Puffed at end of flight - WattFlyer RC Electric Flight Forums - Discuss radio control eflight

Batteries & Chargers Discuss Li-P, Li-Ion, NiMh, Nicad battery technology and the chargers that juice 'em up!

Puffed at end of flight

Old 07-27-2009, 02:38 AM
  #1  
constantCrash
prefectionist
Thread Starter
 
constantCrash's Avatar
 
Join Date: Jan 2007
Location: MN
Posts: 1,919
Default Puffed at end of flight

Alright, I think i know the answer to this question but I'm going to ask anyway.

I have a PZ corsair with a bP 2814-6 1400kvt motor on it running a 9x4.7 prop and a 40 amp esc.

My batteries are 1800 and 2200 mah 3s 20C Zippy's that are 1 year 6 months old. At the end of a 6 minute spirited flight the other day my 1800mah battery was puffed on the top cell. I left it sit and now it feels normal again.
33amp peak 29-30 unloaded ~ 320watts.

Motor came down at ~120 degrees, battery was at 130 degrees.

I assume that this battery is toast and not usable anymore correct?


The same thing happened again today on one of my 2200mah zippy's although to a lesser extent (just barely puffy).

It's not a big deal at $20 a battery, but These batteries have been babied up until now (never dischared to less than 20%, never left charged, never used at more than 10C) I guess you get what you pay for, but dissapointing none the less.
constantCrash is offline  
Old 07-27-2009, 02:58 AM
  #2  
Nitro Blast
Community Moderator
 
Nitro Blast's Avatar
 
Join Date: Aug 2005
Location: Sunny San Diego Ca
Posts: 4,052
Default

I dont know about 'toast', but you can be assured the performance of the pack will rapidly diminish. In other words, yes, its the beginning of the end, but if you don't crank on the pack it will last a bit more.


If you have a 'lighter' use aircraft (kind of hard with a PZ) like a slow stick, that would be a great place for a battery pack who's days are numbered.

Its a good idea to balance a slightly off pack every charge, that seems to ensure you get every charge you can from it.

Keep your wide open throttle to shorter bursts. Learn some conservative throttle practices and those packs will last longer. The trick is they will get hotter, faster. So go easy on 'em.
Nitro Blast is offline  
Old 07-27-2009, 03:34 AM
  #3  
skiman762
FFFC
 
skiman762's Avatar
 
Join Date: Feb 2006
Location: North Carolina
Posts: 1,008
Default

seems odd you puff 2 packs I'd be looking over things good to be sure the problem isn't in the plane
I have some 3 year old packs that still haul the mail
skiman762 is offline  
Old 07-27-2009, 04:17 AM
  #4  
Louis
Member
 
Join Date: Apr 2007
Posts: 391
Default

...

Last edited by Louis; 08-22-2009 at 07:46 PM.
Louis is offline  
Old 07-27-2009, 05:59 AM
  #5  
CHELLIE
Super Contributor
 
CHELLIE's Avatar
 
Join Date: Oct 2006
Location: Hesperia, So. Calif
Posts: 19,255
Default

ok lets see, the 1800mah 20C pack is good for 36 amps, and the 2200mah 20C is good for 44 amps, you were Drawing 33 amps max with your set up, and the lipos are 1 1/2 year old, THATS EASY, your lipos were Weak, not giving the max amps needed, they were being pushed beyond there limits being old, so they got hot, due to internal resistance, and puffed, Take it Easy on Old cheapy lipos, and they will last You Big Bully You Take care and have fun, Chellie
CHELLIE is offline  
Old 07-27-2009, 01:37 PM
  #6  
skiman762
FFFC
 
skiman762's Avatar
 
Join Date: Feb 2006
Location: North Carolina
Posts: 1,008
Default

And unless he has in-flight data I would bet his unloaded amps are really loaded amps closer to 35-36 in the air. I know the myth of unloading has been debated but most data supports that they load in the air not unload from a static stalled condition on the ground. Also the hotter the motor and battery get the more amps it will draw as the internal resistance goes up Time to try less prop
skiman762 is offline  
Old 07-27-2009, 01:41 PM
  #7  
Matt Kirsch
Super Contributor
 
Matt Kirsch's Avatar
 
Join Date: Jul 2005
Posts: 2,086
Default

Also, the 130 degrees was only the surface temperature of the outer cells. The middle cell, and the inside surfaces of the other two, will be much hotter.
Matt Kirsch is offline  
Old 07-27-2009, 02:58 PM
  #8  
constantCrash
prefectionist
Thread Starter
 
constantCrash's Avatar
 
Join Date: Jan 2007
Location: MN
Posts: 1,919
Default

I use a Wattsup meter on everything, correct it was done on ground only though. I use the Turnigy touchless temp probe for heat measurements. I almost never fly over 1/2-2/3 throttle. I also balance on every charge as I use CellPro chargers exclusively.

Thanks guys, I'll keep them around for my lighter duty planes until they are completely toast.

And yes the BP motor is good for 18-30 amp continuous but up to 40 burst, I've got it set so i'm doing about 33-36 peak and full throttle settles down to ~ 29-30 continuous. I'll fly it with the wattmeter in it once and see what it comes down with as a new peak.
constantCrash is offline  
Old 07-27-2009, 03:18 PM
  #9  
Liquidity
Combat Vet
 
Liquidity's Avatar
 
Join Date: Jul 2007
Location: GA
Posts: 2,049
Default

I have puffed 3 zippy lipos when I was running them not even close to their specified limit.
Some lipos just suck
Liquidity is offline  
Old 07-27-2009, 04:29 PM
  #10  
Nitro Blast
Community Moderator
 
Nitro Blast's Avatar
 
Join Date: Aug 2005
Location: Sunny San Diego Ca
Posts: 4,052
Default

I won a FullyMax battery at a raffle.

One charge, one flight, FAT BATTERY.


I never used it again.
Nitro Blast is offline  
Old 07-28-2009, 02:57 AM
  #11  
Nathan King
Member
 
Join Date: Jun 2007
Posts: 56
Default

Originally Posted by Liquidity View Post
I have puffed 3 zippy lipos when I was running them not even close to their specified limit.
Some lipos just suck
I have found them to perform just as well as ThunderPower packs three times the price. In fact, mine are still going strong after two seasons.
Nathan King is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
BEX
Batteries & Chargers
4
01-04-2009 06:41 PM
JohnnyOo
Beginners
14
06-04-2008 03:13 PM
HET overkill
Electric Ducted Fan Jets
1
05-29-2008 11:25 AM
Mr.Clean
Batteries & Chargers
6
03-14-2008 01:56 PM
nova801428
Batteries & Chargers
38
03-26-2006 09:25 AM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Quick Reply: Puffed at end of flight


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.10811 seconds with 13 queries