Changing the # of cells in a LiPo pack

[SB]

Could i buy a 6S pack at 4500mAh and cut it apart and make it 2 3S packs at 4500mAh?
the batteries are all in series inside a pack so the amperage should not change.
i am very good with a soldering iron.
Can this be done? I'd just have to buy bulk balance connectors for 3S packs and solder them on.
sounds like no big deal to me.

What do you think?

Thanks in advance

[kgfly]

In theory yes, but why on earth would you ? I don't think you would save much, if any, money over simply buying two 3s packs from the start.

It is dangerous and there is a high probability of damaging one or more cells. Apparently soldering to the thin aluminium tabs on the individual cells requires special solder/flux and is quite hard to do safely and successfully. Not recommended.

[SB]

I'm just finding 6s packs on sale left and right.
seems to be a popular size for small-mid size electrics.
well thank you for the info. I'm gona research the flux/solder part alot!! more before i dive in.
I'll definitely post the results when/if i attempt this.

Thanks again for the fair warning

[SB]

Well I Started with a 2S1P Experiment.
I wanted to make my own LiPo night blade so i needed to split a 2S Pack.

After removing the shrink wrap, getting the double stick tape to let go between the two cells,
the fun part began. i decided to remove the built in balancers from the cells to get a feel for working on the actual LiPo Leads.

I found that 465 Degrees Celsius works great. if You Don't Have a Commercial Grade Soldering System. you could use a quality 30 Watt Soldering iron. (Which is about 480 Degrees Celsius). after talking to some of my other electrical engineering friends. LiPo's should not have a soldering iron of that size on them for more then 6 seconds. or you WILL damage the cell. also make sure the iron is all the way warmed up before you start, some of my friends always try to rush and use the iron 10 seconds after they plugged it in.

ok now that I'm done babbling.

To solder a new LiPo cell that has never been used in a pack before you must know how to use Flux and Solder.

To solder a cell that you are taking out of a pre-made pack like you buy from the hobby store. most of the hard work is done for you as the packs already have solder on the leads. all you need to do is (BE CAREFUL) reheat the solder on the LiPo lead remove the Wire leads. either mark the leads before you take them off, or use a Multi Meter to figure it out later.

Soldering new leads on is the same as coming off a battery pack.
Tin your lead first.
less then 6 seconds on the battery pack.
seal your work.

Hope this helps some of you out there.

P.S. if any of you have a fancy soldering iron that uses ultrasonic pulses to do the work instead of just a heat element DO NOT USES THEM. i tried the pack immediately Puffed and within 30 seconds combusted.

[Automan]

I did cut away a swollen cell from a lipopack once.... it was dangerous, sitting there with a exactoknife a milimeter from a swollen cell, cutting with a very gentle touch and knowing what would happen if i slip. But all went well, cant by any means recomend anyone doing something like that, it is dangerous and stupid, and should be avoided at all cost.

Split up lipopacks as SB did is maybe not that dangerous as playing with a swollen lipo, but it is still dangerous and in my opinion should be avoided... not worth the risc, there are no gain in price etc... it could end very bad.

The above is NOT something a newbie in electrics and soldering should try, it would for sure end very bad, possible death. It is not a thing to be taken lightly for your own sake.

[SB]

:eek: I forgot the disclaimer

i agree with Automan
playing with this battery technology in any way shape or form is a risk in itself!!!

The Whole time i had 2 chemical Fire Extinguishers Within less then an arms reach from me as well as i had my dad in the next room watching tv with his extinguisher next to the couch.

This is not something for the faint of heart. it is an attempt at your own risk.

[kamtsa]

[QUOTE=SB;428935] I forgot the disclaimer [/QUOTE

Too late, the house is burnt down and my eyebrows are gone.

;-)

Kam

[Gary JP4]

Just for the record the chemical fire extinguishers wont put it out. They might help put out the others things that the Lipo fire ignites but may not last long enough for that either, especially on a big Lipo. Covering it immediately with sand works pretty well at suppressing the fire but the smoke keeps coming out at a reduced level. I would keep a healthy quantity of sand on hand in a large container to dump on the Lipo and a fire extinguisher on hand for the things that start on fire before you get the sand on the Lipo. For all this to work it assumes you don't get burned to badly to fight the fire. You may want to have back up. I would do it outside.

Where did you get your heat shrink? It looks like it would take about 5 inch dia heat shrink or bigger for a 3 cell.

[SB]

I get my Heat shrink from 3M. :) I really like there 3:1 leaves room for error when ordering