HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 07, 2012, 10:53 PM
Australia, VIC, Coburg
Joined Jan 2012
1 Posts
Discussion
lipo batteries

Hi can someone help me out, i put in a lipo 5000mah 2s 30c into a 1/8 truck with a 70amp ESC and the battery expanded, that is so far 3 batteries that have done so, any help would be great, thanks
thephantomsguest is offline Find More Posts by thephantomsguest
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 08, 2012, 12:51 PM
Registered User
LaTuFu's Avatar
United States, VA, Bedford
Joined Oct 2011
178 Posts
Have all 3 batteries been the same specs? Same age?

On the one hand, a 30c 5000 mAh battery should certainly have no problem supplying a 70a ESC. On the other, if it is driving a motor for a 1/8 truck, that could be the problem. 70a ESCs are usually meant for smaller scale (1/10) vehicles.

What size motor are you running with the ESC?

What temps are you getting on the ESC and the motor when you are running it?
LaTuFu is offline Find More Posts by LaTuFu
Reply With Quote
Old Feb 08, 2012, 07:42 PM
Registered User
Megarallycar's Avatar
Joined Jan 2012
11 Posts
Step up your "C" rating on your lipos. I dont recommend 30c for 8th scale at all.... Nothing below 40c for 8th scales.
Dont run soft packs on 8th scales
Dont run without Deans or TRX plugs for 8th scales
Dont run higher than a 12 gauge wire. Thats the smallest you should ever go.

Lipos are getting cheaper you know. You can pick up a Gens Ace 40c 5000mah lipo for 33$ on hobbypartz.com. Try and replace that lipo with one of those. There allot better and will last allot longer. They got great punch and dont lose there performance through out the use of the pack. Its a great sturdy, pack with consistent levels of performance through-out the whole run.
http://www.hobbypartz.com/98p-40c-50...se-direct.html
Megarallycar is offline Find More Posts by Megarallycar
Reply With Quote
Old Feb 09, 2012, 08:39 AM
Registered User
LaTuFu's Avatar
United States, VA, Bedford
Joined Oct 2011
178 Posts
Quote:
Originally Posted by Megarallycar View Post
Step up your "C" rating on your lipos. I dont recommend 30c for 8th scale at all.... Nothing below 40c for 8th scales.
Dont run soft packs on 8th scales
Dont run without Deans or TRX plugs for 8th scales
Dont run higher than a 12 gauge wire. Thats the smallest you should ever go.

Lipos are getting cheaper you know. You can pick up a Gens Ace 40c 5000mah lipo for 33$ on hobbypartz.com. Try and replace that lipo with one of those. There allot better and will last allot longer. They got great punch and dont lose there performance through out the use of the pack. Its a great sturdy, pack with consistent levels of performance through-out the whole run.
http://www.hobbypartz.com/98p-40c-50...se-direct.html
While I agree with you completely, I don't think the C ratings are the main culprit here. I think the ESC is not large enough for the application.

A 30c 5000 mAh battery (assuming its an accurate C rating) is capable of providing 150a to the ESC, so it is more than enough for a 70a ESC.

The 70a ESC is the issue, imo. Especially if it is matched to a true 1/8 motor like a 2000kv or 2200kv...
LaTuFu is offline Find More Posts by LaTuFu
Reply With Quote
Old Feb 09, 2012, 08:50 AM
Car Junkie trying to fly
Y2kGTP's Avatar
United States, FL, Deltona
Joined Oct 2005
1,175 Posts
It could also be the brand of batteries, or a possible bad lot. a few years ago I had a couple 35C batteries from Amain (their own brand) and they puffed after 15-20 minutes on a 1700kv motor in a 1/8th buggy.

They had a known issue and replaced them for free for me.
Y2kGTP is offline Find More Posts by Y2kGTP
Reply With Quote
Old Feb 10, 2012, 07:28 AM
Registered User
wparsons's Avatar
Canada, ON, Markham
Joined Aug 2008
8,818 Posts
Quote:
Originally Posted by LaTuFu View Post
While I agree with you completely, I don't think the C ratings are the main culprit here. I think the ESC is not large enough for the application.

A 30c 5000 mAh battery (assuming its an accurate C rating) is capable of providing 150a to the ESC, so it is more than enough for a 70a ESC.

The 70a ESC is the issue, imo. Especially if it is matched to a true 1/8 motor like a 2000kv or 2200kv...
If the ESC was the culprit here, he would be frying ESC's, not puffing lipo packs. I would bet that the packs are old and tired, and can't supply enough current, or he's over discharging them.
wparsons is offline Find More Posts by wparsons
Reply With Quote
Old Feb 10, 2012, 02:48 PM
Registered User
LaTuFu's Avatar
United States, VA, Bedford
Joined Oct 2011
178 Posts
Quote:
Originally Posted by wparsons View Post
If the ESC was the culprit here, he would be frying ESC's, not puffing lipo packs. I would bet that the packs are old and tired, and can't supply enough current, or he's over discharging them.
Not necessarily. If there is nothing wrong with the ESC, its just underpowered for the application, it could be struggling along just inefficient enough to create issues for the batteries and/or the motor. But not enough to fry itself.

Regardless, the OP has disappeared, so who knows...
LaTuFu is offline Find More Posts by LaTuFu
Reply With Quote
Old Feb 10, 2012, 03:00 PM
Car Junkie trying to fly
Y2kGTP's Avatar
United States, FL, Deltona
Joined Oct 2005
1,175 Posts
It might be 70a continuous, but who knows the peak current it can pass. An ESC is just a valve controlling current between the battery and motor.

Batteries usually puff if pushed too hard. Who knows the battery brand in use, several of the cheap ones are likely overstated for C ratings.

My gut feeling is cheap packs.
Y2kGTP is offline Find More Posts by Y2kGTP
Reply With Quote
Old Feb 12, 2012, 07:56 AM
Registered User
wparsons's Avatar
Canada, ON, Markham
Joined Aug 2008
8,818 Posts
Quote:
Originally Posted by LaTuFu View Post
Not necessarily. If there is nothing wrong with the ESC, its just underpowered for the application, it could be struggling along just inefficient enough to create issues for the batteries and/or the motor. But not enough to fry itself.

Regardless, the OP has disappeared, so who knows...
If the batteries can happily supply 150a constant, there's no way you'll puff them (without over discharging) with an ESC rated for 70a constant.

My vote is either not a true 30c (or tired packs), or over discharging.
wparsons is offline Find More Posts by wparsons
Reply With Quote
Old Feb 14, 2012, 07:22 AM
Registered User
LaTuFu's Avatar
United States, VA, Bedford
Joined Oct 2011
178 Posts
I agree with your math and your statement, but the fact remains, we need to know more about the batteries he has used. If all 3 batteries were the same age, manufacturer, specs, etc. then yes, I would definitely look at the batteries as the main culprit.

But he's tossed a 70a ESC into a 1/8 vehicle. There may be a motor that is underpowered for the application. Gearing could be totally wrong. Any of those factors could also contribute to the battery getting overheated, and they could absolutely puff regardless of current flow.

At this point, it's pure speculation anyway because the OP is long gone from this thread.
LaTuFu is offline Find More Posts by LaTuFu
Reply With Quote
Old Feb 14, 2012, 07:38 AM
Registered User
LaTuFu's Avatar
United States, VA, Bedford
Joined Oct 2011
178 Posts
wparsons...one other thought hit me as I was doing something else...

What do you think about the possibility of cells out of balance?

If he's not balancing his cells when he charges them, that would potentially lead to an overdischarge/puffing scenario, no?

And if it was something he was doing consistently, it would show up across all of his batteries...
LaTuFu is offline Find More Posts by LaTuFu
Reply With Quote
Old Feb 15, 2012, 06:32 PM
Harry from Atlanta, Ga.
Old Sloppy's Avatar
Buford, Georgia
Joined Sep 2006
145 Posts
Critical information is missing.

Does he live way up north ?

What tempature are the lipo cells ?

How long did he run it before the cells puffed ?

cold cells will puff (caused by the low voltages of a cold battery)

overdischarge will puff cells.

Harry
Old Sloppy is offline Find More Posts by Old Sloppy
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold 2 used Sky LiPo 1300mAh 4s 40c-80c Lipo Batteries -= GYRO =- Aircraft - Electric - Batteries & Chargers (FS/W) 2 Dec 26, 2011 07:18 PM
Discussion Using a E-flite Lipo balancing charger with Turnigy Lipo batteries Eagle-RC.com Batteries and Chargers 2 May 18, 2011 11:47 AM
Discussion Many Lipo Batteries Back in Stock! Sky Lipo + Gens Ace maarset HobbyPartz.com 2 Apr 05, 2011 04:04 PM
For Sale Parkzone DC 3.7V LiPo Charger, 2 Parkzone 110mAH LiPo Batteries and 4 AA Batteries schwimmair Aircraft - Electric - Micro & Indoor Airplanes (FS/W) 4 Nov 21, 2009 09:28 AM
For Sale Parkzone DC 3.7V LiPo Charger, 2 110mAH LiPo Batteries and 8 AA Batteries schwimmair Aircraft - Electric - Micro & Indoor Airplanes (FS/W) 1 Nov 15, 2009 10:02 PM