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Old Nov 07, 2007, 01:09 PM
Southern Pride
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Haralson County GA. USA
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A123 racing / B&D VPX 1100 mAh CBA Graphs

OK this is thread number ?? on these cells but they sure have sparked a lot of interest as many have been waiting on them for close to a year.


Update: These cells are steel not aluminum and are easy to solder. The polarity is the same as normal cells reversed from the A123 racing 2300 mAh cells.

12-10-07 Official A123 Racing specs.

http://www.elektromodely.sk/A123/APR18650M1_2007-05.pdf


DeWalt 18V with the 1100 mAh cells

http://www.rcgroups.com/forums/showp...92&postcount=1




Added: 12-25-07 Merry Christmas -- Seasons Greetings.

Nice photos of pack disassembly here:
http://www.rcgroups.com/forums/showp...76&postcount=1

Snip:

Quote:
The capacity at 1C discharge to 2.0V ranged from 963-1005 mA-h

Capacity at ~15C discharge to 2.0V is ~ 950mA-h with ~2.725 avg V.

AC impedance is 15-16 mohm

Effective DC internal resistance @ 50% SOC ranged from 36-39 mohm


My weights:

2cell pack as purchased 123 gr. / 4.34 oz.

1 cell with 2 1/2" 14 ga. leads and APP connectors 48.6 gr. / 1.71 oz.

3S pack with 6" 14 ga. leads APP connector and PQ balancing leads. 137.7 gr. / 4.86oz.

4S with 6" 14ga. leads ,Deans Ultra and PQ balancing leads 6.4oz.


Cells are .715" dia X 2.535 long , not counting tabs.


I have a single and a 3 cell which I will be testing. Graphs will be posted as soon as possible.
Let the fun / torture begin.

First CBA at 6 A / capacity 940 mAh
Second graph with 6,9 & 11.9A discharges

Next up single cell.

Hint : Remove the Label from the pack and it is obvious how to open them. I opened top (contact) end and just pulled cells right out.

Official A123 announcement here:

http://www.rcuniverse.com/forum/fb.asp?m=6614191


Snip:

Quote:
The VPX packs from Black and Decker do indeed have our newest 18650 cell. It is the same M1 chemistry that is so popular in our 26650 Cell.
11-15-07 Added a couple of short static runs to compare 1100 to 2300 under a motor / prop load.


11-26-07 Added 4S A123 100 / Thunder Power PL 3S1320 Graph

Single cell discharges of each also on same graph

11-27-07
Time for a little more abuse.
4S charged on balance Pro HD at approx. 8A 10 min. charges and 8A Discharges but only to 11.2 volts.




12-31-07 Another thread where a 4S 1100 pack is receiving addational abuse.

http://www.rcgroups.com/forums/showthread.php?t=793209
Charles
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Last edited by everydayflyer; Jan 11, 2010 at 08:19 PM. Reason: Added 4S A123 / 3S TP PL Graph
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Old Nov 07, 2007, 04:00 PM
Southern Pride
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Haralson County GA. USA
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A123 1100 mAh single cell Receiver / Servos Flight pac

Single cell graphs and photos of 3S pack.
Added: single cell discharges at 1,2 and 3A.

For the benefit of those who have a difficult time reading graphs.

Third attachment :

Fully charged cells no-load voltages were 3.46 --3.51. This is where a A123 cell ends up after a full charge to 3.6-3.65 volts per cell.

1 amp. load applied and voltage dropped to 3.3 per cell which would be 6.6volts for a 2 cell (receiver / servos) pack.

Voltage held between 3.2 and 3.1 per cell 6.4 - 6.2 volts for a 2 cell pack for most of the cells capacity or approx. 850 mAh.


As per the note on graph the actual cell voltages were approx. 0.1 v greater at the cells terminals. There was a 0.1 volts drop in the tap leads and associated connectors.This drop should be similiar to what can be expected in an aircraft with normal receiver / servo wiring.

Charles
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Last edited by everydayflyer; Nov 09, 2007 at 07:35 AM.
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Old Nov 07, 2007, 04:26 PM
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Edf,
I don't understand the graphs, what is the run-time of these tests.
Sorry if I'm missing something.
thanks
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Old Nov 07, 2007, 04:38 PM
Southern Pride
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Haralson County GA. USA
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I can post the times howerever a close guess is easy.

6A/1.1(nonimal capacity)=5.45 C . 60 min./5.45=11.00 min.
9A/1.1=8.18C ,60/8.18= 7.33 min.

Here is a link I posted long ago on how to read a CBA Graph.

http://www.rcgroups.com/forums/showp...89&postcount=2


Actual times for a single cell discharges ,graph not yet posted.

@6A 9:43
@9A 6:38
@12A 4:59

Charles
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Last edited by everydayflyer; Nov 07, 2007 at 04:43 PM.
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Old Nov 07, 2007, 04:48 PM
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I actually think these cells may be perfect for transmitters
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Old Nov 07, 2007, 05:02 PM
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Looking at the graph, it does not apear they hold voltage like the 2300mah packs.
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Old Nov 07, 2007, 05:16 PM
Southern Pride
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Volts per cell will be easier to see when I upload single cell graph(s).
At 15A held right at 2.7V.

Remember theses are only rated 47.8% of the 2300s cpacity.


Charles
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Old Nov 07, 2007, 06:33 PM
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A friend just returned from Czech Republic-- he said the guys are running the 2300 cells in large flat aerobatic foamies - and they like the setups better than LiPos - cost/durability etc.. I am going to do a 3 cell 3200 in my big 435 sq ib 12 ounce dry aerobat - 480 E flite motor
the weight is 2.something heavier than the TP2100 3 cellpack - Iwill set them into fuselage above wing -gives perfect vertical cg
woops ! wrong page - can they move this post?
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Old Nov 07, 2007, 06:48 PM
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Nice plane Dick

But if you just remove those 10mm diameter steel bars @#$%$#, and replace them with 2mm carbon rod ,it would fly a lot better

Oh please excuse my little joke

Yes if you put battery on the model centreline it will fly nice , its a hassle but worth it

A candidate for the new 1100 cells for real light on the wing flying too
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Old Nov 07, 2007, 06:51 PM
Nick Radle
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I just picked up a dozen Li-FeP04 1200mah cells from hobbycity.com. They claim to be the same as A123 cells but I don't think so, and here's why. I am using a Thunder Power 1010C charger with version 2.3A firmware, making it "A123" capable. For those cells, it has worked fine and I get a full charge on the cells, no problem - not so with the 1200's...
According to their data sheet, they ship with a 50% charge, and peak charge voltage is 3.9 volts. Right out of the box, I attempted to charge each cell individually, and they all only accepted 45-120mah? "Hmmm, maybe they came fully charged", I thought to myself..."let's see how much I can take out of them". I set the discharge cutoff to 2.5 volts and a 1.2 amp discharge. Each cell only gave me 550-650mah before reaching 2.5 volts???
So here's the question - does any hobby-related company make a digital readout charger capable of charging any lithium-iron phosphate battery, having and adjustable peak voltage detection? In looking around, I have found li-fe batteries rated at anywhere from 3.0 to 3.3 volts, nominal, and 3.6 to 4.0 volts peaked, so they all obviously have different charging requirements.
I really don't think I just got a set of bunk cells, I just need a charger that will fully charge them!
Another interesting observation with these cells is that the positive and negative side of the battery is the same as a Ni-cd, whereas the A123's are reversed...
Here is a link to where I found the batteries:
http://www.hobbycity.com/hobbycity/s...8&ParentCat=85
And here is my only luck in finding higher v/cell chargers so far:
http://www.batteryspace.com/index.as...OD&ProdID=3286
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Old Nov 07, 2007, 06:54 PM
Southern Pride
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Quote:
I am going to do a 3 cell 3200 in my big 435 sq ib 12 ounce dry aerobat - 480 E flite motor
the weight is 2.something heavier than the TP2100 3 cellpack

Well I have a blue foam flate plate Edge 540 ,approx. 360 sq.in. wing area ,10.6 oz. WO battery which I have flown hundred of flights with 3S LiPolys from 850 mAh PQ to 1700 Electric Power and VamPower.

My favorite packs have always been TP ProLite 1320 due to their terrific power/ capicity to weight ratio.. I have already reprogramed LVC to 6 volts and as soon as the winds cooperate a little I have give it a good with this 3S 1100 mAh A123 pack which is really no heiver than some of the 1700 packs I have flown on it.

May have to prop for a few more amps. to make up for lower voltage but 7.5V at 20 amps. is 150 watts and AUW right at 16 oz. should be plenty of power..

Charles
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Old Nov 07, 2007, 07:03 PM
Southern Pride
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Bodywerks there are several Threads on the copy cat cells. One such is here

http://www.rcgroups.com/forums/showthread.php?t=767379

It would be nice if this Thread stayed on actual A123 Racing cells.


Charles
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Old Nov 07, 2007, 07:31 PM
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I like the idea of these smaller A123 cells, but it is unfortunate these are the same price ($10/cell) as their bigger brother.
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Old Nov 07, 2007, 07:37 PM
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Quote:
Originally Posted by rick0007
I like the idea of these smaller A123 cells, but it is unfortunate these are the same price ($10/cell) as their bigger brother.
Do you mean retail price of a123-2300 vs retail price of the a123-1100?



Chris
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Old Nov 07, 2007, 07:55 PM
Nick Radle
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not a problem. Thanks for the link...
You do know that "A123" batteries are also manufactured in China, though, right? It's just a brand name, and they are not the founders of this technology, just exploiters
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