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From: Brent Regan <brent@regandesigns.com>
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Michael writes:  <<I never claimed to be an expert>>

Then perhaps you would be wise to take the council of someone who IS 
experienced.

<<The SECOND link in my post is a thread with several hundred posts on 
designing, building, and testing cells.  Have any of the naysayers read 
the thread, in depth, or done similar research?  >>>

Wow. Reading the anecdotal results of anonymous hobbyists is not 
"research", it is entertainment (for some). Reading about or doing 
actual experiments with the appropriate equipment and collecting 
reliable and repeatable data is research. My income depends on doing 
quality R&D so I appreciate the danger of searching the internet for 
data that supports your position and then taking that as evidence you 
are right. You can find supporting information for ANY position on the 
internet.

<<< I also have read <snip> that deep discharging, such as Hamid had 
done, is different than the minimal discharge we would expect from an 
engine start.  The small discharge contributes to less need to balance 
the cells.  Quite different from the total-loss system in an RC or 
solar-powered environment.>>>

Wrong, wrong and wrong.

The Wave Glider had a 10 -30 day (depending on payload power) "no sun" 
duration so it was a mixed cycle, not deep discharge.

Engine start is not a minimal discharge event. A 300 amp load for 30 
seconds represents about a third of the available energy at those rates 
from a typical 20 AH battery. (careful, I set a trap here)

Cell imbalance is a function of the number of charge / discharge cycles, 
the depth of discharge / charge, the rate of discharge / charge, the 
temperature, and cell initial "matching". If you start with matched and 
balanced cells it will take longer to require balancing. Rate is one of 
the more important factors because it also effects temperature due to 
I^2R losses. Double the current and you get four times the heat.

<<<I'm an experimenter.  I can't just sit on the sidelines and wait for 
"someone else" to do the research, testing and development, then jump on 
the bandwagon.  That's why I'm building an experimental aircraft.  I 
thought this forum would be a good place to discuss development and 
testing of new systems rather than quickly declare it "too risky" for 
intelligent discussion.>>>>

I am all for experimentation, just not at 10,000 feet with peoples lives 
at stake. I have been a contributor on this list since the beginning and 
I have assisted the NTSB with several accident investigations where 
people died because the pilot ignored fact in favor of their own 
"opinion".  Flying is serious business. Lithium batteries are sensitive 
to mishandling. Neither tolerates ignorance or arrogance well.

Lithium batteries can and have been used in aerospace applications 
successfully but it requires a careful, detailed and intelligent design 
to mitigate the risks to an acceptable level. The risk levels that can 
be tolerated for an EV motorcycle or car are significantly higher than 
for a manned aircraft.

The word "Experimental" in Experimental Aircraft is not a directive to 
take foolish risks. It does mean that you and you ALONE, as a pilot and 
builder, are responsible for operating AND building an aircraft that is 
SAFE.

If I am not "intelligent" for pointing this out, so be it.

Regards
Brent Regan