EVcast #98: Interview with Charles Stancil on Pulse Charging

At time 4:44

 " Home charging unit that has a transformer ... the transformer performs its duties in terms of stepping up the power...".

   Hopefully Mr. Stancil mis-spoke here.

   Transformers DO NOT "step up the power" of the electricity.  You cannot take, say, 10KW of electric power, put it through a transformer, and get, say, 35KW of electric power.  This violates the law of conservation of energy.

    Transformer DO take electricity at one voltage and change it to electricity of another voltage.  I have one on my desk here

Input: 120 Volts 0.5 Amps = 60 Watts
Output: 12 Volts 1.5 Amps = 18 Watts

   So we get less power out than we put in.  No violation of the laws of conservation.  The difference between input and output is lost in heat in the transformer. 

   Mr. Stancil's comments ("stepping up the power") imply that he is getting more power out of the transformer than he is putting into the transformer.  This is not possible.

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Next problem.

  Charging at 35 KW for 10 to 15 minutes (0.16 hours to 0.25 hours) is 5.6 KWH to 8.75 KWH.   He claims this battery is 35-40 KWH.  If you put 5.6 to 8.75 KWH into a 35-40KWH battery, it will NOT be charged.

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One more problem.  23:27

"Can you get this 10 minute charge with at 30 Amp 220 Volt circuit in my home… The answer to that is YES provided that you build a transition unit that when you come out of your outlet you go into this transformer box that has to be the interface between the outlet and the charger."

So he is claiming 30 Amp 220 volt input, which is 6,600 Watts, into the magic box will give you 35,000 Watts output.  That is 5 times more power out than went into the transformer.  This is not going to happen.

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"  Using the Pulse charging technique, you don’t abuse the battery the way it normally gets abused, which is overcharging, undercharging and the pulse charging techniques provide the opportunity for increased cycle life."

  This is a little weak.  Firstly, if he has done the testing, why not say how many cycles the battery survives using Pulse Charging.  Secondly, there is no doubt that overcharging batteries reduces cycle life.  However, Pulse Charging and Overcharging are not related. 

   You can overcharge with Pulse Charging, just like you can overcharge with other techniques.  In fact, I read a paper out of Australia where they were using Pulse Charging on Lead Acid batteries and were severely overcharging them and had to stop the testing.

   On the flip side, you can use other charging techniques, like shutting off the charger after 1 hour, and completely avoid overcharging.  Pulse charging is not a magic fix to these problems.

   I suspect that gentle charging with a normal charger will have just as good of cycle-life as pulse charging.  But if there is data to prove me wrong, let's take a look at it.

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Here are a couple of links that briefly talk about prolonging battery life with pulse charging:

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/63/34172/01629004.pdf?temp=x

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TH1-4CS4GCS-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1&_urlVersion=0&_userid=10&md5=8a4581f7e76f81e7395ae49f59d22a55

There are many other references via Google, along with other companies that make similar claims for prolonging battery life using Pulse Charging, though most involve lead acid batteries.  Now, I am no engineer or scientist, so I certainly do not know if pulse charging will prolong battery life, but there does seem to be a fair bit out there that thinks it does.  It is good to be skeptical about this, which John has done a good job of- so I will play devil's advocate a bit;-)

Mr. Stancil’s patent for this is from 10 years ago, so he has spent a long time on this- link to the patent is:

 http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=8&f=G&l=50&co1=AND&d=PTXT&s1=%22Stancil%3B+Charles%22&OS="Stancil;+Charles"&RS="Stancil;+Charles"

Also, during his interview, he mentioned, more than once, smart charging- in fact, very smart charging using the batteries chemistry along with an accurate measuring of the battery's State of Charge, so I do not think his system will overcharge the battery, and this seems very much by design.

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Now, the big problem with Mr. Stancil’s claim of Pulse Charging, is what seems to be pushing more power into a battery than is coming out of the wall, and for that…I have no answer;-)  But then again, I am no Electrical Engineer.  But, if I had to guess, I would guess that Mr. Stancil’s box has more than a Transformer.  What else, I have no idea.  So where does that leave us?  Well, certainly, we need to be skeptical and not bet the butter money on it until some proof is proffered.  But in the meantime, we can also take a look at the man making these claims.

Mr Stancil has been a Research Engineer at Georgia Tech Research Institute for about 15 years.  This Institute is the non-profit, ancillary arm of Georgia Tech, one of the top Engineering Schools in the country.  The GTRI hires a large number of Georgia Tech graduates in fact, along with having Georgia Tech professors on their staff.  Mr. Stancil’s name can be found in a variety of issues and interviews, mainly in transportation, over this time frame.  He also has a few patents in diverse areas.  Bo and Ryan of course mention a couple, including the Pulse Charge patent, and a patent for regenerative braking.  But he also has a patent, or patent pending, for something called the "reconnaissance round," a way to take real time pictures on the battlefield.  It seems Mr. Stancil was also a Vietnam War helicopter pilot- but you can see him and his story at the following links:

http://www.gtri.gatech.edu/casestudy/birds-eye-view

And for a better story on his background for this:

http://findarticles.com/p/articles/mi_qa5438/is_/ai_n21343708

I add these links for a couple of reasons- they show something of his character I think, and his methodology.  During his interview, he joked that he searched for ‘good enough’ instead of perfect, much to his colleagues chagrin at times.  But this statement, along with his previous endeavors, point to a very practical Engineer.  Not a Professor, not a Scientist, not a Salesman, but an Engineer.  So- before his claims are disregarded out of hand, I think I will take a wait and see attitude instead.  It will be interesting to see what he brings out.  A quick charge solution is just one more missing piece of the future for a seamless, successful, EV evinced world.

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The big three automakers are the victims of the "EV Curse".  GM's capitalization is down 94% from its 2000 high.  They are reaping what they sowed.  They could be riding hign on a EV -1 crest instead of Toyota reaping profits from its Prius.  It's like they say "You reap what you sow".  I am not going to buy another car until I can plug it in.  Even the Volt is a gimmick.  The carmakers don't want to give up their lucrative maintenance business with $125 per hour rates.  An engine that doesn't get used regularly breaks down earlier than one that is.  Keep up the good work.  Jim, from the surburbia capital of the World, Long Island, NY.

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Paul,
  While I appreciate the push-back, there is clearly reason for caution here in assessing the benifits of pulse charging.

   It is wonderful in the internet age that we can get abstracts of technical papers.  However it is very unfortunate that we cannot read the full papers unless we are willing to pay $31.95.  So until I am sufficiently motivated to drive down to the MIT library and copy the articles,  I will have to rely on the information freely available on the web.

Point 1:
  http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/4459873/4459874/04460398.pdf?arnumber=4460398

  In this 2007 paper on pulse charging of Li-Ion batteries, they claim only at 15% improvement in charging time over standard constant current -- constant voltage charging (dumb charging).  Hardly a breakthrough.

Point 2
  http://www.maxim-ic.com/appnotes.cfm/appnote_number/913/

In this application note from Maxim (an integrated circuit manufacturer) they discuss the benefits of pulse charging.  The advantages include "operating efficiently" and only a "small number of external components".  The disadvantages include input voltage source that is current limited requiring a special power supply.

   So the point of me bringing this up is that there are NO claims of rapid charging, or improved battery life, or anything special.  The benefits are simple trade-offs in engineering design.  If pulse charging had all these tremendous benefits, don't you think Maxim would mention this in their application note?

Point 3
 http://www.powerdesigners.com/pdf/Tech%20Brief%20Negative%20Pulse%20Charging%20Techniques%20Myths%20&%20Facts%20-%20Final.pdf

Tech Brief:  Negative Pulse Charging Myths and Facts.

  So fustrated by the claims of Negative Pulse charging supporters, Mr. KutKut felt the need to write a paper just to set the record straight.  Now to be fair most of the comments are about a special type of pulse charging called "negative pulse charging".  However some comments are about pulse charging in general.

   Here is one important point.

Myth:  Negative pulse charging results in faster recharge rates compared to constant current charging.

FACT: There has been no substantiated scientific evidence to prove that.  In fact many studies have found conclusive evidence that the recharge rate is a function of the charging current and nothing else..

  So he is claiming if you want a fast charge, only increasing current achieves that goal.  Pulse charging does NOT improve charging time when compared to any other method that uses the same charging current.

   So we will see what happens with the Pulse Charging claims.

   Quick charging of EV battery packs appears to be possible.

http://www.autobloggreen.com/2007/05/30/aerovironment-successfully-quick-charges-altair-nanotechnologie/

  In this story AeroVironment used a 250KW Charger to charge a 35KWH battery pack in 10 minutes.  They did this in front of an audience to give the claim more credibility.

  Note that the number do add up for AeroVironment
      250KW x 0.16 hours (10 minute) = 40KWH
which is only slightly more than the 35KWH capacity of the battery.

   So the only question is were do we get 250 KW supply.  Let's review the numbers

  6.6 KW (what we can get from a 30 AMP 220 Volt wall socket in a house)
 35 KW (the charging discussed by Mr. Stancil)
250KW (the charger used by Aerovironment)

So we can see that it takes a huge amount of power to do the 10 minute charge.

Thanks
John C. Briggs

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As an Electrical Engineer (degree from Cornell University), the only way that I can see to achieve a fast EV charge at home when you only have a 30A 220V outlet is to slowly put power into an electrical storage device (e.g. battery pack or (ultra) capacitors) over a longer period of time, and then rapidly transfer that power to the EV during the EV charging. As an analogy, think of filling a bucket with water using a straw sized hose over time, and then rapidly emptying the bucket by dumping it out all at once. An adequately sized electrical storage device is likely to be a bit expensive given the current technology though.

Steve

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Steve,
     I appreciate your input here. 

     I think your approach is perfectly reasonable.  I think I heard about this approach before related to EESTOR technology.  Cost may be a serious issue for this plan.  It basically means having a large (expensive) battery pack in the car and a second large (expensive) battery pack in the home.

     If batteries become cheap enough, then this idea seems great.

Thanks
John C. Briggs

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I think this appears somewhat low of a price for fuel-efficient vehicles and diesel engine assembly produced by US auto companies.

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