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Old 05-27-2008, 01:41 PM   #1
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Default Should ROAR limit LiPO Capacity in Stock Classes

Should ROAR limit the capacity for LiPO's in Stock and SuperStock racing?

Are there any benifits for racers to have to $150 packs when a $60 pack will do? In stock racing voltage is king. What keeps the voltage higher longer is the higher capacity. So a higher capacity pack should have an advantage.

One of the reasons for stock is to limit the cost. If a racer has to spend $90 more for a battery than that defeats the purpose for racing that class.

Besides capacity, I think ROAR needs to be more strict on the Maximum height of LiPO's. Make them the same as NiMH cells.

23.0mm Max, 21.5mm Min. This will give the manufactures better guidance in designing a car for LiPOs.
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Old 05-27-2008, 01:45 PM   #2
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Cars should be designed to the max dimensions (the +3mm). It will then fit everything that big or smaller. Lipo makes would then all just make their batteries the max dimensions set by ROAR.

What really needs to be standardize with lipo is the plugs and placement of the plugs!
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Old 05-27-2008, 01:49 PM   #3
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ROAR already has rules for the maximum physical size of the packs, it's the different ways the packs have their wires/connectors and balancing plugs coming out that is giving car owners fits
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Old 05-27-2008, 01:50 PM   #4
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The only advantage of a bigger lipo, is more run time. if you only run 5 to 6 minutes a heat, including mains, you could run all day without charging, With a maxamps 8000 mah 2s lipo. They are only 60 grams lighter than a NIMH pack, so not much balance effect. If you use 32 or 3600 orion's you'd need to charge or but two or three packs at more to do that. this is not about rules, this was to answer your question about the advantages of a bigger LIPO. I think the current ROAR and RC Pro rules for electric class (not pro truck in RC Pro) is a 5000 or 5400 mah LIPO
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Old 05-27-2008, 02:00 PM   #5
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The maximum dimensions set forth by ROAR already work to limit capacity.
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Old 05-27-2008, 02:02 PM   #6
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Yep... dimensions already limit capacity.....
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Old 05-27-2008, 02:03 PM   #7
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Quote:
Originally Posted by trailranger View Post

Besides capacity, I think ROAR needs to be more strict on the Maximum height of LiPO's. Make them the same as NiMH cells.

23.0mm Max, 21.5mm Min. This will give the manufactures better guidance in designing a car for LiPOs.

In 2008 Rule book:

8.3.2.2.2 The maximum case size shall be as follows:
Length: 139mm +0mm/-3mm
Width: 47mm +0mm/-2mm
Height: 25.1mm +0mm/-3.0mm
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Old 05-27-2008, 02:05 PM   #8
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I'm pretty sure the 3200 and 3600 packs will all of a sudden go up in price if the governing bodies put a limit to stock racing....lol

I say set a limit of 5400 for all classes and that should stabilize the battery of the week......
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Old 05-27-2008, 02:29 PM   #9
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mah limits are not necessary. The max case size limits are already limiting how much battery you can get in to the max case. You don't think we wouldn't have already seen 6000 mah and larger packs already if it were possible?

Yes there is an advantage to a larger lipo. If you want to argue price and that stock is suposed to be cost controlled racing, then your money ahead with that one $150 lipo lack vs. the 4-5 $60 nimh packs you used to carry when racing stock. Not to mention that you'll be replacing those 4-5 nimh packs twice a year. That's a total of over $500 a year in batteries vs. $150 for the big lipo pack that I'll be racing for the next couple of years. Sounds like a HUGE savings to me
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Old 05-27-2008, 02:31 PM   #10
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We just go lipo packs legalized for racing, and already people are complaining. And I am going to post something here that people may disagree with, but I think it to be true:

Budget minded racers are not going to win. And it is not even about the money, it is about the mindset. You know "that guy" at your track who can whip anyone with anyones car. He is not budget minded, he does not set limits, his expectations are never met, he will never be satisfied no matter how bad he beats the competition. It is a complete mind set, he will do whatever it takes to be "that guy". Unfortunately that guy cannot be constrained by anything. What I am trying to say, is that if you set limits on anything, you will be constrained by them, they will bleed over to other things as well, and you will always be beat by "that guy".
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Old 05-27-2008, 02:58 PM   #11
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I usually don't post in these types of threads, but trilerian's post made so much sense to me that I have to reply.

I tune motors for people, and our shop also carries batteries and whatnot - we're a small shop, so I often see where most of the product goes and who uses it and how people do with it and so forth. We just pumped out motor #1000 a few weeks ago in fact, which I was proud of.

That said - I have found that the performance margins of the motors, batteries and other gear we've sold over the years have been so much closer than people actually think that it's not even funny. The existing rules in place whether it be for motor designs, battery cases, dimensions, and whatnot already provide more than adequate limits on the absolute performance of the products.

Unfortunately, I'd also have to say that the range on the performance/capacity/whatnot is so much narrower than the range of skills using the product in 95% of the situations that most of the other rules and metrics are completely redundant. (No offence to anyone out there that races our stuff!)

More rules will not make competition better/closer/more fair/etc. More practice, better understanding of set-up, and better nerves and intuition for driving are the #1 determiner of performance on the track.
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Old 05-27-2008, 03:08 PM   #12
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Posts # 9, 10 and 11 were right on.
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Old 05-27-2008, 03:14 PM   #13
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Old 05-27-2008, 05:45 PM   #14
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Quote:
Originally Posted by trailranger View Post
Besides capacity, I think ROAR needs to be more strict on the Maximum height of LiPO's. Make them the same as NiMH cells.

23.0mm Max, 21.5mm Min. This will give the manufactures better guidance in designing a car for LiPOs.
Quote:
Originally Posted by Dawn Sanchez View Post
In 2008 Rule book:

8.3.2.2.2 The maximum case size shall be as follows:
Length: 139mm +0mm/-3mm
Width: 47mm +0mm/-2mm
Height: 25.1mm +0mm/-3.0mm
And a more strict approach would be to set the maximum to height 23.0mm +0/-1.5mm so that the capacity is limited in the future. This would be the same restrictions as NiMH.

The volume of six NiMH is 107ml.
The volume of one LiPO is 163ml

That is 58% more battery by volume for LiPO. Any improvments to LiPO power density would result in a 58% larger increase of capacity improvement than NiMH with the same improvement in power density. I would expect in the future, the power denisty of LiPOs to increase. Capacity is great for longer run times, but when runs are only 5-min it only adds cost to the battery.

If racers want to have longer racers, that is fine. The cost of racing goes up with more the longer the runtime due to tires and wear.

If ROAR keeps the Minimum weights higher then racers will buy the higher capcity packs at higher cost because performance will increase by having 2000~3000 extra mah vs. just using extra balast. If ROAR keeps the "tall" LiPO's in play for Stock Classes the same will happen, racers will be buying more expensive battery packs because they are allowed and have a significant performance advantage over the lower capacity packs.

If ROAR says it limiting capacity by limiting the volume, then why a 58% volume increase over NiMH?
Reducing capcity can be had by one these three limits: Total Weight, Total Battery Volume, or a Capacity Maximum rule.
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Old 05-27-2008, 05:50 PM   #15
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the question that really needs to be posed is, if a higher capacity pack holds a better voltage longer, at what point does the extra weight negate any benefit to the "more efficient" pack?

The electric 8th scale guys might have something to say about the current size dimensions but thats another discussion.
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