Results 1 to 13 of 13
  1. #1
    RC Competitor
    Join Date
    Oct 2011
    Posts
    54

    Nimh gets too hot after run, 190'F

    I am using Slash 4x4 on stock 7 cell nimh battery with 18/54 gearing.
    After each run, the temperature of battery would be around 190'F. I can not even hold my battery at this hot.
    Is it too hot for the nimh battery? Is there any dangerous when the battery is too hot like that?

  2. #2
    RC Qualifier
    Join Date
    Sep 2011
    Location
    Earth, Milky Way.
    Posts
    926
    This is my opinion: Buy a LiPo!
    This is a signature.

  3. #3
    RC Champion
    Join Date
    Feb 2011
    Location
    UK
    Posts
    1,936
    now in my rustler that battery got as hot as 180F and it's not good and one of the solutions is to get a lipo but if that's out of your budget or you're not prepared charger and safety wise just drop around 6t on the pinion and it will run cooler
    Does more $ = More fun?
    Rustler VXL

  4. #4
    RC Enthusiast
    Join Date
    Nov 2011
    Location
    Englewood, FL
    Posts
    39
    Yes that is dangerously hot ! You may have damaged it already. Try gearing a few teeth down on your pinion gear, and that will likely lower your temps. Read your manual carefully, the info you need is in there. Toasty warm is fine, but if the pack is burning hot stop your run and let it cool down !!
    3905 Emaxx

  5. #5
    RC Racer
    Join Date
    Aug 2011
    Location
    spruce grove alberta
    Posts
    131
    Ya thats pushin it for sure. Thats why i run lipos haha. Its really a great solution!
    1/16 summit vxl/Slayer3.3/T-maxx2.5/HPI savage.28

  6. #6
    Marshal ksb51rl's Avatar
    Join Date
    Nov 2006
    Location
    Northern NJ
    Posts
    15,125
    Quote Originally Posted by Liam1234 View Post
    I am using Slash 4x4 on stock 7 cell nimh battery with 18/54 gearing.
    After each run, the temperature of battery would be around 190'F. I can not even hold my battery at this hot.
    Is it too hot for the nimh battery? Is there any dangerous when the battery is too hot like that?
    Quote Originally Posted by http://traxxas.com/support/Motor-and-battery-pack-gets-hot-after-every-run
    Motor and battery pack gets hot after every run
    Article #10155

    The motor or battery should not become too hot to touch. Inspect the following to help determine the cause.

    Motor is dirty or damaged
    Give the motor a thorough cleaning and then install it back on the motor mount.

    Drive train is binding
    Remove the motor's pinion gear and roll the vehicle on a flat surface to check the drive train for binding.

    Hot electronics
    Let model cool down between runs.

    Model is overgeared
    Re-gear the model with a lower tooth pinion gear to lessen the load on the motor.


    Recommended reading
    Re-oiling the motor Bushings
    140F is not too comfortable. 190F is damaging.
    Alt-241 on the number pad =

  7. #7
    RC Racer
    Join Date
    Oct 2010
    Location
    Southeastern US
    Posts
    177
    160F is the safe max on nimh,are you running the battery right off the charger? If so what is the very ending temp after charge? Do you run the truck until it depletes the battery? Safe range coming off charger is 115-125F,I like about 115F if any highter you need to adjust your delta peak if you have the option on your charger,I tend to let my battery cool for 30 minutes before running depending on the outdoor temps,it will get hotter for a few minutes after charge completes.If you run your truck until it just creeps it will cause the battery to become very hot and will cause cell reversal "damage",when my truck gets to about 1/2 power I stop,pull the battery let it cool for about a hour and recharge

  8. #8
    RC Racer
    Join Date
    Oct 2010
    Location
    Southeastern US
    Posts
    177
    Note the 160F is the very max temp the nimh can handle before damage can occur,below 140F is the max I'd want to see at the end of running my trucks. I'm not up to par on Slash gearing so I cannot say you are geared correct for your driving habits.190 is way too hot though.Any mechanical binding down to gear mesh can cause over heating of the battery

  9. #9
    RC Racer
    Join Date
    Jan 2006
    Location
    Sydney, Australia
    Posts
    189
    2 day old 8.4v 3000mah Traxxas NiMH charged at 3A that came with my Rustler VXL hit 180f today after running on very short grass. I guess it is a big ask for a NiMH to keep the supply up to the brushless motor..

  10. #10
    RC Enthusiast
    Join Date
    Nov 2011
    Location
    Englewood, FL
    Posts
    39
    Running on grass is REALLY hard on the electronics. Drop your pinion gear by a few teeth, and go easy on punching the throttle in the grass. Try to get onto some pavement and let it zip around to help cool off. Check the temp every few minutes to see when during the run it is getting that hot, then you can give it a short break to prevent. Ideally you could also boost your NiMH to the larger capacity 4-5,000mAh packs.... that may help too. Study the chart too.



    Try a 25 tooth pinion gear, that's the $5 short term solution to extract the most effecient power from a 7 cell 3k mAh pack... IMHO.
    3905 Emaxx

  11. #11
    RC Turnbuckle Jr. mike-susieq1's Avatar
    Join Date
    Nov 2010
    Location
    California
    Posts
    4,825
    no matter what nimh and brushless power will most if not all the time will get very hot above 140F and with brushed it wont be so bad but if your over geared it will do it as well just more with brushless since they drain the pack so much and demand the amps very quickly.
    Gear down and let it cool after say 10mins of running maybe even 5-8mins of running say let it cool for like 5mins then run again but your best bet is upgrade to Lipos and you wont have that issue and you will enjoy the increase performance and runtime and your motor/esc will like it better too and its lighter as well.
    You might want to also cut some holes out where the battery is to cool it off a little better this helps.
    worse case strap a light ice pack to the battery haha J/K.
    DEU 8:18 ESV

  12. #12
    RC Enthusiast
    Join Date
    Nov 2011
    Location
    Englewood, FL
    Posts
    39
    If I was TRX ...which I'm not... lol.... I would gear all the models LOW, and state in the manual that it is geared low and slower for new users, and to reduce heat. Include a medium pionion and then the "speed" pinion, but with a major warning label about how to run it. Right now it is buried deep in the owners manual. I doubt many peeps read thru the whole thing.
    3905 Emaxx

  13. #13
    RC Turnbuckle Jr. mike-susieq1's Avatar
    Join Date
    Nov 2010
    Location
    California
    Posts
    4,825
    yup many people dont read manuals they are printed for a reason and when i called traxxas the first time they asked me did you read the manual before running the car and before charging the battery. which i did i always read the manuals to everything and i mean everything the radio i buy, the computer, phones, shelf haha yup everything because they will have something in there you need to know.
    DEU 8:18 ESV

Posting Permissions

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