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  1. #1
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    Batteries blown up, need LiPo experts (many pics)















    Gentlemen... ladies (if there are any female E-Revo drivers out there).

    Here's the story in a short haul. My E-Revo began with all stock parts, and Nimh VENOM 5000 batteries. I ran the REVO on stock for about 23 runs until I made the change to twin VXL. The stock speed was clocked at 28 MPH, the brushless Twin VXL brought it up to 33 MPH. The reason for the 33 MPH speed was because I was still running the 5000 NIMH batteries.

    Today, I drove the Revo with it's new brushless setup on a construction site. My mistake was running it after the Revo AND it's two Venom 5000 NIMH batteries have bin cooking in the back of my truck. I believe when I started the run, the batteries were at 90* F already. After a 10 minute run time I drove it in to diconnect the batteries.

    The two Nimhs were FRIED. The black shrink wrap had shred to pieces due to the high temperatures. Temps of the batteries were at 279* F. Normally they would be at 168* F.

    My mistake for running them at such hot temperatures. My LHS experts have done this before, they told me they should have bin at room temperature before running.

    The batteries have been recycled, I now own two VENOM 3s LiPo packs.
    As you can see in the images, I bought the whole "sha-bang." Total of $550 after Tax.

    Gentlemen... My wallet hurts.

    Now heres my problem, and I'm hoping that some of you drivers reading this have ran into the same problem in hopes you know how to get around it.

    The Venom LiPo packs I bought as you can see in the pic does not fit well in the E-Revo's battery bays. As you can see in one of the pics, I did remove the plastic tension spring from the bay. I did manage to squeeze one pack in, but getting it out was like yanking a cop away from a donut shop. I couldn't even close the door.

    I look to the professionals who have much more experience in LiPo and Brushless systems than me.

    How do I get these batteries in the bay, or are they not meant for the E-Revo due to their size?

    Does the VXL system have a good LiPo voltage cut-off? I read that it does have one, but what I'm asking is... "Is it idiot proof?" Cause guess which idiot fried his 5000 Nimh batteries from leaving the Revo in the back of a HOT truck. If I drive the E-Revo now with Lipo, will the VXL system cut off before I could do further damage to the battery packs?

    SquaredVXL, I hope you're reading this, or Muttman. SquaredVXL, you've gone down this path long before I have, I am merely inspired by what you have already done to yours.

    Thank you in advance everyone.

    P.S. I'm running 22 pinions on both motors,
    Last edited by DockBrown88MPH; 07-12-2008 at 12:14 AM.
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  2. #2
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    The ESC's have the LIPO cutoff activated from the factory.. Just make sure you have it activated. If the lights are green once on then they are activated and you are good to go and it will auto sense if you have 2 or 3 cell lipos. If the lights are red then that means you have lipo safe turned off.

    As for those batteries I cant comment on them as I do not know their size nor cable orientation. All I can say is squeeze them in there if you can and if not then you have to swap them out for something smaller. Hope that helps a bit. Best of luck and congrats on a really neat truck! i like your heatsinks better than mine! Who makes those?
    E-Slayer (Tekno/Neu) / E-Platinum Revo (Tekno/Neu)

  3. #3
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    Also if at all possible try and trade those Lipos in for another brand... I've heard a few horror stories about them. I don't have first hand experience so I don't take everything I read as fact. But I have heard enough bad about them that I personally wouldn't run them. Just an FYI.
    E-Slayer (Tekno/Neu) / E-Platinum Revo (Tekno/Neu)

  4. #4
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    1. Vxl system is totally tard proof, it auto senses how many lipo cells and auto sets the LVC accordingly, it works well. Just make sure that the light is green when you turn on the esc, that indicates lipo mode.

    2.) the venom packs are 5400, taller than say MaxAmps 5000s by a few MM's. The venoms just barely fit in the emaxx with extended battery hold downs, if you can get them in the erevo im surprised, just make sure they dont get too hot being crammed in there.


    edit: or what he said LOL

  5. #5
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    Quote Originally Posted by vxlsquared
    The ESC's have the LIPO cutoff activated from the factory.. Just make sure you have it activated. If the lights are green once on then they are activated and you are good to go and it will auto sense if you have 2 or 3 cell lipos. If the lights are red then that means you have lipo safe turned off.

    As for those batteries I cant comment on them as I do not know their size nor cable orientation. All I can say is squeeze them in there if you can and if not then you have to swap them out for something smaller. Hope that helps a bit. Best of luck and congrats on a really neat truck! i like your heatsinks better than mine! Who makes those?
    VXLsquared, sorry to break the bubble, but I don't know what brand these heat syncs are O_o. I just bought what fit. Honestly, I like the heat syncs on yours and Muttman's more. They're heat syncs that say "you're only going to see us in your rear view mirror for a split second."

    I'll take your word for it... I'm gonna return these Venom's tomorrow and pick up Maxamps if available.

    Thanks for the advice. I come from R/C planes, and Heli's. I'm honestly walking blind in Traxxas Revo territory. It's a surprise that I even managed to install all of this just by reading and looking and what you've done to yours.
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  6. #6
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    Quote Originally Posted by DockBrown88MPH
    VXLsquared, sorry to break the bubble, but I don't know what brand these heat syncs are O_o. I just bought what fit. Honestly, I like the heat syncs on yours and Muttman's more. They're heat syncs that say "you're only going to see us in your rear view mirror for a split second."

    I'll take your word for it... I'm gonna return these Venom's tomorrow and pick up Maxamps if available.

    Thanks for the advice. I come from R/C planes, and Heli's. I'm honestly walking blind in Traxxas Revo territory. It's a surprise that I even managed to install all of this just by reading and looking and what you've done to yours.
    I appreciate the kind words... I'm glad my information was put to good use. lol.

    Good luck with it and let us know what you clock yours at once you get the lipo situation sorted out.

    P.S- If you are into flying I'm sure you are familiar with ***** lipos. I suggest getting some of them if you want to save a little money. They are great lipos but the only problem is the wait. Make sure you get the ***** R's. The MAH is not that great but the discharge rates are pretty good.
    E-Slayer (Tekno/Neu) / E-Platinum Revo (Tekno/Neu)

  7. #7
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    1st Starting with nihms at that temp is totally acceptable.Most perform the best right off the charger and prewarmed.They just could not handle the power. 2nd While the VXL lvc is idiot proof if you ever notice a drop of performance with lipos,it's time to stop driving. 3rd.If your wallet hurts MA are not going to make it feel better.There are lots of similar performing lipos for the money. These will do fine at half the cost . http://www.spcracing.com/index.php?productID=60
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  8. #8
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    My buddy just got the 3 cell SPCRacing.com lipos for his V-Twin Emaxx and couldn't be happier. The batteries never get more than a few degrees above outside temperature (been in the 90's here too). Great cells and the price can't be beat!

  9. #9
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    The venom 3s lipos are decent but if they don't fit then they're no good for your application.
    Get your vote on.

  10. #10
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    Quote Originally Posted by asheck
    1st Starting with nihms at that temp is totally acceptable.Most perform the best right off the charger and prewarmed.They just could not handle the power. 2nd While the VXL lvc is idiot proof if you ever notice a drop of performance with lipos,it's time to stop driving. 3rd.If your wallet hurts MA are not going to make it feel better.There are lots of similar performing lipos for the money. These will do fine at half the cost . http://www.spcracing.com/index.php?productID=60

    I'm all new to this as you know. Thanks for replying. So, correct me if I'm wrong. If I had ran my E-Revo with all stock parts in the SAME condition at 90* F to start with, my Nimh batteries would not have blown? So is it because Twin VXL just needs more power to withdraw from the battery?

    I'm a bit confused, because, the VXL system is capable of running Nimh and LiPo. Would that mean running Nimh batteries on them all explode?

    If running them at 90* F strait off was perfectly ok, what would cause them to heat up at such high temperatures and blow up like that?

    Thanks a lot everyone, and kudos for the website. I might consider those if my LHS doesn't carry Maxamps.
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  11. #11
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    All these things depend on how you drive and the quality of cells.If you run wot for 10 minutes in a brushless using a lower quality nihm then the fact that they were fried is not surprising.A quality nihm pack that is made in side by side construction will do fine.A word of advice.Whenever your running a new battery,esc, motor,gearing or setup,try checking temps every couple minutes till you know how it will react.
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  12. #12
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    Nimhs just plain and simple arent the best choice for a BL powere MT- too much current draw which reuslts in hot batts. They work obviously, but the speeds and temps you recorded are a clear indication of how well... or not, lol. 90*f starting temp isnt too excessive really, since lipos themsleves do better if they are warmer to start with, just seems that the case of toasty venom nimhs strikes again....
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    you guys are extremely helpful. I just got home from my LHS. Go figure, they don't have MaxAmps cause they don't make a profit off them... weak...

    Well, I had to settle for less since my returns were only valid for in store credit. Ascheck recommended a good set of LiPos online for nearly half the price. I'm going to buy those as a 2nd spare since you guys have heard or has good experience with them.

    So what I got now are twin 7.4V 5000 MAH Lipos by Venom. I know, I know... it's on the weak side.

    I'm currently charging the first one with my Triton 2 and Equinox balancer. Tell me if I'm doing this right, cause I sat down to read the manuals on the charger and balancer.

    I set the Triton 2 to 5000 mah, and to LiPo. Connected to the charger is the Equinox. I set it to Interface Mode, and it recognizes the battery as 2 cell. So I'm assuming it's balancing the charge for both cells. Cell 1 LED's seems to be lit more often so I'm assuming Cell 1 is a bit off balance.

    So, do LiPo batteries have memory? and... do I have to discharge Lipo's to 3.0V per cell? Because that is an option on the charger, and I'm wondering if the care of LiPo batteries require discharging to that voltage everytime I'm done with the batteries. What would happen if I don't discharge them and just charge them after I'm done with each run?

    My charger currently says it's charging at 1.0 Amps. Is that right? cause the battery label on the back says "Charge Rate: 5 Amps (1C).

    How long do these LiPo batteries take to charge? Better yet, what kind of batteries do you guys have, and how long does it take for you to charge it?

    sorry for so many questions, I'm all so new to this level.

    Thank you so much for all of your help. I'll start a new thread with videos, pics, temp, and speed data if all of this modding and upgrading comes to a success.
    Last edited by DockBrown88MPH; 07-12-2008 at 03:41 PM.
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  14. #14
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    You are only supposed to charge at 3 amps through the equinox,unless you have the special adapter.I just balance them and then charge them.You do not need to discharge them.When charging a lipo will you will get a cc/cv charge.Which means at first your amps will stay steady up to 8.4 volts,then the voltage stays there and the amps start to drop,till full charge is reached.The first few cycles might seem a little weak,or charge weird ,but after a few cycles they should even out and perform better.
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  15. #15
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    Ideally you will recharge lipos after a run, otherwise they may be left a rather low voltaage that is only going to gradually get lower (self-discharging). If you plan on using them again with in a short time, fully charge them, otherwise you can put a storage charge into them (50-75% capacity). Charge time depends on the mah of the battery, and power out put of the charger; if you can charge at 1c, that will mean a 1hour charge time. I have more info about kinda stuff in my FAQ (battery section).
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  16. #16
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    Quote Originally Posted by asheck
    You are only supposed to charge at 3 amps through the equinox,unless you have the special adapter.I just balance them and then charge them.You do not need to discharge them.When charging a lipo will you will get a cc/cv charge.Which means at first your amps will stay steady up to 8.4 volts,then the voltage stays there and the amps start to drop,till full charge is reached.The first few cycles might seem a little weak,or charge weird ,but after a few cycles they should even out and perform better.

    Yeah, I'm starting to see that. The batteries begin to charge at 5 Amps, and then rapidly starts dropping down to 1.0 then 0.5. I'm guessing although is says its charging at 5.0 Amps at the start, the Equinox is only pumping out 3.0 Amps of juice.

    Thanks Ascheck.

    My first E-Revo run with BL and now LiPo soon to come when 2nd battery is finished. I'll def post vid here of what kind of power this think will be getting.
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    If I can get at least 15 minute run time off these, I'll be satisfied for the time being. The stir fried Venom 5000 Nimhs I had gave me only 10-12 minutes run time, and 33 MPH.
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  18. #18
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    Ascheck.
    Asheck I would think you'll be happier then with the nihms.
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  19. #19
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    Just one comment here.. the spc batts are rated at 12c where the venoms are rated at 20c... will there be any loss in performance with the lower "c" rating? I have the 4K venom packs for my v-twin revo and so far they have run quite well.. but we'll see.

  20. #20
    RC Turnbuckle Jr. asheck's Avatar
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    There shouldn't be.The chances of The Venoms being accurately rated are slim to none.Where as the Spc's are.I would bet the Venoms would test right around the 12c mark also.
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  21. #21
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    12c x 5000mah = 60amps, 20c x 4000mah = 80amps. There is a noticeable difference, but a 6s lipo system with a slower motor will pull less amps than a 4s lipo system with a faster motor. If the same motor were used in both cases, you'd probably see higher current draw still. That said, the venom's 20c rating seems a little optomistic posibly, and the 12c rating of the SPC seems a little low maybe.... You'll soon see whats what.
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  22. #22
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    Its like magic...
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  23. #23
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    I'm back... from my first run... and I must say... I'm out of energy

    Gentlemen... I will NEVER put another Nimh battery in my E-revo EVER AGAIN~!

    Hahahaha, wheelies... hahahaha, oh wow... these batteries were just so cheap, I thought they would perform no better than my Nimn 5000 Venom's, but no... I was beyond wrong. I pushed the throttle, and I can't do it without popping a wheelie!!! I managed to document the 2nd run after taking a break. I didn't clock the run time, but no doubt, it was LONGER than I expected.

    I couldn't get an accurate run time. I followed the tip to constantly check the temp on these babies. These batteries spiked no higher than 120* F. I'm here in 90* F weather.

    I did a voltage check the MOMENT I notice a performance drop. The moment I couldnt pop a wheelie on full throttle I stopped. I checked the battery voltage on both. One was at 6.7v, the other was around 7.5v When I began they were at 8.4v.

    I broke a ESC fan cause I was driving without the lid

    So what's the safety zone on these batteries? How hot is too hot?

    Seems that the reverse motor is working less harder than the forward turn motor. I'm assuming this base on the higher temps of the forward turn motor and battery. Is this ok, or do I need to lower the motor?



    How am I doing guys?

    I'll post vids, run times, and more photos of this beast tonight.
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  24. #24
    RC Turnbuckle Jr. asheck's Avatar
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    Cool man,lipos compared to cheap nihms are a big jump.I always keep my lipos under 120.But with my 8000mah packs they rarely go 10 degrees hotter then it is outside.It sounds to me like you might need to adjust a pinion gear mesh,and that could explain 1 motor hotter then the other.
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  25. #25
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    Good good. Lipo temps should be no more than about 120-125*f I believe, so you are fine there. I havent watched the vid yet, but did you make yourself an UNLSOW harness for the lipos? Im guessing not, so that would explain the uneven temps and battery voltages. Since you stopped running before the LVC kicked in you are fine, but if you use the harness you will find your batts stay more even, and the motors should run at a more even temp too. Simple to make, see my FAQ for details.

    Glad you had a good time- even with cheaper or lower spec lipos they will blow nimhs out of the water.
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  26. #26
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    Quote Originally Posted by Suicideneil
    Good good. Lipo temps should be no more than about 120-125*f I believe, so you are fine there. I havent watched the vid yet, but did you make yourself an UNLSOW harness for the lipos? Im guessing not, so that would explain the uneven temps and battery voltages. Since you stopped running before the LVC kicked in you are fine, but if you use the harness you will find your batts stay more even, and the motors should run at a more even temp too. Simple to make, see my FAQ for details.

    Glad you had a good time- even with cheaper or lower spec lipos they will blow nimhs out of the water.
    man, no kidding... I ain't going back to Nimh with this thing. So what does that harness do exactly? Can you post a direct link to your FAQ on how to do it? Can I just buy a harness instead of making one? call me lazy...
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  27. #27
    RC Turnbuckle Jr. asheck's Avatar
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    even with cheaper or lower spec lipos they will blow nimhs out of the water
    I have to say that my SPC 6cell sport packs are just as good as my 4000 25c hecell.They get about the same runtime and everything.I had said I would never buy nihms again,but decided to try them after all the rave reviews.They lived up to the hype,and will do over a 70amp discharge.
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  28. #28
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    Ok, camera's out of batteries, and vid camera is toast from doing a barrel roll with my Revo (accident).

    Run-time was def longer. My stop watch was acting up, chalk it up to back luck, but I estimate it would be around 15-20 mins.

    This is weird... now, when I had driven brushless with 7c Venom 5000 batteries, I was clocking 32 MPH. After I switched to LiPo, I clocked the speed at a max 33 MPH... I thought my GPS was broken, that maybe it only goes up to 33 MPH. I drove home at 55 MPH and it read it just fine.

    This is weird. I was never able to accelerate so quickly before. I was never able to pop a wheelie so easily, but it's still clocking at 33 MPH.

    My pinions on the shaft of each VXL motor is 22. If I drop back to the 19 stock pinions, will the speed increase or decrease. Will the run-time, increase or decrease? I keep hearing driver's who have done a similar setup clock in around 40-45. Maybe it's because they are using better batteries than I am.
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  29. #29
    RC Turnbuckle Jr. asheck's Avatar
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    Well a 7cell nihm should be close to 1 volt above the lipo.Volts are what gives you speed,amps give you acceleration. (way simplified)So the added amps of the lipos are giving you much better punch and acceleration,yet the overall voltage ends up close to the 7 cells.If your temps are all good,you can gear up some.
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  30. #30
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    http://monster.traxxas.com/showthread.php?t=423790

    Scroll down to section 14. You cant buy one saddly, but Wade7575 can build you one for a small fee.

    I dunno, my nimhs are lame compared to even my cheap lipos, but I suppose good nimhs will work alot better. That said, for $140+ I can have 12 A123 cells for a 6s2p setup, so.... personal preference I guess.
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