Dual vs. Single motor

[OptimaMan]

There seems to be a lot of people thinking dual motors would double the power of an RC car these days... but let me explain some things.

First of all, a single small measly Basic motor can almost output 1 horsepower. A Basic XL can almost put out 2 horsepower. If you were to add dual C50maxx, we're talking 4 horsepower!!! Now, to do that, you would need 3000 watts! You figure out how many amps and volts that is.

Basically, most 1/10 RC's can't handle that kind of torque and power. If you have gotten it to the point where it could, then the next problem is that running a single brushless is more efficient usually than 2 because the majority of the BL for cars are most efficient at around 50 or more amps! Having 2 motors pull 30 amps each vs. a single pulling 60 amps, the single motor will actually have higher power output!

If you were able to somehow manage to squish like 30 cells into a car, you'll have to pull over 50 amps to really go beyond the power rating of a larger Hacker or Lehner motor. At this point, we physically can't stick more cells into a car/truck and that's why a lot of guys believe going with one powerful bl is more efficient than two motor setups.

BTW, this is my opinion and if you disagree, I'd like to hear it here.

[n2rcn4fun]

your point is well taken ...as bl motors have a tremendous amount of tourqe//i do not understand y a 5800 will not power a emaxx with no problems running two packs in serries would give a little extra power but the run time would be twice as long.......i guess its not the motor but the esc that cannot handle it..

[BlueBeast8-Port]

Hello, couldnt you jsut put 2 c50 in for instance on the hacekr car sport esc which handles 12 cells. couldnt you hook you 12 cells to each motor and esc and be fine? Wouldn't your torque increase a ton and some speed?

[OptimaMan]

Getting 2 C50 maxx motors and 2 Hacker Master Sports would run you approx 900 bucks and wouldn't give you anymore power than a B50XL motor with a nice Schulze controller. The B50XL or C50L with a really nice Schulze controller would cost less too and be more efficient!

[glassdoctor]

I agree with Optima here.

First thing that comes to mind is the boat guys. They can run 100 mph on brushless power and they use single motor setups. They have been running brushless motors and tons of bateries for years now... There must be something to it. ;)

BlueBeast.. yes you COULD do that. If one C50 on 12 cells is good, then 2 on 24 is even better, right? Well, yes more power is good, but there is more than one way to make the power. The other way is to go with a more powerful motor and/or feed it more batteries.

If you take the same 24 cells from a dual c50 setup, what can you do with them in a single motor setup? You can go with a low k/v motor with tremendous torque and use the high volts to generate the high rpms you want.

Maybe OptimaMan can elaborate some more if this isn't what he had in mind...

Not that there is anything wrong with a dual motor setup... but really, the right single can already be "too much" power if there is such a thing.

[glassdoctor]

Has anyone run the C50L or XL in a Maxx yet? I would really like to try a B50/C50 L or XL and feed it a 6 cell lipo pack...lightweight 22volts. That would be AWESOME! :D

That's my plan for an 1/8 buggy but I don't know if I can part with the $$ just yet.

motor/esc $600+
6000 22.2V lipo pack @$400 ea.

[OptimaMan]

Glassdoctor: you're absolutely correct and that's what I'm thinking.

One funny thing though. I have a hard time controlling my emaxx on 12 cells with a small basic 4200 motor. It goes up to 30 mph in first gear doing wheelies and spinning out the whole time. Then I get it going in 2nd and it's doing over 40 - the Proline Bow Tires BALLOON so much - have you seen swami's video of his rustler going 60? That's how these tires look too. Completely uncontrollable and it wipes out.

What do you guys intend on doing anyway? Race or set speed records? Heck, if anybody here lives in the Chicago area, come on by - I'll show you how uncontrollable it already is!

[n2rcn4fun]

so the 4200 is that fast i am looking for 25 mph and run time hook up two 6 3300 pack in parellel and wounder if that would give good power and long run time with a 4200?

[MegaMe]

Glassdoctor: you're absolutely correct and that's what I'm thinking.

One funny thing though. I have a hard time controlling my emaxx on 12 cells with a small basic 4200 motor. It goes up to 30 mph in first gear doing wheelies and spinning out the whole time. Then I get it going in 2nd and it's doing over 40 - the Proline Bow Tires BALLOON so much - have you seen swami's video of his rustler going 60? That's how these tires look too. Completely uncontrollable and it wipes out.

What do you guys intend on doing anyway? Race or set speed records? Heck, if anybody here lives in the Chicago area, come on by - I'll show you how uncontrollable it already is!

how much runtime do you get though?

btw IMO a 4200 on 6 cells in parallel would not be enough for an emaxx . i think with all that weight it would be under too much load and so create lots of heat for the motor and controller and hence not be very efficient (and it seems efficiency is what you want.

a 4200 on 6 cells is good for a 1/10th size car not a monster truck. and more generally from an e-maxx opinion seems to me that a "mild" brushless motor on 12/14 cells would be more efficent and maybe have better torque than a "wild" brushless setup on 2 6/7 cell packs in parallel. perhaps either a basic-xl 3600 or 3100 on 12 cells would be good for you.

[OptimaMan]

MegaMe - I think you misunderstood me. I use 12 cells in series - not 2 6 cell packs in parallel. I use the 12 cells in series and gear it short so the motor and controller don't see so many amps. In first gear, I believe I get over 10 minutes of runtime.

In parallel, 6 cells absolutely does not have enough speed - I only get about 18-20 mph with the same setup - but still has tons of torque (easily wheelies).

I have a mild brushless - a Basic XL3100 and it works great with my emaxx with 12 cells, but it doesn't hold a candle to a Basic 4200 when using only 12 cells in series. With the XL3100, I geared 18/66 and got 38 mph. I can gear the 4200 with a 13/66 and have the same top speed and more torque and similar efficiencies. Now, if I go to more cells like 18, then the XL3100 would be a total beast and the 4200 would simply blow up.

For me, I like to bash around and jump around doing about 30 and I like to get about 10 minutes of runtime. So, this is why I have this setup. I don't care so much about crazy speed because it just flips and rolls anyways. This summer I might actually take my emaxx racing so 30 mph and 10 minutes of runtime seems reasonable to me.

[glassdoctor]

I would add though, that if someone already has a single setup, then it would be tempting to add another rather than buying a different and more expensive ssetup. The bigger motors cost more and the esc to handle them cost way more. So I can feel for you... I have a C50 and sometimes wonder what a B50 8L or an XL would do on more cells, but my controller could not handle that.

BUT, the other way to look at this "problem" is that rather than just duplicating what you already have, you could put it in another truck or sell it and put that $$ into the new setup. You can always get good money back on BL stuff. And this way you have a different motor/esc to try and compare.

So I hope to do this sometime... BL can be addictive even when your truck sits all winter :)

[n2rcn4fun]

well we race a lot so top speed is no big issue, the 21 maxes on the track we race at the longest straight are going tops 20mph..so if i had the touqe and had a longer run time 20 mph will still win anything faster would be hard to control..i was hoping to beat them with instant power as a gas has to spool up ..heck i would be gone.....anyone who has raced know one flip and u loose a half a lap..i want a smooth consistant good speed ..ain't looking at going mach 5...lol ..so any help would be great..thanks

[glassdoctor]

n2rcn4fun, I know what you are wanting, but I'm not sure what to recomend exaclty.

Do you run 5 minute qual. and 15 min. main? That's not bad for an E, but 20 and 30 minute mains can be a problem unless you have a really slick battery change system worked out.

What I am thinking is something like an 8-10 cell setup for your setup.. preferably as little as possible. Then you can double up the packs for extended runtime...15 maybe 20 minutes for the mains... without ending up with 24+ cells to lug around the track...

14-16 cells is much better than 24! But I'm not sure what motor/gearing setup would work the best... I only have a C50 and have never tried to run less than 12 cells.

Optima has probably done this with the 4200?

Would something like 8 cells be enough to wake up a 4200 to 25 mph? Maybe a 5300?

I know this goes against the "more cells, lower gear" mantra.... this usually means a hot (as in temps) high-amp setup, right?

Really it sounds to me like a stock E on 14 cells is plenty fast enough... you just need the equivelant in a BL that's more efficient and runs cooler... and on only 6-9 cells...

[OptimaMan]

It'll work.. if you only want 20 mph in first gear, you can certainly get a 3100 kV motor and put 12 cells to it. Or get a 4200 and put 8-9 cells and double it up to have 6600 mah. Nice thing about less voltage and gearing a little taller is that it's more driveable (not so many wheelies), but you will be pulling more amps so the controller might get too hot. I have driven my maxx with 6 cells - a bit slow because it tops out around 20 mph in second gear! It also puts a lot of load in terms of amperage to the controller. So I believe going lower voltage is going to be problematic for controllers.

[baih]

optima man,
which controllers are you using??

[n2rcn4fun]

i am thinking about going to two novak 5800 systems....i might get longet run times and not heat up the esc if properly geared then locking in 1st gear....i think that way there would be lesst amps need per motor and ith efficiency of the motor 5800rpm/volt might be an advantage ..what your opinion..

[baih]

i have considered the dual novak brushless motors also. i have my truck sitting here with a new extreme brushless chassis and no motors yet. cant decide which way to go. anyways i asked a guy on the maxx traxx forum that was running the novaks. he said he had to gear down two teeth to keep from overheating. its now the same as running the titans.

[Mr. Constructor]

As for a Maxx, there are only 2 solutions:
1. a Plettenberg Big Maxximum (or the smaller Maxximum series)
Or:
2. A Hacker c50 (or a B50 when you like the extra power of these more sturdy shafts!!)

then connec them to a esc wich could handle around 70 A (the warrior as a cheap solution) and then run it with 12-18 SMALL cells (maybe the FAUP from Toshiba, they´re only 2000 mAh, but will take you over 10 min, when geared right (the motor should be in the final rpm (depending on cell count ) around 30-40% above the Titans, then you´re right, the truck ist still driveable AND leightweight AND the running time could be upgraded (by another 12-18 FAUP cells) and the weight goes up, but not that fast !!

wich setup is better, the 30 cells on a 6 kg car (illoustrious i know that!!)
or the 15 cells on a 3 kg car ???

the less weight off course, the running time is equal, the speed too, but handling and ease of use is WAY better in the small setup !!

What i mean, not ALWAYS the more cells the better it is, the clever ground setup is the way to go !!
(some cars could take a few more Volt´s some not, the weight to power ratio of the whole Car (or the whole electric system) is what counts, calculate this a little around, then you might find the best setup.

My next 5th conversion should get a 27 Ah (no writing error!!!) 12,6 Li ION !! battery wich should catch the 60 min driving line with ease !!! (and in a car that is around 7-8 kg ready !!)

the system is still in the calculation, but the figures are really good !! (100A cont. 400 peak(for 30sec !!!), is guaranteed from the manufacturer !!!

But pricing will be very high and these cells are ONLY for 5th or same big cars, the system Batterys only is around 2,3 kg !!! (but then 12,6 V at 27 Ah !!!)