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Old Mar 16, 2015, 03:52 PM
Kid at heart..
United States, TX, Houston
Joined Apr 2014
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Motor and ESC stays cool but battery is running super hot.

So I tried a new prop and also some new batteries on the Pursuit this weekend. Its a TFL 48mm prop, balanced, sharpened and de-tongued. Its from the Princess Yacht. The boat runs very nice and fast. Had a bit of chin walk, so I lowered the prop angle a bit and that fixed the chin walk. However, I noticed the batteries are very hot after the runs. The motor and ESC is only barely warm to the touch, but the three batteries I put it through all came back very very hot. They were not puffed or anything, just hot. So hot that you can't really hold it in your hand for more than 10 seconds. It won't burn you or anything, but just a lot hotter than what I am used to. The batteries are Zippy 4000mAh 6S 45C batteries. They were on sale a couple of weeks ago and I though I'd give them a try. So question is, with the ESC and motor being only barely warm to the touch, is it an over prop issue or is just not so good batteries? I'll have to change props this weekend when I have more time to narrow it down, but hopefully its just prop and not batteries, that would suck...
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Old Mar 16, 2015, 08:04 PM
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United States, IN, Greensburg
Joined Jun 2014
692 Posts
After talking to a fellow club member about his Spartan batteries im starting to break in all of my lipos.

I bought 3, 1000mah 20c 3s Zippies for my Mad Shark recently.I did a few brief test runs with 2 of them and they just get warm.But I pulled the 3rd lipo straight out of the pink bubble wrap and ran a heat race with it brand new, it runs very hot now and its puffed bad enough to start a tear in the heat shrink.

Venoms packaging actually advises a break in.


"Safety Guidelines For LiPo batteries By Venom RC.

New Battery Break-In

New LiPO battery packs may require 12 or more charge/discharge cycles before the battery's optimum performance is reached.
During this time, it is recommended that the battery pack is not discharged over 7C. 7C = 7 x 1C, where 1C= battery pack mah capacity 1000. Example: [(1250mah 1000) x 7] = 8.75 Amps Recommended Maximum Discharge Rates During Break-In Period
800mah Capacity = 5.4 Amps
1200mah Capacity = 8.4 Amps
2000mah Capacity = 14 Amps"

Here's another bit I found interesting, regardless of the C rating it appears the capacity also impacts the true discharge capability.

"Discharging Instructions
Never discharge a LiPO battery pack at more than the manufacturers recommended discharge rate.
The discharge rate is:
Battery pack capacity (mah) 1000 x Pack C rating
Example for 15c packs: (3200mah 1000) x 15c = 48 Amps
Example for 20c packs: (2100mah 1000) x 20c = 42 Amps"

http://www.racingdevil.com/pages/tips.html
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Old Mar 16, 2015, 08:41 PM
Kid at heart..
United States, TX, Houston
Joined Apr 2014
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I am not so sure about that break in. The 1000mAh 20C batteries you have can only have a sustained discharge rate of 20A. The MadShark I think pulls in more than 20A (It has a 35A ESC and that sometime blow as well) so I think the battery that ran full charge is swelling because your MadShark is pulling more than 20A constant, much more than the battery can handle and causing it to overheat and swell.

You are correct in the second part regarding the discharge rate. A 20C - 1000mAh battery can only discharge 20A constant, whereas a 30C - 1000mAh battery can discharge 30A constant. On the same note, a 15C - 5000mAh battery can discharge 75A constant, so the discharge is based on the capacity of the battery * it's discharge rate.
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Old Mar 17, 2015, 04:22 AM
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United States, IN, Greensburg
Joined Jun 2014
692 Posts
Yea I remember your Mad Shark stories, that's part of the reason I raced the boat on those 20c batteries, I trust the lipos more then the stock esc.I was already planning on upgrading the esc before I started trying better props outdoor in April, it was worth the $15 I spent on those lipos to be able to catch that last indoor winter race before I started upgrading.I just mentioned it because I was suprised at how different the packs looked afterwards.Its either break in related or a huge difference between identical Zippy packs.

Sorry if the break in theory is off topic, I just wanted to toss it out there in case anyone else knows of any solid info.Besides from Venom all I can find about the topic is a ton of forum posts.
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Old Mar 17, 2015, 08:29 AM
Kid at heart..
United States, TX, Houston
Joined Apr 2014
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Hi Micro, I actually appreciate the discussion, so no need to be sorry that's what these forums are about, to discuss and share thoughts and ideas. Keep them coming my friend..
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Old Mar 17, 2015, 08:56 AM
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Joined Apr 2010
962 Posts
The packs get hot if
1) you run them down too long
2) too much current being pulled thru the packs too quickly (amps too high)

Try backing off 30 seconds on your runtime and see if that helps. If still hot, then you have an amp load problem with your packs being on the "critical path".

Try removing any extraneous resistance from your system-- ie, upgrade your connectors to 5.5mm bullets and remove any serial harnesses if you are using those.

Ensure you are not running "wet" which increases amp load.

If those actions don't help, then your only other choice is to try premium quality packs or drop down on the prop a bit.

I run high quality hyperion 35C packs which stay nice and cool. Compared to my buddies who run cheap "45-65C" packs which come in hot and puffed. My packs are 4-5 years old now and still going strong. I also get a nice long constant voltage vs. other packs which start to dump early. Note, I don't have any experience with Zippy packs.

Chief
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Last edited by BHChieftain; Mar 17, 2015 at 09:02 AM.
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Old Mar 17, 2015, 05:24 PM
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United States, IN, Greensburg
Joined Jun 2014
692 Posts
Quote:
Originally Posted by hangtheman View Post
Hi Micro, I actually appreciate the discussion, so no need to be sorry that's what these forums are about, to discuss and share thoughts and ideas. Keep them coming my friend..
I'm glad to hear that, I just finished ordering a Spartan lol

I've been wanting one since I bought my Summit when it first came out in 08/09 and Tower has a St Pattys Day coupon that got the easy payments down to $129x3, I couldn't resist that deal.

I'm going to need alot of big 3s packs now.The club I joined has a unlimited class I can run it in.
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Old Mar 21, 2015, 08:18 AM
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Joined May 2012
531 Posts
If the batteries are hot and nothing is more than "warm" the batteries either can't supply the current or you ran them down way too far, like almost to 0 volts. This is guaranteed to do permanent damage to a battery, may run hot no matter how you use it now.
Do you know the voltage of the packs when you were done the run? They should be at about 3.7v resting which will drop to about 3.2 when under load. How many mah went back in the battery when you charged it, should never run them lower than 20% remaining capacity.
If you have a 5000mah pack it should NEVER take more than 4000mah to charge it back to full. (just an easy example)
I've never had that much luck with HK batteries, they work - for a while. All my HK packs have died, I have other high end packs that are 6 years old and a still functional, they balance perfectly still but I know they have lost some of their kick.
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Old Mar 21, 2015, 01:42 PM
Kid at heart..
United States, TX, Houston
Joined Apr 2014
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Thanks Sibe, I think it's just the batteries are overrated and can't handle the load. My ESC is set to LVC at 3.2v and they showed about 3.65 v per cell when I recharge them.
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Old Mar 22, 2015, 04:05 PM
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What motor/ESC? Also you mentioned batteries....plural, you running 2p?
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Old Mar 23, 2015, 08:05 AM
Kid at heart..
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Hi Scorp, the motor is a Leopard 4082 1600kv and the ESC is a Seaking 180A V3. I am not using the batteries in parallel, just single. The batteries are rated 4000mAh @ 45C, so they should be able to handle 180A, however, I have narrowed it down to the batteries. Seems like these Zippy batteries are rated higher than what they can actually deliver.
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Old Mar 23, 2015, 08:34 AM
I feel the need for speed!
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Southern U.S.
Joined Jun 2008
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You may have exceeded runtime. That setup should be pulling in the 100-120a range, the prop is a bit in the "largish" side for that hull and motor. If you plan on running it that way I would suggest two of those packs in parallel, or better yet two 5000 40c's in parallel. Zippy's are actually pretty decent batts, not many folks run a single 4000mah with a motor that size.
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Old Mar 23, 2015, 05:53 PM
Kid at heart..
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Joined Apr 2014
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Thanks Scorp. I'll try to see if I can fit two of them in the hull to run them in 2P.
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