a few companies went under; few others cut back (and continue to do so); all of them started conserving cash.  I was fully expecting the interest in batteries to go back to pre-boom times.  This blog was not meant to be a spot for rumors and news, so what does one write about?

Surprisingly (!), I have been wrong.  

Folks are still starting companies.  Some are bootstrapping; others are getting small investments.  Series B and C investments are still happening, although valuation are probably not be where they were in 2010.   I don’t have any hard numbers, but I seem to hear about a new company every few weeks or so.  Anecdotally (and surprisingly), it does appear that there is growing activity in batteries.

The last battery boom was fuelled, in part, by the hope of replicating an A123: “If A123 can make a product and get a contract with an OEM in a few years, maybe we can do that too”.  Now we know that it takes thrice as long, and three times as much as we all thought (how we can accelerate this will be the subject of a future post).  So, what is driving the renewed interest?

This aspect requires exploration.   

On the other hand, these are interesting times indeed in the world of batteries. Tesla’s gigafactory promises to decrease cost of Li-ion batteries to less than $200/kWh over the next few years.  There have been claims that the costs could go down even further.  In a blog titled “One battery chemistry to rule them all” I argued that there is no winning chemistry.  For cars, I argued that Li-ion will win, but the specific chemistry is far from clear. For grid storage I argued that the time of discharge was so varied that it was pretty much impossible to predict which chemistry would win. 

Here is a quote from that article “Each chemistry has its pros and cons. There are four criteria one looks for in a battery: Cost, life, performance, and safety. No one chemistry is the magic bullet that satisfies all these criteria. Each choice leads to a compromise. As of today, it appears hard to predict the winner.”

That was 2010.  This is now.  How things have changed!

Li-ion has gotten cheaper and will get cheaper in time.  Tesla’s play is going to force all the other companies to also embark on vertical integration.  In commoditized markets like energy, cost is the main driver.  Of the four criteria, cost ends up being THE important one.  And the one who holds the cost advantage is well poised to be a winner. 

How does a non-Li-ion battery company survive in times like this?  Would they ever get the scale up to the point where their cost would compete with the big Li-ion players? Who would fund these companies to reach that scale?  Would Li-ion become the silicon solar cells equivalent, killing all other chemistries? What is the floor on Li-ion battery costs?  Would the vertical integration exclude some classes of Li-ion favoring others?  Would the locked-in investment in a certain form factor of batteries relegate newer (possibly better) designs to the sidelines?

This aspect also requires exploration. 

But the cost reduction from the big players, and the promise of the bit less than $200/kWh battery is not enough.  Cost targets for a 200-mile electric cars stand at $125/kWh for mass commercialization.  My gas-powered Subaru goes almost 400 miles on a tank.  If we decide EV’s need to have the same range, then the cost has to be even lower.  We probably do need these batteries to last 15 years as opposed to the 7-8 years that they are expected to last.  And would we ever find ourselves (in some distant future) charging our batteries in a few minutes as opposed to hours? 

Everyone says that we need batteries at $100/kWh for the grid.  Some have argued that this is not enough.  I have seen numbers that suggest that we need to be at $50/kWh if we want to cut the (electric) cord and use solar generation and battery storage and be at cost parity with the grid electricity.  And do we really want to replace our battery every 8 years?  And how big a Li-ion battery is one willing to put in ones home?  When I see PR announcements on behind-the-meter residential storage batteries, the battery guy in me knows that I would not want a significant fire-hazard adjacent to the walls of my house!  

From a pure technology perspective, the multitude of chemistries has a place in this evolving world.  Flow batteries do make sense, in long discharge-time applications.  Advanced lead-acid may very well be the ultimate chemistry, if we can solve the cycle life issues.  Other aqueous systems could all provide cheaper, safer alternatives to Li-ion, if we can spend time and resources (as we did with Li-ion) to get them to meet their potential.  The next generation of Li-based systems and non Li-based systems may very well be needed for the next jump in cost to occur. 

In most battery people’s minds there is a roadmap (akin to that in semiconductors) on the future generation of batteries.  Today we have Li-ion, then we would move to the advanced version’s of it with newer anodes and higher voltage cathodes, then onto the metal-based anodes allowing next generation cathodes to come in and so on.  This is the roadmap that the big players will follow.  But we also need to think about enabling disruption and changes to this roadmap that allow leapfrog innovations. 

This needs careful thinking. 

When I first started this blog (on Feb 9, 2010), there was so much activity (and noise) in batteries that I felt that there needed to be a forum to talk about it and set the record straight.  I had thought that, after the bust, the need was gone.  Clearly that is not true.  There is a need to talk about the lessons learnt from the last boom-bust cycle, the changing landscape, the roadmap for development of new batteries, the market drivers and challenges etc. 

TWiB is an ideal forum to have this conversation and so I have decided to bring it back to life.  I need to think about a sustainable way to do that, so that my busy schedule (you will be amazed at the number of Netflix shows I need to catch up on) does not stop activity on this site.  There is great stuff on the web on batteries and cleantech, but I can’t find anything that has the kind of close juxtaposition of technology and market analysis that TWiB brings.  And I’m a lot more entertaining (?) to read. 

So stay tuned. 

Venkat 

p.s.  All these topics would be discussed at the 2015 Bay Area Battery Summit on Nov 3 2015.  Click here for details

2015 Bay Area Battery Summit

Folks:  As you all know, these are very interesting times in the landscape of energy storage.  Batteries are getting cheaper, and promise to continue to drop as vertical integration becomes more common.  We are seeing more EVs on the road and stationary storage, both on the grid and behind the meter, is starting to become part of our conversation.  But we still need better technologies.  Can we get batteries to last 25 years?  Can we make them more energetic so that we recharge them less frequently?  Can we get them to charge in 15 minutes? 

These are important questions however, technology is only part of the solution.  The business climate is changing rapidly.  Startups like Seeo are getting acquired and I believe that this is the start of a new trend.  I'm seeing more energy startups getting into this game after a hiatus of almost 3 years.  I'm seeing more investors put money into batteries.   Lawmakers all over this country are paying attention and starting to wonder how they can make a difference.

On Nov 3, we will bring together experts to discuss all of these aspects: including the present status of battery technology, lessons on how to succeed in the market, how start-ups can compete with big players, does policy help or hinder, what new innovations are important for investors.

With keynote talks, technology updates, and panel discussions, we hope to have an in-depth conversation on the status of the technology, the market challenges, and the role of policy.   At the end of the day, we will have a reception with posters that showcase the latest in the technology.

Some of the Keynote speakers include:

• David Hochschild, Commissioner, California Energy Commission
• Mateo Jaramillo, Director of Powertrain Business Development, Tesla Motors
• Danny Kennedy, Managing Director, CalCEF, and President, CalCharge
• Cheryl Martin, Former Acting Director, ARPA-E, Founder, Harwich Partners

• Hany Eitouni, Chief Technology Officer, Seeo Inc. 
• George Crabtree, Director, Joint Center for Energy Storage Research

 Whether you are an energy storage researcher, developer, policy maker, or investor, you will find the meeting to be of interest. So join us at this exciting event.

For more details, click here

To register click here

Are you charged up? Because we are ready to go!

Succeeding in the battery space is hard.  One needs a technology that has some advantage over existing technologies; the advantage has to be large enough that one can compete with existing players, especially ones that are in Asia.  The technology has to be manufacturable at a low cost so that one can compete without requiring a large cost premium.  And one has to to maintain the advantage as competitors try to catch up.  

But its not just about the technology.  If you don't have a technology that satisfies a market demand, then its equally likely that the company will not succeed.  

And in some markets your efforts may be stymied by the regulatory policies that may prevent the battery being developed from being used. 

What this means is that to succeed, you need to have the right battery technology, the right manufacturing methods, go after the right markets, and use regulations to your advantage.  Tall order for any one person to do by themselves!

So how does one learn about all of these things?

Say Hello to CalCharge: The consortium that Berkeley Lab and CalCEF have formed to accelerate innovation by forming a regional innovation cluster. Read about CalCharge here.  

CalCharge has teamed up with San Jose State to start what we are calling "Battery University"- a professional educational program that will address the technology, market, and policy challenges. You can learn all about this and get the latest news about batteries in California at a kickoff event scheduled for next Tuesday Feb 12th at 6 PM at the Network Meeting Center in Santa Clara.  

Former Senator Bingaman, who was the Chair of the Senate Energy and Resources Committee, will provide us his views on storage, the importance of regional innovation clusters, and the role the federal goverment can play. We also have a roster of great speakers from SJSU, Applied Ventures, and Proctor and Gamble.  

More importantly, you may even have a chance to see me speak. 

Learn all about it here. 

It is the start of something great.  Its a good way to learn about storage, and to network.  We will even have a setup to watch the State of the Union at 6 PM before we launch into the program for the day.  

So come join us to get charged up.  

Venkat

 

And here are the lucky winners

I have a new found respect for movie actors (not stage actors, mind you).  Being in front of a camera makes you self conscious in a way being in front of an audience does not.  I can see why Arnold stuck to one liners! 

Anyhooo... last week, I asked via a video blog to send in your questions on all things batteries.  The response was infinitely better than I expected (ponder that sentence for a second and you will see two ways to interpret that). I answered a few of the questions.  

The questions were all very interesting ranging from how we can make a battery that is five time better and five times cheaper to how one can become a battery scientist (start a blog?). 

The clip with the answers is below.  I assume there will be followups.  You can post them in the comments and I will answer them.  It may be during the Holiday break, but I will answer them.  

Venkat

Ask and you shall receive... maybe

This is a bit embarrassing.  TWiB is getting updated twice in a week!  I shall try to average things out after this by not posting for a couple of years!  Just kidding folks.  Changes are on the way.  2013 will be a bonanza for all seven of you.

But, let us get back to the task at hand.  My Lab has decided that sitting on planes all day is not really "doing work".  So I have been asked to get some tangible things done for a change.  But first, they would like me to prove that I actually know something about batteries!

So, please watch the video below and ask your questions.  I will be answering a few of them next week in another video blog.  

So ask away.  

Venkat

What’s all this hubbub about a Hub?

All seven of my fans are aware that I have not been blogging much over the last year and a half.  Part of the reason is that I had, for all practical purposes, relocated to Chicago since the summer of 2011.  I (and many others) spent that one year working on a proposal with Argonne National Lab, which culminated in an announcement that our team had won.  The proposal was for an energy storage (i.e. battery) hub.  This is great news all around.  I have gotten a lot of questions on this, so I decided to write this post to get some information out. 

First, the announcement from DOE is here.

Now comes the FAQ.

There is already so much battery research going on.   What’s the big deal?

Ahh… the million dollar (or the $120M) question!  There is a lot of wonderful battery research already happening (and I’m part of a couple).  But we have very big challenges.  We need batteries that have 5 times the energy density of today’s batteries and have to be 1/5 the cost.  Right now, battery energy densities evolve at just 5% a year!  So the Hub is doing three things that are very different from existing battery efforts:

1.  It puts scientists and engineers, materials researchers and theorists, industry and academia all under “one (virtual) roof.”  This idea is not new (Bell Labs comes to mind and this was essentially Energy Secretary Steve Chu’s vision when he started the Hub proposal process), but it is new to batteries.  And doing this in a deliberate fashion instead of hoping for self-assembly is very important.

2.  It embarks on a new process of innovation.  This is a bit too detailed so I will not elaborate more, but let me just say that what we are planning to do in the Hub is very different from what has been tried in the past.  We hope that this new way of looking at batteries will help us find completely new materials that store energy, beyond what we can dream of today. I’m really excited about this.

3.  It brings together researchers who really understand batteries and puts them in close connection with folks who are experts in, say, materials, but who might be new to batteries.  I would posit that innovation occurs when this connection is made and new thought is brought to an old field.  This, too, is something that can be a game changer. 

But 5 times increase at 1/5 the cost in 5 years?  What are you smoking?

Folks who read my blog posts will know that while I may have one or two flaws (although nothing comes to mind at this moment), naivety isn’t one of them!  We fully appreciate the difficulty of the goals.  But this is what the world needs.  If we want electric cars (EV) everywhere and a way to store energy from a solar panel on our roofs, we need to do this.  That is the bottom line.  Let us not be naive in what the world needs.

So we are dreaming big.  But we are not violating any laws (well… maybe Moore’s Law for batteries, but not any laws that actually matter, like, Faraday’s Law).  These are theoretically possible.  It is however, hard. Very hard.  Hence, the need for a Hub.

And talking about smoking, it’s not all about energy and cost.  Safety will be an important aspect of our studies.  So will battery life and efficiency. 

I don’t care about EVs.  However, I do want my iPhone to last a bit longer. Can we get a Hub for that?

Anyone who really understands batteries will tell you that a good battery is a good battery.  So, on the way to making a better EV battery, we will probably make a better iPhone battery. Actually the path to an EV goes through the consumer electronics world. 

Our focus, however, will be on better EV batteries, and better grid storage batteries.  Think long discharge times.

Think long life.

Think cheap. 

So, what is this, a new kind of Li-ion battery?  Aren’t those like 20 years old or something?

First off, today’s Li-ion battery is not the same as your father’s Li-ion battery.  Far from it.  Having said that, we are looking at things that will go beyond Li-ion.  Actually, if everything works well, we may have a new kind of battery, which may have no lithium in it. 

What is Berkeley Lab’s role in this? 

Berkeley started working with Argonne on this proposal three years ago.  Our efforts intensified a year and a half ago.  Argonne and Berkeley Lab are the two big labs in battery research in this country focusing on vehicle batteries.  Our team was rounded out by labs and universities that brought grid storage experience and other specific expertise.  And we tied in with companies to ensure that we can deliver something scalable and manufacturable. 

Berkeley Lab has a very well known battery program already that understands everything you need to know about a battery and can translate fundamental knowledge to lab-scale prototypes, a very well known materials sciences program that can make any material at any scale, computing facilities that can predict things that have never been possible before, and a bunch of user facilities that can help see things at scales that are unprecedented.  We will be using all this in the Hub. 

You can read about the Battery Lab role here

Material Science, computation!!  Why are we spending tax dollars on these ivory tower projects? Can we get a job’s Hub instead?

Funny you should ask.  One of the underlying principles of Hubs is to get stuff out the door.  It is not science for the sake of science, but science with an impact.  This ethos is built into the Hub.  There will be hiring of not just postdocs and students, but training of the next generation of scientists and engineers.  There will be technology transfer to our industry partners in the Hub and to other companies that we have ties with. And, we will be moving things to the marketplace via startup companies.  We are trying to build a complete innovation network.  I wrote an op-ed recently in the San Jose Mercury News on how these networks will be critical in creating jobs.  You can read that here.

So, is Silicon Valley going to move to Chicago? 

Please.  Get real.  Chicago is a plain. Not a valley (I think).  So, Storage Plain, maybe?

But seriously, Chicago is trying to get a Silicon Valley-type idea in place focused on batteries.  So are Michigan and Boston (although they have a head start). 

Probably the biggest such collection of companies in batteries is located right here in California.  A few months ago, Berkeley Lab teamed up with CalCEF to start CalCharge, an innovation consortium focused on batteries.   You can read about it here.   

I’m really excited about CalCharge, too.  In addition to all the battery research in California, the Hub will provide us with more tools to innovate.  We are now very well poised to move technology to market in a rapid fashion. 

So, No. Silicon Valley will not be moving to Chicago. Instead, we will have four centers where innovation ecosystems will thrive.  And they will all help create jobs. 

Now that you are not travelling, can we expect more blog posts? Or, at least a change in title to, “This Year in Batteries”?

Maybe.  But I’m beginning to realize that I have missed a full year of TV watching.  Numerous episodes of Sherlock, Downton Abbey, and This Old House beckon.

But let’s not start jumping to changing titles just yet.  Lord knows how many more months it will take to get back my seven readers to the new site.  TWiB will be going through a change (based on a suggestion by a colleague).  Stay tuned.

Venkat 

Are you tired of Li-ion yet? Then it’s time to go beyond it.

Those of you who are faithful followers of this blog (all 7 of you) should know that I come from the school of thought that you always need a better battery.  I even have a law for this, which I call the zeroth law of batteries and it states:

The performance of any battery will fall (just) short of our expectations irrespective of the complexity of the device it is powering.  

This is true for our cell phones and Roomba’s.  And true for electric cars and plug-in cars.

That is, unless you have low expectations. 

The world has seen some dramatic changes in battery technology over the last 20 years, ever since the Li-ion battery became commercial.  For one, the smartphone revolution would not have occurred if not for the batteries.  A lot of improvements are still possible with lithium-ion, and we project that battery energy densities will double when we succeed in controlling more energetic anode and cathode materials. 

But what happens after that?  At the pace at which my smartphone is evolving, with Retina Display screens, 4G networks, and movies playing off of the air, it’s hard to see a doubling in energy being enough. 

Question then is: What is after Li-ion batteries?  And is there something out there?

The answer is: Yes.  But getting there is not going to be easy. 

I wrote about this in two blog posts titled “A brief history of batteries- Part 1” and “Part 2”.  These two posts describe possible battery chemistries of the future and make the point that to succeed we really need to understand the past.  And it is written in the style of the movie “Pulp Fiction”. Can any battery textbook beat that?

I would suggest that you read this blog post first. 

Once you do that, you will want to know: So what is the progress in these chemistries in the two years that have elapsed since the blog post? 

You will get an answer to this question if you show up at the Claremont Hotel in Berkeley CA between June 5-7, 2012 (a month from today)*.  This will be the venue of the 5^th in a series of symposia titled “Beyond Li-ion”.  In a 2 ½ day period various researchers, who are at the forefront of this field, will tell you what the latest trends are. 

It is an impressive speaker list, which you can see here. 

As a bonus, you will get to come to Berkeley Lab to see our Lab facilities.  More importantly, you may (I should emphasize the fact that this is a real possibility) actually get to shake my hand! 

To attend you will need to register, which you can do here.   

Hope to see you all (and I mean all 7 of you) there. 

Venkat

p.s.  Please don’t ask me to waive your registration fee.  Being a co-organizer means that I write blog posts to promote the meeting. It does not mean that I can come up with the cash to pay for your meals.




* The previous version wrongly gave the date of the conference as July.  It is June 5-7, 2012  

TWiB is back (hopefully with actual content next time)

Over the last year numerous (!!) folks have asked me why I have not written a blog post.  Even at the best of times, the title “this week in batteries” was a wee bit optimistic.  A better title would have been “this month in batteries”, but TMiB is not a pronounceable acronym.  But the last year has been particularly slow going at TWiB. 

Turns out that I have been extremely busy this last year.  We had decided to remove cable television and move to using a Roku box with Netflix.  You will be amazed at how long it takes to get through all the seasons of Lost, CSI, 24, Community, and the rest Netflix’s content (answer: a year!). 

Anyway, all good times come to an end and I’m pretty close to being stuck with watching things real time. 

While I’ve been glued to the box, many things have changed in the battery world.  President Obama decided he wanted EVs Everywhere, my home state of CA decided that they wanted 15% EV and PHEVs by 2025, and Governor Brown has decided he wants charging stations everywhere.

Meanwhile, battery energy densities, after evolving at 5% a year, doubled this year. 

Simultaneous, one battery company declared (Chapter 11) bankruptcy, another company is having financial difficulties, cars are catching fire, and batteries are catching fire. 

To top it all funding to cleantech seems to be getting harder. 

Is there a mismatch between what the government wants to see and what batteries can deliver?

And are we about to hear a “pop” (of a bubble bursting)? 

It seems like someone needs to be discussing these issues.  And I can't think of any other forum but TWiB to do it.    

Unfortunately, I beginning to realize that at this stage, I’m more qualified to talk about why season 2 of Community seemed worse than Season 1, than I’m about the status of battery technology.  So, over the next few weeks, I’m going to brush up on my knowledge and hope to be back to writing regularly. 

So stay tuned folks… I’ll be back. 

Venkat

To be, or not to be (green), that is the question

The title above was going to be my next blog post for GigaOm.

But, they thought a better title was “How Plug-In Hybrid Cars Could Be Game Changers”.

I still think my title is clever (and I’m sure Shakespeare would approve), but on a site like GigaOm, it does not say anything about the content of the blog post.   I’ve never worried about things like that, but it’s the price you pay for playing in the Major Leagues :-) 

Anyway, I’m beginning to think about the Chevy Volt.  Not sure I agree with the title, but I’m seriously thinking about it.    

Read all about it here

Venkat 

One year and a change in TWiB

Over the past couple of weeks, I have been in conversation with the folks at GigaOm network to be a guest writer for their cleantech blog called Earth2Tech. 

After consulting with my employer (Lawrence Berkeley Lab), I have signed an agreement with GigaOm to be a guest writer.

What this means is that when I write a blog I will send it to them.  If they think the post meets their needs, then it will appear on their site.  This page will be updated with a small abstract of that post and a link to their site. 

If GigaOm decides to not use that post, then the post will appear, in its entirety, on this page. 

This Week in Batteries started just over a year ago on Feb 9, 2010.  Over the last year, I have made ~30 posts on subjects ranging from the costs of PHEVs, the way to make a battery last longer, the batteries in your Roomba, all the way to how to calculate the energy density of a battery.

Making a blog post has become a hobby for me (probably the first true hobby I have ever had.  Collecting stamps just did not cut it!).  But like all hobbies it tends to be a fairly low item on the priority list.  Regular readers will have noticed the long hiatus’ I have taken when work has demanded more of my hours. 

When I wake up on a Sunday and feel like writing, I spend the morning making a post.  If I have something else to do, then I don’t make a post.   On average, I probably spend 2 hours on a blog post. 

The return on the 2 h investment has been very gratifying.  I average 5000 hits a month (please don’t ask how many of those are self hits!) with a peak at 10,000.

I have also become convinced that if I really worked at it, I could make this blog popular.  But this requires a lot more of my time.  And even if I did spend the time, I’m not sure how much more popular I can make it. 

On the other hand, GigaOm gets 4 million hits a month.  And some of their blog posts gets picked up by the New York Times, CNN, Business Week, and The Street. 

Being able to get my posts onto GigaOm increases the visibility of this blog significantly, so the relationship is a no brainer. 

The first post is now up on their site.  Its called the “The Three Laws of Batteries (and a Bonus Zeroth Law)”.  Check it out.   They even added some nice pictures to accompany the words. 

For the regular readers of this blog, this only means that you will need to, occasionally, click on one more link before you can read my post.

So wish me luck.

Venkat 

I'll be back... in 8 hours

Some of my readers have wondered why I have been off the blogosphere in the last few months. The reason is that we brought a house and the move from the apartment to our new place has been a bit of a time sink.

First we went through the four stages of home buying:

Stage 1: What the &%#@ do you mean they accepted our bid? I thought you said we were lowballing?

Stage 2: When you use words like "downpayment", does this involve us giving you a check?

Stage 3: I assume roof's are like batteries? Meaning, when you say it is at the end of its life, there is still 80% left, right?

Stage 4: Keep repeating after me: "Owning is better than renting" and, please, stop asking "why?"!

Then we realized that owning a house also meant owning things like leaf blowers and lawn mowers! So, when I saw that there was a battery-powered lawn mower, I jumped at the chance to push my favorite technology forward.

I was looking forward to using my expertise in batteries to maintain and extend the life of my lawn mower for many years to come.

I was not particularly looking forward to mowing the lawn, but owning a battery-powered mower seemed to make up for that.

Until I realized that the top-rated battery-powered mower uses lead-acid batteries.

Lead-acid!!! really! How old school can one really get.

My first thought: Start a battery company to make Li-ion batteries for lawn mowers.

Then I started thinking about this some more. There must be a catch here. So I started digging into what it was.

Let us do some math: The battery for this lawn mower cost ~$270/kWh. That is one expensive lead-acid battery. Presumably, it is a deep-discharge battery, and so it is better made than a car battery.

And there is probably a significant markup.

Did I mention that the mower was on sale for $300! More like a mark-way-way-up.

Considering a typical Northern California growing cycle, this mower will probably be used ~50 times a year (once a week). These deep-discharge batteries can probably go a few hundred cycles. So I'm thinking 4-5 years easy.

But the bigger problem is going to be the calendar life. Sulfation can kill these cells.

Having said that, the battery is probably going to be at the top-of-charge pretty much through its life (think about it: Mown for 1 hour. Keep it plugged in all week). And remember our rule for lead-acid batteries: Keep them charged. So I think we can expect to get ~3 years from these cells.

Lets do some math for a Li-ion battery. I bought one a few weeks ago. This battery will probably last me 3 years and get me ~300 cycles or so. So it has similar specs to the lead-acid battery.

The Li-ion battery, on the other hand, cost me a whooping $2300/kWh!! No... really. This is what it cost me.

Now... knowing Apple, a new word has to be coined for their level of markup. But still this is one expensive battery.

At this price, a Li-ion lawn-mower-battery would have cost me $800!

All you MBA-types are probably cringing because you all know that cost and price are very different from each other and that the price is dictated by what the market is willing to pay (my wife is an MBA and she gave me this spiel).

Granted. So let us do a cost-differential comparison. This comes out to be ~$50/kWh more expensive for a Li-ion cell. Using this, the cost of a Li-ion battery for this mower would be higher than the lead-acid battery by... the price of lunch!

Not at Chez Panisse. But at the LBNL cafeteria (same quality, but at a much lower price?)

So why not use a Li-ion instead. After all it is almost 5x the energy density.

The mower that I have been talking about in this blog is a push mower. So the battery does not need to drag itself. All it has to do is turn the cutting blade. And space is not a big constraint. The mower's size is dictated by the size of the blade anyway.

So why bother using a new type of battery when you don't really see much of a benefit?

Frankly, although I have not looked at the life-cycle, I'll take a bet that it is probably better for the environment to use a lead-acid battery considering how much of this lead is recycled. In comparison, all you recycle in a Li-ion is the high-value metals in the cathode. The rest, literally, goes down the drain.

Maybe the math will change for a self-propelled mower. Or if the weight of the mower is an issue. But I don't see any reason to jump to using a Li-ion battery for the mower I was looking at. This business plan does not appear to have much legs.

So what did I do? I got the corded version of this mower. It cost me $100 less.

I guess the price that I'm willing to pay to push my favorite technology forward is less than $100!

In my guilt I decided to do my part for the technology by buying a Roomba.

I'm not sure if you guys know about this amazing robotic vacuum. It is pretty interesting to watch. It has sensors that make it slow down when it approaches objects, detect dirt, and prevent it from falling off of stairs.

It is not particularly good at vacuuming. But it feels like it is cleaning the floors and isn't that what's important!

But here is the kicker. The one I have has a Ni-MH battery.

I suppose I should be thankful it is not a lead-acid, but Ni-MH? COME ON!

The last time I checked, the cost of Li-ion and Ni-MH batteries were pretty comparable. And the energy density of Li-ion is 2-3x greater. And remember that in this machine (unlike the mower) the vacuum has to drag its battery along. And space is a big deal. The smaller the footprint, the smaller the space it can vacuum.

So why use a 20th century battery for a 21st century machine? Strange.

A web search revealed that Li-ion Roomba's have apparently died prematurely. If this is the case, then iRobot (the company that makes the Roomba) needs to change battery suppliers.

The vacuum I got goes through 2 rooms and then runs out of juice. It could have finished my house in one charge if it had a Li-ion of the same size. Or you could have a better vacuum on it so that it actually picks up dirt instead of moving it around and still only vacuum 2 rooms. You get the point.

When I first saw this machine, I thought that all the things on Terminator (the movie) were coming true. Jokes apart, it really is a pretty decent robotic cleaner which does indeed find its way around. You can, pretty much, set it and forget it.

But then I realized that we had nothing to worry from the machines as long as battery technology evolves the way it has been in the past.

When Arnold Schwarzenegger's character said "I'll be back" on T2, he (it) actually meant "I'm running out of battery and I need to go find an outlet and charge for 8 h. I will then come back to look for you for the 1/2 hour my battery lasts. Wish me luck".

So much for the machines taking over.

If you constantly complain about how batteries are not evolving fast, did you ever consider for the second that maybe we are out to save the world in our own way?

Venkat