batteries getting very hot

[00teggygsr]

Hey guys I'm a newbie to the electric RC world. I have had some nitros but got tired of the headaches. I got my MERV about a month ago and lately after I run a battery through it the battery is so hot I can't even hold it. They are stock batteries with all stock electronics. The motor and esc are barely even warm. It's a vxl. Is it normal for them to get that hot?
Thanks for any help or tips to make this thing run better.

[50togo]

nimh do run pretty hot .until you upgrade to lipos probably good idea to have a few extra packs to give them a rest. do you have a temp gun so you know how hot?
lipo batteries don't get as hot

[jimbo74]

are you running them in series? that makes things a lot hotter/worse.... especially if you haven't changed to the samller pinion gear

[00teggygsr]

I haven't shot them with a temp gun yet. I have 2 batteries so I make sure they cool off before before and after charging. I have only ran it in
Series a couple times but I stoped doing that after I realized how hot they are getting. I am running just 1 battery and its still getting real hot

[50togo]

Maybe its your terrain your driving on. You can go smaller on the pinion to make it run cooler

[mike-susieq1]

smaller pinion wont make a difference with the stock series 1 nimh battery. I find that the stock nimh doesnt provide enough amps to the esc/motor so there for heats up fast. i've ran stock nimh, upgraded to 1600mah and still gets hot just not nearly as hot though. stock nimh got hot just like this one mentioned too hot to handle so therefore way over heated for a battery.

[00teggygsr]

I'm running on asphalt and hard packed dirt is all. I will go up to bigger batteries and see what that does. Thanks for the help

[mike-susieq1]

no matter what nimh batteries you get they will always get hot maybe not as hot but will still get too hot for the batteries to be. your best bet is to get lipos down the road or stop running the batteries when they start to become warmer just near hot then thats it wait for the battery to cool and use a different nimh then the second 1 you have and while you run that the first battery will have cooled enough by then to run the rest of it. just make sure your also not running the nimh's down all the way, you should run them till the performance goes down when you notice your not going fast anymore then its time to stop running them and switch batteries then.

[Maxximum Overdive]

Stop playing with those silly Nimhs! Go lipo and forget the heat! Stick with 2s, more than enough power and will save your ESC and motor.

[50togo]

Yep.stick with 2s until you want a new level of power! Then 3 cell for some Max fun

[00teggygsr]

Thanks for the help. I have been thinking about going to liposuction. With 2s what will the run time and performance be like compaired to stock?

[Jimmie Neutron]

Run time depends on mAh, not cell count. Because of that, run time is difficult to answer without knowing which batteries you plan on getting.

With LiPo, top end will be slower. But, it will feel faster because it gets to top speed faster.
Hope that made sense, lol.

[50togo]

Don't you mean less top end than running nimh in series

[mike-susieq1]

i think neutron meant to say that on the second part of his post. i know when i use to run series and then got my 2s lipos it felt like the speed got their faster but just not as fast as series nimh which was fine by me since at the time i didnt have room to go that fast. lipo will be a total difference for you to the OP.

[Jimmie Neutron]

Parallel:
6 cell NiMh fully charged; 1.6 x 6 = 9.6v
2 cell LiPo fully charged; 4.2 x 2 = 8.4v

Series:
12 cell NiMh fully charged; 1.6 x 12 = 19.2
3 cell LiPo fully charged; 4.2 x 3 = 12.6
(LiPo cannot be ran in series with stock ESC)

Speed = voltage

So; in either case, parallel or series, initially top end will be slower with LiPo.
But; also keep in mind that voltage drops a lot less with a LiPo pack than it does with a NiMh pack. This means speeds will be much more consistent with LiPo.

[50togo]

Under load it won't pull those voltages even lipos will drop from 8.4 to into the 7's and I wonder if nimh drops more than lipos. After a few runs it will be no contest

[mike-susieq1]

when i run my lipo and then run my nimh or the other way around no matter is see my nimj drop after just 2 mins of running only compared to my lipo after 30mins when it gets to lvc. my nimh during those 2 mins is faster than my lipo but only those 2mins only then after slower. my lipos i can wheelie and the nimh nope after the 2mins.

[Beaz]

That's sorta how I felt when using Nimh. mike-susiq1, but +100 for lipo obviously.

[Cipher_Jones]

You need a temp gun to find out what temp the batteries are running at, and to find out if you burned any cells out. There are specific instructions in the owners manual on running 12 cells or 3s lipo. It sounds like you did not follow them and damaged at least 1 cell. A good charger can tell you this, but if not a heat gun will find the bad cell also.

Also, running them in parallel will drastically reduce battery temperature. You wont get the huge speed gain of going to 14.4v, but you will get a small speed gain (as opposed to 7.2v x 1), extended runtime, and lower battery temps.

The only real reason to get lipo (in a traxxas 1/16 model) is longer runtimes IMHO. There are the same limitations to 3s as there are to 14.4v, and if you are running parallel NiMh you can just gear up a bit to make up for the slight voltage increase of LiPo.

[50togo]

The main reasons I went lipos besides longer run time is stronger longer run time and more punch all the time. They are lighter, run cooler and longer battery life

[Jimmie Neutron]

Also, multiple LiPo's can be charged at the same time... NiMh's cannot.
Less time charging = more time driving.

[Cipher_Jones]

Also, multiple LiPo's can be charged at the same time... NiMh's cannot.
Less time charging = more time driving.

Ill remember that next time I'm charging multiple NiMh's.

[50togo]

I think what Jimmie means its not safe to charge two nimh together at the same time. One will peak before the other and over charge

[Jimmie Neutron]

That is exactly right, 50.

Just because I feel safer when I sleep with a hand grenade. Doesn't mean I'm always right.

[jimbo74]

That is exactly right, 50.

Just because I feel safer when I sleep with a hand grenade. Doesn't mean I'm always right.

wait... what's wrong with that?

[mike-susieq1]

i like using my nimh's still when lipos are done running if i plan to run more or family are around want to drive, i wouldnt let them use lipos because of the increased punch you get from them so nimh work good for beginners in my book and household.

[50togo]

I was surprised when my daughter jumped right into it and drove like a pro!