Wattflyer RC Network: RC Universe :: RCU Magazine :: RCU Forums :: RCU Classifieds :: RCU User Reviews :: RCU YouTube
Home Who's Online Calendar Today's Posts RealTime Post Spy Mark Forums Read
Go Back   WattFlyer RC Electric Flight Forums - Discuss radio control eflight > R/C Electric Power - Batteries, Chargers, ESCs and More > Batteries & Chargers
Register Members List Wattflyer Extras Articles Search Today's Posts Mark Forums Read Social Groups

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

Thank you for your support (hide ads)
Reply
 
Thread Tools Display Modes
Old 04-06-2014, 04:34 PM   #1
JetPlaneFlyer
Super Contributor
 
JetPlaneFlyer's Avatar
 
Join Date: Mar 2009
Location: Aberdeen, Scotland
Posts: 4,396
Thanked 489 Times in 455 Posts
Awards Showcase

5kW  Outstanding Contributor Award  1kW 
iTrader: (0)
Friends: (8)
Default Big Sparks!

Today i was hooking up one of my 6s batteries to the charger only half concentrating on what i was doing and I must have accidentally bridged between the + and - bullet connectors with the male bullet of the charging cable.

There was a big flash and this is what the 5.5mm bullets looked like a millisecond later:


The burned male (red) connector on the left is the charger cable, the two connectors on the right are the +/- off the battery, all are beefy 5.5mm bullets. the spark blew the end off one bullet and burned a hole straight through the side of the other!

Close up:


Luckily that was all the damage apart from a couple of tiny burns on my finger caused by flying molten metal (sounds worse than it was). Normally I keep a cap over the male (negative) battery terminal until I've connected the positive side up, but today I must have been daydreaming.. There's a lesson to be learned - Always concentrate when working with LiPos!!


This wasn't the only lesson though. I went about replacing the battery bullet connectors. These were original factory supplied connectors on the Turnigy LiPos.

Here's what the soldering socket of the male connector looked like:


Notable is the TOTAL lack of any solder in the socket All that was connecting the wire to the bullet was a thin fillet of solder between the side of the wire and the edge of the bullet, and that only ran around half the circumference. I shudder when I think I was pulling 140A through that connector.

So lesson number two - Re-solder every connector on your LiPos! (especially cheap ones)
JetPlaneFlyer is online now  
  Reply With Quote
Old 04-06-2014, 05:41 PM   #2
xmech2k
Ya got any Beeman's?
 
xmech2k's Avatar
 
Join Date: Apr 2009
Location: San Diego, CA
Posts: 2,616
View xmech2k's Gallery21
Thanked 247 Times in 245 Posts
Club: CVMRCC, SEFSD
Awards Showcase

1kW  Outstanding Contributor Award 
iTrader: (0)
Friends: (7)
Default

Oops! Thanks for swallowing your pride and sharing that with us, and glad there wasn't any major injury or damage. A good lesson.
xmech2k is online now  
  Reply With Quote
Old 04-06-2014, 05:56 PM   #3
sidybee
Member
 
Join Date: Feb 2014
Location: middle of cali
Posts: 75
Thanked 1 Time in 1 Post
iTrader: (0)
Friends: (0)
Default

i think they call that ark welding lol
sidybee is offline  
  Reply With Quote
Old 04-07-2014, 12:40 AM   #4
CHELLIE
Super Contributor
 
CHELLIE's Avatar
 
Join Date: Oct 2006
Location: Hesperia, So. Calif
Posts: 18,410
View CHELLIE's Gallery13
Thanked 2,140 Times in 2,049 Posts
Club: Chino Renegades RC Flying Club
Awards Showcase

Scratchbuilders Award  Scratchbuilders Award  Ambassador Award  100mph Speed Demon 
iTrader: (4)
Friends: (309)
Default

I hate that when that happens I have done that too It sure is a wake up Call

I may be getting Older, But I Refuse to grow Up I am Having to much Fun to Grow Up LOL
CHELLIE is offline  
  Reply With Quote
Old 04-07-2014, 04:11 AM   #5
Larry3215
Look out for that tree!!!
 
Larry3215's Avatar
 
Join Date: Mar 2006
Location: Gig Harbor, Wa USA
Posts: 6,806
View Larry3215's Gallery63
Thanked 692 Times in 671 Posts
Club: Kitsap ARCS & E-FLAPS
Awards Showcase

90 Minute Thermal Duration  60 Minute Thermal Duration  30 Minute Thermal Duration  4kW 
iTrader: (6)
Friends: (21)
Default

Thats very scary seeing the lack of solder in that bullet!

I did almost exactly the same thing one time. I was charging at the field and one of the exposed male bullets touched the frame on my truck while connecting the charger.

I not only ruined the connector I shorted, but I also blew one of the aluminum tabs on one of the cells in the pack. It blew just like a fuse.

It took me a while to figure out why the pack read zero voltage after I soldered on a new connector! I knew it couldn't possibly have discharged down to zero that quickly.

Not paying attention can get expensive!

I think I need a signature.
Larry
Larry3215 is offline  
  Reply With Quote
Old 04-07-2014, 05:26 AM   #6
kyleservicetech
Dennis V
 
kyleservicetech's Avatar
 
Join Date: Apr 2008
Location: Wisconsin, USA
Posts: 8,002
Thanked 696 Times in 678 Posts
Club: www.racinercclub.com (I'm the newsletter editor)
Awards Showcase

Outstanding Contributor Award  3kW  2kW  100mph Speed Demon 
iTrader: (1)
Friends: (20)
Default

Originally Posted by JetPlaneFlyer View Post

This wasn't the only lesson though. I went about replacing the battery bullet connectors. These were original factory supplied connectors on the Turnigy LiPos.
Notable is the TOTAL lack of any solder in the socket All that was connecting the wire to the bullet was a thin fillet of solder between the side of the wire and the edge of the bullet, and that only ran around half the circumference. I shudder when I think I was pulling 140A through that connector.

So lesson number two - Re-solder every connector on your LiPos! (especially cheap ones)
Yikes
140 Amps through that??? You're right, that was very fortunate to not have blown out in flight.

DennyV
Retired and the days are just too short, busier than ever!
kyleservicetech is offline  
  Reply With Quote
Reply

  WattFlyer RC Electric Flight Forums - Discuss radio control eflight > R/C Electric Power - Batteries, Chargers, ESCs and More > Batteries & Chargers

« Previous Thread | Next Thread »

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Are RC events getting too big to be safe? AEAJR RC Radios, Transmitters, Receivers, Servos, gyros 35 08-18-2013 09:57 PM
Great Planes Giant Big Stick Conversion kyleservicetech Sport Planes (Formerly I/C & Gas Conversion) 37 08-14-2013 11:08 PM
$100 scratch build contest-Extra pro cncfoam Scratch and Kit Built Aircraft 65 07-15-2011 07:47 PM
Hobby Topgun 90mm Mig 15 (the BIG ONE) 4stripes Electric Ducted Fan Jets 3 06-13-2011 06:36 AM
For Sale Big axi motor 2.4ghz Motors and Speed Controllers for sale & WTB 0 03-26-2011 08:25 PM


All times are GMT +1. The time now is 09:36 PM.


Powered by: vBulletin
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2005 WattfFlyer.com
RCU Eflight HQ

Charities we support Select: Yorkie Rescue  ::  Crohn's & Colitis Foundation



Page generated in 0.17783 seconds with 29 queries