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Old 03-12-2016, 05:05 AM   #31
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So they'd be no good for open mod either since you take around 5000mAh out during a run.
Do they ever run them in a stock class equivalent to 13.5 or 10.5 blinky?
Yes, you're right. Those batteries are specific to JMRCA 21.5 2s 1/12th scale racing. I would love to try one with a 3.5 motor... lol.

The JMRCA 21.5 2s 1/12th scale class is from what I hear very close to 1s 10.5 blinky.

Move the video to 3:05:00 mark for JMRCA 21.5 2s for the A-Main.

I'm the one who launched his car into the crowd coming on to the straight...

https://www.youtube.com/watch?v=xDPZc22Ra6o

Modified A-Main is at the 3:28:00 mark.
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Old 03-12-2016, 05:13 AM   #32
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Originally Posted by Skiddins View Post
So they'd be no good for open mod either since you take around 5000mAh out during a run.
Do they ever run them in a stock class equivalent to 13.5 or 10.5 blinky?
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Yes, you're right.
Not quite.

A 3500mAh 2s battery has the same energy capacity as a 7000mAh 1s battery. When the 2s battery is matched to a motor that gives equal power output as a given 1s motor/battery combo, the run time will be the same.
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Old 03-12-2016, 06:18 AM   #33
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1/12 2s
1/12 1s

I see no argument here

This is a discussion about how much we love our methods of 1/12 racing in different corners of the world

Kind of like which Ice Cream is your favorite flavor
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Old 03-12-2016, 07:11 AM   #34
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1/12 2s
1/12 1s

I see no argument here

This is a discussion about how much we love our methods of 1/12 racing in different corners of the world

Kind of like which Ice Cream is your favorite flavor
You are 100% correct.

The only thing what I don't like on a lot of the comments is the underlying message that everyone needs to change something on the existing rules. Only to may get one or two more racer.
The only thing what is created by this constant changes is to scare off people, because they are afraid/annoyed of the constant rule changes.
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Old 03-12-2016, 07:17 AM   #35
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Before I write, I summerize 1cell and 2 cell attribution.
1cell 17.5 speed = 2 cell 30.5 or more
1cell 13.5 speed = 2 cell 25.5
1cell 10.5 speed = 2 cell 21.5
I have experience 2cell 25.5 over two years. Those two was the same on same weight 730g rule.

Current regulation has no limitation on battery weight. It makes manufacture rapidly progress battery capacity. When I met 1cell might be 2004, it was SMC 2800 or 4000 mAh cell. I'm not sure precisely. But now capacity is developing over 8000 mAh. This means gain more speed for open class, whilst no need capacity for stock class. In addition, battery price runs up ceiling price for our budget. For stock 1 cell racing 13.5 and 17.5, it is over capacity. They are enough 4000 mAh.

Capacity on Lipo battery directly links battery weight as well as price. The more weight, the more capacity and price.

Taking into consideration from 10.5 to 17.5 speed on 1 cell, required capacity maybe approximately 5000 mAh. Applying for 2 cell, battery capacity is 2500 mAh.
The battery I introduced Orion and Yokomo 1600 mAh are short short supply on 13.5 and 10.5.

'durtbag' found out the battery match those condition. I did not know such battery already on US market.
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http://www.amainhobbies.com/rc-cars-...100-15/p423773

I have one of these, used with the Orca VX3 and I can run both ways 1s or 2s


2 cell 2800 mAh is perfect for 1/12th 2 cell stock.

Last edited by landau; 03-12-2016 at 08:36 AM.
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Old 03-12-2016, 07:34 AM   #36
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1cell 13.5 speed = 2 cell 25.5
1cell 10.5 speed = 2 cell 10.5
Typo. 1cell 10.5 = 2 cell 21.5

Rule of thumb: Double the voltage, double the number of turns = same power

Second Rule: 1/12 is fun no matter what!
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Old 03-12-2016, 08:50 AM   #37
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several companies make the 2s (super slim) (lightweight) (low profile) shorty batteries that are near the same size as a 1S pack. they have been on the US market for awhile, but 1/12 scale in the US is predominately now set at 1S, so they are rarely talked about as a option.

http://www.amainhobbies.com/rc-cars-...asc319/p444465

http://www.amainhobbies.com/rc-cars-...ep2110/p363145

http://www.amainhobbies.com/rc-cars-...430229/p447929

http://www.stormerhobbies.com/cgi-bi...ns&pn=FAN26215

sorta like brushed 27T motors the US used in stock racing for a long time, when i lived in Japan for 2 years, they raced 23t spec motors there, i believe EU ran other spec winds
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Old 03-12-2016, 11:25 AM   #38
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those low profile packs are pretty cool for sure but the fade.... we drop about 3000 mah in 13.5 single cell 1/12 over 8 minutes. 1800-2000 for a 17.5 2s touring car in 5 minutes. so there is less weight but the motor will still draw what it wants to draw. over 8 minutes 3000mah would be pushing it and the fade would be pretty damn crazy. even if you ran a justock i should think it would JUST make it.
surely a 21.5 should draw less than 17.5, but from what ive seen of 21.5 touring cars in canada, they are getting very close to 17.5 in top speed.

im up for trying most things that don't cost a messton from existing, would just impose more tech responsibility on clubs trying to run both int eh same heats.

track in vid is pretty neat. id like to race on layouts liek that. what surface is that? seems a little slick.
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Old 03-12-2016, 11:38 AM   #39
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A couple of us in Arizona have run 2S 13.5 and 17.5 boosted at TQ in chino with the modified 1/12 scales. 8 minutes is no problem and i'm running the Protek 2900 mah battery. The usual drain was about 2100 mah per race.
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Old 03-12-2016, 05:37 PM   #40
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12th stock racing in Japan is unique. Some race are 1 cell others are 2 cell, like as US rule.

1cell 13.5 and 2cell 25.5.
1cell 17.5 and 2cell 30.5
just curious about rollout for these. would 2cell 30.5 have a less ridiculous rollout (17.5 is lingering in the 95mm to 105mm range) or does parity bring the rollouts in line with each other?
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Old 03-12-2016, 05:52 PM   #41
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So they'd be no good for open mod either since you take around 5000mAh out during a run.
Do they ever run them in a stock class equivalent to 13.5 or 10.5 blinky?
You have twice the voltage though. A 2s 3500mah pack is the exact same amount of total power as a 1s 7000mah pack. So for 2s mod you would probably run something more like a 10.5 instead of a 3.5.

Remember we used to run mod with just 1200mah, LOL.
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Old 03-12-2016, 10:03 PM   #42
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just curious about rollout for these. would 2cell 30.5 have a less ridiculous rollout (17.5 is lingering in the 95mm to 105mm range) or does parity bring the rollouts in line with each other?
I don't think I can answer your question, but what I can say is my first 2s experiment was with a 17.5 that was setup for 1s and ran it on Blinky with roughly 50mm of rollout, as I figured with twice the voltage I'd want about half the rollout. After an 8 minute run the motor was barely above 100F. Because I was running in 1/12th modified I turned on the Boost, but had I stayed with Blinky I think I would have ended up around 60mm of rollout.
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Old 03-12-2016, 11:34 PM   #43
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For reference, in the same races as AZ Wolfie and nissan man I ran a much more standard modified 1/12 setup with a 4.0 turn and no boost, and they had the power to keep up just fine. My standard mod running 1s used about 4500-4800 milliamps. Lap for lap they might be using less juice.
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Old 03-13-2016, 07:42 AM   #44
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1. Roll out on 2 cell racing.

2 cell 25.5 rollout is just the same as 1 cell 13.5. 78-82mm D4 with 12.5 rotor.
I do not know 30.5. The 2 cell 30.5 race have been held on Yatabe Arena every month since three or more years. The race is limited Yokomo motor. For this reason, roll out on other motor would little bit change.


2. Half of 1cell battery is unbalancing weight.

I have bought over 30 1cell battery packs since these ten years, almost for modified racing, and seven or ten stock. On modified or open class, I blow battery capacity up within 8 minutes. According to progressing on battery capacity, I changed motor from 5.5T to 3.5T adding turbo boost.

I started 13.5 Stock racing 2012. Then next was 2 cell 25.5. Now I race 1 cell 13.5 and 17.5 on RSD Houston. I think Stock 13.5 requires 3000-3300mA, 17.5 maybe 2500.
My battery is 7000 or over, other racers too. Stock racers use only below a half of capacity on current Lipo battery on market. Half of it is not only vainness as well as unbalancing weight.

This is because, 1 cell battery laminated juxtaposition in battery cell case. If 7000mA battery suppose, the pack consists of two 3500mA cells. In the battery case, they are upper and down position.

Racers prefer light wright and lower CG on his/her racing car.
From the former point of view, 1 cell stock racing gain the weight 75g or over, half of battery weight. This is over 10% of gross weight.
From latter, despite requiring capacity is half or low on 13.5 and 17.5, we gain over weight. Furthermore, all racer would put on balancing weight on lower position if it need. However 1 cell battery seems to put on upper position as if it pursue unbalancing weight. No need upper cell within the battery case for 1 cell 13.5 and 17.5. It is enough down position cell because the cell capacity is 3500mA or over.

I am a r/c racer. I prefer lower CG on 12th racing.
If permitted, I hope I can put those weight gain on as lower position as possible, like as aluminum chassis. This is one of the reason why 12th stock is suitable for lower capacity 2cell(if possible, limited weight) rather than 1 cell.
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Old 05-28-2017, 03:06 PM   #45
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Ran 17.5 in 1/12 with shorty slim 3900 mah defy battery and motiv mc2 17.5
Ran 39/88 with 40.5 mm tire. Spec tire

Was 1.3 second as faster than stock 1/12 1s times of top guys at track

Ran on spec tires with pro lite bmr.1 body

Amr probably better choice. But we gonna try the proto pf12 body

It's fast and tire wire not too bad

Going to roll out lower next few try's
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