Another LiPo fire.. - Page 4 - RC Groups
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Jan 20, 2004, 08:18 AM
Registered User
Can you charge the individual cells from the center tap or is it just for checking voltage.
Seem like one good solution is using a plug-in pcb board for pack construction that allows you to unplug to charge cells individually.
I'm sure this has already been mentioned. I think someone already sell something like this.
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Jan 20, 2004, 08:39 AM
Fly For Fun
Can individual cells (in a Li Po pack say 3S2P Tanic) be monitored while charging is taking place?

Mike
Jan 20, 2004, 09:52 AM
Alphabandaid

Like the grill idea.


Actually, I've been using Lipos since they came out a year ago, ballooned one pack when I charged it aon nicad setting.
Other than that, I have very little time and experience with nicads or hydrides since I got into electric abotut the same time.
I like the grill idea for charging, and will go and get one this week. After reviewing the video, the flame seem to dictate a cover of some sort, more than the open pyrex dish I use.
Also, a fire extinguisher, and smoke alarm in area of the charger would be good idea, and dedcated lipoly charger to avoid picking the wrong setting.
Stuka/Alphabandaid
Jan 20, 2004, 09:55 AM
Does anyone hear a cat?
headless's Avatar
Bill, yes, taps on packs allow you to not only check the voltage but also to charge each cell individually, allowing you to balance the pack whenever you choose. I have 2 TANIC packs with JST plugs embedded into the pack that allow balancing of each of the 3 cells. All TANIC packs sold nowadays have the option of taps being included on the packs.

funflyrc, not from what i have heard. The tanic taps, for example, all share the same ground wire, thus if you hook up any 2 taps or even the main charge lead and one of the taps, you will short the pack out and fry it. The taps are specifically made to check cell voltage and balance them out. Every few cycles i check each of the 3 cells in my 3s packs and make sure they are within .1v of eachother. If they are not, i charge each one separately until they are completely charged, thus are balanced.

I have a tp860 pack here that was damaged in a crash yesterday; nasty sickly sweet smell, no fire though. I think only 1 of the cells is damaged, perhaps 2. Anyone have input on WTH i should do with this pack? It's sitting in a big concrete area inside a fireproof container right now and has been for a day. No visible puffing of the cell but i can smell that nasty sweet smell and i'm just about sure one of those cells is FUBARed.... i am not comfortable trying to solder a lipo cell but i don't want to throw away all 3 cells if only 1 or 2 is fried...
Jan 20, 2004, 10:02 AM
Registered User
Is there a diagram anywhere to show how to wire in chargeable taps?
Jan 20, 2004, 11:20 AM
Registered User
WJ Birmingham's Avatar
Davensocal;

Not having read all of the replies since I posted last...

Would you please check (using another pack), your speed controller, and ensure it's cutting off at 3V/Cell?

WJ
Jan 20, 2004, 12:02 PM
Registered User
Headless,
To deliver a coup de grace to a bad Lipo immerse in some salty water for a day or two. This will render it impotent.
-Mike
Jan 20, 2004, 12:10 PM
PittsLover
houfek's Avatar
"immerse in some salty water for a day or two. This will render it impotent."


Jeez.......I'm staying out of the salt water !!

8*)
Jan 20, 2004, 12:14 PM
Registered User
Hofek, your on a roll. Your kill'n me!
Jan 20, 2004, 12:22 PM
PittsLover
houfek's Avatar
Bill......
You belong to too many threads.....
Jan 20, 2004, 12:34 PM
Registered User
and eveywhere I go ther you are.
Jan 20, 2004, 01:02 PM
Does anyone hear a cat?
headless's Avatar
does the cell have to be punctured for the saltwater to work on it?
Jan 20, 2004, 01:08 PM
Registered User
I think it discharges from the tabs
Jan 20, 2004, 01:19 PM
Registered User
There have been two salt water immersion scenarios discussed in the past:

The first is to immerse an unpunctured cell in salt water, which results in discharge through the tabs due to the salt water's conductivity.

The second is to puncture the cell with a non-metallic object after it has been discharged, and soak in salt water to neutralize the cell's electrolyte. This second scenario is not really necessary, and should probably be discouraged as someone might only get it part right and poke a hole in an undischarged cell with a metallic object, creating an instant dead short and major fireworks display. The goal should be the safest possible discharge before disposal of a bad cell.
Jan 20, 2004, 01:21 PM
Does anyone hear a cat?
headless's Avatar
Thanks Dave, i knew i had heard multiple scenarios involving saltwater but didn't remember the exact reasoning behind each one.

If only 1 or 2 of the cells in this pack are actually damaged can i send the pack to thunder power to get it re-created with replacement cells?

Daryl