RE: A123Racing Battery Questions (Full Version)

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everydayflyer -> RE: A123Racing Battery Questions (2/14/2007 4:33:31 PM)

http://www.a123systems.com/html/a123racing/rcdevkitspecs.pdf



dt1 -> RE: A123Racing Battery Questions (2/14/2007 6:34:48 PM)

Hi folk. I know that the casing is aluminium and that soldering is really bad, but are the centres of both ends solderable or are they also aluminum?
Thanks, David.



Red Scholefield -> RE: A123Racing Battery Questions (2/14/2007 6:55:49 PM)


quote:

ORIGINAL: dt1

Hi folk. I know that the casing is aluminium and that soldering is really bad, but are the centres of both ends solderable or are they also aluminum?
Thanks, David.



Try to get them with tabs welded on. The ones from DeWalt packs have these and they can be trimmed to allow a good soldering surface or used as they come in packs of 4 by just folding the end 4 cells on each end over to make 2 2 cell sticks.



dt1 -> RE: A123Racing Battery Questions (2/14/2007 7:50:27 PM)

Thanks, I understand that tabs are available and are the correct approach. When they break off can anyone tell me please if the ends are solderable?



madmoony -> RE: A123Racing Battery Questions (2/14/2007 8:24:14 PM)

Hello dt1,
I soldered all my cells inline.When i got them,there are no taps at the ends,just these round areas of a solderable metall(nickel?)Use some grinding paper to make some slightly wipes over the surface and solder them with ordinary solder.
Use a iron with at least 80 watt and a hammershaped end.
I have used these packs(3S2P) under hard conditions and they are performing very well.

Grz Burkhard



dt1 -> RE: A123Racing Battery Questions (2/14/2007 8:29:16 PM)

Great. Thanks for this information. I feared the one end might be ali like lipo cells.
David.



nriedel -> RE: A123Racing Battery Questions (2/15/2007 6:48:56 AM)

Got a question, I guess for Brian?: We are using 880 cells to power a streamlined (full-size) electric car to race at the salt flats. I took some batteries to a place to use a resistance spot welder to weld on longer (nickel) tabs onto the batteries, but the tech wasn't able to get them to stick very well. Are the ends of the batteries where you weld on the tabs made of the standard nickel or are they some other material? I took the tabs from a battery in for an electron spectrograph and they show up as nickel, but I couldn't very well stick the battery in to see what the battery's ends were made of ;). Is there some trick to getting a good weld with a resistive spot welder (lower power, etching or scuffing surface etc.) ? Thanks for any ideas you can provide.

Nick
Electric Vehicle Team
Brigham Young University

electricbluestreamliner



elhepilot -> RE: A123Racing Battery Questions (2/17/2007 6:26:45 PM)

I have purchased batteries and charger from A123 and a Dewalt pack. I changed all the packs to 2S (side by side) configuration and so far use two sets in series for a 4S2300 mah pack. I have used them with an AXI2820/10 and the results are great. I am building a Twinstar II with two "long can" 400s and 6x4 props and plan to use an A123 4S setup.



OCR99 -> RE: A123Racing Battery Questions (2/18/2007 1:09:27 AM)

Are you going to use a balancer or dont you think its nessesary?



everydayflyer -> RE: A123Racing Battery Questions (2/18/2007 1:23:10 PM)

Not dirrected to me but______________.

I have been using LiPoly batteies fro 3 years, I have over a hundred pack, .I have 9 LiPoly chargers and matching balancers, a CBA,and 3 in-flight data loggers . I test batteries,chargers,balancers and in-flight Data Loggers for vendors. I have a fair amount of experience with Li cells.

I have followed A123 cells for close to a year and have used them for over 4 months now. One of my 123 packs has 180 cycles on it now.

Do you have to balance them? No you do not however it is foolish not to provide for checking and balancing. I feel in most cases it is easier to go ahead and balance than bothering with deciding if it is necessary or not.


I have had a A123 pack go over 25 cycles and still be less than 0.005 imbalanced and I have seen one be close to 0.10 imbalanced after a few cycles .. Thats' 20 times as bad.

A123 Racing places balancing leads on all of the packs they build / sell. Their chargers automaticly balance at the end of charge. DeWalt 36V packs have a balancer / power management module built in to them.

If you feel luucky then do not bother to add a $2 balancing pigtail to your pack.


Charlesi



elhepilot -> RE: A123Racing Battery Questions (2/18/2007 7:08:25 PM)

Bought the A123 charger which has built-in balancer. You can see the leads in the photos. Purchased five balancer leads from A123 which I installed when I converted packs.



OCR99 -> RE: A123Racing Battery Questions (2/18/2007 9:36:26 PM)

Thank you very much for info Everyday flyer and Elepilot.Everyday flyer have read much of your stuff on 123s i have learned alot thank you
Rick



OCR99 -> RE: A123Racing Battery Questions (2/18/2007 11:19:42 PM)

HOW GOOD IS THE ASTRO BLINKY FOR BALANCING 123S



everydayflyer -> RE: A123Racing Battery Questions (2/19/2007 1:55:07 PM)

The original (LiPoly one) does not work with A123 cells unless you over charge them.
Astro Flight now has a A123 model.

Hyperion LBA6 (now discontinued) or Thunder power 205V or 210V Smart balancer work fine.



Charles



bradpaul -> RE: A123Racing Battery Questions (2/20/2007 1:20:36 AM)

Astro now has a specific A123 "Blinky". It works very well as there is just not much capacity above 3.6v to bleed to bring a pack into balance. Cost is great too...... about $25.00

I had used a Hyperion LBA10 before buy it needs the voltage to be above 3.7v to begin to balance. Since I got the Astro A123 "Blinky" the balancing process just takes a few minutes.

So if you are looking for a inexpensive way to charge and balance A123 packs, you can "hack" the Astro 109 to charge A123 packs for about $5.00. If you have a Nicad/Nimah charger a Lipodapter+ (Dapter) will allow you to charge A123's for $40.00. Then add a Astro A123 Blinky for $25.00 and you are set to go.

Brad [;)]



OCR99 -> RE: A123Racing Battery Questions (2/20/2007 1:49:00 AM)

On astro 109 what do you have to do to it for 123s?I know one for sale cheap



Rick



bradpaul -> RE: A123Racing Battery Questions (2/20/2007 2:24:32 AM)

Here is the thread:

http://www.rcgroups.com/forums/showthread.php?t=602445

Brad



engleswing -> RE: A123Racing Battery Questions (2/21/2007 10:23:15 PM)

I am building a 4 star 60 electric using a e-flight 60 what combo would you recommend



OCR99 -> RE: A123Racing Battery Questions (2/24/2007 12:13:34 AM)

THANKS FOR INFO DOES ANYONE KNOW WERE TO FIND DIAGRAM FOR A BALANCER HARNES FOR BATTERIES ANY WEB SIGHT OR ANYWHERE?


RICK



everydayflyer -> RE: A123Racing Battery Questions (2/24/2007 1:48:58 AM)

http://www.rcgroups.com/forums/showpost.php?p=3320890&postcount=29



Kraeuterbutter -> RE: A123Racing Battery Questions (2/24/2007 1:38:45 PM)

sorry for asking about a post so long ago:

@batfish wrote:
quote:

Nightshift,

I'd recommend two of the 2s1p 2300 packs.
They will give you the same performance - no more worrying about which pack is the "best" pack.
As with other Lithium technologies, these batteries have an extremely low self-discharge rate so you don't have to worry about peaking them right before racing. You can even charge them a couple days before the race and not notice any decrease in the battery's performance.
The A123Racing packs also shouldn't heat up during a 5-minute race, and can be put directly onto the Hypersonic charger to be freshly charged again in about 10-15 minutes. If they happen to get a little warm, you may want to let them cool for a few minutes before charging them.
You can always have one pack charged while using the other, so you should never be out of business.


hmm. iam wondering about:
"charge them a couple days before the race and not notice any decrease in the battery´s performance"

i have made other experiences!
i use the FePo4 as 4s1p in my heli and 5s1p in another heli..

it makes a significant difference when the batts are charged and what temerature they have..

batts charged (8A current), flown after charge... medium Power
batts charged again (8A current) without any "let the batts cool down" after they came warm out of the heli, charged within 15min and used emidiatly after charge (around 30°C) - better performance

batts charged again (8A) and flown AT THE NEXT day (so 12 hours) resting --> worst power

result:
the voltage is at least 1volt lower (in the 4s pack) then when used imidiatly after charging and the batts are warm!

i have now found this tests in a german forum:
batts at 20°C
[img]http://www.rc-network.de/forum/attachment.php?attachmentid=59139&d=1170621501[/img]


and
batts heated to 40°C
[img]http://www.rc-network.de/forum/attachment.php?attachmentid=59142&d=1170621592[/img]

thats a not too small difference !!! can be significant for racing !






Kraeuterbutter -> RE: A123Racing Battery Questions (2/24/2007 1:46:26 PM)

Gerhard has measured this:
http://www.rc-network.de/forum/attachment.php?attachmentid=59849&d=1170957817

the red one is at room temperature
the green one is at 50°C
more infos about that topic: http://www.rc-network.de/forum/showthread.php?t=63180



everydayflyer -> RE: A123Racing Battery Questions (2/24/2007 4:02:16 PM)

Similiar experience

http://www.rcuniverse.com/forum/fb.asp?m=5465200



They do work well after setting for hours or days but they work better when warm just like Lipolys.

I find that LiPolys and A123s need to be atleast 80F to perform close to their best and 100-125F is even better. Trick is to be close to 125F without going over as that shortens their life.



Post here

http://www.rcgroups.com/forums/showpost.php?p=6563340&postcount=3

contains a FMA Direct prepared life cycle projections based on discharge rates and temperatures reached along with other data such as voltage depression.


Charles



OCR99 -> RE: A123Racing Battery Questions (3/24/2007 2:45:46 AM)

I am putting together funtana 40 with size 60 eflite should have more then enough power problem i have is goiging to use 123 batteries total 7in series 2 parallel going to end up with aprox 8 lb if i cut batteries in 1/2 will cut flying time but save about 1 lb i think with size of wigns mite be ok.any sugestions?What approx flying time be with 7 cell?

Rick



dick Hanson -> RE: A123Racing Battery Questions (3/24/2007 2:40:16 PM)

yep warm is better
on the LiPos -in cool weather -- we use the windshield defrosters in the car and warm em up -then stick em on and fly. big difference



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