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Lithium batteries

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teblejw

Joined: 19 Nov 2013
Posts: 14

Posted: Sat Mar 15, 2014 9:36 am Post subject: Lithium batteries

Bob,



Don't know which message it was in, but you mentioned that you we were working on the last battery article for Kitplanes that would include lithium batteries.  I hope you will look at the EarthX batteries.  They are now recommended on the Viking website, so I've read their promotions.  They actually have a section on their website for experimental aircraft applications and they claim to deal with charging/discharging issues that other lithium-iron-phosphate batteries don't.  I learned the hard way (had a meter lead plugged into the wrong socket) that a brief inadvertent short of a Shorai battery will ruin it.  Still haven't heard of any explosive failures of batteries with this chemistry.  I look forward to your article.



Tom

Sent from my iPad

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nuckolls.bob(at)aeroelect
Guest

Posted: Sat Mar 15, 2014 11:10 am Post subject: Lithium batteries

At 12:35 PM 3/15/2014, you wrote:

 	  Quote: 	
		  

<tomblejwas(at)yahoo.com>



Bob,



Don't know which message it was in, but you mentioned that you we 

were working on the last battery article for Kitplanes that would 

include lithium batteries.  I hope you will look at the EarthX 

batteries.  They are now recommended on the Viking website, so I've 

read their promotions.  They actually have a section on their 

website for experimental aircraft applications and they claim to 

deal with charging/discharging issues that other 

lithium-iron-phosphate batteries don't.  I learned the hard way (had 

a meter lead plugged into the wrong socket) that a brief inadvertent 

short of a Shorai battery will ruin it.  Still haven't heard of any 

explosive failures of batteries with this chemistry.  I look forward 

to your article.



Tom


	


   Excellent input . . . thanks. I'll add them to the 'research'.

   So far I've submitted three articles that speak to battery

   selection and operations in general. The 4th is taking longer

   than I thought . . . input from folks like yourself have

   been helping me peel away the layers of the onion . . .



   In the mean time, I'm submitting an article on mean time

   between failure and how it has little or nothing to do

   with system reliability. The article will be a prelude to

   chapter 4 on lithium batteries where I'll remind readers

   that irrespective of their battery choice, the electrically

   dependent engine places new requirements on batteries.



   Builders they need to look past the marketing rhetoric

   for weight, cranking ability and any mumbling that

   speaks to 'safety'.  It's unfortunate that all the smoke

   and fire (no pun intended) has pushed performance issues

   to the back of the bus.



   The article are to remind builders that they need

   to purchase to design goals then test and maintain

   to those goals.



   A Kitplanes reader wrote Paul Dye to take issue

   with a statement I made to the effect that I'd

   never read of an accident where a backup system

   would have made a difference. The "box" into which

   the pilot driven was profound and in-escapable.



   He related the fact that during a flight behind

   his electrically dependent engine, a wire came

   loose ad "took down the main bus". He said that

   the presence of a back-up battery and a constellation

   of switches to access it saved the day.



   Through a couple of exchanges I discovered

   that he had a hefty alternator and a 34 a.h.

   battery . . . both of which became unavailable

   to him thus forcing dependance upon a small

   'backup' battery.



   I suggested that while his particular system

   WAS tolerant of that particular failure,

   it was not very robust. I hoped to engage

   him  in conversation that would reduce his

   reliance on a backup battery . . . but he was

   rather unhappy about my assessment.



   The point to be pondered is that no matter what

   kind of battery you have on board, failure

   tolerance has little to do with choice of parts,

   their MTBF numbers or their marketing position

   amongst the stars of products.



   I'm getting no outpouring of data to support anyone's

   marketing hype. E-mails are brushed aside with

   an assertion of no comment, use on airplanes is

   not supported, or simply ignored.



   This has been an interesting exercise . . .



   Bob . . .

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fvalarm(at)rapidnet.net
Guest

Posted: Sat Mar 15, 2014 5:43 pm Post subject: Lithium batteries

Bob,



I agree that EarthX, based on their forthcoming dialog, substance in their

answers, and willingness to support the amateur aircraft builders (even

encourage the use of their batteries in our aircraft, and why) has them on

my short list for when I finally need a battery for the RV7A.  I strongly

suggest that you get in touch with them for your article. It will be very

easy to have an audience there.



Bevan



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mike(at)aeromotogroup.com
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Posted: Sat Mar 15, 2014 5:57 pm Post subject: Lithium batteries

Mr. Brent Regan is apparently an expert on the use of Lithium batteries in

aircraft.  I attempted to start a discussion on the LML list a few years ago

and he shut me down with his expertise.  You may want to tap into his

exhaustive research on the subject:

http://lancair.net/lists/lml/Message/57030-P.txt 



Michael



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nuckolls.bob(at)aeroelect
Guest

Posted: Mon Mar 17, 2014 5:45 am Post subject: Lithium batteries

At 08:53 PM 3/15/2014, you wrote:

 	  Quote: 	
		  

<mike(at)aeromotogroup.com>



Mr. Brent Regan is apparently an expert on the use of Lithium batteries in

aircraft.  I attempted to start a discussion on the LML list a few years ago

and he shut me down with his expertise.  You may want to tap into his

exhaustive research on the subject:

http://lancair.net/lists/lml/Message/57030-P.txt


	


   Brent and I have crossed paths in the past but

   I'm having trouble recalling now when, where and

   in what context. I'll drop him a note and see

   if he would be willing to collaborate on the

   last installment of the series on batteries.



   Thanks for the heads-up!



   Bob . . .

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dlj04(at)josephson.com
Guest

Posted: Tue Mar 18, 2014 7:53 am Post subject: Lithium batteries

Perhaps those who have had LiFePO4 or other lithium batteries fail after 

deep discharge would be willing to disassemble the various brands and 

report what they find inside. This would possibly be more useful than 

asking the sales people from the battery packagers for data they don't 

wish to reveal.



I have been working with several groups who are researching electric 

aircraft. The energy density and other characteristics of the available 

cells are well known; at best a packaged battery is the sum of the cells 

inside. If there is a BMS there are three simple questions to ask: is 

there a low voltage disconnect during discharge, is there a high voltage 

disconnect during charge, and how many cells are monitored together in 

determining these voltages?



--

David Josephson

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