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dragon_no_fly -> RE: New 1100 mAh A123 available everywhere and no word here! (11/22/2007 7:50:35 PM)
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Well, I finally got around to building my first 3S A123 1,100 mAh pack and
actually, my very first battery pack. I topped-off each 2S pack on the Black
and Decker VPX charger and then disassembled them. I took the packs
apart, but left the cardboard sleeves on each cell, since I wanted to take
advantage as much as possible of A123's welded tabs and solder joints.
I used one of the cells from the other 2S pack and soldered this into
series as the last cell in the pack and then placed my +/- motor lead wires
in parallel to the entire pack. I carefully measured the flight pack's voltage
and it was measuring a steady 10.60 Volts on my Sperry DM 4100A multi-
meter. I then plugged the pack into my heli and...............NOTHING!
The Phoenix-10 nor any of the servos came to life. I plugged, re-plugged
it in several times, but still, nothing!! I then placed the newly made pack
on a Whatt's Up meter and I had to look very close at the faint display
as it was only measuring 3.37 Volts; as if it were in parallel with only
one cell. I was stumped to say the least and I was about to post a
question here, but I decided to do a split-half troubleshooting method
on the pack; that is, I first chopped off the JST connector and measured
the voltage of the pack directly to the leads, still nothing, I then went
and measured the voltage drops off of each cell from ground and they
added up in series until I came to the last cell. The last cell was causing
the heli's electronics to not power up and was causing the Whatt's Up
meter to only "see" a single cell so I made a quick lead and placed the
+/- directly onto the first and last cells' +/- points respectively and then
the Whatt's Up Meter powered-up to life as normal and saw the 10.60
Volts!!!! It was the stock Black and Decker wire extension that came
off of the - part of the last cell that was bad somewhere inside! I de-
soldered this wire, made my own one, re-soldered the battery-to-motor
JST connector back on and sure enough the Whatt's Up meter saw the
10.60 Volts and the heli's electronics were powered-up. Below is a
flight test with a fixed pitch heli (an all brushless one that is the same
size as an ESky HoneyBee FP one). I know this is only an A123 1,100
cell thread, but I just want to show the Volt and Amp readings I was
getting for my heli which has a JustGoFly 300DF outrunner for the
main motor.
[Original]
Had a 12 tooth main motor pinion
[Modded]
Placed on a 14 tooth main motor pinion, since the 12 flew it, but was
just a little bit mushy and I like instant "pop" on my setups. The 14
tooth allows for an even greater climb away performance using these
new A123 1,100 mAh cells, than my old setup had with the 12 tooth
setup. The 14 tooth pinion was necessary over the 12 tooth pinion,
since these cells were putting out a little less volts and the weight of
the heli went up by about 1/2 Ounce.
[Measured readings on a Whatt's Up meter]
(Pack had been sitting around for three hours, since last charge and
I made about a 2 minute flight on the battery using the 12 tooth
main motor pinion setup)
1/2 Throttle: 9.20 Volts @ 6.30 Amps
Full open throttle: 8.75 Volts @ 8.60 Amps --> VERY GOOD
Tomorrow I will have to order the Polyquest balancer leads/connectors,
since I do not have any and I will more than likely order a new charger,
one that does everything! I am seriously considering this charger:
Hyperion EOS 0610i NET, since it can EASILY charge a 4S pack of these
A123 cells at up to 10 Amps and can charge all other kinds of batteries.
Granted, it is very early yet, but I am liking these new cells A LOT!
Thanks A123!!! Thanks to Red Scholefield, dick Hanson, Everydayflyer
and others for your information about the cells and how to actually
make a flight pack. I will post a picture of the finished flight pack
soon.
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