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-   -   how many cells can i run? (https://www.rc-monster.com/forum/showthread.php?t=7310)

damaxxman 06.21.2007 09:48 PM

how many cells can i run?
 
how many cells can i run on my 9XL? im runnning it in an emaxx. im using a mm esc and a ubec. i wanna stick with NiMh or NiCd. i dont wanna not run lipos to much $$.

BrianG 06.21.2007 09:49 PM

For cool running, 16 cells would be about the limit.

damaxxman 06.21.2007 10:03 PM

if i run lipos wats is the max?

BrianG 06.21.2007 10:07 PM

Well, 16 cells is 19.2v (1.2v per cell). Since lipos are 3.7v per cell nominal, that would be about 5s.

damaxxman 06.21.2007 10:09 PM

ive heard of people running like a pair of 5s lipos with the 8xl and mm esc? this was in a revo.

damaxxman 06.21.2007 10:18 PM

i was looking at this web site
http://home.comcast.net/~milemarkers...-Brushless.htm

said (Potent power and run times when paired with 6S LiPo batteries.)

BrianG 06.21.2007 10:22 PM

Well, technically, you may be fine. It depends how long the motor will be at max rpm. If you are doing speed runs, the motor will reach max rpm and stay there longer, and will be prone to overheating. If you are racing, you probably will not reach top speed, and if you do, it won't be for long. Like I said, the generally accepted rule of thumb is 35000 rpm max. This comes from many users' experience.

damaxxman 06.21.2007 10:28 PM

so i fi run 16 cells or 5s lipo i should be able to run 35000 rpm all day long?

damaxxman 06.21.2007 10:29 PM

o and wat do u think ill get for like topspeed with that 16 cells?

luvsrc 06.21.2007 11:21 PM

35-40mph depends on your gearing

BrianG 06.22.2007 12:06 AM

Quote:

Originally Posted by damaxxman
so i fi run 16 cells or 5s lipo i should be able to run 35000 rpm all day long?

Sort of. Any of the XL motors will get hot after a while. After all, you are dumping some pretty substantial power into it. I usually run a packs' worth, then let the motor and ESC cool for ~20min, then run again. If that's what you mean by "all day long", then yes.

AAngel 06.22.2007 12:20 AM

There is no non stop running with a Feigao motor. If there is, I haven't found the setup yet.

zeropointbug 06.22.2007 02:15 AM

Quote:

Originally Posted by AAngel
There is no non stop running with a Feigao motor. If there is, I haven't found the setup yet.

Why are you being so naive AAngel? Of course there is a none stop Feigao setup... a 10XL on 3s LiPo. :005:

damaxxman 06.23.2007 06:13 PM

are the xl motors one of the better motors to put in my emaxx or would say the novak hv be better? or what do you think is best, out of all the brushless motors?

Serum 06.23.2007 06:19 PM

you mean out of all brushless motors? that would be Neu or Lehner. My personall favorite would be the XL from the options you listed. that site you mentioned; it might sound nice, but in real life you'll get an overheated system in the blink of an eye when running an 8L on 14 cells.

Please read the sticky in the brushless section, it's named 'information about brushless in general'

damaxxman 06.23.2007 06:24 PM

so me running a 9xl is not that good or its decent?

Serum 06.23.2007 06:30 PM

on how many cells?

damaxxman 06.23.2007 06:43 PM

16cells or can i run more?

BrianG 06.23.2007 07:00 PM

You can run as many cells as you want as long as the ESC you are using can handle it and whatever motor you pick doesn't exceed around 35,000 rpm. If you wanted to use 100 cells (120v), you'd have to run a motor with a kv of around 290 to maintain that 35000 rpm "golden rule".

Using a motor that will exceed that rpm will be OK as long as it isn't running at that speed for long. For speed runs, the motor would be running at its peak and wouldn't be advised. In racing, it should be ok since you won't be hitting top speed all that much. But be warned, the motor will get quite warm. You could move to a higher-end motor like a Neu or LMT to help with that though.

damaxxman 06.23.2007 07:04 PM

wat is better the Neu or Lmt?and wat motor would be the best? O and could i run the motor with my setup now? i have a mm esc with a ubec that i go ton here.

damaxxman 06.23.2007 07:10 PM

but i dont wanna spend too much money i woudl perfer to keep it under $200.

BrianG 06.23.2007 07:13 PM

For the MM, the LMT would be the best bet. The MM tends to have trouble running the Neu motors until a software fix can be made. Both the LMT and Neu are very high quality, so it's a matter of personal preference. Mike should be able to get LMTs pretty soon so availablity won't be a problem.

For a MM on 4s or 12-14 cells, I'd go with the 1940/7 or 8. Or for a bigger motor, a 1950/6 or 7. I wouldn't go much higher in voltage than that on the MM. Some people have been able to use 5s (~16 cell equiv), but that's pushing it IMO.

AAngel 06.23.2007 07:13 PM

zpb, you're cracking me up over here!!

With the Mamba Max, I'd keep it to 4S in a truck. Or whatever nimh equivalent there is. 5S with the MM is pushing it, especially if the truck is heavy with big tires.

The 9XL is better than the Novak setup for your application and it will give good solid performance.

damaxxman 06.23.2007 08:26 PM

wouldn't a 7xl or 6xl be the best? because i can run more rpms per volt.

Patrick 06.24.2007 12:03 AM

Higher kv motors (lower turns) have less torque than lower kv motors and generally draw more power (if everything thigh else in the setup is kept the same). They are more sensitive to changes in gearing than lower kv motors and everything usually runs hotter, because they draw so much power.
I burnt out 2 quarks using a 7xl on 14 and 12 cells and a lot of other people have had thermalling problems with them as well. A 6xl would cause even more heat issues.
Most people find it's better to use higher voltage and lower kv motors to get good speed and power with cooler, more reliable running.
My 7xl ran hot and so did the esc and batteries. Going to a neu 1515 2.5d (1700kv) and gearing up for speed actually had about the same performance, but cooler running. Now I run that motor on 5s lipo and have no heat issues, more performance and better runtime.

Serum 06.24.2007 03:24 AM

damaxxman; please read the sticky in the brushless section about the KV of a motor, it's in the thread information about brushless in general

SpEEdyBL 06.24.2007 02:07 PM

If you want an inexpensive setup, get the novak HV4.5 system. It's actually made to run in r/c cars, let alone monster trucks! Plus, there is no such 35,000 rpm rule with this motor. Just run it on 12-14 cells or 4s lipo and you should be fine. I am going to test the 8xl against the HV4.5 in less than a couple weeks. Unless you are dying to buy get a setup, it may be worth waiting for my results.

zeropointbug 06.24.2007 02:12 PM

LOL

Yeah, it appears that Novak makes their 'OWN' rules about shaft size and rpm for monster truck.... :rolleyes:

damaxxman 06.24.2007 04:23 PM

yea i've seen the hv maxx and talked to alot of people about those. i dont think that they r that great. i've heard you dont really get anymore top speed. plus its realy not that cheap. what like $265. i got my whole setup for the 9xl for under $200. so u go do your test and let me know. o and you sure vidoe tape it too.


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