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Old 12-16-2007, 09:17 PM   #136
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after all these postings u start to understand somthing and how each side is thinking.
lipo advocate dont mind running against nimh batteries........thats a good thing
nimh advocate dont mind running against lipo.....thats good
*******so what is the arguements about******
clup races already allowed<most of them at least>lipo against nimh
proplem is big events that follow roar guide lines
lipo is not legal so that is the proplem,once they allow it case is over
so i would say let roar legelize lipo,and allow the 2 batteries to run against each other,u run ur beloved nimh and i run my beloved lipo
thre should be no weight rule so lipo can show its advantegous,lighter car less strain on motors and tires,at the end isnt that what roar wants,the best for the hobby
and once they run against each other,each battery will show its advantege,and then let the better battery win.and without u knowing it racers,companies factories and evryone will autumatically goes with the best
correct me if i am wrong please
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Old 12-16-2007, 09:17 PM   #137
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Bill- Motives that you can only speculate on since you were not there and you were not inside the heads of the people who spoke to see what they were thinking.

You have written a number of things that insinuate peoples' motives that may be a lot of speculation. There really isn't a debate to me as NiMh is the legal battery on the major racing scene with Lipo and NiMh running side by side on the club racing scene. When the major sanctioning bodies decide to make a change then racers will make that change.

This really isn't about Lipo's being able to run alongside of NiMh's, instead it seems to be about running only Lipo's. I honestly think Scrubbs is on to a lot.

Hey Bill, were you one of the people wanting 3K's and then 3.3K's and then 3.8K's...???? Oh well, I'm done, nothing more to say. Have fun trying to force your will upon others with your philosophical fundamental of: it's easier, less maintenance, better, and in the long run less expensive routine so everyone should just switch right now.

Because even if it is, the very nature of competition has a way of pushing the boundaries and forcing those that are game to push them also and then others have to. Then all of a sudden costs are up even more, no maintenance and fair playing fields (didn't we hear that with the 3K's???) and everything else slogans go out of the window.

Oh I know, at that point there will be something else to push that will be the silver bullet to provide us with that holy grail of no work, no driving, no guts, and no glory racing.
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Old 12-16-2007, 09:28 PM   #138
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why are we still running sub-c cells??

Well, I dont need to write paragraphs to answer that. A) Better voltage B) They dont scare the crap out of me C) Startup costs (need 2 lipo's IMO) D) Legal. E) I enjoy building my own packs, and I can rebuild / maintain them easily.
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Old 12-16-2007, 09:30 PM   #139
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darnold- you are exactly right.

Competition has a way of forcing racers to do anything to gain an edge, even though everyone else gets that edge too, and of course the suppliers comply. I have no doubt that new lipo's will come along with higher c ratings and that racers will push lipo for every last inch, but I don't care about that. There will always be guys faster and better, I am looking at what I have to do to maintain my equipment, and what I have to spend. For that, brushless and lipo can't be beat at the moment. In the future, who knows.

As for LIPO and chassis weight, it makes no sense to weigh down a chassis beyond the balance point. If I were to run brushless (I have 2 systems in other cars,) I would add 2oz to the battery side and would be at 51.5oz balanced. That is still 3oz under weight, and that 3oz makes a small difference in tire wear, motor current draw etc. Besides, adding more and more weight to the battery side makes it hard to maintain the chassis dynamics (in terms of where the weight is.)

Last edited by billjacobs; 12-16-2007 at 10:01 PM.
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Old 12-17-2007, 06:16 PM   #140
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Quote:
Originally Posted by Danny/SMC View Post
It seems like Lipos offer more memory effect than sub-c cells.

So basically we have seen that cycling discharging a 2 cell pack down to 6 volts at 35 amps will keep the voltage as high as possible and the IR low.
I disagree - see below

Quote:
Originally Posted by trilerian View Post
How long does this take to notice with the lipo, how many cycles on the track? And do you do a full cycle or just discharge after use?
answer - the memory effect of lipos is almost not measureable (see below)

Quote:
Originally Posted by Danny/SMC View Post
This happens once you run your packs on the track in low amp draw situation like stock and 19t. The more you run them without cycling them at high discahrge rates the more it will drop. If your the type of racer who believes that .02-.04 in voltage makes a difference then you will need to discharge them every few runs or so.

Another thing that we noticed is that by fully discharging your pack it will perform better.

For all of those who doubt what I'm saying and udnerstand battery cycling numbers here are actual numbers that someone provided me. This guy uses the Orion 3200 pack.

Cycling was done on a T35 Lipo GFX using a 35 amp discharge down to 6 volts.

Four cycles were done in the same day and basically as soon as one cycle finishes they other one starts.

runtime - voltage - IR
Cycle 1: 314 - 6.76 - 17.1
Cycle 2: 322 - 6.95 - 12.3
Cycle 3: 326 - 7.01 - 11.2
Cycle 4: 328 - 7.03 - 10.8
Danny, I think you might be interpreting the data incorrectly.

I've tested for the memory effect on Lipos and it almost doesn't exist. See the attached plot of a pulse discharge on a Kokam battery. The pulse is over a 30C discharge rate.
The battery was given exactly 500 partial discharges (3.1V cutoff at a 35C rate which is approx 50% discharge depth). The dark blue line represents the plot of the last partial cycle.
The battery was then subject to a series of full discharges. The pink line is the first full discharge (2.8V cutoff) after all those partial discharges, and the green line is the 2nd full discharge (also 2.8V cutoff).

All plots pretty much fall on top of each other.

There is no difference between the last of the 500 partial discharges and the first couple of full discharges. There is no memory effect going on here.

Cycling a lipo battery all the way down does pretty much nothing other than take away cycle life.

I think the main reason that you are seeing such a difference in results is that the first cycle is on a cold battery. After the first cycle, the heat is retained and there is tons of data showing that a Lipo battery discharges much better with higher temperature. Per your quote, the other cycles were started immediately after the first and a 35amp discharge generate a lot of heat.

This can all be confirmed by all the racers currently using lipos out there. With NIMH, all of us felt that NIMH batteries felt "flat" when charged the day before or if we didn't discharge them all the way down. I don't know the actual difference in discharge numbers, but it was enough to be easily felt.

With lipo, I have never experience a "flat" run. They feel the same all the time. Whether it's been through a bunch of partial discharges, the punch is incredibly consistent.

I've also never seen any data to suggest a difference in discharge whether the previous discharge was a high or low rate. Cycling a lipo is not needed.

It's a matter of time until everyone comes out with lipo warmers

Anyways, this isn't an arguement, I just wanted to make as much data availiable for all the lipo users.

-ling
Attached Thumbnails
why are we still running sub-c cells??-partial-discharge.jpg  
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Old 12-17-2007, 06:16 PM   #141
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...
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Last edited by linger; 12-17-2007 at 06:17 PM. Reason: double post...crap
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Old 12-17-2007, 06:48 PM   #142
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Quote:
Originally Posted by trackpower View Post
after all these postings u start to understand somthing and how each side is thinking.
lipo advocate dont mind running against nimh batteries........thats a good thing
nimh advocate dont mind running against lipo.....thats good
*******so what is the arguements about******
clup races already allowed<most of them at least>lipo against nimh
proplem is big events that follow roar guide lines
lipo is not legal so that is the proplem,once they allow it case is over
so i would say let roar legelize lipo,and allow the 2 batteries to run against each other,u run ur beloved nimh and i run my beloved lipo
thre should be no weight rule so lipo can show its advantegous,lighter car less strain on motors and tires,at the end isnt that what roar wants,the best for the hobby
and once they run against each other,each battery will show its advantege,and then let the better battery win.and without u knowing it racers,companies factories and evryone will autumatically goes with the best
correct me if i am wrong please

The min weight rule is not a NIMH rule. Its a sedan guideline rule. I can go on and on about things to make my car faster by breaking rules. Why not run foam tires on asphalt. its lighter and has more grip. why not cut the wing higher past the guide lines or hey I found a secret to winning stock stick a mod motor since its faster..

The fact is no matter what form of racing you participate in there will be rules and its up to you to get the most speed within those rules...
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Old 12-17-2007, 07:05 PM   #143
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Originally Posted by billjacobs View Post
IOne more thing, BL and LIPO have done more to bring in new racers and gotten back retired racers, than they have ever turned away. Touring car racing is on the decline precisely because of the costs involved, and lipo and brushless reduce those costs tremendously.
...........yup...........brushless and lipo will bring racers back (me included)........500.00 TC chassis that come out every 4 minutes are what is driving racers away............why run electric TC when you could run 1/8 on-road for the same price..........
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Old 12-17-2007, 07:09 PM   #144
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Originally Posted by Taylorm View Post
...........yup...........brushless and lipo will bring racers back (me included)........500.00 TC chassis that come out every 4 minutes are what is driving racers away............why run electric TC when you could run 1/8 on-road for the same price..........

the prices of sedans kinda surprised me too. Especially when comparing it to 1/8 onroad....
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Old 12-17-2007, 07:16 PM   #145
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Like I said

game over for the Nk-Ml ...

It was nice while it lasted , but its over now ....
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Old 12-17-2007, 07:25 PM   #146
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Quote:
Originally Posted by C_O_jones View Post
It was meant to be funny, you lipo/Bl guys need to lighten up some!

My 4200's that I bought back in July, finally wore out, and I did use them a LOT!
So while waiting for the new batch to arrive, I picked up a lipo, Orion platinum 4800, not very impressed, used it fri night for a club race and sat out the 3rd qual to get it charged up again. I ran 19t rubber with a checkpoint and could not get the the 3600 back into it in time. I wont buy another one, not when the top of the line lipo cant keep up, power loss was noticeable too.

fred, problem is you didn't buy the "top of the line" the orion 3200 is way way better then the 4800, and IMO the core lipo is better then both of them, you did see me passing 4200's on the straight in salem didn't you. i managed to cranked out a 9.7 in the middle of the hack fest that were the mains. see you wednesday maybe? i'll check that lipo for you and make sure everything is ok
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Old 12-17-2007, 07:36 PM   #147
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Default linger and lipo

I love reading linger's posts. Nothing like knowledge and data to make a point. I hereby vote for linger as the best poster on batteries on rctech, even though he only posts about LIPO.
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Old 12-17-2007, 07:41 PM   #148
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The racers ultimately control what sedan's cost. If racers didn't buy $450 sedans + $100 in hopups, no one would make them. The last new kit I bought was the tamiy ta04-r for $170. Every other kit I have bought has been used for about 1/2 price. So my sedans cost about $225 with hopups, (I have x-ray, tamiya, and losi sedans,) with the exception being an rdx a while back but with all the extras it came to 1/3 the price of new.

You cannot blame x-ray, corally, tamiya, etc for making $450 sedans if the racers buy them. Lately, I see more and more newbie's with the high dollar sedans. I wish my parents bought me r/c stuff.

Last edited by billjacobs; 12-17-2007 at 07:52 PM.
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Old 12-17-2007, 09:21 PM   #149
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The racers ultimately control what sedan's cost. If racers didn't buy $450 sedans + $100 in hopups, no one would make them. The last new kit I bought was the tamiy ta04-r for $170. Every other kit I have bought has been used for about 1/2 price. So my sedans cost about $225 with hopups, (I have x-ray, tamiya, and losi sedans,) with the exception being an rdx a while back but with all the extras it came to 1/3 the price of new.

You cannot blame x-ray, corally, tamiya, etc for making $450 sedans if the racers buy them. Lately, I see more and more newbie's with the high dollar sedans. I wish my parents bought me r/c stuff.
i hear u
if money is not an object,a newbie can buy anthing he wants,but for the majority,how do u justify this to ur parents,think about it.hobby shops will tell the newbie who wants to race,most of the time he is the catch of the day,to be competitive u need the following:
new hiteck chassis.....$430
competitive speedo....$160
competitive servo......$100
1 stock motor...........$35
competitive radio.......$275
4 matched packs........$260
average good charger..$150
discharge tray...........$100
motor comm lathe......$150
2 sets of tire............$60
body.......................$20
transponder.............$100
parts,hopups.paint,etc$60

total.....................$1900
take this list to ur parents and good luck,i know had i gave them this list,i would have never seen a race track in my life.so i started with an rtr for $300
2 stick packs $40,and a cheap good charger$80,tires $60.and i started racing
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Old 12-17-2007, 10:53 PM   #150
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Default cost of racing

trakpower: Most guys I see racing have all of these things, but they have much more than $1900 sunk into r/c.

As an exercise, let's see what brushless and lipo cost:
new hitech chassis.....$430
competitive speedo....$200
competitive servo......$100
1 bl motor.................$80
competitive radio.......$275
2 Lipo packs.............$240
average good charger..$100
2 sets of tire............$60
body.......................$20
transponder.............$100
parts,hopups.paint,etc$60

total.....................$1700

This can't be, how can lipo and brushless be cheaper?
And you have a motor that will last and batteries that will last. How is this possible?
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