Discussion List (Batteries)

[Jerry Budd]

>OK, how's this:  I got seriously involved in electric power until my three
>sets of batteries shot craps after about 25 cycles each, was going to go
>back to IC for a while until it looked liked the batteries were going to
>hold up better, but my source for the interim airplane and power unit got
>later and later so I was effectively out of the loop for the season.  I've
>kept myself busy with other stuff(good and bad)--and don't know what the
>latest skinny is on batteries.  Anyone?

OK, I'll bite.

Currently, I have 84 flights on my Abbra (1st flight was July 4th), 
all on three sets of battery packs (TP5300's), with the fllowing 
cycles:

Battery Pack #1 - 36 flights
Battery Pack #2 - 29 flights
Battery Pack #3 - 19 flights

On a typical Masters flight I use between 3200 and 3800 mAh depending 
on the wind, how large/small of maneuvers I did, and how fast I flew. 
My practice flights normally consist of flying the sequence, then two 
or three additional maneuvers, and landing.  Every once in a while 
I'll use around 4000-4200 mAh, but that's not the norm, usually I 
restarted the sequence or repeated a particular maneuver a couple of 
extra times.  All of these flights lasted < 10 minutes (my timer is 
set to 8 minutes).  I've had no issues with the batteries, in fact 
each set of the batteries charge up to very close to the same amount 
of mAh replaced after a flight (comparing left vs right).  When I 
plug in the TP 5 cell balancer after a recharge session, it barely 
does anything at all, just flickers for a couple of seconds and then 
goes out.  My conclusion is that these batteries are very closely 
matched wrt impedance (which is what I'd expect/hope for).

My peak current on the ground is ~70 amps and my batteries come out 
of the airplane after a flight at less than 110 deg F.  Motor temps 
range from 130 deg on a 70 deg day to the 150's on a 100+ deg day 
(I'm thinking I need to do a bit more work on the baffling around the 
motor).  The speed controller operates at ambient temps.  Here's the 
equipment breakout:

Motor: Hacker C50-14XL
ESC: Hacker Master 90-0-ACRO
Batteries: Thunder Power 10s4p 5300mAh
Prop: APC - 22x12e
Motor Mount: Budd Engineering

Thx, Jerry
-- 
___________
Jerry Budd
Budd Engineering
(661) 722-5669 Voice/Fax
(661) 435-0358 Cell Phone
mailto:jerry at buddengineering.com
http://www.buddengineering.com
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