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Old 08-08-2007, 11:11 AM   #16
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Ling-Thanks for the discharge data. I'll just note that a 10C discharge rate for the 4600 mA-h pack from Horizon is 46 amps. More than enough probably. My plans are to only try these indoors, where track space is limited. This is several months away as our indoor track is under construction. A pack of half this capacity is simply inadequate for mod motors. Now if we put the pack in the car and it has no punch, compared to a 5 cell NiMH, that would be a show stopper as would be poor cycle life. The cells are rated to 160F. The 123 Web site has cycle life data as well but only at 5A discharge. The higher capacity pack will probably not overheat as much. It might be that all brands are not the same. This is the story with LiPo's

Thanks for the post guys. Someone needs to give these new cells a long term test.
John

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Old 08-08-2007, 11:25 AM   #17
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Did anybody ever locate a source for those Saehan-Enertech cells? :-)
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Old 08-09-2007, 12:52 AM   #18
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I thought I would put this little quote in from an article on the Li-ion nanophosphate battery. It is clear to me that the break through that was achieve by MIT and incorporated into this 123 battery is that it has very small clusters of the phosphate, thus the term nanophosphate. (The prefix nano is 10^-9 and is used here to just indicate small, possibly nanometer sized particles). The small particles speeds diffusion, inside the cell, which leads to faster charging and discharging ability. For this reason names not using this term "nano" may inadequately describe this new generation of Li-ion Batteries.

Syndrome: I took a look at Saehan Enertech and did not find this new type of battery listed in connection with that company on the Web. I did find that 123 systems does have factories in China and Korea which actually make their cells and gather or make the materials for them. Which cell are you refering to.

My speed control and TC5 were shipped. They are not here yet

Here is the quote:

"The secret inside A123's battery is a nanophosphate material discovered by M.I.T. professor Yet-Ming Chiang. Thousands of times smaller than the micron-sized materials used in first generation lithium-ion batteries, A123's chemistry enables it to have twice the power density of competitor products, said Vice President of Business Development, Ric Fulop. "

I plan to make up a dummy pack, from c sized cells, for now just to see how it would fit in the TC5. They would only be suitable to replace 5 cell racing due to the lower voltage of the 2S2P pack. For now I will be running a single 2s1p LiPo outdoors with car balancing tricks up my sleeve.
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Old 08-09-2007, 02:00 AM   #19
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Syndrome: I took a look at Saehan Enertech and did not find this new type of battery listed in connection with that company on the Web. I did find that 123 systems does have factories in China and Korea which actually make their cells and gather or make the materials for them. Which cell are you refering to.
Ah, sorry, I was speaking about plain old LiPo. It was mentioned to me that the cells have favorable voltage over Kokam, with similar cycle life.
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Old 08-09-2007, 10:18 AM   #20
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... I'll just note that a 10C discharge rate for the 4600 mA-h pack from Horizon is 46 amps.

Thanks for the post guys. Someone needs to give these new cells a long term test.
John
John,
The amperage limitations I mentioned for conventional lithium phosphate does not apply to the A123 "nanophosphate" cells. The A123 cells are a completely different animal. They put out TONS of current. Your goal should be to find a way to drain as high a current as you possibly can with the limited voltage. According to A123's own testing data, a single cell was tested at discharge rates of 100A, 150A, 175A, and 200A for 5 seconds at a time. Max power was achieved at 175 amps (since the voltage drop at 200 was too significant) at 240 watts over 5 seconds for just a single cell. That's a C rate of 80 which beats any lithium polymer.
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Old 08-09-2007, 10:30 AM   #21
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Syndrome: I took a look at Saehan Enertech and did not find this new type of battery listed in connection with that company on the Web. I did find that 123 systems does have factories in China and Korea which actually make their cells and gather or make the materials for them. Which cell are you refering to.
John, Syndrome,
Actually, the world is smaller than you might think. In addition to making their own lithium polymer cells, Saehan Enertech does all the electrode coating for A123. I asked them why they are helping out a "competitor" and the answer sounded like "if you can't beat them - join them". After coating, the electodes are cut and stuffed into cans somewhere in China. Someone on RCgroups posted that this was done at Shenzhen B&K, but when I went to B&K, I didn't see any evidence of A123 cells being produced there.

John - if you are still doing your pan car/lipo thing - try cells from Saehan Enertech. I guarantee you better cycle life and higher voltage than anything in your arsenal - and no, I'm not affiliated with this company. These cells are very similar in performance to the "old" Kokam cells. Multiplex just launched a lineup of lipos made by Saehan Enertech - though Hitec is pretty clueless on just how good their lipos really are. I bet Hitec doesn't even know who makes their cells. Robbee and Hirobo also uses those cells, but I don't think you can find them in the USA easily.
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Old 08-09-2007, 10:38 AM   #22
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Speaking of nano-particles,
Kokam showed me some very large lithium polymer cells they made with altairnano chemistry used on Phoenix Motor cars (1:1 electric car).
Conventional Li-Po is limited to a 2C charge. Kokam says their nano-particle lipo can take a 12C charge with no effect on cycle life. That's a 5 minute charge. They also say that the cycle life is beyond phenomenal. IMO the cycle life on Kokam's conventional lipo is already phenomenal so I can't even imagine better. Don't expect to see this cell out to the general market anytime soon, I think they are still working to make it 'mo better.
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Old 08-09-2007, 11:41 AM   #23
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ling-Thanks for the additional battery data. I think we are on the same page now when talking about the Li-Ion Nanophosphate battery from 123 systems. It should be worth a test. My LiPo's are due for replacement in a couple of months. I'll look for the Saehan -Enertech cells. They might be more available by then.
John

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Old 08-09-2007, 07:28 PM   #24
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Originally Posted by John Stranahan View Post
linger-Thanks for the additional battery data. I think we are on the same page now when talking about the Li-Ion Nanophosphate battery from 123 systems. It should be worth a test. My LiPo's are due for replacement in a couple of months. I'll look for the Saehan -Enertech cells. They might be more available by then.
John
Found it! If you get a chance look up Xtreme RC magazine, Nov. 2006 edition, and see pages 122-123; they did a test on these packs and report their findings...they also mention an A123 Charger for those packs...

I wonder if these cells can be used as 4 cell saddle pack set-up for use on a t-bar 1/10 wide pan car?
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Old 08-09-2007, 07:38 PM   #25
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The 123 cells are not going to fit in the battery slots of the pan chassis. There should be plenty of space on a t-bar 1/10 car to fit them though. If you put the side by side pairs sideways on the car they stick out about 7 mm from the edge of the chassis. If you put the side by side pairs longways they fit nicely on the pan chassis. They will be the thickness of the chassis higher than they need to be. They should easily be faster than four cell. Not as good outdoors as a good 2s LiPo.


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Old 08-10-2007, 04:33 PM   #26
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The Goods
The goodies are starting to trickle in. In the Photo at left the LRP Sphere Competition TC edition with X11 3.5 turn motor. Part #80601. In the pic at right a new Associated Factory Team TC5 in the box.

Topics to come:
Likes and Dislikes of the kit itself before I run it.
Front to Rear Weight Balance, Side To Side Weight Balance, Corner weights (using the scales) on the first setup.
MIP Tweak Station at the track
Roll Stiffness Setup at the track
Many Track Tests with 2s1p Lipos and discussions of , Caster, Shock Oil weight, Droop, Roll Center, etc.

Our track is being resealed and leveled. First test will likely be next Thursday on a fresh high grip surface.

A couple of preliminary notes. The X11 3.5 is definitely a cored or slotted motor. This means a steel core is used to wrap the wires around. This amplifies the magnetism produced by the electricity in the wires by a factor of about 14. Efficiency is good this way. You can tell by just spinning the arm with your finger and feeling the manetized rotor cog on the slots. I would have it no other way in a touring car or wide pan if you have medium to good traction. The new TC5 uses almost all metric screws and bearings. Of course you knew that.
John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-lrp-pro-comp-x11-3.5-reflection-resized.jpg   Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-lrp-pro-comp-x11-3.5-box-resized.jpg  

Last edited by John Stranahan; 08-10-2007 at 10:08 PM.
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Old 08-10-2007, 07:30 PM   #27
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TC5
The pic shows a very nice looking set of shocks that come with the TC5. Here are some assembly tips.

Shock Assembly
Use the technique in the manual and not the tool that comes with the kit. Start with the shaft assembled with all the parts. When you try to stab these into the shock body you will find that the shaft needs to be centered at the same time as the O-ring seal retainer needs to be centered in the body. This makes it difficult. Instead back the shaft out of the retainer .5 inch. Then there is room for your fingers to push the retainer in first. now the shaft will easily find the hole in the shock bottom and the whole assembly can be seated by pushing on the shaft with a dowel rod or tool. This reduces the force involved and avoids damage to the O-ring.
I set the length between the body and the upper end of the lower shock end to .425 inch. I used the small foam for less gas shock effect. If everything goes right the shock will reextend to alsmost its full length when you push the shaft in. If not you either have some friction or bubbles. Try again.
The shock shaft to bottom shock mount is stronger if you don't go past the last thread. I use a small pair of diagonal cutters on this last thread to hold the shaft and spun the last half of the ends on by gripping the ends with a small crescent wrench. The flat on the cup is sufficient grip for the wrench. No pliers here on either end.
The black plastic bushing nests perfectly in a shock top and will hide there from you.


Bevel on Shock Piston Holes
I am running outdoors on a large track. For this reason I started with 35 weight oil front and back. I also put a .010 inch bevel on the top of each shock piston hole. This softens the uptravel. The car will go through bumps with much more even traction this way without bouncing badly. See the pic of the Losi Piston at right. I put the bevel on by hand with a 1/8 inch Bit.

John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-associated-tc5-shocks-003-resized.jpg   Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-losi-jrxs-shock-piston-bevel-001.jpg  
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Old 08-11-2007, 01:28 AM   #28
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Li Ion Nanophosphate fit in the TC5
The assembly is complete enough to check the battery space. Here is my pair of dummy cells meant to simulate the size of 123's Li Ion Nanophosphate. It looks like it's a go. There is just enough length between the two aluminum bulkheads for a pack 135 mm long. The fit on the width of the chassis is helped considerably by the front belt which is offset to the left of center. Weight balance should be fine with a brushless setup. My indoor test will be a while but I thought I would report on the space now in case one of you 5 cell guys wants to try these cells.
John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-simiulated-li-ion-nanophosphate-fit-002-resized.jpg  
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Old 08-11-2007, 01:44 PM   #29
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Strengthening Caster Block Pivots

After a lot of experience with this type of pivot, I started filling the space between the caster block pivot bushings and the male threads with blue loctite. This Loctite paste does an especially good and neat job. Note the barrel of loctite that forms on the threads of the ballstuds. This keeps the ball stud from working back and forth in minor crashes and loosening the plastic threads of the Steering knuckle. Eventually the ballstud breaks or the plastic strips out without this mod. The loctite prevents movement that wallers out the threaded hole or can break the ballstud by bending it back and forth. This metric thread is slightly bigger than #4-40, so it might hold up better than previous Associated Cars.

Removing Loctited Screws
To remove these loctited screws heat them for 15 seconds with the soldering iron. Light smoke. This will loosen the locktite without damaging the plastic parts.

Prevent Chassis Tweak (a permanent twist to the chassis)
I see this problem over and over. A guy with a twin plate chassis car is driving poorly. He tightens all the chassis screws and the car is back in good shape. When the screws get loose the chassis can tweak. Also while they are loose the holes are wearing themselves bigger. Chassis Tweak causes problems and results in uneven or unpredictable weight transfer when turning left vs right. I put a layer of this Loctite paste under the heads and a small portion of the threads of each screw that secures the top or bottom plate to the bulkheads.
If you pick up the car and twist it one hand on the front and one on the rear, it should not creak and take a new set. This causes chassis tweak in a mild crash. If all these screws are loctited at the very beginning you will prevent wear of the holes in the chassis and will prevent chassis tweak.

John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-locktite-caster-block-pivots-001-resized.jpg  

Last edited by John Stranahan; 08-13-2007 at 11:04 PM.
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Old 08-11-2007, 03:14 PM   #30
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so the A123 individual cells are slightly larger then a C sized battery?
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