cmavr8

Hello everyone,

I have a 3 cell 1250mah (or 1300, can't really remember) pack, packed in a lot of newspaper and in a plastic/glass container.
I have left it like this for 2 months, after it had swelled like a baloon...

Last time I inspected it (horrified of the stories and videos about exploding lipos) I found out that only one of the three cells is damaged.

I was wondering (and searching the forum accordingly) if I can somehow disassemble the battery, take the defective cell out, and reassemble it, so that a useful 2-cell lipo will occur.

Has anybody tried it? Any tips on disassembling? I will google the web for assembly instructions (I don't think there are disassembling guides...) and use them reversed.

Thank you for reading!

Walt Thyng

My Feedback: (9)

Haven't had a chance to read it, but there's an article in the current Quiet flyer on jus this topic.
Walt

PS I've got the same problem with about four no=balance leads TP packs.

cmavr8

What do you mean by " four no=balance leads TP packs."? Do you have 4 broken packs? I think we can do it.

Look [link=http://www.dream-models.com/eco/LipoPack.html]here! [/link]. It should help...

Walt Thyng

My Feedback: (9)

Thanks Chris, looks like a very helpful site. I have several varieties of damaged packs. Three 2 cell TPs, two 3 cell TPs and an 8S2P Maxamps
Walt

cmavr8

Ok, I tried to do it!

I prepared the workspace (see pic, lipo is in the glass compartment), I unpacked the lipo and cut its plastics. I undid the soldered connections, too.

But I can't separate the cells! I want that 3rd cell out of there!

I think they are hot-glued together... They are really tight..

Any ideas on how to do it?

Thanks

peter_larsen

I think it's worse than hot glue, I belive the've used double sided tape to stick the cells together and that will be a pain in the b**t to separate.. I really don't have any good tips on how to do it since the cells are quite fragile and if you were to puncture one of the cells it could cause a fire.. I'd be very careful with that if I were you, having said that I just came to think of the rotor blades.. You could try to separate the cells by using the back edge of a rotor blade gently pressing it down between the cells.. It just might work, it's sharp enough to act as a knife but non metallic and the surface is smooth so it will hopefully not damage the cells..

Disclamer, you try this at your own risk, end disclaimer..

cmavr8

Hey peter! Thanks for the reply..

I think I am lucky if it is double sided tape... I don't see anyway unglueing hot glue when you have no access to it...

The rotor idea is very good! I will try it with an old/broken blade. I think I'll go with the samurai style... Outside (balcony) with a manned fire extinguisher (and a couple more standing by) and of course the camera+tripod, in case we have a nice fire...

My only concern is, can they EXPLODE? Or just catch fire like we've seen in videos??

(I fully understand you are not responsible for anything that happens to me, even if the idea was yours... )


BTW: those pictures of you flying heli: are LOVELY!

cmavr8

Ok, I [link=http://www.rcuvideos.com/view_video.php?viewkey=815b7e38a9dad05ad42e]did it![/link]
( click on the link above to see the video)

The pictures show the third cell, the other two cells, and the 3rd cell packed in plastic bag, so that it does not have enough oxygen to catch fire... (it will stay at the balcony for about a month...

cmavr8

I have a 3 pin connector, and want to make this 2-cell lipo a charge-balanced one... Do you know how I should connect the three cables to the 4(actually 3) terminals of the lipo?

I have the picture of the original, 3-cell lipo being balance-connected, if that helps...

cmavr8

Ok, update. I contstructed the 2cell battery. It is charging right now (balanced).

I wish it works and it does not explode.

I'll test it in the morning and brief you.

(Cooking monitor shown in picture. The alarm will go off if a set temperature is reached...)