I need your input guys... - RC-Monster Forums

Dagger Thrasher · **I need your input guys... -** 09.01.2005, 01:02 PM

Hey guys,

It's me again. I know you're probably all getting fed up with me asking about BL setups for my Dagger, but at last I think I might actually be able to get some money to afford a system in the next few months (famous last words, lol!).
Anyway, as Mike and a few others of you know, I was planning on running a twin Feigao 8S/Warrior 9920 system. However I have come up with an idea for a system, which as far as I can work out would be more torquey, lighter and cheaper. I am having a custom chassis cut for me right now with a 16 cell capacity.
So I was thinking of using a pair of Feigao 16S (yes, 16S) motors. These would both be hooked up to a single Warrior 9920 controller, and be powered by 16 cells in series. Both motors together would still only give an amp draw of around 82A, and each would reach an RPM of around 42,000. Again, with both motors together I believe that they would be well within the Warrior's RPM limits. I am also considering possibly doing a similar setup using 14 cells and 14S motors.

So how well would this work? As far as I can work out, this would give much more torque (my main concern), be a little lighter and less expensive. And it wouldn't be any harder on the batteries than my original setup.

What do you think? Any input is really appreciated. Thanks!:D

Sneeck · 09.01.2005, 01:18 PM

I think your truck will not move at all. 1 brushless controller can't control 2 motor's due to the microprocesor. You'll need a 2nd speedo.

That is quite a cool project. twin bl dagger on 16 cell's. w00t.

Dafni · 09.01.2005, 02:36 PM

Agree, as far as I know you have to have one ESC per motor.

Are you really set on this dual setup? How about just one motor ?? Or is this dagger a dual only truck?

For 16 or 14 I would suggest an 7XL. Nice ballance of rpm and Torque (note the capital T!)

Just my opinion.

Dagger Thrasher · 09.01.2005, 02:54 PM

Darn...I was sure I'd read somewhere that is was possible to hook up two BL motors to one ESC as long as they didn't collectively exceed the Speedo's RPM limit. Oh well, thanks for your help guys.

The Dagger is a "dual only" truck, Dafni...twin gearboxes. Running one motor would result in 2WD, wich would suck, lol. Here's my machine (it's a very outdated pic but it gives the idea anyway...front and rear motors):

She'll weigh in at 3.5-4.0kg with the 16 cells, new chassis etc. Aha! Wait a minute, I have an idea. I could stick with the 16S motors and 16 cells (two 8 cell packs in series), but have two Warrior/MGM controllers sharing the full 19.2V of power. The cells should be able to handle the amp draw without a problem and the controllers will be running well within their limits. It will be more expensive but it should run well. How about that setup?

I really appreciate your help everyone...sorry about this but no-one has ever attempted a BL system in a Dagger (at least, not in one like this) and I just want to get it right. And this thing has to eat nitros too (reputation at stake, lol). Thanks!:)

coolhandcountry · 09.01.2005, 03:32 PM

I remember hearing that you can run two motors off one controler as well. I think it was in my esc maneul. I think you have to line the motors so they are in the same place. I don't think it is going to work in your case. If you run the 16s you should be able to drop back to the 70 20 and save a few bucks. I hope it works out for you. Two 16s s would kick but on 16 cells i think.

MetalMan · 09.01.2005, 04:33 PM

You can run dual motors on a single controller, but this really only works when both motors will ALWAYS be turning at the same speed, like in a E-Maxx. I don't think this would work with your setup, since the front motor would most likely be spinning faster than the rear.

Your second idea is better (2 controllers). The batteries will be able to handle the amp load of both motors. This way, you can use 2 Warrior 7020 controllers.

Serum · 09.01.2005, 05:03 PM

It depends, it is not recommended, but it CAN be done.. Two motors on one esc. The reason why it's not reccomended is not clear to me..

The controller simple throws out pulses that make the motor turn. What you are doing with the low kv motors is getting a higher resistance, putting them parralel to your controller will get a lower internal R,

To keep a long story short; It can be done and it is been done before. With sensored motors it's impossible. with non sensored it simple can be done.

Like metal men says; the motors need to be connected to eachother (mechanic) to turn the same speed.

Serum · 09.01.2005, 05:05 PM

One sexy dagger bytheway!

MetalMan · 09.01.2005, 05:28 PM

The reason why it can't be done all the time is because the controllers need to sense the position of the rotor. If there are two motors, and they aren't spinning at the same speed, then the controller can't sense the position of the rotors. But in an E-Maxx, the motors have to spin at the same speed (because of the gearing), and so the controller can sense the rotors' position more easily/properly.

Dagger Thrasher · 09.02.2005, 04:28 AM

Thanks all! I'll go for the twin controller 16S setup then...she should have more than enough power. What I'm also going to is hook two 33,000 uF power caps to the batteryin parallel to make one big 66,000uF cap. This should even-out the voltage ripple on acceleration and give more low-end punch. And I worked it out...this system should pump out about 1574W, which should be fun in a truck that weighs less than 4kg...

Thanks again everyone, you've been a real help. :D

09.02.2005, 11:36 AM

I don't know that the caps would make for more bottom end punch, I remember a kid on URC putting a massive one that he found in a dead TV on his Rustler or something and it sucked. When he gave it full power, the cap had to charge up and slowed the vehicle. Not sure if that'd be the same for you, but just saying what happened last time someone tried it.

Dagger Thrasher · 12:40 PM

Hmm, I've heard mixed reviews. Some people notice a big diefference, some don't...maybe it's because they only make a difference when the amp draw is high and kid was only running a mild motor? Who knows, but thanks for the heads up.:) If it doesn't work then it doesn't...it's not an expensive mod to do. If anything, I'm gonna wrap the caps in aluminium tape so they'll look cool, lol:cool: