Breaktru Forum

eCigarette Forum => Battery => Topic started by: redwolfe on February 04, 2013, 12:59:33 PM

Title: A Lesson Learned: Tip about LIPO tabs
Post by: redwolfe on February 04, 2013, 12:59:33 PM
Well, I learned the hard way these lipo tabs are rather fragile against repeated bending last week. I got my PCBs I made and was bending the lipo tabs over onto the PCB pads to check the fit and the negative tab of the lipo just snapped off.  :wallbash:  :facepalm: I don't remove the kapton tape until I start soldering so I knew right away what I did. There goes $4 down the crapper. Lesson learned. So don't bend those tabs until you are ready to solder them!
Title: Re: A Lesson Learned: Tip about LIPO tabs
Post by: Breaktru on February 04, 2013, 01:45:57 PM
Wow. Too bad about that. Didn't think they were that fragile. I've soldered my share of li-po tabs on to wires. I'll have to be careful next time.
Title: Re: A Lesson Learned: Tip about LIPO tabs
Post by: redwolfe on February 04, 2013, 01:49:24 PM
Well, they are fragile similar to how if you twist kanthal or nichrome around when it's secured between connectors to break it off. I must have bent the tab back and forth a bit too much to get it to snap off like that.
Title: Re: A Lesson Learned: Tip about LIPO tabs
Post by: CraigHB on February 04, 2013, 04:09:39 PM
I've broken them before, but on the ones with the thinner tabs like the 1000mAh cells and some big 2C cells I was working with before.  The positive strap is the delicate one.  When you do anything that stresses it, pinch it as the base to secure it and it won't break.
Title: Re: A Lesson Learned: Tip about LIPO tabs
Post by: mick8844 on July 26, 2014, 02:20:08 PM
I am building an sx 350 mod. I have chosen some 20c 2200 mAh batteries(hobby King) I will need to solder them together and I am a little worried about the process. Any one have some tips on #1 how to tell pos. from neg. (there is a mark but it is in the middle between the tabs) and how should I do it with jumpers or tab to tab how much heat can they take before thermal problems etc. Any help is appriciated.

mick
Title: Re: A Lesson Learned: Tip about LIPO tabs
Post by: CraigHB on July 26, 2014, 03:44:26 PM
Yes the small marking they put on positive and negative come off easily with any kind of solvent.  I sometimes put a negative mark with a black felt pen on them.  The tab positions are generally the same from one make of cell to the next.  If worse comes to worse you can check it with a voltmeter.

As far as heat tolerance, if you use a variable temperature iron set at 600F, there isn't a huge concern with overheating them.  Just don't heat them any more than you have to.  Don't use one of those cheap 25W pencil type irons, they're too hot. 

You want the solder to flow quickly once the tab is heated so you should buff them and flux them before soldering.  I use Scotchbrite available from any hardware store.  Any non-conductive abrasive will work.  Emery cloth can to the job as well.  I usually tin them first prior to soldering them to a wire or PCB.
Title: Re: A Lesson Learned: Tip about LIPO tabs
Post by: mick8844 on July 27, 2014, 05:08:16 PM
Craig, first I want to thank you for your knoledge and williness to share it. I have read almost all of your posts and you are quite informative. That brings me to my next noob question I don't know how to use the multi meter to check for pos. and neg. on a battery. The rest I think I have got. I do own a weller soldering station that I have been using for some time. I practiced on old mother boards for a month or 2 before trying to build anything. so that part I have.

Thank you in advance
Mick
Title: Re: A Lesson Learned: Tip about LIPO tabs
Post by: CraigHB on July 28, 2014, 04:42:46 PM
Welcome, you really should understand how to use a multi-meter before doing anything with electronics.  I can't think of a single task in electronics that does not require the use of one.  You should be able to find plenty of tutorials with some web searching.  There's pretty much nothing you can't figure out how to do with some research on the internet.