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Old 11-11-2007, 11:12 PM   #1
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Default 1/12th Scale and Lipo

Hello all,

I've been running off road for many years, and have an interest in dabbling with some carpet racing. I've seen some guys at my local track running 1/12th scale cars, and they've really caught my eye.

In my preliminary research, it seems that most 1/12th scale cars run 4 cell NiMhs.

My question...Are there any battery manufacturers building Lipo packs for these cars? Are there mods you can do?

Any help would be appreciated. Thanks!
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Old 11-12-2007, 07:51 AM   #2
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A LiPo equivalent for 4 cells is pretty much a no go. A 1S pack is 3.7v (not enough voltage) and a 2S pack is 7.4v (way too much). You could probably put in a soft sided 2S pack (wouldn't recommend it for safety reasons) , but a beat up stock motor would probably be faster than a well tuned mod due to the voltage difference.

I think there are a couple of guys that tried it and abandoned the idea.

Chris
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Old 11-12-2007, 08:42 AM   #3
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Quote:
Originally Posted by ckearns View Post
A LiPo equivalent for 4 cells is pretty much a no go. A 1S pack is 3.7v (not enough voltage) and a 2S pack is 7.4v (way too much). You could probably put in a soft sided 2S pack (wouldn't recommend it for safety reasons) , but a beat up stock motor would probably be faster than a well tuned mod due to the voltage difference.

I think there are a couple of guys that tried it and abandoned the idea.

Chris
Yes, there is no way a 3.7V LiPo would be competitive against an NiMH 4-cell pack. But I think a 3.7V LiPo cars racing against each other could be a very interesting class.
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Old 11-12-2007, 08:46 AM   #4
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Originally Posted by Rick Hohwart View Post
Yes, there is no way a 3.7V LiPo would be competitive against an NiMH 4-cell pack. But I think a 3.7V LiPo cars racing against each other could be a very interesting class.
hmmm...that would be interesting
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Old 11-12-2007, 08:49 AM   #5
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I was looking into driving a pan car, but once I found out that no one uses lipo AND brushless in them, I also abandoned the idea.
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Old 11-12-2007, 09:10 AM   #6
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The oval guys hve been experimenting with using 7.4V LiPo in their pan cars with Novak 21.5 motors. SWTour would be the right guy to give you details, but I think they've found them to be very similar in speed to a 27T+4cell car. In fact, nearly identical as I recall. So, maybe there's some hope for LiPo in 1/12 in that regard?

As far as battery placement, I wonder if you could get away with using smaller cells that are usually intended for 1/18th scale? There's a guy around here using them in a T2R with a silver can motor with pretty good success. How much capacity could a 21.5 brushless use in an 8 minute race? Again, just something to consider.

Anyway, LiPo in 1/12 is problematic at the moment for a number of reasons, but it seems like there's some possible solutions out there for people willing to give it enough effort. If I were messing with it right now, I'd probably go down the 21.5T/7.4V LiPo road and see where that leads.

http://www.shopatron.com/product/par....15996.0.0.0.0
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Old 11-12-2007, 09:17 AM   #7
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Quote:
Originally Posted by Rick Hohwart View Post
Yes, there is no way a 3.7V LiPo would be competitive against an NiMH 4-cell pack. But I think a 3.7V LiPo cars racing against each other could be a very interesting class.
I think so too. With 3.7V all you have to do is motor up a little to get back to the same speeds....the cars will be a lot lighter after all. Stock speeds could probably be met with a 10.5 instead of a 13.5. Mod would motor up from a 4.5-5.5 to a 3.5.
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Old 11-12-2007, 09:21 AM   #8
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Is the 3.7v enough for electronics, or would a receiver pack be required?
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Old 11-12-2007, 09:40 AM   #9
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Quote:
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Is the 3.7v enough for electronics, or would a receiver pack be required?
You would probably need one. But most 4-cell racers use one anyway.
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Old 11-12-2007, 10:05 AM   #10
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funny you should bring this up, i wanna make a brushless lipo pan car soon that should go like a rocket, iv been reserching and for a 540 size can, a mamba max 5600 kv 3cell lipo is so far the best combo, iv found a few others but i dont know enough about them to use them

one more thing, a good high quality pan car is VERY VERY expensive
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Old 11-12-2007, 10:10 AM   #11
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Josh Cyrul told me there was a guy at his track that was running 2-2100mah cells in parrallel to make a 4200mah 3.7v pack. With a Novak 3.5 he can race with the guys running 4 cell and 5.5T BL mods.
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Old 11-12-2007, 10:48 AM   #12
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Quote:
Originally Posted by AdrianM View Post
Josh Cyrul told me there was a guy at his track that was running 2-2100mah cells in parrallel to make a 4200mah 3.7v pack. With a Novak 3.5 he can race with the guys running 4 cell and 5.5T BL mods.
Quote:
Originally Posted by Rick Hohwart View Post
Yes, there is no way a 3.7V LiPo would be competitive against an NiMH 4-cell pack. But I think a 3.7V LiPo cars racing against each other could be a very interesting class.
I once tested a 3.7V lipo putting a bunch of smaller cells in parallel for 4.0Ah worth of capacity. I used a smaller 170mAh lipo and Novak regulator as a receiver pack. Even with a 7 turn - it felt as slow as a 1/12 scale stock car. I couldn't gear it high enough as the bigger pinions pushed the motor against the T-Bar. I should revive that experiment and test with brushless since they seem to do better under low voltage compared to brushed. I think it's really a better solution to go 7.4V and motor down - 21T brushless or even mabuchi.
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Old 11-12-2007, 11:15 AM   #13
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I am very happy with my 7.4V/mabuchi:
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1/12th Scale and Lipo-lipo-12.jpg  
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Old 11-12-2007, 11:41 AM   #14
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well the A123 cells are 3.3v i think... a bit closer to 4.8v
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Old 11-12-2007, 01:29 PM   #15
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We've seen a Mamba Max (1/18th) motor run on 7.4v LiPo, and that has definite possibilities. I think it was a 6800Kv motor, and it went as fast as a 19T. The car didn't need a receiver pack, and weighed in about 500g.

There wasn't any time to adjust handling in depth, so it wasn't a perfect comparison. However, you can see that with the right adjustments to springs and other settings, the car would be very fast round corners, even if it (currently) lacks a little top-end against a Mod.

To continue the 12th appeal of low(er) cost and easy maintenance, this is an excellent avenue to explore, giving access to both LiPo and BL technology without any large expense for either the existing driver, or the new driver. I'd like to see this taken up and developed, as it would cost much less, and be easier to run, than any other option for LiPo and BL.
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