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Dec 30, 2006, 10:42 AM
Proud member of LISF and ESL
Discussion

Can someone explaine the advantage of A123 cells?


I have searched and found lots of threads on peple ripping open tool packs for the cells, and discussing how to charge them but what is the reason for doing this? What advantage do you get from these calls as opposed to Lipos, Lion or NiMh cells?

Let's keep it basic to begin with please. Then, if there are some who know the real deep issues, let's add that later.

Why am I interested?

I am about to buy a CellPro balancing charger. They have two versions, one of which handles A123 cells. While I have heard of them, I don't know why or where I would want to use them.

Hope you guys can enlighten me.
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Dec 30, 2006, 10:49 AM
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pmackenzie's Avatar
Compared to Lipo.
positives:
little or no fire risk
more durable in crashes
Larger number of cycles
much faster charge, 15-20 minutes is no problem
cheaper
negatives:
heavier for the same capacity.
lower voltage per cell. you will need more in series
only one available size

Pat Mackenzie
Dec 30, 2006, 11:05 AM
Proud member of LISF and ESL
Thanks Pat, that was great!

I saw that most of the discussion seems to be around use in larger planes so I presume that that single size is fairly large. Guess I won't be using them in my planes in the near future.

If you have any other info, or can point me to a resource where I can read up on the cells, I would appreciate it. Just interested.
Dec 30, 2006, 11:28 AM
Proud member of LISF and ESL
Everydayflyer,

Thanks for the links. The second one was the most helpful. In fact I think I saw that thread some time ago but did not recall the content.

Much appreciated.
Dec 30, 2006, 11:37 AM
I don't want to "Switch Now"
pmackenzie's Avatar
The cell size is : 26.15mm dia x 65.5 mm long (~ 1 1/32 x 2 5/8)
weight : 70 grams ( ~ 2.5 ounces)
3.6 volts fully charged, 2.5 volts under 30 amp load
Capacity 2300 mahr
You can buy Dewalt packs from ebay, or prebuilt packs from Tanic packs.
The latter is probably the least expensive way to get a few cells to try out.
http://www.tanicpacks.com/catalog/pr...865e536e13b608
There is also A123racing:
http://www.a123racing.com/

For smaller packs the price advantage over Lipo is less of a factor.
When you start looking at large packs then it comes into play, making larger planes/helis much more affordable.
Pat MacKenzie
Dec 30, 2006, 11:44 AM
Closed Account
I don't discount the reduced fire hazard one bit. Yes, larger and heavier, but a nice compromise over Lipos. No this isn't meant to start a "flame" war. I use Lipos alot too!

Dave
Dec 30, 2006, 12:04 PM
characters welcome!
Mark Wood's Avatar
I use quite a few of the V28 Milwaukee (Moli) cells both in large helis and sport planes. About the only improvement over the Molis I can see is that the A123s have a much higher discharge capacity 30C vs 15C.
The V28s are the same size albeit a bit heavier due to the steel can vs aluminum, charge just like lipo to 4.2 volts, can also be charged at up to 3C and because of the higher voltage I need fewer cells to get the voltage that I want to run. Weight is a wash between the two because of that and my packs are physically smaller than the A123s because I need less cells. The eMoli capacity is 3000 mah vs 2300mah of the A123.
So, where is the advantage of A123s over Molis besides discharge capacity or am I missing something?

mw
Dec 30, 2006, 12:12 PM
Southern Pride
everydayflyer's Avatar
Quote:
So, where is the advantage of A123s over Molis besides discharge capacity or am I missing something?
This has been discussed several times in the past several months.

For me I can purchase A123 cells aka DeWalt for $11 or less each.
I can pull over 70A burst from a 8.5oz. 3S or 11oz. 4C.
I get 7 min. flights and 9 minutes Truck runs which is plenty for me.

Most every post I have read made by experience 3D Heli and Fix Wing pilots indicate that A123s outperform eMolies due to their far superior burst capabilities.

4C is not the upper charge limit either as some are charging at 10C plus.


Charles
Last edited by everydayflyer; Dec 30, 2006 at 12:20 PM.
Dec 30, 2006, 12:12 PM
Occasional Flyer
I use them in my trucks:

Over Lipo - because they are robust, can take a physical beating with no fear of puffing or fire, less LVC concerns and super fast charge times.

Over Nimh - because they hold their voltage better, lighter, run cooler, no repeaking before use, very low self discharge and super fast charge times multiple times a day.
Last edited by Marv829; Dec 30, 2006 at 12:22 PM.
Dec 30, 2006, 12:46 PM
Registered User

A123 Cells


Quote:
Originally Posted by aeajr
I have searched and found lots of threads on peple ripping open tool packs for the cells, and discussing how to charge them but what is the reason for doing this? What advantage do you get from these calls as opposed to Lipos, Lion or NiMh cells?

Let's keep it basic to begin with please. Then, if there are some who know the real deep issues, let's add that later.

Why am I interested?

I am about to buy a CellPro balancing charger. They have two versions, one of which handles A123 cells. While I have heard of them, I don't know why or where I would want to use them.

Hope you guys can enlighten me.

http://www.fmadirect.com/support_docs/item_1229.pdf

You can read the above and see if they fit your applications. Not for little airplanes!

http://www.fmadirect.com/detail.htm?...193&section=45


fred@fmadirect.com
Dec 30, 2006, 01:22 PM
Proud member of LISF and ESL
Thanks everyone. This will be a great resorce for me and for many.

As I tend to be in the under 3 pound electric plane class I probably won't be using these unless they start to make them in smaller sizes. However I am always looking to the future. I just ordered the FMA CellPro 4S balancing charger for my Lipos. I ordered the one that will also handle A123s in order to be prepared for that day.

Keep it coming.
Dec 30, 2006, 02:10 PM
Registered User
Quote:
Originally Posted by aeajr
...
Keep it coming.
https://www.rcgroups.com/forums/show...&postcount=117
Jan 23, 2007, 08:12 PM
just look at it smokin'
z-matrix's Avatar
hi guys,
A123 charging is a standard charge method:
standard charge method 1:
CCCV 3.6V Cutoff current = 1/10

10A fast charge for A123 looks like: 10A CC, small transient part: CV, and cutoff after current falls between 1A

charge can be topped off to 0.1C but it will be not much additional capacity,

since these cells have very low internal resistances about 8milli ohms.

can someone give information about charging A123 below 0C ?

my samples have not arrived, so i can not test anything, and having difficulties ordering any (in europe).
Jan 23, 2007, 08:39 PM
Registered User
say fred, the question i have for u is if u can charge the a123 cells at 10 or more amps, is the cellpro just for balancing once u charge the batteries?


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