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Old Sep 23, 2006, 11:34 PM
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GregG's Avatar
Antioch,CA,USA
Joined Dec 1999
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THE A123 cell Thread, tell us how you're liking your pack

The recent crop of metal canned lithium based power cells looks like it's the safest source of electrons going, right now anyhow. I've been watching the Emoli cells as well as the A123 cells. From everything that I've read here it looks like the A123's have been pushing out a bit more performance than the Emolis. The prices are pretty decent as well.

Anyway, I thought that it would be great to have a current thread in the Battery Forum for everyone to share thier experiances. I've seen threads in other forums but IMHO this is the right place to share for everyone watching and/or searching. Please feel free to share any and all info and pictures. It would be great if you could share your voltage under load and amp readings as well as the rest of your power system specs.

Another thing that many of us might be interested in is any source for these cells that you might find. Web addresses for these suppliers is a plus. Thanks guys.

Greg Gallegos

Edit:
For easy access I'm adding the following question and answer from much later on in this thread.

Quote:
Originally Posted by GregG
Does anyone know the exact pins on the stock Dewalt pack that pertain to the + and - for 36V?
Quote:
Originally Posted by everydayflyer
The two outer most ones. Positive on right (a single) and negative one the left (two slots / contacts ) on this side.

Charles
Thanks Charles.
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Last edited by GregG; Sep 14, 2007 at 08:32 AM.
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Old Sep 24, 2006, 09:16 AM
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I have no graphs but I have run a 6S2P setup pulling about 80 amps and so far so good. I will try to get voltage data when I get a chance to setup the recorder.

I would also like to know what people are doing for charging?
Right now I am using a Lipo adapter thru a Astro112Deluxe but can only manage a max charge rate of 7.5amps. I'd like to be able to get that up to 15amps. Any Ideas??

Thanks
Pete
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Old Sep 24, 2006, 10:00 AM
know it all
Miami, Fl
Joined Nov 2003
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the heavy duty Orbit pro will soon have an update for the a123 cells, they call it Lifep cells or something like that, I believe that charger will do 10amps, that is a 13 minute charge! lol
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Old Sep 24, 2006, 10:47 AM
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Alexandria, VA
Joined Mar 2006
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I would love to see a 13 minute charge for these large batts! How does one update the Orbit pro? Is that just a software update? I guess you'd have to send it in?

I'm curious to see how these cells will work in a 10S lipo (50 size) heli.

Keep em coming!
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Old Sep 24, 2006, 03:41 PM
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Mountain View, CA, USA
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You're supposed to charge these cells to 3.6V/cell, but I wonder how much capacity they lose if you only charge them to 3.5V/cell? If you charge a 6S pack with a LiPo charger set to 5S, that's 4.2 * 5 / 6 = 3.5V/cell.

Anyone who has some A123 cells want to try this and measure the capacity difference?
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Old Sep 24, 2006, 04:37 PM
jrb
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Edina, MN, USA
Joined Oct 1999
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The a123s are solid choice for a new technology cell!

Lots of amps out and can be recharged quickly too.

The aluminum can is a far more package than a plastic bag.

And the aluminum aid in cooling the cell post flight too!

Plan to try a quick charge with direct connection to my deep cycle battery – planning 30amps.

Here’s my previous thread with lots of data and a great means for making a pack – MEC SPTs; nothing but good experience to date: http://www.rcgroups.com/forums/showthread.php?t=559827 .
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Old Sep 24, 2006, 04:49 PM
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New Hampshire
Joined Jul 2004
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My A123s

Hey All

I currently run 5S2P in a a Hanger 9 51-D PTS that I converted to electric.
The data for this set up http://media.putfile.com/benchmark video of that setup and the AWU is 6lb 6oz http://media.putfile.com/part6

I will be using 6S2P in this plane that I also am converting to electric http://www.raidentech.com/ulbi12055scn.html

So far here are my

Pros: Fast charge times (20 min, I have a big power supply), Sturdy (these survive nose in crashes), can vary pack shape to fit most locations, and 18 min flight times (P-51), AND SAFETY, I charged my S5 then threw on a S3 (forgot to change voltage) 25 min later I hear a POP ( same sound as popping a bubble in bubble wrap), I immeditally knew what it was and grinned, because of what the out come would of been if I had done that to a Lipo.

Cons: they hold voltage to the END of their charge, so NO warning when your LVC kicks in, power to weight ratio is still better than with Lipos ( for me this has been a good thing, with all these E-Conversions I'm doing the extra weight helps me for CG)

In the end, I'll use the cheap Chinese Lipos on my park flyers, but on any thing else I'll use these. OOHH and I got a Dewalt pack off E-Bay for $96 shipped @ $9.60 per cell this is a bargain.

Now that I have said that, there are even BETTER batteries being developed by a start up in Ca. Altar I think is the name, soon we should start hearing about this company.

Once I finish the Ultimate, I'll post the data on that

Brent
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Old Sep 24, 2006, 07:36 PM
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Sethml,
I use the Astro 109 charger, with 5cell the total pack voltage is 21v. My flight time is the same as charging to 3.6v. I get 8min flying a Hacker B50-10L
5.2:1 GB, 13x8 prop. Flying a G.P. SloPoke 46. It's a do nothing aircraft, but a good test bed for anything new. By the way, lost 20oz from flying NiMh (16cells), flies much better on the diet.
I'm very satisfied with the A123 cells. I recommend them to anyone flying 40 size and up. Haven't paralled any yet but it should be no problem
John
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Old Sep 24, 2006, 09:14 PM
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Joined Dec 2001
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An earlier post mentioned a "pop" sound when a 3s pack was charged as a 5s. Is that the M1 cells safety going off? If yes, do they fail to an "open" state?
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Old Sep 24, 2006, 10:04 PM
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New Hampshire
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FlyingW

Yes that was the pressure relief popping on the M1. NO they are still sitting @ voltage (as I type), I suppose I should test them to see if there is any usable life remaining.

Thanks for the idea

Brent
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Old Sep 24, 2006, 10:15 PM
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M Ashmore's Avatar
Bakersfield, California
Joined Aug 2003
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Quote:
Originally Posted by jcyr1
Sethml,
I use the Astro 109 charger, with 5cell the total pack voltage is 21v. My flight time is the same as charging to 3.6v.
jcyr1 - So, you're charging the a123's to 4.2v. Have you seen any negative effects?

Mike
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Old Sep 24, 2006, 10:33 PM
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Mountain View, CA, USA
Joined Jan 2005
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Quote:
Originally Posted by phat23
jcyr1 - So, you're charging the a123's to 4.2v. Have you seen any negative effects?
I'm assuming he's charging a 6S a123 pack as a 5S LiPo, as I suggested. So he's charging to 3.5V per cell, rather than 4.2V or 3.6V.

If the last 0.1V of charge doesn't add many MAh, that's a great thing, because it means we can charge 6S packs as 5S LiPos, or 12S as 10S LiPo (which I want to try).
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Old Sep 24, 2006, 10:50 PM
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Ahh........got it.
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Old Sep 24, 2006, 10:57 PM
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United States, AZ, Surprise
Joined Jul 2002
404 Posts
Sethml,
Sorry for the confusion. Yes I'm charging 6S1P, Astro treat it as 5S. I don't think the extra voltage matters in this case. The packs take about 2000-2100mah. The 4S packs are a little touchy. Charge for about 15 min @ 6-7A, then carefully watch the voltage. As it approches full charge the voltage suddenly ramps up at a rapid rate, at that point I shut off and fly.
John
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Old Sep 25, 2006, 02:15 AM
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Antioch,CA,USA
Joined Dec 1999
12,333 Posts
Wow, great responces. I hope that these cells get even easier to find and well used.

John (jcyr1), what is the amp draw and voltage under load for your pack?
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