Building lipos?
 

Ok, Im sure this has been asked a few times, but I couldnt find it

My buddy has 2 flight power EVO lite packs that each have 5 or so run on them in his heli, there 18C, 1320 mah packs

He said he will give them to me if I want them, and I was pondering about taking them apart, and making a 3s pack, so with that said

How hard is this to do? Is it just positive to neg? Do I need to put something inbetween the cells so they dont short?

I probably wont do the balancing leads just because I will be buying other packs, this is more a pack to get me going:mdr:

Thanks!

If I recall correctly, you might need a special solder and flux to join certain types of tabs/ solder on wires. Aluminum solder I think, but dont know what flux/paste sorry.

Working with Lipo's is a PIA. I made several packs and repaired a few. Depending on your cells you may need a special soilder. Not all cells require it, depends on the tabs.

Just the same it is not worth it. One mistake and you got a fire, or a wire will become a fuse if you are lucky.

Everytime I work with Lipo's I tell myself it's not worth it and I am just going to buy a pack next time or chuck the pack instead of repairing it.

I build A123 packs and highly recommend the DIY method for those cells.


Highflier

I dont know, I might attempt it, and I might not

I guess you guys think its pretty hard, I have never even really thought about it, so IDK

I went out of the country on a work assignment and was supposed to be gone 3-5 weeks, was actually gone almost 13weeks. All the lipos I had were stored 1/2 charged. They all puffed, but only the cell on top. The cells that were on the bottom appeared fine. Decided to try to salvage and rebuild using the good cells.

Mine were glued together so aggressively, I couldn't get them separated without damaging the cell membrane. I never got the the point of having to deal with the wired end either. I thought cutting the shrink off would be all there was to it, but not with these. They must have been epoxied or something. Maybe yours will be diff.

I dont know, I dont have them yet, so I cant say

I guess I will figure it out when I get them

Its not that bad. You just need to be very careful not to short anything out. Just double and then tripple check your polarity and connections before putting wires or tabs together. Make sure you keep some sort of covering like electrical tape over any connections you are not working on at that moment, it helps prevent the Oops from happening. I have repaired a few packs and combined others into one pack as well and it is sometimes a pain to get the tape that holds the cells together separated. Just remember... slow and gentle. It takes some work, but its not that bad.

Fixing lipos is a pain, especially if the tabs are al and have been "spot welded" together. You have to spereate them and be careful not to damage the tabs, or snap the soft al. I use a single edge razor blade to break the welds by rocking it slightly while wedging it between the tabs where they are welded.

You will need zinc solder and the appropriate flux to get it to stick to al tabs. Cheapbatterypacks.com sells both and are not too bad on price.

I have repaired at least 25 maxamps packs (maintaining my investment :tongue:), and built/combined at least 40 other cells (maybe more) into packs. I like to use a sharpie to mark the polarity ( + & - ) on the cells on both sides near the tabs. Makes it easier to get them assembled right. Cover the tabs with good electrical tape, and make sure to protect the ends of the lipos. I like to use some cardboard on the non tab end, and usually some soft plastic on the tab end.

A small pair of needle nose pliers helps to hold the tabs together as the solder cools, that helps make the best connection. Just be careful not to short over the other tabs...

well heck you could always send em my way if you dont want to, lol

This should help get you started.

I've had to repair a few MaxAmps packs myself, and it wasn't nearly as hard as I thought it would be.