Discussion List (Batteries)

[Gray E Fowler]

Richard

I am not a battery expert, but like everyone else on the list that does 
not stop me from having an opinion about batteries.
First, electric airplanes do not exactly drive the battery 
market,......even if 50% of the FAI finalists use them. No other 
applications 
that I am aware of uses these batteries in the manner that we attempt, 
which is that massive current draw. What electric planes do 
to batteries is damaging, as demonstrated by your 25 flights. 
I would not expect the battery market to develop a battery capable of long 
life and extreme current draw since no one else uses 
batteries in such a manner.

Invest in bottle of Windex, clean the oil. 



In fairness to the manufacturers, I don't think they really understood 
that
guys potentially would go out and fly 50+ flights per week.  When I 
finally
got all my infrastructure charging act together and made time to
practice--which wasn't all that much, I still was clicking along at a 35
flight/week pace right up to our first contest in mid June.   As you may
recall, I was using 20C 3200s on a shared cost beta program.  At 11 lbs.,
the airplanes were gobbling up 63-68 amps at times and significantly 
heated
the batteries and shortened their lives.  The manufacturer came out with
some 15C 4000s--but there was still the problem of amp draw and heat.  The
consensus at that point is the batteries aren't very happy at much over 
10C.
The problem I had/have is anything over the smaller batteries was going to
blow the weight limit--plus, as more information was coming out from some 
of
the top guys that they were getting around 50-60 flights on the larger
packs.  Since I'm not a top dog, I would pretty much have to foot the 
entire
bill to switch to the larger units.  As it appeared to me--the batteries
just aren't quite up to the task for the average guy--so I made an interim
decision to go back to IC for the rest of the season--hoping the battery
guys would come up with something more acceptable for '06.

That didn't pan out very well either, so I was effectively out for the
season.  (Lots of other contributing factors also)  What I told the 
battery
manufacturer was what a guy really needs is five sets of batteries(with 
the
then current stuff) and immediate service for turnaround.  Have three sets
for flying and one or two sets traveling to/from.

I'm sold on electric--particularly for a guy with limited practice time. I
could go on and on....

Richard



Gray Fowler
Principal Chemical Engineer
Composites Engineering
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