6s to 4s conversion issue

[Ham]

Morning All,

I had finally decided to have a go at re jigging my puffed cell 6s 16ah HK lipo to a 4s 16ah after much reading on here and other sites, however:
I have stripped the pack open only to find that rather than having 6 pouches in there, as per the videos I have watched, I find 12.

This has thrown me: my mind tells me that it is simply 6 lots of paralleled cells (each single pouch being 8ah) soldered in series to achieve the required ah rating. Anyone else come across this?

With soldering gun in hand I went about it in the same way I would have with 6 pouches. Foiled again at this stage as my soldering gun will not melt the solder on the tabs! It melts my spool of wire just fine but wont even put a dent in the terminals on the battery.

Any help with any of it is appreciated!

 

[dogman dan]

For battery repairs, you really need the big fat tip on the iron. Wattage can be small, but store enough heat in a big tip, and it will melt the solder.

Are the bad cells on the end of the stack of cells? if so, you can just snip tabs to remove the puffers. Then resolder the discharge wires to the new end cell. In many towns, the best place to look for a fat tip iron is a craft store, in the stained glass stuff.

 

[Ham]

Cheers Dan,

I have managed to get one apart and sorted to 4s so far with the Dremel...my solder guns are old and clearly utter balls.

 

[Ham]

Can anyone confirm that each of the 12 pouches in the 16ah pack is 8ah that have just been paralleled to reach the 16ah needed on these packs?

I want to hook them up to a charger now to see how they behave as 4s but before i tell the charger they are 16ah I'd rather know for sure!

 

[Ham]

All done now and charged OK, test run on the bike done and what a difference 14s makes over 12s. Fun fun fun.

I'm so pleased I gave this a go, it has given me much more confidence with batteries and it really was far more simple than I had worked it up in my mind to be.

Thanks for all the help to everyone on this forum for the write ups and how to's.

At times it seems very daunting reading through so much information on a problem and not quite fully understanding. My advice to anyone trying to do this is have a go, be careful, slow and sensible and all should be fine.

Learn by doing.

Thanks again.

 

[dogman dan]

FWIW, your guns are fine, they are just designed for a different type of solder job. all you need is a tip that is big, with lots of mass to hold heat.

Learn by doing is what this forum is all about.

 

[Ham]

I'm seeing that now from other posts that I've long forgotten the title of where people suggest a hammer shape tip: do you know the name of said tip so I can grab some?

Thanks

 

[Mugenski]

Found this listing however I don't see how to order it. Perhaps outs of stock? http://www.radicalrc.com/item/Hammer-Head-Soldering-Tip-103821 Maybe give them a call?

Also did you find you needed any special flux/solder to reattach the tabs? I'm hoping I don't have to use any of that nasty aluminum flux to get the job done.

 

[Ham]

Found this listing however I don't see how to order it. Perhaps outs of stock? http://www.radicalrc.com/item/Hammer-Head-Soldering-Tip-103821 Maybe give them a call?

Also did you find you needed any special flux/solder to reattach the tabs? I'm hoping I don't have to use any of that nasty aluminum flux to get the job done.

Ah so they are called hammer head tips, seems obvious now Thanks for the link.

I just used some old reel I had lying around as I read in another thread that someone else had successfully used standard flux. My soldering is shite so I will keep a close eye on them but they seemed pretty firm and have performed OK so far...