BL Runtime Setup?
 

Hi, I'm pretty new to RC Monster-Trucks. As my freind buyed hisself a Revo, I was very impressed and so I was thinking about to buy a Revo on my own. Only Problem I don't like Nitro cause over here in Germany u arent allowed to drive a nitro outside a official race-track.
So i thought about a electric version of the Revo. Then I saw The BL Revoxx from Dafni and was very impressed.
Now that i want to build one BL Revo on my own after Dafnis example, i have a question refering the runtime of a Bl setup.

What is the best BL setup to get a great runtime with the Revo. I thought about a Lehner Basic 3100 or 4200. Has somebody some experience what runtimes are achievable?

Hi Rannick:D Good to hear, mate!

As I told you, I'm not an expert when it comes to different BL setups. But I can give you something to read about the Lehners:
http://www.rc-monster.com/forum/show...p?threadid=537

I'm sure Mike, Serum and the others will give their opinions as well.
This is the right place to get some good advice and excellent service.

Another information you should provide is the number of cells you want to use.
I choose 14 on my Revoxx because I already had a couple packs, and they fit just perfect in my design.

Thx for the fast Reply Dafni! :D

I want to use 14 cells even if i m not pretty shure about it. is there more runtime with more cells ore only more power.
It would be great if somebody can write some detailed information to the runtime of different setups.
BL compared to normal motors or twin motors.
lets say i have 14 cells GP3300 Akkus:
then i put different Motors on my truck what would change with the runtime.
For example:
-Lehner basic 3100
-Lehner Basic 4200
-Lehner XL 2400
-550er twin Motor (e-maxx setup)

with what of this motors i would archieve the greatest runtime.

I read on http://www.rc-monster.com/brushlessmotors.php That the lehner basic 3100 provides long runtimes. That sounds good :) :P

How about the Novak HV?

Or maybe a Feigao XL? Can you run an XL on 14 cells at all?

Our 'merican friends will get back on this. :) I'm interested on this, too.

HV Maxx would give long run times, but it would be slow pushing a Revo?

hmm what means slow pushing.
And how long is a long runtime.
I m pretty new to this so pls be lenient with me :p
I dont want to drive to extrem with my revo but long.
So Runtime is more important for me at the moment even if I dont want a motor that is to slow, that only allows me to drive with the speed of a slug.
A good compromise between Power and Runtime, but with a little bigger eye on the runtime!

HV isn't very fast (to the point around, 35mph). Although it will give you the runtimes you need. It all depends on the gearing and weight also and not to forget the batteries.

35mph is far enough even 30 mph would be enough.
As batterie packs i would use 3300 or 3700mAh with 12 or 14 cells.
Offers the HV a better runtime then the Lehner Basic 3100?
and if I use the HV engine what runtime I will archieve circa(15-20min)?

Well with stock Twin Titans I get 15 minutes with a good set of GP3300s (@ 3500mAh). I think the HV would draw more power, so your looking maybe 10 minutes most with 3700s - but I don't have one and really can't be sure.

As I said it also depends on the gearing and weight of your truck.

Hmm only ten minutes is a bit low. cause i would have to buy at least 6 batterie packs to drive a half houre. And then all this reloading. Isn't theire any possibility to reach higher runtimes. Maybee with other motors.
and whats up with the gearing how have i to set up the gearing?
I wanted to archieve runtimes around 20min.

hope there is any possibility :)

I'm gone for a while now. Going to look soccer (Germany vs Australia)with some friends. so cu tomorrow!

You will get a 12-15 minute runtime on BL with the GP3300's

You won't go flat out the whole time.

Enjoy the game!

Is this the HV?

Any other brushless motor on 14 cells I would expect alot less.

No, i easy managed this runtime with my heavy savage and 16 GP3300's with a plettenberg bigmaxximum. so i guess the 9L would do about the same on 14 cells.

I just heared in another forum long days ago...
that a guy with two 550er twin motors, with a runtime of 10-15 minutes, ask how he can increase his runtime.
They said go BL. But now it sounds that BL decreases the runtime more then increase, i'm confused :C:

So for a good runtime would it be better to drive one BL or two normal motors?

I mean the degree of efficient should be very high on BL Motors, so i thought when u use a BL motor that contributes circa the same power like the normal twin motors(stock e-Maxx), it would increase the runtime.

I'm interested in this too, and I'll keep an eye on this.

This much I learned: The trouble is, BL needs more voltage, and delivers more power, so the advantage in runtime is not that much. I might be wrong, though.

I have searched a bit around while waiting on some feedback and found this little graphic from a lehner Basic XL 1200 witch is set under 18V (15cells) looks after a nice runtime because of the low Ampere count of 26.03 + a high efficiency of 92% even if the amount of power might be not to high.http://www.lehner-motoren.de/diagram...18v/grafik.gif

But I'm not to sure about it. Can anybody tell me something to this Graphic?

That won't tell you anything about run time, just the out-put of that motor.

I belive a HV would be your best bet for good runtimes.

the 17 V should be the output of the motor?
Its the voltage from the batteries or other sources.
and what is this Ampere line from?
The Output parameter are only the Um and the Ncm

Hmm dont understand this and u only answer the HV would have the best runtime, but why? can u pls explain it a bit more... and can u explain the graphic?

The graphic is for the power not runtime. It varies with the truck, the weight and the gearing.

The HV is very reliable and has a low power output compared to most other Brushless motors, so less energy will be used resulting in longer run times - but still enough power to get good speeds and torque.

Thats the best I can explain and not sure if I am right so don't count on me.

The xl1200 on 15 cells would most likely have more power AND more runtime than the Novak HV system. More cells means it automatically has more available power/energy and the efficiency is greater as well.

I would be almost 100% sure the power would come from a very expensive digital power supply. That way they can easily alter voltage and current very precisely.

The Um output is the rpm of the motor (22432), and the Ncm is the torque (17.93). Power is directly proportional to rpm and torque. Therefore if torque is high and rpm is low, overall power is the same as if torque is low and rpm is high (bad explanation,but you should be able to understand...)

In fact, all the (electric) motors are the exact same, when you calculate them back.

It is the power that they take, vs the power they throw out (efficency) all the motors give the same amount of torque and watts if you calculate it back to raw numbers..

If you have got a brushed and a brushless setup that throw out the same power, in most of the cases (99,9 percent) the brushless setup has got higher efficiency, so it will run longer on the available energy. if they are fed with the same amount of energy the power output of the one that is most efficient will be the highest. (if mechanical losses on both vehicles are the same)

One thing is also nice to know about brushless motors;

the difference in torque from one and another motor from the same serie, but with different winds, is allmost the same, when compared to eachother.

And Rannick;

Please notice, that you linked to a picture directly from BK, if you can host it yourself, please do so. And if you can't please let me know.

The brushless motor is going to run more efficient than the brushed motor.

Keep in mind that your runtimes will most likely drop when racing due to the constant current draw.

The Novak HV boasts a 20% longer runtime so you would probably be looking at up to 18 minute runtimes depending on your power source.

Mike, correct me if I'm wrong but the xl1200 on 15 cells would run at 21600 RPM. So, in order to compensate for the slower rotating motor you would need to gear the transmission higher. In gearing the truck higher, won't you increase your current draw (AMPs) in turn lowering your efficincey/runtime?

True, the xl1200 would need tall gearing to achieve the speed, but on 15 cells, it would still likely draw less current than the HV (which is only rated for 14 cells, by the way). The xl1600 or xl2000 would be my choice for runtime and overall performance on that cell count, but the xl1200, even with tall gearing, would still deliver excellent power and runtime. Also note that 17 volts times 26.03amps would be constant 442.5 watts of power or 407 watts (more than 1/2 horsepower), factoring in efficiency(442.5X92%), which is higher than the Novak's power rating of 375 watts(Not that the power rating necesarily determines its output ).

Thx for that many replys.
Exp. Thx mike u thin out the fog that surrounds BL from my view a bit :)
So as I dont want to high top speeds 30mph would be enough. I dont need to make the gearing to tall. I think my choice will fall on the Lehner basic XL 1200 when the times come. But first I need a Revo Rolling chassi :)

One more question in dafnis Revo conversion thread
the 10L was eulogized for high runtime.

would a 10L or a basic XL 1200 do better?

XL1200 would do better.

K, thx, :)
Then my decision is made.
I will get myself a lehner basic XL 1200 :)

i would suggest buying a good higher end speed controller, such as the 9920, because when you decide to upgrade from the xl1200 (which you will), you dont want to be stuck with having to buy a nother speed controller because the one bought cant handle the more powerful motor. so, my suggestion would be get a GOOD speed controller and a less powerful motor and as your ready just upgrade the motor instead of the whole system.

Hmm yes ok, I want to buy the 7020 / 3BEC WarriorCar he goes up to 70A.

only thing is if you think you will ever want something like the xl3100 you would have to get the 9920. its only a little more and WELL worth every penny. even if you dont end up getting a motor similar to the xl3100 if you ever resold the 99920 it would bring much more money.

either ones a good controller though.(no wrong way to go)

Hmm u might be right :) i will overthink it once again. Thx for ur effor to bring me on the right path :)

I agree, the 9920 is a better controller choice. the xl1200 could be run on 20 cells with the 7018 controller, though, which would be pretty silly in the power department! All The Lehner basic xl motors are capable of the same power output, but the slower turning motors make the power with voltage as opposed to amperage. Personally, I would run the xl2000 motor. It will have excellent runtime, as well as the ability to easily achieve your speed goals and could take some additional voltage if you want to push the envelope. The xl1200 is a great choice for higher voltages (25 volts or so would likely be the sweet spot for the xl1200, while 17 or so volts would be the sweet spot for the xl2000).

Why is it refered to as a 9920 and a 9918? I'm guessing your just rounding the numbers up?

9920=99 amps at 20 cells
9918=99 amps at 18 cells

The controllers were recenlty re-labeled to 9920, reflecting some testing and the controllers proven abilty to hanlde 20 cells. The recent controllers have a 9920 label as well as double wires for the motor and battery connections.

So is the 9918 on your site actually a 9920? Which can now handle 20 cells?

I changed the name on my sight to reflect the new labels(9920 is listed on my site instead of the 9918). If you have a 9918, it can handle 20 cells.

Rannick, I would go for the 9920, too.

BTW, I also got it confirmed from BK that this 18/20 thing is just a name change. Perfectly identical electronic components, that's what I was told.

DAF

Yes, the same goes for the 18120, it has become 20120 and the 30120/30150 became 36120/36150.