12th Scale (and oval) and Lipo - Making it work soon.
 

Yes, you knew it was going to happen after LiPoly and Brushless were approved by ROAR in 6 cell applications..

Now its time to look at getting some loving for the 12th scale and oval guys.

Your mission, should you choose to accept it, is to figure out what capacity you can get in an area of 23mm H X 92mm L x 49mm W. This is the total area of my "link style" 12th scale 4cell side by side battery area. You could also use the 44mm dimension to keep the adjustability in the car.

T Bar cars.. T bars are 22mm wide so you'd need a jumper to clear that. 43mm W X 46mm L for saddle packs but most current tbar cars have part of the battery sliding under the mid-deck where the center post mounts to so some shifting would need to be designed into them.

I figure there's some math to get a rough idea on capacity..

Thats the first thing.

7.4v or 3.7v.. lets compare
3.7v
1) somebody was saying it took an 8.5turn to = stock speeds?? any clarification on that?
2) Some of us could use that motor elsewhere but definitely not the majority.
3) Still need a rx pack - more stuff to balance in the car and things to go wrong, replace, etc.
4) do servos even work at this low voltage??? or is some great new servo redesign needed thats going to toss all those other servos i have out to pasture?
5) needs an LVC???
6) both weigh less

7.4v
1) don't need that rx pack, less glitch related issues or drop outs.
2) escs already exist with lvc to handle these
3) both weigh less
4) anything else i'm missing??

Second thing is brushless motors.

Where do we go on winds. Use 17.5?? do we go 21.5, lets get some input from the guys doing the testing with pan cars. with 3.7 the rumor was you had to motor way up and I can't see any joe blow using it elsewhere. Some guys are discussing going to smaller motors like a 380. I have no use for them elsewhere. I don't need a redesigned 12th scale in the next year to "take advantage of the smaller size" nor do i want the 12th scale of the month syndrome. We have to ask ourselves, at what point does 12th scale not actually measure up to 12th scale?? 12th scale of what?

I'm for keeping with 05 or 540 size brushless motors
a) i use them across the board with my other cars
b) goes with a.. back up motors are the same..
c) parts between the motors would in theory be the same
d) roar will be approving some of those that we will use shortly lol
e) I think changing the size will severely segment 12th off from the potential growth to be had.

So let's get some constructive banter going like the BL/LIPO thread.

If you do race 1/12 scale, I apologize now, but NONE of the actual 1/12 racers that I know are in any hurry to run LiPo. Those of us that do want to run brushless are already doing so.

I don't subscribe to the "NIMH of the month" club, I buy race packs once a season, and I've never vented or exploded a cell. I'm in no hurry to run LiPO in my cars. I've had plenty of experience with them in airplanes and helis so I'm in no way anti-LiPo, I just don't see a need to tamper with a successful formula.

I'm sure that sometime soon we'll see a new battery chemistry come along that has the weight, size and voltage to replace NIMH directly. I say let's wait it out.

If I've come off as bashing your post, then I apologize again. It's not my intent.

We are going to be at a cross roads here with 1/12th in the next few years probably. With LiPo getting very popular and now legal under ROAR rules the hobby seems to be heading in a direction away from Nickel based batteries. This poses a problem for 4 cell classes in that there really is no voltage equivalent to a 4 cell pack and in 1/12th scale there are space issues to be concerned with. Even if new LiPo packs get to the point where they can be mounted to the same area as our current NiMh packs, the reduction in weight of the batteries is likely to trigger new designs to rebalance the cars. This has caused some people (myself included) thinking that it might be time to reinvent the class and maybe move to a smaller motor. It might not be either but it's a good time to look into it at the very least.

Personally I like the idea of going to a smaller motor like a 380 (360?) because of the possibilities it opens up in body design, additional chassis space, and things I can't even fathom yet.

It would be interesting to hear from some of the manufacturers on this. Perhaps there is even a cell of comparable voltage and size in the near future that we are unaware of.

Mason-

up here in the north I have seen some 1/12th racers running a three cell single voltage in their on road car.

I believe it was a 1300 mah x 3 cells = 3900 mah. The gentleman had a receiver pack using a LRP brushless speedo. I have no lap times to tell you how the speed was but at the club they were using 13.5 novaks. I believe the gentleman ran a 10.5 for his runs. Seemed faster than the 13.5's.

He said he has run without receiver pack with no problems. He ran a Genx so it fit just like a regular pack. He also said he needs to add weight but overall was just fine.

There are some pictures. I will post later. The Lipo was in a lexan hard case shrink wraped.

I think single voltage would be just fine and plan to run the same thing in my 1/12th car.


Heck this would also be a way to slow cars down.

Roar should of included 4 cell as well. Rule for 4 cell lipo replacement could of been as follows. Hard case, same size, single cell voltage 3.7v-4.2 v. Use as many cells as you like as long as you keep same dimensions.

Oh well it will just take some more information to show Roar that it can work.

Why not be out front instead of catch up. Oh well all in time.

Some radios may be able to work with a voltage that low but for sure the Spektrum system will not. Sounds like they were using 3 cell 1/18th scale packs. I wonder how well those smaller packs will hold up to the amp draw of a 540 sized motor over the long term.

yeah I posted something about this in the lipo thread with no response...

I was thinking 2 in parallel and 3.7v but then I really wasn't thinking about personal transponder issues and receiver issues.

good point.

I know 12th uses more battery than touring etc. due to increased run times so we need to make sure that it will make run time especially for 19 and mod classes... we are pushing the limit as is with 4200 and 4600's...

I think 7.4 is really WAY too much back in the 90's stock 6 cell ran with 4 cell mod and even back then 6 cell stock was faster than 4 cell mod it just didn't handle as well. I'm sure that not the case now as mod is stupid fast now, but the problem will still be there..

we'd probably have to run 21.5's to even get close to what stock is now and I'm not sure that's slow enough...

This will work but you will NEED a receiver pack. But many drivers use a receiver pack with 4-cell.

3.7V is not slow. It will not be as fast as the same set-up with 4.8V, but you will be able to carry much more cpacity with a 3.7V LiPo so you can gain back soe of the lost speed with faster motors or a step up in class. OIr make 1/12 races longer.

You don't need a rxr pack as such but rewire using a single aaa battery or even smaller size in line will allow you to run your 3.7 volt pack even with spectrum.

Most of the 1/12 guys I see are more "racer" types-people who are not upset with current Nimh batteries. They probably even like them.

That's why i think it may be worth it for everyone to wait a bit for batteries to catch up with us. A friend of mine who races, and is in the electronics industry, says there are batteries that would be much better suited to 1/12 than what is out there now, but they are just not available, yet.;)

I've run both voltages in 12th and either one is fine with me. With the 3.7v stuff you have to add a receiver pack. One advantage of having all of the cells parallel is that they can handle the higher currents.

A single cell pack that is 5400 mAh will only handle 54 amps at 10C or 81 amps at 15C. This is enough for pretty much all of the motors that we can throw at it even in mod.

If you go with 2 cell voltage, the capacity goes way down (about 2700 mAh) and you'll have problems with dumping. The capacity will be what limits the speed here, not so much the motors. Haven't tried a 17.5 on 2 cells but I'd bet that you could dump with it.

Even though I would prefer 2 cell voltage in mod, the pack wouldn't handle the current (27A at 10C and 40A at 15C). We'll be spiking the pack above this in mod and it will probably hurt the cells. The cool part is that 12th would be oldschool again and you'd actually have to use strategy along with driving the car. That would be a good thing if you ask me.

I agree I like the idea of 3.7 better I guess we'll all just have to run a lipo receiver pack too...

3.7 will be plenty fast... mod will still be ballistic 19 turn now is almost as fast lap time wise as mod at the national races

stock is stock its not supposed to be fast but 13.5's at 4.8 volts is way faster than a brushed stock so maybe in 12th we stick with the 13.5 and the 3.7 volts and it will work itself out...

For me, this isn't a 12th debate. We are already running BL. The issue with LiPo is weight. IF you change the weight distribution in a 12th scale, it will require new chassis' to get the cars to handle. For 12th, it isn't as simple as 'going LiPo' it then means we have to design new cars.

The other thing to consider is that batteries are only really an issue at the very top level. 12th is the drivers class, and any good driver will beat the average Joe (me!) with cells out of a power drill! I regularly get beaten by other drivers with 19T motors, when I am driving Mod, and they are using old cells.

12th is on the up, and the thought of changing everything in one go, in an uncontrolled way, fills me with dread. Let's start an Open class, where those that want to experiment can do so. Once a consensus is reached, let's propose a Rule change to our Associations. But please, spare 12th the nightmare that has been TC for the last two years - it didn't work for them allowing anyone to do anything, it hurt numbers of drivers, shops and manufacturers - we don't want to do that again, surely?

The first thing that has to happen is more then a couple people need to try and have hard data. When "there was this guy that did and he said it kicks ass" stories, it feels like a urban legend kind of thing. If I had a 12th scale laying around, I would tinker with it. That is where this has to start. 12th scale racers tend, in my experience, to be very die hard and "passionate". Expect a lot of resistance and negative banter.

12th scale drivers tend to be purists that like the way racing should be. This is why the evolution of 12th scale seems to most to be slow, only the best designs stick around for the long haul. Every few years a design that was tried comes back, people try it, and then it disappears again. Until a person that wants to affect change to 12th scale that comes along and truly understands the cars (I.E. what moving which components to where will effect everything within the whole scope of the car), the changing of the rules regarding these cars should be left to a consortium of the current industry leaders in the manufacturing of the chassis, and the industry experts that lead the way with power and electronics.

12th scale currently has a winning formula that the majority of people that race them don't mind (and possibly prefer) sticking to. People that don't know or understand the intricacies of the chassis' should not be affecting the rules changes for these cars. I started racing 12th scale in '91 and don't feel that I am the expert on chassis design. I am sure that there are others out there that want to affect change just because they feel that 12th scale shouldn't be 'left behind', that shouldn't be messing with it until they understand how the cars really work.

Does this sound like a lot of resistance? I am sure that I am not the only one that passionately feels this way. I am not against alternate power sources for 12th scale. I think that with such a seemingly simple formula that we have now, we shouldn't mess it up just because a few people that don't race the class want a particular technology to disappear from RC all together.

No one here is calling for a change NOW. We are looking to the future to try and figure out a way 1/12th can continue as a class with the changes in battery technology. Most industries outside of RC are moving or have allready moved away from Nickel based batteries and with ROAR and Tamiya's acceptance of LiPo is only going to help RC move in that direction as well. Right now we can see what is happening in other classes and have an opportunity now to be looking at what to do with 1/12th in the future as Nickel batteries start to go away and be ready for that rather then caught off guard.

This entire thread is about the discussion of the future. Whether or not you like it, change is a constant. I'm not saying that we're running it tomorrow. or next month.. but soon. As time goes on with the power tool industry, nimhs wil be phased out of the majority like nicds were. Did they go away completely? no, you can still find el-cheapo power tools with nicds (and you get what you pay for), the 2nd tier stuff is nimhs and then you get up to the high end of things.

Let's not piddle around and wait a few more years until somebody already has some c.ckamami product out there that people start using and it becomes nearly too late to make a decision on this. Let's work it out for the better. You guys want "growth", don't shut the door on the opportunity to make it happen.

If you are not going to be realistic, that's fine. I'll thank you for your 2 cents and let you be on your way.

:tire:

I agree that there is a lot that needs to happen with the cells before they'll be good enough for 12th. They need to be able to source more current and we need a cell that will fit both types of cars (saddle and stick).

The weight thing isn't really an issue. You just add lead. It's really quite easy and not that expensive.

KO PROPO 302F
 

most of the people who knows me, if they see me without a 1/12 scale at the track they would think something is wrong (TRIPS):lol: with that being said, in the short time i have been running 1/12 scale the reciver of choice for me has been KO-PROPO 302f -- it has a nice little boster circut in the reciver to allow it to operate below 3.7v the only thing you'll need thier speedo (VFS-series). The new speedo from KO (C3) sould have lipo cut out but don't quote me on that.

That's a cool sounding reciever...But that is just 1 case where it is going to work. We need something that will work across the board.

Why not just leave the 1:12 scale alone and make a new scale?

It is understood that any change in weight, motor, battery will greatly affect the car forever. With indoor tracks getting more expensive, maybe a slightly smaller scale would be better so less space would have be to leased or bought for the actual track.

1:14/15/16 scale pan car...Change the motors to 380. Make a 6-cell 2/3A battery tray. This would allow LiPO or NiMH during the transistion. Make the parts metric since the golbal enconomy is bigger than the USA.

The 1:18 pan cars are just a little too small for my taste, the 1:12 are perfect and the 1:10 too big for most indoor small tracks. The problem is that you can not outright change anything on the 1:12 class and expect the results to be the same. So I opt for a newer slightly smaller class and a slightly smaller part bag when I go to the track.

We already race 1/14 scale SportWerks Recoils here every week....

For oval we started a 21.5/lipo class. Simple rules: Novak 21.5 brushless motor, Team Orion/Peake 3200 hardcase lipo. Minimum weight still undecided.

Because sooner or later 1/12th will have to change due to a lack of battery support.

Hehe, I think sub-c's will be around for quite some time.

On a different note, A123 Lithium Ion Nanophosphate batteries could possibly be an option. They are superior to LiPos.
http://www.evworld.com/images/a123_csize.jpg
Each cell is about the size of a full C battery, but a little longer. 3.3V per cell, 2300 mAh.
Designed to take a 10 amp charge! Wack 'em over and over in the same day.
Chemically designed so they cannot explode.
Hard case.
After 1000 cycles, they only drop 5% of their initial capacity!
They only drop 3% of a charge per month!
Something silly like a 70-90amp continuous discharge rate.
$8 per cell.

Dewalt and Black and Decker are using them in their cordless Lithium packs. Full size car companies use them in their electric cars. RC air plane guys love them.
I practice oval with a 13.5 and two A123 cells. I'm pretty sure I've lasted 8 minutes before. I bet the 6.6V with a 21.5 will be just about right. I doesn't require a chassis change for oval, but probably would for road course. The weight would be centered more to the centerline of the chassis, so that would be nice.

Probably...but with LiPo now allowed in 6 cell we will see a switch in emphasis by the manufacturers and matchers. Though they may still be around in the future it will be more and more difficult to get good race packs. Look at NiCad...it is still around but it's near impossible to find good race quality packs. And that only took a few years to happen once NiMh was legalized.

Interesting battery...once again though they may work in existing chassis to fully realize their potential will still need a chassis redesign. Whichever technology gets adopted in the fugure manufacturers are not going to just keep using an old chassis design just because it will fit. Everyone tries to get a competitive advantage...especially manufacturers.

What kind of charger would be required?

I use my Team Checkpoint (or ICE) charger, even though it wasn't designed for it. I charge it at 10 amps, and manually reduce the amps as it reaches 7.2V. As soon as it reaches 7.2V at 3 amps, it's ready. Basically, it shouldn't go over 7.2V. I use the Li-Ion setting, but it really doesn't actually get to the CC-CV feature during the charge. Most chargers with Lipo or Li-Ion settings don't charge A123's properly since the batteries are 3.3V per cell instead of 3.6V or 3.7V per cell. It's just a software programming thing that I wish we could update.

You don't have to manually reduce the amps as I do. You could set it at 3 amps and then stop the charge when the battery hits 7.2V. There was one time where I missed it completely and simply forgot. It went up to 7.8V, peaked and the charger detected the delta peak. But this was higher voltage than the manufacturer recommends. A123 has their own charger, but I don't know much about it. Hyperion EOS0606i, EOS1210i , and EOS0610i 6S have the proper programming for the A123 cells. There are other brands too, but I just don't know them. The biggest air plane forum (RCGroups.com) has a huge forum dedicated to batteries and chargers.

Since the air plane guys are not racing, they don't have any rules and therefore they end up using the newest RC technologies first. For example, they were running brushless, lipo, A123 cells long before we were. If my memory servers correctly, I think the Spektrum 2.4ghz was first used with air planes as well.

About the A123 M1 cells, Many of the higher quality LiPO chargers with balancers built in have LiFePO4 chargers. I use the Hyperion 610i, which is capable of a 10amp charger rate while balancing.

The car most capable of a conversion would be the old style 4-cell saddle pack cars. They had slots long enough for the A123 m1 cells but not wide enough. Using a drill press and a bandsaw someone could whip out a prototype chassis in an hour that would fit the M1 cells. The slots were long due to the T-Bar being long. The t-bar was long because 1:12 used to have 6-cell saddle packs. Back at square one!

The second most capable cars of conversion would be Darkside MX2 and the Diggity Designs 3d series. The cars would still need a new lower chassis but little other work.

This is just me talking, but if 26650 or 18650 sized cells were allowed, I would say cut the race time from 8-min to 5-min. The reason for the reduction in time would be that fitting four 26650 cells in the car will be hard so capacity will be limited to 2300 for A123 cells and 2700mah for brands like Falcon. Over time, these cells will be in the 4000 range and the race time can be taken back to 8min.

LiFePO4 requires a different charging technique from lipo according to everything i've read by the manufacturer and distributors/oems making stuff for it. If you aren't going to use the proper charger for it, i hope you are atleast using the same techniques they describe their charging method to be for your safety sake.

Actually most of the link cars with the pack going across the chassis allready have long battery slots since they have adjustments to move the battery foward an back to shift the balance. They probably would be the easiest to convert. This is cars like the Gen X, Db12R, and others. The Darkside and Diggity with the in-line batteries would be a bit more difficult of a conversion as all new battery slots would need to be cut.

And that is all fine for the change over period to the new technology. But I imagine we would quickly see even more radical changes in chassis design to try and maximize the weight difference. Possibly even something so far out as the electronics toward the back (including the servo) to try and get some more weight on the rear and the batteries toward the front.

Mason has a good point,

Just because you can abuse LifePO4 cells more than any other battery including NiCD you still need to be wise about your cell handling. Never overcharge, over discharge, leave batteries connected when not in use or try to attempt the vidoes shown on YouTube about the abuse these batteries take.

If you have a LiPO charger and would like to balance charge a LiFePO4 pack without spending another $100 to $200 for a charger there are things like the "Daptor" which should allow you to charge the A123 cells. Do some research before trying it, I just heard of the "Daptor" last week.

I Saw something today that made me wish I had brought my camera with me to the track. One of the local guys, Roland Shao (hope I spelled that right, Roland) came out with something that really made me take notice. He took an old Diggity 1/12 chassis, put a two cell 7.4v LiPo in it, with a brushless 1/18 Mini-T motor in the pod and a Quark speed control (he had to fabricate a little adapter plate for the motor to fit, but it looked like an easy enough thing to make.) When he first showed it to me, it had the body on and it looked like your everyday normal 1/12 scale car. He handed it to me and said "that's ready to run", to which I replied "yeah, when you put a battery in it." That's when he turned it over and I could see what was going on.

My first reaction was that no way would it work well. The motor looked absolutely TINY in the pod (you could have fit three of them in there) and with the Diggity setup of the battery running longitudinally up the middle I expected it would simply be WAY too nose heavy to handle.

Then he did some laps. To make a long story short, it looked absolutely GREAT out there. Didn't put a stopwatch on it, but I'd bet money it would have been the class of the field against 19 turn cars, no doubt whatsoever it would have demolished the stock field. I drove it some, and I have to say it drove VERY well. Tire wear seemed a LOT less that we get now, I guess the reduced weight takes care of that, and the times I saw it test the integrity of the boards it took no damage at all (again, the lighter weight probably had something to do with it.

The only issue I could see was that it dumped after 6 minutes or so, but no one was driving to make run time... And this was with a 1500mah Lipo pack. And did I mention the thing was FAST with a capital F. I'd pretty much bet a paycheck that with a bit milder motor and a 2074 or 2200mah LiPo (which are pretty common among the TRex Heli guys) it would have made time easily and still given the 19 turn guys a hell of a run.

I'll be the first to admit that I tend to resist change, but seeing this car in action made a believer of me. Our track (360 Speedway) will run a class if 5 people show up. I'm going to prepare something to run, it just seemed like there was no downside to this... Faster, lighter, less tire wear, better crash survivability, and so on, and so on... Not that I'm ready to abandon 4 cell 1/12 scale... but I could DEFINITELY see myself running one of these as well. Heck, I'd want one if for no other reason than to have a super low maintenance practice car to run between race days.

I don't know if this is the future of 1/12 scale, but if it does go in this direction, I'm not in the least bit hesitant. If ANYONE would have told me yesterday I'd be saying this today I'd have told them they were outright crazy, but seeing IS believing.

Consider me a believer.

Sounds cool Trips...that is pretty much what Slapmaster and I have been talking about doing. Though with the SCiB cells able to make a 4.8v pack I am thinking this is probably what we are going to see in the future. Personally though I like the 7.4v with smaller motor idea :)

Don't ask, I'm not giving you any lotto numbers. ;)

No!!!! this is the reason im trying 1/12 electric, because its simple and uses 540 motors!! lol Its the variety i love. If there was lipo, they wouldnt be allowed to lower the weight right? people would have to add weight, instead of the Ni-Mh/brushed guys trying to lose weight?

Don't worry Ferrarimk, we are not talking about now...we are talking about the future of 1/12th when NiMh batteries are difficult to get in good quality race cells.

I'm going to try some CR123A Li-Ion cells in 12th to see how they work. These cells are actually smaller than a sub-C cell so the only mod that would be needed is a simple lexan tray that would sit in the battery slots. I'll try both single and 2 cell voltages. Worst case, they'll probably fit into my Recoil. At $20 for 10 cells they're pretty reasonable.

I still think that the best thing would be to actually make a sub-C sized cell but...

I know that this thread is a look toward the future but I think that it's a good thing to capture where we're at now.

1) There are no Li-Ion/Fe04 cells available that even remotely fit in the package space of a 12th saddle pack.

2) The only cells that I've found that will fit into a saddle style 12th car would require a bunch of cells to handle the current that 12th draws. Cost of the pack that I built to test was around $100 for 12 cells.

3) Both LiPo and Li-Ion based cells can't make the voltage that we currently run in 12th (or oval).

4) The oval guys are using LiPo packs with high wind motors. They seem to be pretty happy with this combination (LiPo & 21.5).

phew :sweat: I just dont see the need for such drastic changes whether that would be now, or in the future. Sure lipo and brushless will take over eventually, but ill promise you that they wont change motors to fit batteries, its never been that way, and i hope it never will. Until they find a 4.8v lipo, i aint switchin :D

Well look back at how long it took NiCad to get phased out of racing when NiMh was legalized. Sure you can still get NiCad packs but those are all sport packs. Once NiMh was legalized the entire race manufacturing switched to NiMh in a relatively short time. Now the only class that LiPo is not legal in is 1/12th...how long will it be until the same happens with NiMh? Probably a bit longer then it did with NiCad because they are still being used in 1/12th but it will happen. So with current LiPo cells not being able to make 4.8v we are stuck with 3.7v or 7.4v choices (unless SCiB works out). With 3.7v it will be necessary, in most cases, to run a reciever pack :( 7.4v on the other hand is going to have a ton more power then we currently do so something needs to be done there to temper the power. The 2 choices is to change the wind specifications for each of the 1/12th classes or to change the motor entirely. Smaller motors have more then enough power in BL to power a car the sized of a 1/12th, are lighter, and take less space then a 540 motor. The lighter we can make the class the less wear and tear there will be and less damage in a crash.