Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks
10-07-2007, 10:18 PM
#286
Fathead-Thanks. Should be an interesting experiment. I'll post a setup if it changes much. My car was a little nervous also at first. It would spin out on occasion on power. The problem seemed to be too much roll stiffness. I had a purple front spring on. What was happening is that it was responding to bumps poorly. Went to blue front and softened the rear with green and a standard ball front diff and the car really settled down and drove well. I could then use huge power. Then I put on the locked front diff and it settled down a little more and I could drive it harder in the corners. This required a blue rear spring. That last setup change that I made to rear toe made it easier to drive harder as well. Rear toe is about 2.75 degrees now. Interestingly it gave medium corners more traction in the rear (the car is more tight), but improved rotation of the rear on the hairpins (more loose). I wish I could have run that third heat.
The car will come around once you tinker with it enough. I am pretty pleased at the moment and running 2 year old rubber tires.
John
The car will come around once you tinker with it enough. I am pretty pleased at the moment and running 2 year old rubber tires.
John
Last edited by John Stranahan; 10-08-2007 at 08:13 AM.
10-08-2007, 09:32 AM
#287
John - you really should not be charging your FMA 4800 at 10 amps. Charging over 2C really kills the cycle life even if the manufacturer claims that the cell can handle 2C. Both capacity and internal resistance takes a bit hit and you get this odd crystal buildup when repeatedly charged at 2C. The battery actually degrades more during a 2C charge than a 20C discharge.
Attached is a pic of what happens to a lipo when subject to a 2C charge. It was dead in less than 200 cycles at 2C, but was good for over 1000 cycles at 1C.
Attached is a pic of what happens to a lipo when subject to a 2C charge. It was dead in less than 200 cycles at 2C, but was good for over 1000 cycles at 1C.
10-08-2007, 09:48 AM
#288
Linger-These packs measure very close to 5000 mA-h. 10 A is close to 2 C. From my testing 50 cycles is what I am going to get before I no longer find acceptable performance. I don't need to extend the battery life over 200 cycles. Now if indeed this charge rate is more harmfull than my 45 amp average discharge during the race then I should cut back a bit. I am under a time constraint while racing. It is nice to have a charged pack at the beginning of a heat. I will cut back a little and race on a 90 % charge. Glad to hear you comment on these crystals. I suspect that is what perforated a layer and caused my last battery fire.
john
john
Last edited by John Stranahan; 10-08-2007 at 02:43 PM.
10-08-2007, 10:25 AM
#289
John,
What I'm trying to say is that it's a hell of a lot cheaper to buy more packs and chargers than it is to charge at 2C. See the attached pic. The Y axis is analagous to capacity. The cells that drop in capacity very quickly are the ones charged at 2C. That chart is of Kokam cells, but I have similar data with a lot of other cell manufacturers. Compare that to the ones charged at 1C. BIG difference.
Also, I just looked up the spec sheets to the Saehan Enertech Cells (the likely cells used in the FMA revolution lineup). Their max recommended charge rate is 1C and they consider that "rapid charge".
What I'm trying to say is that it's a hell of a lot cheaper to buy more packs and chargers than it is to charge at 2C. See the attached pic. The Y axis is analagous to capacity. The cells that drop in capacity very quickly are the ones charged at 2C. That chart is of Kokam cells, but I have similar data with a lot of other cell manufacturers. Compare that to the ones charged at 1C. BIG difference.
Also, I just looked up the spec sheets to the Saehan Enertech Cells (the likely cells used in the FMA revolution lineup). Their max recommended charge rate is 1C and they consider that "rapid charge".
10-08-2007, 02:43 PM
#291
Ling-The solution seem to be a third charger and use of an extra pack for practice before the race. That Scorpion charger is presently at a good price. I will see if it is still available.
Here is a note from the manual of FMA's new charger. Old LiPo's at 1 C but
unattended.
I will study your discharge data in a bit and make a post about it.
john
Here is a note from the manual of FMA's new charger. Old LiPo's at 1 C but
For recently-manufactured lithium packs, set charge rate up to 3C. Packs in good condition
should charge without cell damage. However, use caution and don’t leave the charger
should charge without cell damage. However, use caution and don’t leave the charger
unattended.
I will study your discharge data in a bit and make a post about it.
john
10-08-2007, 03:05 PM
#292
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Hey Ling,
That looks like a good graph. Were the packs around the 40 mark the orion Platinum Edition cells by any chance? They seem to hold pretty good numbers. Or are these not specifically rc batteries?
Cheers,
Warwick.
That looks like a good graph. Were the packs around the 40 mark the orion Platinum Edition cells by any chance? They seem to hold pretty good numbers. Or are these not specifically rc batteries?
Cheers,
Warwick.
10-08-2007, 05:35 PM
#293
Warwick-Those cells are made by KoKam but are not the Orion cells. They are of a smaller capacity than we use (only 750mA-h) and are produced as samples, for testing, that might be used in a custom application. I studied the graph and had some communication with Ling. On the Y axis is the energy epended on a discharge which is related to capacity. The striking result is that the cells charged at 1C are represented by the lines that don't drop very much as we go to the right. This means they have little loss in energy output with each additional cycle even at high discharge rates. They achieve upwards of 400 cycles. The lines representing cells charged at 2C drop steeply. You can see the little steps as each discharge cycle reduces the output of the cell. They tend to end at 125 cycles or so. The battery can be considered dead or unusable where the line ends. At least the testing stopped there.
1C for my roughly 5000 mA-h cells is 5 amps. 2C would be 10 A charge rate.
I have personal experience with Apoggee Lithium Manganeese cells charged at 2C which they recommended. The drop in runtime was very fast. The drop in runtime with a couple of months storage after they were no longer satisfactory in the car was exceptionally fast and complete.
Some of the other cells I have charged at 2C on occasion with much better success. If indeed the charging deteriorates the cell more than the high heat with high discharge rate then it would be worth testing this new battery at 1 C charge rate only to see if it actualy will last longer in high Drain RC car use. I have ordered a third battery charger to effect this.
Interestingly when I first tested the LiPo scorpion pack I posted that probably we would need three batteries and 3 chargers to use these cells effectively. Others proponents of LiPo said no. Is it worth this much expense is the likely question. Well the TC5 looked really good compared to the Nitro's even on the straight last race.
What we don't see on this graph is what is happening to the Voltage. It does no good to really pamper a cell so that it achieves 400 cycles if the voltage is subpar for RC car performance after 50 cycles and requires replacement. It is very possible that Average Voltage and Capacity are lost at similar rates. It is certainly worth a pampering test. These cells have only had 10 amps for about 10 minutes each just for the race.
1C for my roughly 5000 mA-h cells is 5 amps. 2C would be 10 A charge rate.
I have personal experience with Apoggee Lithium Manganeese cells charged at 2C which they recommended. The drop in runtime was very fast. The drop in runtime with a couple of months storage after they were no longer satisfactory in the car was exceptionally fast and complete.
Some of the other cells I have charged at 2C on occasion with much better success. If indeed the charging deteriorates the cell more than the high heat with high discharge rate then it would be worth testing this new battery at 1 C charge rate only to see if it actualy will last longer in high Drain RC car use. I have ordered a third battery charger to effect this.
Interestingly when I first tested the LiPo scorpion pack I posted that probably we would need three batteries and 3 chargers to use these cells effectively. Others proponents of LiPo said no. Is it worth this much expense is the likely question. Well the TC5 looked really good compared to the Nitro's even on the straight last race.
What we don't see on this graph is what is happening to the Voltage. It does no good to really pamper a cell so that it achieves 400 cycles if the voltage is subpar for RC car performance after 50 cycles and requires replacement. It is very possible that Average Voltage and Capacity are lost at similar rates. It is certainly worth a pampering test. These cells have only had 10 amps for about 10 minutes each just for the race.
Last edited by John Stranahan; 10-08-2007 at 05:52 PM.
10-10-2007, 02:57 PM
#294
I sent a note to Paul at Titanium Racing. They have a pic of the new spool design up again on the Web site. He replied promply that it is available and would ship for the TC5 if i ordered under the old picture. I ordered one up. I requested a set of outdrives by e-mail as there does not seem to be a way to do this on the spool items page.
This new design has some advantages over the old. The outdrive cup is secured by a flange behind the outdrive bearings. This should make for a more wobble free or concentric spinning setup even after a bump on the track. Test to come.
John
This new design has some advantages over the old. The outdrive cup is secured by a flange behind the outdrive bearings. This should make for a more wobble free or concentric spinning setup even after a bump on the track. Test to come.
John
10-11-2007, 06:52 AM
#295
Hi John: About the Foam tires...
I have run them on My TC's for almost 2 yrs. The car's performance will improve in handling and speed. Use 37-38 shore all around. we like the Nitro Shoes 37's all around. They wear better. The best tires are Kyosho foam tires...they are very consistant and have very nice grip and wear from the first run. They are expensive though...if you give the Kyosho foam a shot, use 35 rear and 38 fronts...
With foam tires, remember to move the rear bottom shock mount position a hole towards the inside, since the 30mm rear wheel will rub on the bottom shock ballcup and bind or grind it down quickly.
Use 6.5mm starting ride height all around- by the time you finish your 2nd pack it should be around 6mm. Check ride height every 2 or 3 runs and adjust.
Also, when you start using the foams, they are usually 63mm. Dont true them down. start them off like that wear them w/ every run...they'll work better than rubber tires even at their staring 63mm stock diameter! When they get to 58mm...oh my goodness!! The car will pick up over all speed and handling will be sharper...check your gearing- you might need to add a tooth since the rollout changes as the tires get lower.
THere's no comparison...you'll be .5 sec faster per lap, easy with the foam tires. Let us know how it goes...
I have run them on My TC's for almost 2 yrs. The car's performance will improve in handling and speed. Use 37-38 shore all around. we like the Nitro Shoes 37's all around. They wear better. The best tires are Kyosho foam tires...they are very consistant and have very nice grip and wear from the first run. They are expensive though...if you give the Kyosho foam a shot, use 35 rear and 38 fronts...
With foam tires, remember to move the rear bottom shock mount position a hole towards the inside, since the 30mm rear wheel will rub on the bottom shock ballcup and bind or grind it down quickly.
Use 6.5mm starting ride height all around- by the time you finish your 2nd pack it should be around 6mm. Check ride height every 2 or 3 runs and adjust.
Also, when you start using the foams, they are usually 63mm. Dont true them down. start them off like that wear them w/ every run...they'll work better than rubber tires even at their staring 63mm stock diameter! When they get to 58mm...oh my goodness!! The car will pick up over all speed and handling will be sharper...check your gearing- you might need to add a tooth since the rollout changes as the tires get lower.
THere's no comparison...you'll be .5 sec faster per lap, easy with the foam tires. Let us know how it goes...
10-11-2007, 06:29 PM
#296
Tech Apprentice
foam tires
We run foam 19-turn TC on a sugared asphalt track. Many run Nitro Shoes Rears on all four corners. The Nitro fronts are made of a harder different type of rubber. Electric TC don’t have the weight to make them work and need more steering than nitro cars so you may want to try rears all around. You’ll likely have to narrow the rims as they are 30 mm wide. I cut mine 28 mm wide on my tire lathe with an Exacto wearing a face shield and standing off to the side. I’ve run carpet foam tires on colder days but they tended to wear very rapidly on hot days. We'll see 120ºF track temperatures. I run 38 front /35 rear or 37/35. We run carpet set-ups on the cars with a slightly higher ride height (5.5 mm).
Great thread. I’ve also enjoyed the 1/10 pan car thread. My non-RC friends are always surprised at the level of engineering that goes into these cars.
Great thread. I’ve also enjoyed the 1/10 pan car thread. My non-RC friends are always surprised at the level of engineering that goes into these cars.
10-12-2007, 08:57 AM
#298
yyhayim, Tuner EM- Thanks for the tips on the foam tires. I have some 35's coming in for a test. Looks like I might need some 37's as well.
when you guys say Nitro Shoes are these Nitro Shoes made for electric cars or Nitro cars. In other words are the hex drives the same? I did notice that the width might be different and Tuner cut that down.
Futaba Brushless Servo
I am using that brushless Futaba Servo. It is working great. It is slightly lighter and more compact than the other servos I am using as well. No problems to report.
john
when you guys say Nitro Shoes are these Nitro Shoes made for electric cars or Nitro cars. In other words are the hex drives the same? I did notice that the width might be different and Tuner cut that down.
Futaba Brushless Servo
I am using that brushless Futaba Servo. It is working great. It is slightly lighter and more compact than the other servos I am using as well. No problems to report.
john
10-12-2007, 11:26 AM
#299
yyhayim, Tuner EM- Thanks for the tips on the foam tires. I have some 35's coming in for a test. Looks like I might need some 37's as well.
when you guys say Nitro Shoes are these Nitro Shoes made for electric cars or Nitro cars. In other words are the hex drives the same? I did notice that the width might be different and Tuner cut that down.
Futaba Brushless Servo
I am using that brushless Futaba Servo. It is working great. It is slightly lighter and more compact than the other servos I am using as well. No problems to report.
john
when you guys say Nitro Shoes are these Nitro Shoes made for electric cars or Nitro cars. In other words are the hex drives the same? I did notice that the width might be different and Tuner cut that down.
Futaba Brushless Servo
I am using that brushless Futaba Servo. It is working great. It is slightly lighter and more compact than the other servos I am using as well. No problems to report.
john
Nitro Foam TC tires work just fine w/ electric TCs...the only issue is the rear 30mm width...they inner wheel will rub on the rear lower shock ballcup and bind. Just move it one hole over and you'll be fine...this varies with the different cars...the JRX-s and Type R dont need to be moved at all...
10-12-2007, 07:05 PM
#300
YYhayyim-Thanks. I took a look at our shop supply of tires. Quite a few brands are available but mostly in 42's. Thanks for the interchange information.
Track Report
120F track Temp, Traction Medium-Low
Only two of us on the track so traction was not as good as race day. I was able to evaluate well that increase in rear toe to 2.75 degree. This was accomplished with 2 degree Associated shims, .5 degree hubs and .025 shims added to the associated spacer. I was very pleased with the handling. Often with a locked diff it is hard to make a change that is really helpful. This was. I drove with no corner exit mistakes now. The rear end is well planted. I could drive really hard. I will add this little change to my posted setup earlier in the thread. Jeff turned on the track timing equipment. I was quickly up to race speeds even though traction was a bit off. I epect some mid 18's next race day. I am getting low 19's and an occassional 18.9 or 19 flat. I really think rubber was the tire of choice today. I will be able to compare the two better later on. Right now I can test the traction foam tires have with the pan car. Speed control and motor worked great at 120F. Front diff is chunking a pin pillow just about every run now that things have worn a little. TIR front spool on the way
John
Track Report
120F track Temp, Traction Medium-Low
Only two of us on the track so traction was not as good as race day. I was able to evaluate well that increase in rear toe to 2.75 degree. This was accomplished with 2 degree Associated shims, .5 degree hubs and .025 shims added to the associated spacer. I was very pleased with the handling. Often with a locked diff it is hard to make a change that is really helpful. This was. I drove with no corner exit mistakes now. The rear end is well planted. I could drive really hard. I will add this little change to my posted setup earlier in the thread. Jeff turned on the track timing equipment. I was quickly up to race speeds even though traction was a bit off. I epect some mid 18's next race day. I am getting low 19's and an occassional 18.9 or 19 flat. I really think rubber was the tire of choice today. I will be able to compare the two better later on. Right now I can test the traction foam tires have with the pan car. Speed control and motor worked great at 120F. Front diff is chunking a pin pillow just about every run now that things have worn a little. TIR front spool on the way
John
Last edited by John Stranahan; 10-12-2007 at 07:19 PM.