Page 2 of 2 FirstFirst 12
Results 41 to 71 of 71

Thread: 4s is doable

  1. #41
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Quote Originally Posted by 8ight-e
    Thats a given on that gearing. Don't forget lipo's can take the amp draw and you can increase your gearing and top end very easily if all you want to do is a few speed passes (notice the chart on usable gearing as well). Keep in mind it's still a 380 motor even if it's "neu quality" it will have a hard time pushing those speeds other than a few asphalt speed runs. As far as bashing and racing goes 38-40mph is going to be the top for reliable use most likely. If you want more think about upgrading to a 1/10 velineon system.

    What I said is a statement through Traxxas.. 40 on 3s
    and this is the vid..
    http://www.youtube.com/watch?v=8XM0teqmpMI

  2. #42
    RC Champion
    Join Date
    Oct 2008
    Posts
    1,226
    Quote Originally Posted by filmmaker
    What I said is a statement through Traxxas.. 40 on 3s
    and this is the vid..
    http://www.youtube.com/watch?v=8XM0teqmpMI

    What is your point.. as they said 3s lipo "out of the box" is capable of 40mph, but um you can order taller gears if you want more I say again 40 is about all you'll want w/ the included motor w/o tons of heat issues. Please note the gearing chart, lots more options available besides the two pinions included in the box.

  3. #43
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Quote Originally Posted by 8ight-e
    Thats a given on that gearing. Don't forget lipo's can take the amp draw and you can increase your gearing and top end very easily if all you want to do is a few speed passes (notice the chart on usable gearing as well). Keep in mind it's still a 380 motor even if it's "neu quality" it will have a hard time pushing those speeds other than a few asphalt speed runs. As far as bashing and racing goes 38-40mph is going to be the top for reliable use most likely. If you want more think about upgrading to a 1/10 velineon system.

    Not hard to get the speeds Traxxas is talking of..
    40mph on 4s
    and 50mph+ on 12cell nimh using a smaller pinion...

    Traxxas has the goods!

  4. #44
    RC Qualifier
    Join Date
    Nov 2008
    Posts
    340
    Anyone notice that in the video the Traxxas guy is using the 2.4ghz system on the mini?

    Which makes me wonder. If they say 2.4 is the way to go on the fullsize brushless version to avoid interference. Why not on the mini?
    Revo 5308
    OS 18tm
    Maximizer 17mm Bead Locks

  5. #45
    RC Qualifier
    Join Date
    Aug 2007
    Location
    Fremont, Ca.
    Posts
    944
    Quote Originally Posted by DIRTDEVIL
    Majestic is correct with his comment. It will not handle 4s power as per the engineering department here at Traxxas.
    <<<<<--Cut to the Important stuff-->>>>>

    Quote Originally Posted by DIRTDEVIL
    Warning: If input voltage exceeds approximately 20 volts, the ESC may be damaged.
    This is the voltage that components start popping at. Traxxas has been pretty spot on in the past so this is likely the very outside limit of the controller.

    Quote Originally Posted by DIRTDEVIL
    Maximum peak input voltage limits are 12.6V in LiPo Mode (see page 17) and 18V in NiMH Mode."
    And this tells us the rest of the story. The ESC's lipo mode is limited to 3s by the LVC. But turning off the LVC you can run 14s NiMH or 4s lipo and still have a little head room. (Running lipos with no lvc is dangerous so spend $15 on an external one if you try this) Running this much voltage will likely push the motor over it's rated safe RPM and likely run very hot...

    So this could be a very fast setup with only simple upgrade to the lvc. I may have to buy one now just to find out.
    [QUOTE=Billstmaxx]if the water can't get out how does it get in??[/QUOTE]

  6. #46
    RC Turnbuckle Jr.
    Join Date
    Jan 2008
    Location
    Lugoff, SC
    Posts
    3,837
    Quote Originally Posted by FyrFytr998
    Anyone notice that in the video the Traxxas guy is using the 2.4ghz system on the mini?

    Which makes me wonder. If they say 2.4 is the way to go on the fullsize brushless version to avoid interference. Why not on the mini?
    Think about it! They are at a toy fair... Don't you think there will be a couple radios being used all at once at any given time?

    They don't use them on the minis or 1/10 VXLs because interference is rarely a severe issue as it is with the huge MMM.
    RIP Bart Hinson
    1992-2009

  7. #47
    RC Champion
    Join Date
    Oct 2008
    Location
    New Lebanon NY
    Posts
    1,137
    but wait, what if you put it on nimh mode and just used an external LVC? wouldnt that work. then we might be able to use 5S i think.
    i bet my Quad could out RIP your Quad!!

  8. #48
    RC Champion
    Join Date
    Oct 2008
    Posts
    1,226
    That tiny esc will blow up on 5s, you will find it blows up pretty easy on 4s other than a few quick speed passes. It's not designed or that, if it were capable of 4s operation safely.. umm I think they would have just released it as stable to 4s and had the cutoff setting built in

    For those going to try this at 4s even I suggest getting a fan and mounting it on top..

  9. #49
    RC Champion
    Join Date
    Apr 2007
    Location
    Valrico, FL
    Posts
    1,679
    Quote Originally Posted by 8ight-e
    That tiny esc will blow up on 5s, you will find it blows up pretty easy on 4s other than a few quick speed passes. It's not designed or that, if it were capable of 4s operation safely.. umm I think they would have just released it as stable to 4s and had the cutoff setting built in

    For those going to try this at 4s even I suggest getting a fan and mounting it on top..

    I'de be kind of surprised if a car this small would even be halfway drivable at anything over 40 mph...thats really fast for something that small, I can't imagine trying to run it over 50 mph...Even the full size revo gets a little squirrely over 40 mph.

  10. #50
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Quote Originally Posted by filmmaker
    Not hard to get the speeds Traxxas is talking of..
    40mph on 4s
    and 50mph+ on 12cell nimh using a smaller pinion...

    Traxxas has the goods!

    oops, ment to say 40mph on 3s!

  11. #51
    RC Racer
    Join Date
    Apr 2009
    Location
    lexington, ky
    Posts
    144
    Quote Originally Posted by DIRTDEVIL
    Majestic is correct with his comment. It will not handle 4s power as per the engineering department here at Traxxas. I feel if anyone would know the limitations of the esc it would be them. And at any point you feel like testing this known fact....please have $45 dollars and a box handy to send it back in and we will gladly repair it for you. This is a quote straight from the owners manual "Alternating; Blinks Red then Green: If the motor has no power, the VXL-3m has entered Over Voltage Protection. If a battery with too high voltage is used, the VXL-3m will go into a failsafe mode. Warning: If input voltage exceeds approximately 20 volts, the ESC may be damaged. Maximum peak input voltage limits are 12.6V in LiPo Mode (see page 17) and 18V in NiMH Mode." If you would like to read this for yourself or feel that you have other questions please feel free to check out the owners manual. http://www.traxxas.com/PDF-Library/7008_7108_manual.pdf

    couldn't you run it in nimh mode and run the 4s with a LVC? i dont see how that wouldn't work?

    Quote Originally Posted by Just go Play

    And this tells us the rest of the story. The ESC's lipo mode is limited to 3s by the LVC. But turning off the LVC you can run 14s NiMH or 4s lipo and still have a little head room. (Running lipos with no lvc is dangerous so spend $15 on an external one if you try this) Running this much voltage will likely push the motor over it's rated safe RPM and likely run very hot...

    So this could be a very fast setup with only simple upgrade to the lvc. I may have to buy one now just to find out.
    Ths exactly what I'm thinking? answer that question traxxas guys.

  12. #52
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    They already have....

  13. #53
    RC Racer
    Join Date
    Apr 2009
    Location
    lexington, ky
    Posts
    144
    Quote Originally Posted by filmmaker
    They already have....

    where? I didn't see anything. WHat I'm saying is if i but the esc in nihm mode which has a overage of power stage for anything over 18v. the esc isn't going to know whether the 16.8v (fully charged lipo(if im wrong correct me)) that is being inputed into the esc is a lipo or nimh battary. There for the esc wont go in to the over power stage and would run the 4s. do you know what I'm saying?

  14. #54
    RC Turnbuckle Jr.
    Join Date
    Jan 2006
    Location
    SoCal
    Posts
    3,930
    First off, the reason they are using a 2.4ghz radio at RCX is because they'd probably lose control using any other frequency. Since all 2.4ghz radio's scan and choose a frequency on their own, there is never a conflict. But if you have some dude turn on his AM 27 or FM 75 radio that's on the same frequency as you, then he will have partial control over your truck. It comes down to whoever is closer.

    I had this situation once and my Venom Failsafe kept me from destroying my truck (it was my Revo 2.5R). However, once he got about 300ft away, the truck would listen to me as long as it was about 1/2 as far from me as it was from him (because my radio would over-power his).

    However, the reason they didn't include the radio is because they wanted to keep the cost down. This is also a likely reason why they didn't include a second steering servo. It is obvious the truck was designed to have a second one, based on the other input on the servo saver and the spot on the chassis. It was probably decided that the truck can get by on one so it was removed to keep cost down.

    Now, as for the ESC, based on the specifications listed, the voltage cutoff is 18V when in NiMH (no cutoff). Now, a fully charged set of 4S Lipo packs is 16.8V, which is within the limits. They say the ESC will be damaged at 20V. So theoretically, yes, the ESC will allow you to run 4S Lipo so long as it is in NiMH mode (no cut-off) and you add an external cutoff or, for whatever reason, run no cut-off (obviously not advised).

    What everyone here should know, is that when a truck runs, there are voltage spikes due to back currents generated during braking and other occurrences associated with regular running. This is why there is always some leeway given. A 3S speed control does not have MOSFETs rated at 12.6V, just as a 4S speed control does not have MOSFETs rated at 16.8V.

    For example, the Mamba Monster Maxx, which we have all come to respect as a robust, powerful ESC that comes in the E-Revo Brushless Edition, is rated to 6S lipo, or 25.2V when fully charged. The MOSFETs are rated to 30V. So right here, to reach the rated limit of the MOSFETs, the voltage spike would have to bring the voltage about 20% over the maximum input of 25.2V.

    So, this puts 5S completely out of the question. 4S, in my opinion, is doable. But not on the stock motor. At 4000KV a fully charged pack would put the motor at nearly 60,000 RPM. I highly doubt this motor is very efficient at these kind of RPM ranges and I even more so doubt the rotor and bearings will even stand up to this kind of RPMs. You would need to replace the motor with a lower KV motor, and preferably a more efficient one.

    Lastly, you should realize that running on 4S is going to require more than just an external cutoff, you will also need a BEC. I highly doubt that the ESC uses a switching BEC, and most BEC's are very taxed when modulating input voltages from 3S. 4S will just cause it to over-heat and fail.

    If you plan to do 4S, I advise you do it carefully and DO NOT expect Traxxas to warranty any part of the system (ESC or Motor) if something goes.

    Personally, I plan to keep the electronics stock, and this is coming from someone who has had their CRT .5 set up at a ~75mph top speed (never got it anything higher than 60, it just took off, for those that were wondering).

    In my opinion, 50mph is PLENTY in this little truck, plenty! I'm probably going to gear it down to 40mph to help with temp and add run time.

    The truck isn't even out yet and you guys are already trying to bend the rules and go crazy.

    You may just find that it is too fast on just 3S lipo.
    BP stands for Brushless Powered - LMT1940/7 CF G2R

  15. #55
    RC Racer
    Join Date
    Apr 2009
    Location
    lexington, ky
    Posts
    144
    [QUOTE=BP-Revo]QUOTE]

    the esc has a bec built it thats set at 6v. so i dont think i need one of them do i? I will need a LVC but how should i wire it.
    http://www.maxamps.com/Novak-4S-SS.htm

    I'm setting up a dual bl truck. I'm going to have 2 4s 1550ma battarys, 2 esc's and of course 2 motors. The esc will be both connected to the recever via a y connector. how do i wire the LVC without having to buy 2 of them? would you just wire the battary sensor wire to both battarys in a parallel series and that way as soon as one dropped below 12.5 volts it would turn them off or no? Please help

  16. #56
    RC Turnbuckle Jr.
    Join Date
    Jan 2006
    Location
    SoCal
    Posts
    3,930
    I'll be surprised if you can fit 2 motor on this truck. It's gonna be a brick with everything you are going to put on it...

    Anyway, as for the BEC, even though the ESC has a built-in one, it will need to be disabled and replaced with an external switching BEC.

    The built in BEC just bleeds off the extra voltage by converting it to heat. When running 2S lipo for 6 cell NiMH, this isn't much voltage. At best its usually going from 8.4V for a fully charged lipo down to 6V. Only a 2.4V drop.

    However, with 3S Lipo, you are looking at a 6.6v drop (12.6 down to 6). On 4S lipo, you are looking at more than 10v (16.8 down to 6).

    To bleed off 10v of power is going to generate tons of heat, and will cause the ESC to heat up, likely frying the onboard BEC, and possibly frying the whole speed control.
    BP stands for Brushless Powered - LMT1940/7 CF G2R

  17. #57
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Quote Originally Posted by BP-Revo
    I'll be surprised if you can fit 2 motor on this truck. It's gonna be a brick with everything you are going to put on it...

    Anyway, as for the BEC, even though the ESC has a built-in one, it will need to be disabled and replaced with an external switching BEC.

    The built in BEC just bleeds off the extra voltage by converting it to heat. When running 2S lipo for 6 cell NiMH, this isn't much voltage. At best its usually going from 8.4V for a fully charged lipo down to 6V. Only a 2.4V drop.

    However, with 3S Lipo, you are looking at a 6.6v drop (12.6 down to 6). On 4S lipo, you are looking at more than 10v (16.8 down to 6).

    To bleed off 10v of power is going to generate tons of heat, and will cause the ESC to heat up, likely frying the onboard BEC, and possibly frying the whole speed control.
    Not if the esc is built to handle 12cell nimh...

  18. #58
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    [QUOTE=josh7owens]
    Quote Originally Posted by BP-Revo
    QUOTE]

    the esc has a bec built it thats set at 6v. so i dont think i need one of them do i? I will need a LVC but how should i wire it.
    http://www.maxamps.com/Novak-4S-SS.htm

    I'm setting up a dual bl truck. I'm going to have 2 4s 1550ma battarys, 2 esc's and of course 2 motors. The esc will be both connected to the recever via a y connector. how do i wire the LVC without having to buy 2 of them? would you just wire the battary sensor wire to both battarys in a parallel series and that way as soon as one dropped below 12.5 volts it would turn them off or no? Please help

    Josh, what two brushless setups are you going to use?

    Just a side note, when I put two battery packs into my mini Slash it adds alot of weight to the small chassis of this little truck and leaves for not much suspension travel on this little gem... So I'm thinking you wll need to do something to correct for the extra weight you will add to this truck, and I really do think it is not possible to run with two like you are thinking it will.

    You are going to add alot of weight to this truck that it was not designed to handle..

    And I'm betting a properly set up stock mini will out run yours in a straight line.. Also lap yours 2 to 1 on the track

    but get pictures if you try this out...
    Last edited by filmmaker; 04-29-2009 at 10:50 AM.

  19. #59
    RC Racer
    Join Date
    Apr 2009
    Location
    lexington, ky
    Posts
    144
    Quote Originally Posted by filmmaker
    Not if the esc is built to handle 12cell nimh...

    exactly. why does this guy want to keep arguing that it wont work? I've proved it will.

    Also how is my car going to wieght a ton? the battary wieghts 68gs more then the maxamp 3s, and the added wieght of the LVC, esc, motor, and alittle more metal for the bracket. Thats it.

  20. #60
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Quote Originally Posted by josh7owens
    exactly. why does this guy want to keep arguing that it wont work? I've proved it will.

    Also how is my car going to wieght a ton? the battary wieghts 68gs more then the maxamp 3s, and the added wieght of the LVC, esc, motor, and alittle more metal for the bracket. Thats it.

    Uh hello?
    you just said it...

  21. #61
    RC Racer
    Join Date
    Apr 2009
    Location
    lexington, ky
    Posts
    144
    Quote Originally Posted by filmmaker
    Uh hello?
    you just said it...

    no i said its not going to wieght that much more..

  22. #62
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Your going to add 10 maybe 15% or more weight to this little truck that weighs about 2lbs, thats alot for the stock suspension to take on.. It will not handle very good..
    That would be like me adding about 24oz (1 1/2lbs) of extra weight to my BErevo.. it would handle like crud

    You will get smoked on the track by a stock mini..
    Last edited by filmmaker; 04-29-2009 at 12:15 PM.

  23. #63
    RC Racer
    Join Date
    Apr 2009
    Location
    lexington, ky
    Posts
    144
    my revo is for bashing when i get done with my truck i bet money that it will wieght the same as a stock mini but double the power.

  24. #64
    RC Racer
    Join Date
    Apr 2009
    Location
    lexington, ky
    Posts
    144
    do you have any specs on how much the stock motor and esc wieghts

  25. #65
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Quote Originally Posted by josh7owens
    my revo is for bashing when i get done with my truck i bet money that it will wieght the same as a stock mini but double the power.

    dought that, a stock mini revo with a single 3s battery I bet wil weigh less than a revo with two motors two esc and two batteries...

    and will most likely out run it on the track any day of the week...

    but let us know and post lots of pics, it should be a cool build!

  26. #66
    RC Turnbuckle Jr.
    Join Date
    Jan 2006
    Location
    SoCal
    Posts
    3,930
    Quote Originally Posted by josh7owens
    exactly. why does this guy want to keep arguing that it wont work? I've proved it will.
    Because "this guy" has been on this forum for years compared to a couple of weeks, and has been dabbling in brushless RC from the times a Novak HV 6.5 was cutting edge and anything sensorless needed an old school BK or Schultz.

    And "this guy" knows and has seen and has done the calculations to prove that the amount of heat generated by forcing the stock BEC to regulate a 3S lipo (or 4S lipo) input down to 6v.

    But ok, I'm fine with that. I know to you guys I might be new cause I've been busy with school a while and mostly post on RC-Monster but to all the veterans here I'm a veteran to them.

    So if you want to completely ignore by fact-based and evidence-backed claims and try it out for yourself, wasting money and frying perfectly good ESC's in the process, please, I encourage you. Just be sure to post what happens so everyone will know what happens and they'll realize who to listen to in the future.

    There are formulas which prove 1=0, so technically I can run 50,000V on my Traxxas ESC because 50,000 is the same as 1+1+1+...1+1 and since 1=0 50,000=0 and 0 volts is within the 18V limit.
    BP stands for Brushless Powered - LMT1940/7 CF G2R

  27. #67
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Quote Originally Posted by BP-Revo
    Because "this guy" has been on this forum for years compared to a couple of weeks, and has been dabbling in brushless RC from the times a Novak HV 6.5 was cutting edge and anything sensorless needed an old school BK or Schultz.

    And "this guy" knows and has seen and has done the calculations to prove that the amount of heat generated by forcing the stock BEC to regulate a 3S lipo (or 4S lipo) input down to 6v.

    But ok, I'm fine with that. I know to you guys I might be new cause I've been busy with school a while and mostly post on RC-Monster but to all the veterans here I'm a veteran to them.

    So if you want to completely ignore by fact-based and evidence-backed claims and try it out for yourself, wasting money and frying perfectly good ESC's in the process, please, I encourage you. Just be sure to post what happens so everyone will know what happens and they'll realize who to listen to in the future.

    There are formulas which prove 1=0, so technically I can run 50,000V on my Traxxas ESC because 50,000 is the same as 1+1+1+...1+1 and since 1=0 50,000=0 and 0 volts is within the 18V limit.

    Awesome love it!

  28. #68
    RC Qualifier
    Join Date
    Apr 2004
    Location
    Saskatchewan Canada
    Posts
    855
    Because "this guy" has been on this forum for years compared to a couple of weeks, and has been dabbling in brushless RC from the times a Novak HV 6.5 was cutting edge and anything sensorless needed an old school BK or Schultz.

    And "this guy" knows and has seen and has done the calculations to prove that the amount of heat generated by forcing the stock BEC to regulate a 3S lipo (or 4S lipo) input down to 6v.

    But ok, I'm fine with that. I know to you guys I might be new cause I've been busy with school a while and mostly post on RC-Monster but to all the veterans here I'm a veteran to them.

    So if you want to completely ignore by fact-based and evidence-backed claims and try it out for yourself, wasting money and frying perfectly good ESC's in the process, please, I encourage you. Just be sure to post what happens so everyone will know what happens and they'll realize who to listen to in the future.

    There are formulas which prove 1=0, so technically I can run 50,000V on my Traxxas ESC because 50,000 is the same as 1+1+1+...1+1 and since 1=0 50,000=0 and 0 volts is within the 18V limit.
    haha exactly, nuf said... i'm sorry but i get offended when newbs tell me and other veterans that they are wrong and have nothing to base it on and ignore the fact that we might just know a good bit about what we are talking about, non the less it's your money you can spend it where you like, but i'll be there to say i told you so when you come on here complaining you fried somethin due to 4s
    Last edited by pedester 99; 04-29-2009 at 09:23 PM.

  29. #69
    RC Turnbuckle Jr. 31794ty's Avatar
    Join Date
    Nov 2007
    Location
    Marietta, Georgia
    Posts
    3,822
    Josh thinks he know everything about something that hasn't even hit the shelves yet. TRAXXAS even said it will NOT work.
    Stampede VXL Mini-T Nitro Stampede RC10T RC10B4 FT

  30. #70
    RC Turnbuckle Jr.
    Join Date
    Nov 2006
    Location
    USA
    Posts
    3,038
    Even my stock brushed mini slash in the dirt is lots of fun!


  31. #71
    RC Champion
    Join Date
    Mar 2007
    Location
    Durham, N.C.
    Posts
    1,303
    If yal want 4s in a small esc, just get a mm with an external bec and sell the mini vxl esc on ebay.

    Problem solved.
    I WILL spank a nitro any day...guaranteed. :)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •