the lehner 1930 and bk9918 esc
 

Hi I've just got in recently. I own an associated t4 with a bk 9918 controller and I've just ordered the lehner 1930/5 turn motor which will be used on the truck. I just want to share the time with you guys choosing the appropriate number of cells to use with this set up: What NO. of cells do you recommend and what is the speed you think that I'm going to achieve with this set up? thanks :L:

I wouldn't go past 8/9 cells or possibly a 3 cell Lipo pack. You are going to want to run a receiver pack as well with that controller anytime you run less than 8 cells. That motor on 8 cells will take your little t4 faster than you need to go!

I thought that 11 cells was going to be perfect for the t4 since 13.2 X 4180= 55176 RPM WITH 1200 WATTS@30 AMPS WOOOOOW I wnder what is it going to be like??!!:C:

Lehner posts a 50000 rpm limit on these motors. I am sure this could be exceeded occasionally without trouble, but the cell counts I recommended keep you within this rpm range. That is a lot of cells for a t4!

Well..you're definitly right, I'll try to use 7 instead of 8 along with a receiver pack and I'll see how powerful the thing is really gonna be, but my truck is a factory team version and I already have plans to modify the thing to the point where it could tolerate such power(11-12 cells that is).

I think you could reach 50 mph pretty easily on 8 cells. Unless you drive on the street, this will be all but uncontrollable. 7 cells will be nice power and nice runtime. 8 cells will be tough to handle in the dirt.

I dont really care if the car handles pretty well or not. All I'm caring of is whether the car(t4) can achieve some insane(and I mean it) speed or not. Lehner posted in their home page that the 1930/4t HI-AMP motor was able to go 87mph on 8 cells in a 1/10 hull. I liked the idea though and went to Fine Design Marines and I've consulted Mr. Fine about using the 1930/5 on the t4 and his reply was the same as yours: To start at low voltage and up ahead, but he said that I can definitly make a speed around 80-85 mph if I'm going to go mad and all. The truck wasnt built by me to race..no, but in fact I like bashing more than racing and also the club that I go to doesn't really race off road machine, but they rather race touring cars instead since these cars' popularity has grown pretty darn big in the last few years and you know...I'm thinking about buying myself a touring car too, but later. Now I'm more conserned about cooling down my lust for speed ah..well??!!! Hey MR. Mike where is every body? I'll be more than happy if they can post their Ideas here too..dont you think so?:P:

80 - 85mph is a tall order. I have had a T2 around 65 mph and it was a handful to keep straight. 45mph seems like a hundred mph when your trying to drive it. You should get some more response later in the day. Many folks are at work now.

85mph wow!!!!
 

I hope your eye hand co-ord is better than mine, i crashed a stock emaxx and maybe 20 mph, how big is the area your trying to drive this beast, 85mph is 125 ft/second, post a vid once your done, it would be wild to see.

matt

Sure it will. Just wait and see. The problem is that I dont know how to post a video though.:W:

As soon as you get over 50 mph things get hairy . 62.5 is my record in my bandit with a lehner 5300 and 8 cells. I am shaking after every run lol.

I use at least 400-600ft of road during these runs.

So I can understand from that : the t4 can exceed 62 mph easily if it is geared properly, because the 1930/5 motor can produce almost twice the power of the Basic 5300. Maybe just maybe I can make 63-65mph with the same setup of yours, but I really wonder what would my car do if it was equipped with a 11-12 cell pack? Things will really start to look incredible.Right?;)

The motor may be capable of providing more CONTINUOS power, but likely the batteries will be the true determining factor of the actual power output. The higher end Lehner motors have more power on paper, but you likely won't notice much, if any, difference on the actual vehicle. The power is actually in the batteries. The motor is merely the vehicle that transfer this power into movement. With the same batteries and the same gearing, the basic motor of similar Kv will perform nearly identically to the high end Lehner motors in terms of actual power output (slight difference due to efficiency, etc.-but this will be minimal and not likely noticed).

Then Li-Poly will be a good choice huh?

LiPo is an excellent choice, so long as you understand and respect the power and handling requirements of these cells, including charging/discharging and the actual discharge capabilities of the batteries.

I also have the associated rc10l3 touring so do you think that I can make som insane speed with it with just 8 cells and a high end motor like the 1920/4 turn motor for example?

You can get some serious speed in the rc10l3 for sure. Your limit will be the batteries ability to deliver the juice. 70-80 should be within grasp.

Hey, Monster Mike, what motor/controller did you use in your T2 to make it clock at 65mph? I think I was able to make such speed with my B4 when it was equipped with a Kontronik fun480-42 motor@12volts the buggy even lift the front end when it reached its peak because of excessive pace. Now I'm using the Lehner 1920/8 motor on the B4 with a Kontronik 55-10-32 controller, but strangely enough the car doesn't accelerate as fast as when it was with fun 480, although the 1920 is "torqueier" than the 480. I think the problem is in the esc itself because the motor might be draining more amps from the esc than the 480. the 480 drains 40 amps continuous and 60 amps surge, but the 1920/8 might be draining much higher amps than that whether continuous or surge, but either way I would like to hear from you people.

The Kontronic controllers are also notorious for only working well with the Kontronic motors. The fun series motors are nice (the one you mentioned is about the same as the 4200 basic). I was using a Shulze 58ce controller and a 6s motor when I did the speed run.

Well..dont you know whats the surge amp rate and the cont. amp rate for the 1920/8 motor? I looked at some info when I visited the LMT website, no info at all. Maybe you can tell. And which controller will suit the b4 in terms of size and the 1920 in terms of power?

The posted information about the motors (max amps, etc.) really is not indicitive of the actual numbers when driving the car. The 480 fun motor will out accelerate a larger motor in a small truck because it has a smaller rotor and can spool up faster. the 1920 can certainly supply more power for longer, though. How many cells are you planning on running in your b4? Mounting the controller will take a little creativity, but should't be too difficult. If you are running 8 or more cells, the 9918 will handle the job with ease. For less cells, the same controller will do, but would need a receiver pack for the best performance. The MGM 80 amp controller could handle the job as well, and is easier to mount (smaller size).

How many cells have you used to make the 65mph speed run? and by the way? haven't you checked the post of my DREAM E-MAXX? guess its a stupid one huh?:o

I just saw your dream e-maxx post. I wouldn't call it stupid, though. A rather nice dream, if you ask me.

I have been 62.5 mph on 9.6 volts(8 nimh cells) in my traxxas bandit with a 9918 and lehner 5300. When I order my 6s motor this week I think I can get near 70 on 9.6 volts, the 6s has a 5900 kv rating. We will see:)

These are short runs and at very high gearing. You would not be able to run this gearing all the time only just for a few passes or it will fry the motor or controller. Although you could just add a couple cells and probably get 60+ mph on normal gearing. I just don't have a ten cell charger so it's a pain for me to run more than 8 right now. I would not run more than 10 on the lehner 5300, 12 volts puts it right under its 65k rpm limit.

With the 5300 and normal gearing my bandit does about 50-55mph on 8 cells right now. Really fun to drive.

I just received the 1930/5 motor, but now I have a problem. When I use 7 cells with the motor it runs nice and cool, but at 12 or 13,2 volts the motor makes a very strange sound and it coggs to the point that it sometimes feel like the speed cont.(9918) cant deliver enough power, it seems as if the controller is about to shutt down. I really have no Idea what's going on. The 9918 works with the help of a 4cell receiver pack and I have took out the black jumper near the red one to disable the BEC system, May be it could be the problem, but may be not. If you say that I'm using too much cells then I dont really think so because there are som people who used 12 cells with such motor without having such problem. Monster Mike, I seek your help.:W:

The 1930/5 will be spinning at over 80000 rpms on that voltage (so yes, it is too high voltage if you want to have the motor for a while!). The controller should still handle it, though. Perhaps you could describe the sound a little better to me. Also, did you change the gearing when you added all those cells? Lower gearing woiuld definately be necessary. Another thing to try is a real receiver pack (5 cell nimh or nicad). the aa batteries are considerably less than ideal.

Well, I really didn't connect the motor to the spur gear yet, but you know, the motor for some reason stopped that wierd sound and its working fine now( after reprogramming the damn ESC) and about the 80,000 rpms, how did you know that the motor will be making such a high rpm rate? when I calculated the whole thing myself the motor was supposed to run at 55000 or more rpms, since the 1930/5 turn is rated at 4180 RPMs per volt so this rpm rate multiplied by 12-13.2 volts will give the 55000 rpms I guess and the receiver pack...Lehner said that I should be using 4 cells if the transmitter, servo and receiver are made by FUTABA.

I actually misread your post and thought it was a 1920/5 motor, which spins over 6000rpm/volt. Even your 1930 will spin that fast with no load, though. Interesting on the Futaba receiver pack thing. I am glad it seems to be working. It is not a good idea to run a brushless motor with no load (FYI), so please don't rev it up without putting a load on it. LMK kow you like it when you have it on your vehicle.

I just saw this thread.

You are safe, running this motor till 85000 rpms.. (it is a highamp version) That 50000 is for the non highamps.. (2240 highamp version permits 'only' 50000 rpm)

Sooooo

85000 rpm's.... Buckle up..

Safe is one thing. Ideal is another. either way, he should be fine, as his motor is a 1930, not the 1920 size I thought it was.

Thanks guys I'll be running the t4 along with the 1930 and the 9918 to day at my local track on 7 cells and i'll see how it will behave. I have also equipped the t4 with an ACER RACING ceramic kit which I think is a very good step to bring out all the power from the motor or most of it since it's times and times better than the stock bearings and much smoother.;)

Hi Mike, do you accept MasterCards for ordering?

Sure do. MasterCard, Visa, Paypal and money orders are all acceptable form of payment.

Here's my report about the T4/1930 5 turn motor and BK9918 controller: - VERY POOOOOR ACCELERATION.
- VERY LOOOW TOP SPEED.
- BATTERY GETS DRAINED OUT IN LESS THAN 5 MINUTES.
- THE MOTOR GETS HOT TO SOME EXTINCT
- I'M VEEEEEERRRRYYYY DISSAPOINTED.
- I'VE ONLY GOT THE CHANCE TO DRIVE IT ONCE CUZ IT SUCKS. IT REALLY DOES.
- COULD THE PROBLEM BE FROM THE BATTERY?
- COULD IT BE FROM THE 9918(WHICH DIDN'T GET HOT AT ALL WHEN I DROVE THE TRUCK).
- GEARING PROBLEM?( I'M USING 20T PINION/87T SPUR)
- COULD IT BE FROM THE MOTOR ITSELF?
- COULD YOU PLEASE HELP ME?

Easy does it mate, i understand your frustration, but easy does it, every single time..

What batteries are you using? Lets start with that.

No binding? the whole drivetrain runs freely?

I have a lehner 5300 on a 9918 I got from Mike , installed in my bandit. It absolutely screams on 8 cells. It should be comparable to your T4. I run gearing around 25/81 with incredible take off speeds and top speeds 50mph+ on this gearing.

How many cells are you running? If you are using the BEC on the 9918 you should at least run 8 cells and no more than 12.

Also answer serums questions. It really sounds like a battery issue.

Guess he's out testing it.. ;)

lol:D

Enjoying his 60mph + T4, leaving us with his capslocked story...

:D

I'm not testing it outside or something its there inside my tool box sleeping like a stupid bear. ARRGGGGGHHHHHH. I just dont understand why? this motor can inflect icredible damage upon my drive train, but in reality its just like 19 turn brushed motor with no acceleration at all. I'm using a 7cell pack 3300 gp and my drive train is smoother than any skin you've ever touched in your life. I'm using Acerracing ceramic kit too.