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Old 05-16-2014, 11:01 PM   #1
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Default How much battery for stock class racing?

I couldn't find answers via search so I decided to make a thread.

In your experience racing in stock classes such as 21.5t, what's the minimum amount of mAH/C rating that is needed? What are your takes on shorty LiPo's in stock classes?

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Old 05-16-2014, 11:51 PM   #2
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Hmm, maybe mid 3000mah minimum for a 5-6min race. C is important in stock. Get the best possible, but over 60 at least I'd say. Of course, the C calculation is proportional to mah. Besides finishing the race, minimum requirements are dependent on how competitive you wish to be.

I've never really seen anyone use a shorty in onroad.
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Old 05-17-2014, 12:05 AM   #3
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For super-competitive on-road stock racing, you'll see guys using as much battery as they can and still make weight to minimize voltage drop over a run even though they could probably run all three or four races on one charge. Touring car can use less than 2000mah in a run, sometimes as low as 1500 or even less for 21.5, 1/12 scale uses more due to longer races and more grip.

For local racing, any decent pack should do. Whatever fits best, in the car and in budget.
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Old 05-17-2014, 12:14 AM   #4
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For super-competitive on-road stock racing, you'll see guys using as much battery as they can and still make weight to minimize voltage drop over a run even though they could probably run all three or four races on one charge. Touring car can use less than 2000mah in a run, sometimes as low as 1500 or even less for 21.5, 1/12 scale uses more due to longer races and more grip.

For local racing, any decent pack should do. Whatever fits best, in the car and in budget.
my personal opinion, as much battery as you can effectively balance your car with and legally run. More maH = more V available for longer. If all things are equal (stock racing) all advantages should be taken.

After 6 minutes of racing I used 3500mah on average with an Orion R10pro/d3.5 17.5T, in an awesomatix that weighs 1400g.
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Old 05-17-2014, 12:29 AM   #5
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Also, be aware that a higher mah pack is heavier , and will raise your Car's CG.... 4300mah 65C (260grams) is good enough for all spec classes, and you can add weight to the chassis(lowering the CG) to make weight....
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Old 05-19-2014, 05:48 PM   #6
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Hi,
If your mains are 7min, how many MAH is best? I have 2x LRP 7200 (100/50c) and 2x TP 6000 (65c). Planning on getting LRP 7000 (110/55c). I find the 7200 really heavy.
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Old 05-20-2014, 01:55 AM   #7
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Originally Posted by Mclarein View Post
my personal opinion, as much battery as you can effectively balance your car with and legally run. More maH = more V available for longer. If all things are equal (stock racing) all advantages should be taken.

After 6 minutes of racing I used 3500mah on average with an Orion R10pro/d3.5 17.5T, in an awesomatix that weighs 1400g.
Yep spot on (for stock racing). Go as big as possible while keeping it balanced and on the weight limit. Better to carry battery capacity (voltage) than a load of lead weight.
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Old 05-20-2014, 02:07 AM   #8
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Originally Posted by samnelso View Post
Hmm, maybe mid 3000mah minimum for a 5-6min race. C is important in stock. Get the best possible, but over 60 at least I'd say. Of course, the C calculation is proportional to mah. Besides finishing the race, minimum requirements are dependent on how competitive you wish to be.

I've never really seen anyone use a shorty in onroad.
I don't want to sound like I'm being an ass about this, but....

I use about 1400mah in a 3 minute 13.5 blinky qualifier.

Half of our A main guys use shorty packs (as they have the mentality that it helps with weight transfer and making their cars as light as possible) but I don't (I use a gens ace 50c 5300... I think lol) - if I finish in the top 3 of the A I am having a good day

I do think shorty packs (where allowed) would help in 21.5 as you have less motor so you need to keep the weight as low as possible to aid acceleration/ power to weight ratio

I don't know exactly the weight difference between a regular and shorty pack - but I am guessing it's @ 100 to 200 grammes.
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Old 05-20-2014, 02:16 AM   #9
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Last edited by tc3team; 05-20-2014 at 02:17 AM. Reason: double post
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Old 05-20-2014, 04:58 AM   #10
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Originally Posted by tc3team View Post
I don't want to sound like I'm being an ass about this, but....

I use about 1400mah in a 3 minute 13.5 blinky qualifier.

Half of our A main guys use shorty packs (as they have the mentality that it helps with weight transfer and making their cars as light as possible) but I don't (I use a gens ace 50c 5300... I think lol) - if I finish in the top 3 of the A I am having a good day

I do think shorty packs (where allowed) would help in 21.5 as you have less motor so you need to keep the weight as low as possible to aid acceleration/ power to weight ratio

I don't know exactly the weight difference between a regular and shorty pack - but I am guessing it's @ 100 to 200 grammes.
A shorty pack usually weights about 200 grams for mid 4000's mah packs.

I'm still on the fence on what to use, I'm going to get a standard size LiPo and I already have 2 shorties and let the laptimes decide whats better
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Old 05-20-2014, 05:30 AM   #11
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A pack around 4000mah to 5000mah should be plenty.
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Old 05-20-2014, 05:40 AM   #12
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Quote:
Originally Posted by tc3team View Post
I don't want to sound like I'm being an ass about this, but....

I use about 1400mah in a 3 minute 13.5 blinky qualifier.

Half of our A main guys use shorty packs (as they have the mentality that it helps with weight transfer and making their cars as light as possible) but I don't (I use a gens ace 50c 5300... I think lol) - if I finish in the top 3 of the A I am having a good day

I do think shorty packs (where allowed) would help in 21.5 as you have less motor so you need to keep the weight as low as possible to aid acceleration/ power to weight ratio

I don't know exactly the weight difference between a regular and shorty pack - but I am guessing it's @ 100 to 200 grammes.
So you guys are either running Mi5s and need to save a lot of weight, or running without a minimum weight rule, which is rarely a good idea as it results in lots of expense on lightened parts.

With a 7200 lipo I still need lead to make the 1350g BRCA minimum weight, so a shorty would save zero weight for me (Xray T4'14).

There are other benefits of a shorty, but only if you redesign the car to make the whole layout more compact.
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Old 05-20-2014, 07:24 AM   #13
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So you guys are either running Mi5s and need to save a lot of weight, or running without a minimum weight rule, which is rarely a good idea as it results in lots of expense on lightened parts.

With a 7200 lipo I still need lead to make the 1350g BRCA minimum weight, so a shorty would save zero weight for me (Xray T4'14).

There are other benefits of a shorty, but only if you redesign the car to make the whole layout more compact.
Correct, we don't have a weight limit.

Sorry if the OP is running to a weight limit, (To me it looks like it's an unknown atm).

We are a friendly club, yet very competitive. We have guys racing with an average to fastest lap gap of 0.4s so I guess everyone is looking for the maximum advantage possible.

We don't go overboard on lightweight parts as we have a combination of wooden and fairly unforgiving track markers, so anything that isn't durable is going to DNF - so it kind of balances that element out.

I race with a T4 '13, with a regular size lipo and must admit, the car feels quite light - but not the lightest.

I've added a bumper brace, front diff, motor guard and a cooling fan/mount, (so it's never going to be the lightest) but gives me a better chance of keeping it intact!

Neither would I go silly with lightweight shells etc etc.... My car is legal in the fact that it's set to blinky mode, yet rather quick down the back straight!

my mentality is that the pro's will always be swapping places in the A - but if they want to dabble with lighter, less durable parts that is their risk and in racing anything can, and usually does happen lol!

The guys with the shorty packs are positioning things with precision and it's quite likely they are seeing a 0.1 or 0.2s advantage per lap and their car looks very well planted pretty much wherever they put it.

If I finish in the top 3 of the A, I've had a good night of racing.
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Last edited by tc3team; 05-20-2014 at 07:45 AM. Reason: extra sentance
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Old 05-20-2014, 09:40 AM   #14
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With LRP Flow, X20 17.5, alum/ti screws, TQ short 14g wire for everything, and a 332g LRP 7200 pack I am between 1320-1330 g depending on what LW body I use (Speed 6 LW or P37 LW) with my Tamiya 418. Beyond trying to balance the car properly I can't see any advantage to running a shorty pack considering I have to add over 2 oz. just to make ROAR legal weight!! I want AS MUCH capacity I can get.

I'll be getting the LRP 7500 cells in the next few weeks--I want as little voltage drop as possible during the run. For 17.5 Blinky--especially on a largish outdoor track the motors ARE going to fade a bit from heat so I don't want the voltage drop of a 4000-5000 mah pack to add to the fade when I am 4 1/2 minutes in!
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Old 05-20-2014, 10:22 AM   #15
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One of my cars needs around 85g added to make minimum weight (it would weigh around 1295g with no lead added). That's with a 305g 6900mah battery. Even if there was no minimum weight here, I would still prefer to have less voltage drop at the end of a run than only a slightly lower COG. Any weight saved would likely need to be added back to balance left/right, so I just don't see the advantage of using a shorty, unless you have no minimum weight rule and can move the ESC or servo over to the battery side. Otherwise you'll just have a slower car near the end of a race, with no real benefit.

Most tracks have minimum weight. The minimum we have here (1380g) is a bit high IMO, but no limit would be stupid. I know a few people who would either switch brands or probably just quit if we did that here.
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