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  1. #1
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    5S lipo on EVX2, Dewalt motor

    Hi

    I have a stock E revo in pretty new condition, and two Venom 5000 NiMH packs.

    I'm was going to buy two 4S ***** lipo's and put them in parallel, and a 12V dewalt motor.
    But I started wondering if the EVX2 could handle 5S lipo's.

    A quick calculation:
    Two 7 cell nimhs fully charged: 2 x 1,45V x 7 = 20,3V
    Two 5s lipo's fully charged: 4,2V x 5 = 21V

    Since it is recommended to use 7cell nimh packs with the EVX2, the EVX2 must be able to handle 20,3V. So 21V should be no problem!
    Ofcourse this setup will draw quite a lot more current than stock, so my estimations are that the EVX2 will hold up, but will require a fan



    Now, If I would be using 5s I'd better not use the 12V Dewalt, but the 14,4V or 18V Dewalt instead.

    The 12V motor has been overvolted by many people here to 16,8V alot with no problems.
    The 18V motor is overvoltable to 24V according to robotmarketplace.
    So the 14,4V motor will probably be overvoltable to 19V or so.

    * I was wondering what the best motor would be, The 14,4V Dewalt or the 18V Dewalt?

    * Will these 5S1P 3000mah *****'s fit in the E revo compartiment?
    http://www.*********.com/*********/s...0mAh_5S1P_20C_
    The dimensions say it's 30mm thick, and the E revo bat compartiments are 29mm .
    But someone in the comments says he's going to use / is using them in his E revo.
    Has anyone of you tried them?

    * And another question: Will the BEC in the EVX2 be able to convert 21V to 6V? Because I would be using two 5s lipo's...

  2. #2
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    I have seen lots of people doing this Dewalt upgrade - can I ask what the benifit is?
    Summit

  3. #3
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    Quote Originally Posted by xtremesummit
    I have seen lots of people doing this Dewalt upgrade - can I ask what the benifit is?
    more torque and they last longer than the titans

    and they're relatively cheap
    runs/parts broken ratio: 8/6

  4. #4
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    The 12v and 14.4v appear to be the same motor ( same numbers on the side of the can).
    The 12v motor will take 5s.
    The EVX-2 will take 5s, but ONLY as 2s + 3s. You must put the 2s on the BEC side of the ESC - it cannot generate the BEC from more than about 9v.
    The evx does not need a fan.
    Time is an illusion, "9am sharp" doubly so.

  5. #5
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    Are you sure about that bluefisherking? I thought I saw someone here that has two 4s lipo's parallel in a stock E revo. That's 14,8V.

    Am I wrong?

  6. #6
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    Hmm, well I was passing on what I understood to be the case (from previous web research only)... I am happy to be corrected... But if I were you I would make sure before buying those lipos...
    Time is an illusion, "9am sharp" doubly so.

  7. #7
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    And I found this in the E revo FAQ:


    It appears 4s can be used. But has anyone ever tried 5s packs?

    And yes I am trying to make sure

  8. #8
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    You will have to do some modifying to get them to fit, but you should be able to make them fit.

    Another thing to consider is, even with two of those packs in parallel, you are only going to get 120amps...that's decent, but not that great. You will be much better off to use [these], and since you are going to have to modify the battery compartments anyway, making these fit won't be much harder than making the other ones you listed fit.

    These will give you 10,000mAh @ 300amps.
    Last edited by Revoš; 04-19-2009 at 06:09 PM.
    Project: BL Revo Race Quad & BL G-Maxx G3R CF Revo

  9. #9
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    Ah, I stand corrected then (sorry), clearly the BEC will work from much more than 2s... but as you ask: is 5s too much? Maybe ask Traxxas support?
    Time is an illusion, "9am sharp" doubly so.

  10. #10
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    Personally, I would stick to 4s lipos with the dewalt 12v. Another member on here tried to do that and he reported temps around 300 degrees. He said the motor held up well and part of the problem was because he was also running heavy 7.5in tires.

    The 18v is really too slow unless you plan on running 6s.

    Hope this helps.

  11. #11
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    Bluefisherking,
    No problem, I learnt much more from you than this one thing you just learned from me...
    If I'd ask Traxxas, won't they just say "The EVX2 is not designed for 5s and will not work. You will destroy it." Might as well give it a try and ask them ...

    Revo1,
    What mods are you talking about? Just removing the black springy thing that holds down the batteries, or something more drastic?
    And I didn't select those 5000mah batteries because of the price and because I was hoping not to have to mod the battery cases.
    (Price: I'm kind of on a budget here, I just bought the E revo. That's why I'm going for the Dewalt motors and not the MMM combo )

  12. #12
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    I've used many 5S set-up on the older evx , but they were all 2 pack set-ups. Apparently the evx-2 can use 4S on the bec side. I can try my evx-2 to see what the max voltage is.

    I test many of them very prcisely with a 24 volt power supply and it is very easy to see the max voltage. Most of the older ones were 22-24 volt max. I'm sorry I haven't tested any of the evx-2. After hearing of the many problems with 14 cells I'd imagine the same max voltage or even less.
    4s Pede, 6S Maxx, 3S Rusty, 6S slash

  13. #13
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    Hobbyguy,
    Is that other member you talk about bluefisherking? And those 300°, were those motor or ESC temps?
    Thanks for the remark the 18V Dewalt would be too slow using 5s lipo. (5s = 18,5V nominal)

    rupert,
    Could you please test what the max input voltage of the EVX2 is?
    And may I ask how exactly you tested those EVX ESCs.

    Bluefisherking,
    Are you sure the 12V motor and 14,4V motor are the same? If they weren't, the 14,4V dewalt motors combined with 5s lipo would be awesome! (IF the EVX2 can handle 5s to make the BEC 6V)

    Revo1,
    Mistercrash assured me that those *****'s (30mm high 3000mah 5S) will fit in the battery cases. Only the black springy thing has to be removed. But that's not a problem ...

  14. #14
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    Yes, that was me with the 300F! It was on the motor, and against all odds the motor seemed fine on the next run. By rights it should really have damaged the magnets but I couldn't dwtect a degradation in performance. It was brought about by running two sets of 5000 mAh (5s) back to back packs on quite tall gearing for those famous large wheels. As for the evx, it was hot but within reasonable operating temps, which is why I sayvthst I don't think you'll need a fan.

    As for the 12v and 14.4v motors being the same, I was quoting others on this forum who seemed pretty sure; When i asked at a local DeWalt centre they did confirm that they had different part numbers so thought that they would be different motors, but couldn't be sure...
    Time is an illusion, "9am sharp" doubly so.

  15. #15
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    You could probably run 5s if you use a 2s and a 3s like bluefisherking said but I have noticed that the evx2 blows at about 21.5-22+ volts so be careful with it and if you wanted to you could use a fan too to keep the temps down and to make it run better.
    Are you an RC addict?

  16. #16
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    Robot Marketplace said the motors were the same, so I would just go with the 12v motor since it is usually cheaper than the 14v. The motor can probably take those temperatures because it is just built way better than traditional rc motors. The 18v motor is slow(1100kv) so it would only be turning 20,350rpm at 18.5v, but you may be able to gear up because of the cooler temperatures and increased efficiency that comes with running higher voltages. At 14.8v, the 12v motor would be turning 24,420rpm.

    With proper gearing, you actually may be able to achieve a higher speed with the 18v on 5s than you could with a 12v on 4s. If you plan on upgrading to a 2-speed transmission for shifting on the fly, I would recommend sticking with the 12v on 4s so you do not have to modify the mount to accommodate the large pinion. With my 12v motor on 4s I use 27/54 for a 21/68 first gear. With this gearing it is just insane. It will do wheelies on demand(or flip the truck over if I am not careful) and the top speed is just insane for a brushed motor.

    Sorry for the long post.
    Hope this helps clear things up.

  17. #17
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    I will test one with a very precise power supply IF it acts like the originals did.
    4s Pede, 6S Maxx, 3S Rusty, 6S slash

  18. #18
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    Bluefisherking,
    Yes those Dewalts appear to be made with much higher quality standards than the Titans , 300F!

    pbmaxx64,
    Have you experienced that yourself? And by "blow" do you mean die?

    Rupert,
    Thanks, let us know the results
    Also, could you tell us the exact measuring method you use? I'm interested because I'm and electronics engineering student.

    Hobbyguy321,
    Why would you apologize for writing a good, long and helpfull reply? Thanks.
    Robotmarketplace says the Old style 12V and 14,4V motors are probably the same, not the new style! They mention nothing about any suspicion of the 12V and 14,4V motors being the same.
    Infact if you look at the weight of the motors in the specs, they're different:
    - 14,4V motor: 15.45 oz or 0.9656 Lbs
    - 12V motor: 18.2 oz (1.14lb)

    So I believe the new style dewalt 12V and 14,4V motors are infact different.

    But which one would be best suitable for my application, I'm not so sure of

    I think it's safe to say the 12V Motor is best for 4s Lipo, since the Dewalt motors are all about torque at relatively low speeds. Thus overvolting the 12V motor to 14,8V (23% overvolted) speeds it up enough.

    If we can use this same reasoning for the 14,4V motor at 5s lipo, the 14,4V motor would be overvolted to 18,5V (28% overvolted).
    Thus this would mean the 14,4V motor will be faster at 5s than the 12V motor at 4s. Right?
    And ofcourse 5s means more voltage, so less current draw for the same power. Less current means less loss (heat).


    Also you could note using the 12V motor at 5s would be even faster, but although the Dewalts are beasty, I don't believe it will survive long at 300F run after run... Even when it would be geared properly it would probably still reach 250F.
    Last edited by Rebelgium; 04-20-2009 at 06:06 PM.

  19. #19
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    I've been running mine with 3s and 2s with no problems.
    Rustler VXL Emaxx 3906 E-Revo Dewalt

  20. #20
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    Rebelgium-
    It sounds like you have it correct. Theoretically the 14v should spin faster on 5s than the 12v on 4s with similar heat and more torque. As for gearing I would start out with 19/68 and buy a few different spurs 54-65 for experimenting.

    This should be a nice reliable and powerful running setup once you get it all worked out. When your ready, you can get a 2-speed transmission to really take advantage of the power. The dewalt has great mid-high end power which makes it great for overdrive gearing. (my responses and badlands balloon like crazy once I hit second gear)

  21. #21
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    I have done some more searching and have come up with this:
    A site with a list of motor specs, the dewalt 14,4 and 18V motors are on it;
    http://www.slkelectronics.com/ecalc/motors.htm
    The results:
    MFR Description Kv Izero Rm GEAR M T/ COMMENTS
    (RPM/V) (A) (mohm) RATIO M P
    DeWalt 14.4V 1230 2.9 61 1.00 F - 16-21 cells
    DeWalt 18V 1130 2.6 72 1.00 F - 20-24 cells

    I'm not sure if these are the 396505-21 and 396505-22 Dewalt motors they're talking about, but the Kv rating seems legit.



    I found some info on the 14,4V Dewalt here:
    http://www.wa4dsy.net/robot/dewalt-drill-motor
    He claims the following:
    Kv forward: 1325 RPM per volt or 19080 rpm at 14.4 volts


    1325 RPM per volt, so at 18,5V it should be 24512 RPM.
    That's slightly faster than the 12V Dewalt at 4s. This means the top speed will be about the same or slightly better.

    But the higher efficiency of 5s vs 4s (higher voltage --> less current) means the truck will accelerate even faster (Right?)
    Because the 5s cells are able to deliver just as much current as the 4s cells (if I were to pick the same mah en C rated cells)

  22. #22
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    Hobbyguy,
    thanks for the advice on the gears, and the advice on the 2speed. I won't buy the 2speed just yet (student budget ), but I will buy it .
    What exactly is "overdrive gearing"? is it a synonym for tall gearing?


    Before I purchase this system, there is only one more darned question left to be answerred:
    Will the EVX2 be able to handle two 5s packs in parallel to make the BEC voltage?

    I hope Rupert will answer this . Also what the absolute max voltage is that the EVX2 can handle to make the BEC, because when freshly charged the voltage of 5s would be 21V!
    Last edited by Rebelgium; 04-20-2009 at 07:22 PM.

  23. #23
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    Quote Originally Posted by Rebelgium
    What exactly is "overdrive gearing"? is it a synonym for tall gearing?
    Basically, yes or more specifically gearing that is just tall enough to make your "low" first gear what second gear would have been normally... which means you then have second gear as an overdrive.

    (If you don't change the gearing, the two-speed keeps your stock gearing as second gear and just adds a low first gear... but if you like speed it is much more useful if you put in the overdrive gearing).
    Time is an illusion, "9am sharp" doubly so.

  24. #24
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    Rebelgium-
    Overdrive gearing is using tall gearing to make first gear what used to be the ratio of the single speed and leaving second gear for shifting on the fly to reach high speeds.

    You will need these items.

    this
    http://www3.towerhobbies.com/cgi-bin...&I=LXTG62&P=ML

    and this
    http://www3.towerhobbies.com/cgi-bin...?&I=LXVDW8&P=7

    It allows me to run 27/54 for an approximate 21/68 first gear and of course 27/54 second. This is great for the 12v on 4s, the motor only gets up to 130 degrees running in grass and 60 degree ambient temps. I have not tested it in higher temperatures.

    I do not think you can run 5s packs in parallel on the evx-2. I might have connected it the wrong way, but when I tried to connect a 9-cell nimh pack to one side smoke poured out of the evx and it just stopped working. It could have just been my esc though because the run before it kept shutting off while I was running 14-cell nimh.

    Hope this helps.

  25. #25
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    I tested my only evx-2 and it's max voltage is 22.4 volts.
    At 22.3 it is rock steady and at 22.5 is quite twitchy.

    I wouldn't be a bit afraid to run a 2S and a 3S on it all season and since the max voltage should really never be above 21 volts or so it should never give trouble.

    I'm not sure about running the 5S on the one connector , but that IS how I tested the max voltage and the steering servo worked fine on the bench. I imagine it would heat up quite more than running a 2S + 3S seperate packs. I also plugged in a 6S on the one side and the steer servo still worked fine.

    I wish I had more samples.
    4s Pede, 6S Maxx, 3S Rusty, 6S slash

  26. #26
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    Thanks for the info on the overdrive gearing.

    So the BEC stil works even with 6s (22,2V) on one connector! Cool. Now the question is how long it will work .

  27. #27
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    One thing going for you is that according to traxxas (above) a 4S can be used on one connector. The evx-1 never had that recommendation that I'm aware of.

    Just because it worked for me on the bench on 5 and 6S doesn't mean it will be reliable on 5S on the dirt with a good servo. I say go for the 5S and let us know. hehe.
    4s Pede, 6S Maxx, 3S Rusty, 6S slash

  28. #28
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    If the worst were to happen, and the internal BEC in the EVX2 would die, would I be able to use an external BEC and just keep using the EVX2?
    Afterall, frying the BEC does not affect the MOSFET H-bridge, so it should be able to run the motors. If an external 6V would be supplied to the EVX2.

    Right?

  29. #29
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    I just started this topic to help me with some questions I had about using an external BEC:
    http://monster.traxxas.com/showthrea...69#post3935369

    While thinking about it I drew the electrical schematic of the EVX2, and came up with an idea.
    I searched the E REvo E maxx and summit forum (they all use the EVX2) and it seems to be possible!
    Here goes:



    I'd use the two 5s packs in parallel, and connect them to the BEC side of the EVX-2. The non-BEC side would be shorted with a jumper.
    This would provide the EVX2 with 5s power, and (as rupert has measured) let the BEC make 6V succesfully.

    Now the question was: "Sure the BEC works on the testbench, but will it continue to work under heavy load? (While racing in mud etc. , thus using the steering servo's alot)

    I'd use an external BEC to power the Receiver and steering servo's. And I would disconnect the 6V wire coming from the EVX2 to the Receiver. (This wire provides the BEC 6V voltage to the receiver and servo's)

    This way the internal BEC will only have to power the EVX2 logics, and not the receiver and servo's.
    That will probably keep the internal BEC unstressed.


    Now some questions I have:
    Would this truly keep the internal BEC unstressed enough to run long runs over and over on 5s?
    Rupert, could you test this? For example by powering the EVX2 with a 5s lipo for a long time, and see if it will hold all this time?

    And what would the rated current of the external BEC have to be? Howmuch current (peak and max current) do the servo's and receiver need?

  30. #30
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    I just received today 2 ***** 5S 20C Lipos from Hobby King, 5 days from purchase to delivery in Scotland from Hong Kong is pretty impressive. As I have the setup you are thinking of running - 14V DeWalt motor and stock EVX2, I thought that in the interests of science I'd give them a run or two with the DeWalt motor before installing MMM combo which is sitting on my workbench awaiting the arrival of Spectrum 2.4GHz .

    Battery connectors changed to TRX type and lipos balanced/charged. All 10 cells were 3.85 or 3.86 volts as delivered before charging, I mention that because I have heard of some Zippies being way out of balance when new, no problems with these.

    First, the batteries are a tight squeeze in the compartments but after removing spring clips at the top and the 2 retainer tabs , they were in and the doors closed - just. The power cables need a bit of persuading into shape to come out of the slots, maybe need a bit of a mod to the compartment door to make this easier.

    Parallel harness and jumper connected, it's time for a trial run in the garden. After a bit of a careful warm up to make sure nothing was going to smoke, everything was fine. The extra voltage sure makes a big difference to the power of the DeWalt - flipped straight on its lid from standstill on paved area with good traction, not that I condone that sort of behavior . Torque and top speed were also much improved over 4S setup.

    After 15 minutes of driving I thought I'd check on temperatures and, in the absence of a 5S LVC, the battery voltage. Motor was pretty hot compared to running 4S, sorry I don't have temperature reading , no temp gun yet. ESC was a good bit hotter than on 4S as well. Lipo voltage still at 20.1V, no problems there. Ran for another 10 minutes and thought it safer for lipos to call a halt and recharge. My gearing was 20/68 as it has been for running 4S.

    So far, so good. I was very impressed with the performance increase, if it could run reliably on 5S it would be an ideal waterproof alternative to going brushless. The biggest concern was how hot the DeWalt motor and EVX2 were but without a temp gun I can't be sure it was anything to be too worried about.I'll try another run once my temp gun arrives.
    Also, I couldn't find a 5S LVC or even a 5S low voltage warning led, which is all I use for my 4S setup, just something else to consider if you go for this.

    So, it's all down to how reliable this setup is, I might just postpone my MMM install to see how it holds up, I suspect it's on the limit of what both motor and EVX2 can handle and it will run hot or overheat.

  31. #31
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    Thanks very much MonkeyMagic!
    Anything for science right


    The 4s setup you mentioned you used earlier, is that 4s with the 14,4V Dewalt motor? Or 4s with a Dewalt 12V motor?


    Is the Dewalt you have the 14,4V new style motor, or old style motor?


    I found these Low voltage warning buzzers on *********, one of which is adjustable from 2s to 6s:
    http://www.*********.com/*********/s...idProduct=8927
    http://www.*********.com/*********/s...idProduct=7226
    I would order the adjustable one.


    About the temps, I'd be surprised if the Dewalts were running too hot, it is being overvolted only a few percent more compared to the proven 4s-12V-dewal-motor-setup.

    The EVX2 running hot was my first suspicion when I first had this idea to,
    but some people here are running 5s setups on their EVX2 , but in a 2s +3s setup.
    So either the 14,4V Dewalt demands more current than those people's motors, or the internal BEC is causing the increase in heat.



    I'm really looking forward to the results of your test run when you have your temp gun

    Please run some more tests while you're waiting for it to arrive, and see if the results are the same as this run.
    Also, can you hold your hand on the EVX2 just after running hard? Or is it too hit to touch?
    Same question about the motor.


    Maybe you should try running with a small fan, which is pointed at both the EVX2 and the motor, just to improve airflow a bit. And then see if the temps are better.

  32. #32
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    Quote Originally Posted by Rebelgium
    Thanks very much MonkeyMagic!
    Anything for science right


    The 4s setup you mentioned you used earlier, is that 4s with the 14,4V Dewalt motor? Or 4s with a Dewalt 12V motor?


    Is the Dewalt you have the 14,4V new style motor, or old style motor?


    I found these Low voltage warning buzzers on *********, one of which is adjustable from 2s to 6s:
    http://www.*********.com/*********/s...idProduct=8927
    http://www.*********.com/*********/s...idProduct=7226
    I would order the adjustable one.


    About the temps, I'd be surprised if the Dewalts were running too hot, it is being overvolted only a few percent more compared to the proven 4s-12V-dewal-motor-setup.

    The EVX2 running hot was my first suspicion when I first had this idea to,
    but some people here are running 5s setups on their EVX2 , but in a 2s +3s setup.
    So either the 14,4V Dewalt demands more current than those people's motors, or the internal BEC is causing the increase in heat.



    I'm really looking forward to the results of your test run when you have your temp gun

    Please run some more tests while you're waiting for it to arrive, and see if the results are the same as this run.
    Also, can you hold your hand on the EVX2 just after running hard? Or is it too hit to touch?
    Same question about the motor.


    Maybe you should try running with a small fan, which is pointed at both the EVX2 and the motor, just to improve airflow a bit. And then see if the temps are better.

    I was running 4S with 14V DeWalt new style motor previously with no problems. I haven't tried the 12V as I believed they were the same as 14V motor.

    Good find on the low voltage warning buzzer, wish I'd seen those when I was ordering *****s last week. I'll add one to my next lipo order once I decide if I want to buy more 4S or 5S to power MMM combo.

    Temperatures- after another run of 20 minutes De Walt is just about too hot to touch, EVX is hot but not too hot to touch. EVX cut the power a couple of times near the end of the run so I assume something was getting hot internally and locking it out, just for 5 seconds or so then reset itself - this never happens running 4S.This is all just blasting around the garden , no high speed runs.

    I'll maybe get a fan to see if it helps but until I get some sort of warning indicator for 5S lipo I won't be able to do a long enough bashing session to see how the motor and ESC hold up to full torture test at the local sand pit/track.

    I'll keep you posted - I may have to give the MMM a try first to get my lipo setup sorted out.

  33. #33
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    Why not go the 2s 3s in series? Buying the 5000mah *****s would cost $72 and be a total weight of 648g. The parallel 5s weigh 786g and cost $85. Running the bec on 2s would definately help with temps, and may eliminate the thermaling all together. Personally I think lower temps outweighs the extra 1000mah.

  34. #34
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    Quote Originally Posted by Zachandandy
    Why not go the 2s 3s in series? Buying the 5000mah *****s would cost $72 and be a total weight of 648g. The parallel 5s weigh 786g and cost $85. Running the bec on 2s would definately help with temps, and may eliminate the thermaling all together. Personally I think lower temps outweighs the extra 1000mah.
    Yes, I think that's a good idea for running stock ESC + DeWalt motor, running 2S+3S in series would be better for the BEC. I bought the 5S to try with MMM combo not really with the intention of hooking up EVX2 to them, curiosity just got the better of me when Rebelgium was asking if it would work.

    I was originally going to get 2 sets of 2S and 3S 5000mAh 25C Zippies to allow a flexible 4,5 or 6S setup for MMM and keeping the amps above 120A but couldn't see the 2S listed at *********. 5000mAh 20C versions are out of stock too and if I wasn't going brushless this would probably be the way to go - I think 100A might not be enough for brushless setup.

    After running the DeWalt on 5S I think I may now have to try and get a 2+3S series setup that works with MMM , 120Amps+ and also lets me run the DeWalt in winter on 5S.

  35. #35
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    There are two options to have the 5s 14,4V Dewalt combo:
    - 2s 5000 20C + 3s 5000 20C *****'s
    = 5000mah and 100A continuous 71$

    or

    - two 5s 3000 20c *****'s in parallel
    = 6000mah and 120A continuous 85$


    The second option is better, the *****'s are good enough to go brushless in the future, and the weight is balanced better than the first option.

    But the problem is, the second option causes the EVX2 to thermal...
    This is probably caused by the internal BEC of the EVX2 overheating because of the high voltage it has to convert.

    If this was a liniar voltage regulator I'd be sure that is the problem causing the thermalling. But I don't know if the internal BEC is a liniar regulator or a switching regulator. (I can't seem to find this info either...)

    This problem could be solved by using an external BEC. (that's another 8$ or 20$ depending on howmuch current the servo's need. I'm trying to find out this info to)



    So the question is:
    Is the 1000mah and 20A continuous more worth the 14$+(8$ or 20$) ?

    I'd say yes IF I was sure this would solve the thermalling problem. But I'm not.

  36. #36
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    I'm pretty sre the BEC is linear in the EVX2.
    Quite a few people have had problems trying to run the BEC on a 3S lipo, so I'd say that a 5S lipo into the BEC will definitely shut it down.
    I'm not sure 5S would also shut it down with an external BEC or not I guess if it did, you could always go brushless, then any packs you picked would work with the mamba monster

  37. #37
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    I would go with the 2s+3s and get 2 sets, as this allows many more options than the 5s. You could run 3s in parallel(maybe you have a kid or little brother), 4s, 5s, or 6s(not on the evx). Slightly less cost but many more options.

  38. #38
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    MonkeyMagic,
    To be sure the overheating problem is caused by the internal BEC, you'd have to try using an external BEC. If the overheating would stop by using an external BEC it would mean the internal BEC is most probably a linear BEC (not as good as a switching BEC, linear wastes power)

    And it would mean it is not the combo of those awesome batteries and awesome moter that is causing the EVX2 to overheat.


    Do you have an external BEC? The one from ********* for 8$ is ideal.

  39. #39
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    Well, partly as a result of this thread I bought a pair of those 3000mAh 5s 20 lipos. I already have a pair of 2s and a pair of 3s, and I wanted another set that would work in both the E-Revo and the Savage Flux... anyway, just thought you'd like to know that the lipos do fit in the compartments, but you can't shut the doors:






    (I have taken the doors off in those pictures)

    You can see how fat they are in comparison to the "normal" 5000mAh 3s 20C-30C ***** lipos in this pic:




    On the up side, one of the reasons that I bought them is that I thought the extra 120A continuous current might be useful (as well as the extra runtime, of course), and in fact I think it does make a difference. First the truck feels just a bit torquier, and the motor temps have gone up from 140F to about 170F after a hard run. The ESC and batts were the same as normal, at around 110F.

    (Note I am using a Neu/MMM here, not the DeWalt.)
    Last edited by bluefisherking; 04-28-2009 at 07:36 PM.
    Time is an illusion, "9am sharp" doubly so.

  40. #40
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    Quote Originally Posted by bluefisherking
    Well, partly as a result of this thread I bought a pair of those 3000mAh 5s 20 lipos. I already have a pair of 2s and a pair of 3s, and I wanted another set that would work in both the E-Revo and the Savage Flux... anyway, just thought you'd like to know that the lipos do fit in the compartments, but you can't shut the doors:


    You can see how fat they are in comparison to the "normal" 5000mAh 3s 20C-30C ***** lipos in this pic:



    On the up side, one of the reasons that I bought them is that I thought the extra 120A continuous current might be useful (as well as the extra runtime, of course), and in fact I think it does make a difference. First the truck feels just a bit torquier, and the motor temps have gone up from 140F to about 170F after a hard run. The ESC and batts were the same as normal, at around 110F.

    (Note I am using a Neu/MMM here, not the DeWalt.)
    I've got the 5S Zippies and although they were a tight squeeze, once I had removed the plastic battery retainer clips from the batt compartment the doors close - just.It's tight around the wires where the leads come out but I'm going to file out a bit of the corner of the door to give them a bit more room.
    It looks like from your last pic you have already taken the tabs out so there might be a difference in size with some Zippies.Mine are 46mm at the fattest end of the battery, 50mm wide with the wire included. Or maybe just an issue with the way the leads come out of the shrink wrap.

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