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Old 11-08-2007, 01:59 PM   #61
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Yes, there are 10 cells in the packs. All dewalt 36 volt packs are a123 cells. I have also heard of people purchasing them at lows on discount for around $70 which is an incredible price. The cells weigh righ at 70 grams. A 2s 2p pack is actually lighter then your typical 6cell pack. The dimensions of the cells are listed at their website.
http://www.a123systems.com/newsite/p..._FEB2007-1.pdf
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Old 11-08-2007, 05:01 PM   #62
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I run 4s2p. Two 4s packs. They are 3" x 2 1/8" x 2 1/8" each.

They weigh 316.4g each, complete, heat shrunk, with a little velcro on the bottom
to help them stay put.
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Old 11-21-2007, 09:59 AM   #63
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I did an A123 pack for my B44. I have a Novak 5.5 bl motor & the 2S2P A123pack powers it great. I ran the car for over 20 minutes (23 but the last minute was slowing) at race pace on 1 charge. They definatly are not as fast as my Maxamps lipo 4400 but it was plenty fast to make the long triple at my track & no one ran away from me on the straight so they are fast enough. Heres a pic of my install:

http://i8.photobucket.com/albums/a43/RBMike/B44A123.jpg
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Old 11-21-2007, 10:26 AM   #64
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Mikes stuff was plenty fast....If I get you some cells Mike could you hook me up?
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Old 11-21-2007, 10:54 AM   #65
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Hey John, It's just like building any other pack but I will warn you all, these cell will suck the heat out of even extreem soldering iron tips. I have a supper hot soldering iron & had a hard time getting them to flow on the can side. Also take note of the polatrity on the cells, the can end is the positive unlike the sub-C's you guys are use too.
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Old 11-21-2007, 11:01 AM   #66
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You can always run a 3.5 or 4.5 if you want to go faster. When you break down the packs keep the tabs on them. The material they are made from is not a good surface to solder on. You also don't want to cover that little blemish either, it is where the cells release pressure if they dead short. Just solder directly on to the tabs that are already on the cells. To build a saddle pack I would take two pairs of cells still tabbed togather. Then I would wire them up in parralel. Don't forget to run a balancing wire either. When you notice the cells start to drop pull them off the track.
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Old 11-21-2007, 11:05 AM   #67
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Ya what party-wagon said is good but I had loose cells (no tabs).

I will also add that this 4 cell pack weighs just over 10oz. compaired to my IB4200nmhi pack at 15.7oz. & my max amps 4400 pack at just over 8oz.
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Last edited by RBMike; 11-21-2007 at 11:17 AM.
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Old 11-21-2007, 02:15 PM   #68
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Quote:
Originally Posted by RBMike View Post
I did an A123 pack for my B44. I have a Novak 5.5 bl motor & the 2S2P A123pack powers it great. I ran the car for over 20 minutes (23 but the last minute was slowing) at race pace on 1 charge. They definatly are not as fast as my Maxamps lipo 4400 but it was plenty fast to make the long triple at my track & no one ran away from me on the straight so they are fast enough. Heres a pic of my install:

http://i8.photobucket.com/albums/a43/RBMike/B44A123.jpg

So your setup gives you 6.6V, 4600mah correct? I have heard the A123s actually give more runtime that what the mah on them would lead you to believe. Power out of them not worried about too much, they are 6.6V after all, so you will probably need to run a hotter motor to compare to a 7.4V pack. Cool stuff.
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Old 11-21-2007, 03:18 PM   #69
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I have my a123 cells layed out the same way in my B44. Running a 5.5 motor geared 18/84. Thinking about gearing up a tooth or 3. I've been having a problem with the B44 rear end washing out when turning under power, and thinking that there's just not enough weight in the back to give me enough traction. So I added 2oz of lead strips down the center between the cells. Haven't gotten to race it this way yet to see if it helps. Judging by what RBMike posted about battery weights, I might still need to add yet more weight to properly balance the car that's meant to have almost 16 oz of battery weight in the back. Any thoughts?

Also, I got a Dapter to use with my ICE charger in LiPo mode, at 8 amps. The batteries usually finish charging after a race while I'm still out marshalling. Lol.
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Old 11-21-2007, 03:40 PM   #70
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Quote:
Originally Posted by Stealth_RT View Post
...I've been having a problem with the B44 rear end washing out when turning under power, and thinking that there's just not enough weight in the back to give me enough traction. So I added 2oz of lead strips down the center between the cells. Haven't gotten to race it this way yet to see if it helps. Judging by what RBMike posted about battery weights, I might still need to add yet more weight to properly balance the car that's meant to have almost 16 oz of battery weight in the back. Any thoughts?

I experienced the same thing when I switched to LiPo in my BJ4-WE.
Adding the weight under the drive shaft AND to the left and right of the batteries cured the problem.
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Old 11-21-2007, 03:49 PM   #71
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Last time I ran these, it was a 2s1p pack in my mf2/mamba 5700 and had no problems making a 6 min main on a fairly good size indoor track ( RCE if anyone's been there). I also had a 2s saddle pack in my XX4 and found it handled great even with less weight. Motor of choice was a 19t in that car.


I saw the new packs last April and they fit with no problems in a truck.


I live about 45 mins. from A123 and when I get a chance, plan on going up there again to get some new packs.


As for the voltage, a slightly faster motor will make up for the 6.6v. However, the lack of punch is perfect for slippery tracks.
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Old 11-23-2007, 11:29 AM   #72
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Great forum, I have learned a lot. Question is more about charging. What are you guys using to charge and method? Are you balancing your cells? Any info in this area would be great.

Mike
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Old 11-23-2007, 06:23 PM   #73
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The best charger for the money for these cells is the a123 charger. It charges at a constant 10 amp rate. The other charger is the mrc 989. It is good to balance these cells every so often. However, they shouldn't get too out of shape if you don't balance them.
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Old 11-23-2007, 07:09 PM   #74
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Using a Dapter from SLK Electronics with my ICE charger. Can charge up to 8 amps and it charges about 90+% of full charge.
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Old 11-23-2007, 11:19 PM   #75
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I use the a123 charger, which also balances them too ( packs come with a balancing plug ), but they're only good up to 3s.
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