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Question for the Lipo people

Question for the Lipo people

Old 07-06-2007, 10:02 AM
  #16  
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wallstreet,
I've experimented running lipo with 1/12th scale a couple times.

Once I wired up a 2 cell pack using some Kokam batteries. Running 2 cells in series (7.4V) was insane. Even with a 10 turn, it was waaay faster than any 1/10 scale mod sedan. Everyone who tried it, nearly fell off the drivers stand laughing. I don't recommend 1/12 scale take this direction unless we mandate mabuchi 540 motors.

Later on I experimented with a 1 cell lipo by wiring up a bunch of small cells in parallel (see pics). The cells were made by Yuntong and I encased them with AE's chassis protection film (which I can't seem to find anymore btw). Even with a 7 turn, it felt a little bit too slow. Kinda like stock, but maybe even slower. The biggest problem is that you can't gear up enough to get the motor to perform better. It would make more sense to test out this 1 cell thing with brushless. They seem to respond much better to a low voltage applications (ie 5 cell brushless is way faster than 5 cell brushed). Unfortunately, I only have one brushless system and it's stuck in my touring car.
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Old 07-06-2007, 10:03 AM
  #17  
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Bxpitbull kinda hit the nail on the head. Until the manufactures of lipo come up with a need for 5V lipo's its going to be hard to get one thats at that voltage. For 12th scale its either going to be go to a lot slower BL motor and 7.4v lipo or 3.7lipo if this is even possible. If you go to 3.7 then that will pretty much eliminate the chance of the holdouts running nimh cells as there would be to large of a voltage discrepancy. If you go to 7.4 12th scale that will require a lot slower motor and it will have to be BL (no problem there). Its highly unlikely that a Brushed manufacture would come out with a Brushed equivalent....but who cares about that too.

Its going to be hard to convince the lipo manufactures to come out with a 5 v lipo just to sell a few thousand a year as they would probably be industry specific for RC. How many power tools have you seen that are 5 volt or 10 volt? Really the only way I think that will happen is if an RC based battery manufacture makes them...such as IB. Then we ALL KNOW what that will be like

Lipo's and BL are the future of RC......Everyone knows that and a lot more are starting to prepare for that and looking forward to it...Myself included!

EA
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Old 07-06-2007, 10:06 AM
  #18  
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very intresting info.... but i would agree the orion/peak cases would need to be used for safety.

That is how i pictured 12th scale lipo... but i am thinking it might be way easier to adapt the cars to current style lipo cases. or maybe make a case that is just a little bit smaller and voltage nearing a 4 cell pack.

Oval guys i assume could use a 4 cell type of lipo pack as well.. Although i know nothing about oval.
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Old 07-06-2007, 10:08 AM
  #19  
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tally is correct. 12th scale will go to 17.5 with the increased voltage. there's no way to change the voltage of a lipo without changing the chemistry.
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Old 07-06-2007, 10:09 AM
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Originally Posted by EAMotorsports View Post
Lipo's and BL are the future of RC......Everyone knows that and a lot more are starting to prepare for that and looking forward to it...Myself included!

EA

i agree completely... said it before and i will say it again... i am just thinking about the future.
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Old 07-06-2007, 10:10 AM
  #21  
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Originally Posted by EAMotorsports View Post
Lipo's and BL are the future of RC......Everyone knows that and a lot more are starting to prepare for that and looking forward to it...Myself included!
I'm speechless! :-)

Novak is selling that 17.5T motor now on their shopatron site. I believe some of the oval guys have used it with 7.4V LiPo (paging SWTour) and find that the speed is reasonable. I'm not quite sure how that would translate in a 1/12, though.

I'd be curious about gearing a faster brushless motor in a 1/12 car with a 3.7V cell like linger mentioned. If it's just a matter of getting the right gears, I imagine that's a problem that's much more easily solved than hoping some LiPo company makes a 5V cell.
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Old 07-06-2007, 10:11 AM
  #22  
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if a manufacturer like orion made a 2s hard cased lipo that was exactly half the size of their other hard cased lipo (so you could actually run two of them in a touring car as a 2s2p setup, i think they would sell plenty given that anybody that runs either saddle packs (pancars, bj4's, older xrays) or any of the link style 12th scalse could use a single 2s. pack.. i could run them as a pair in my tourer or saddles in my PRO10 pan car, or a a single in a 12th..
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Old 07-06-2007, 10:11 AM
  #23  
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Linger, JConcepts puts out chassis protector film now and it is a better deal then what Losi or AE were doing. You get two sheets for about $8.

If all the 12's were designed like the CRC's, Lipo configuration would not be an issue. Just one straight accross cell. There is another design out there, can't remember the name at the moment, that has the cell going down the middle of the chasssis. So there are designs that could utilize Lipo's already.

I am holding out till it does become the "norm" for you still can't use Lipo at any of the big races such as IIC. I don't see the point for me at least to invest in two different technologies just for the sake of havin both to use. I did recently purchase a GFX so I can at least send it back to be updated to do Lipo and still be able to do everything with one charger.
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Old 07-06-2007, 10:11 AM
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The challenges with LiPo are going to be much deeper than 1/12, though. The tradeoff of voltage vs. safe cell chemistry is going to be where the first big war is fought. It's not going to be pretty.
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Old 07-06-2007, 10:12 AM
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the prob with 3.7v is the ESC's need more juice..
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Old 07-06-2007, 10:16 AM
  #26  
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Originally Posted by Yeti35 View Post
I am holding out till it does become the "norm" for you still can't use Lipo at any of the big races such as IIC. I don't see the point for me at least to invest in two different technologies just for the sake of havin both to use. I did recently purchase a GFX so I can at least send it back to be updated to do Lipo and still be able to do everything with one charger.
It can be a good way of saving your good cells for the big races, in some cases. You can run a single LiPo pack in the clubs without much issue, and then bust out some fresh NiMH for the big races. If you weight the packs properly, the only thing you might have to tweak a little is your gearing (between the two packs) as there's some voltage difference between the two. It also makes club racing a little less stressful without the song & dance required to keep NiMH running well. I charge up my packs during the week, and they generally lose less than 10mah if I try to "peak" them on race day. The low self-discharge is really nice.
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Old 07-06-2007, 10:18 AM
  #27  
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Wallstreet, as a 1/12th scale guy, you fellas are in a bit of a quandry. The industry standard is moving toward 3.7, 7.4 and 11.1 and nowhere in sight is there electronics to capitalize on these voltage options. Maybe the esc makers can come up with something to work with li-pos for 1/12 scale.
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Old 07-06-2007, 10:25 AM
  #28  
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Well i am sure that would be something worth looking into as well...


I know charlie from novak was at one time big into oval racing .. hence the 17.5 motor the oval guys are testing in that sw series. So maybe novak will come out with a speedo to run the 17.5 motor with lipo cells.




I am mainly a touring car racer, but tried 12th scale last year and i think driving the cars is a blast. And i am looking forward to the indoor season.

Asking this question is just a way to get info out for everyone to check out.. especially since lipo has only been talked about with offroad and touring car racing.
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Old 07-06-2007, 10:30 AM
  #29  
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Originally Posted by syndr0me View Post
It can be a good way of saving your good cells for the big races, in some cases.
Are there truely good cells out there given that most are runnin IB's anyhow? If GP could have stayed in it I don't know if it would have ever gotten to this point we are at now with arguing the different types of cells. IB pretty much pushed them out of the picture when there 42's came out.
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Old 07-06-2007, 11:08 AM
  #30  
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Originally Posted by tallyrc View Post
the prob with 3.7v is the ESC's need more juice..
Most of the top 1/12 drivers use a receiver battery already. So going to 3.7V will not change anything for them other than potential speeds. I think 3.7V is the most viable option for 1/12 Lipo racing. Even with lower voltage, there is the potential for much greater capacity. So speed loss due to lower voltage will be offset by the ability to take advantage of more powerful motors.
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