Lumenier RB2205C-12 2400KV SKITZO Ceramic Bearing Motor
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Old Jul 13, 2016, 04:46 PM
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Charging a lipo with defect

I know, I know... lipo is dangerous and other important things. Ok, I know it.

I just want to know this other thing: I have a lipo battery 3S and one of the cells inside is with problem, it's not charging any more.

So I decided to do this: in the "white plastic" (plug) that I usually connect to my 3S batttery charger there are 4 wires: black (gnd) and other 3 wires yellow, blue and red. I discovered the red wire belongs to the faulty cell. So I did this: I "pulled" the red wire and removed it from the "white plastic" and I connected this "white plastic" to my 3S charger in the 3S port charger (it has a 2S port charge but I cant fit the white plugin the 2S port). The charger sad to me it recognized 2 cells and it's charging right now.

My question is this: is it safe doing this way? Should I at least buy a "white plastic" (plug) with only 3 roles (gnd and 2 cells wires) to charge this battery in the correct port of my charger?
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Old Jul 13, 2016, 06:05 PM
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Are you saying you have a 3S lipo with a bad cell and you have basically bypassed that cell and intend to use the 3S lipo with 2 charged cells and one 'bad' cell? If so, I strongly recommend you do not do this. The bad cell will still be part of the discharge circuit when in use unless you have also bypassed that cell with your discharge leads.

Don
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Old Jul 13, 2016, 06:11 PM
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In short, NO.

In what order are those colored wires starting with the black wire. Cells have 2 wires, not just one.
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Old Jul 13, 2016, 08:34 PM
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Respectfully I think you are all wrong. My charger said the 2 cells are fully charged and when I measure the voltage with a multimeter it says each cell has 4.2v. The third cell (which is the defect one) has 3.9v. I know it does not look it is defective but it is, when I try to charge that cell it takes tooooo long and it never gets to 4v. So I decided to charge 2 cells separetelly.
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Old Jul 13, 2016, 10:30 PM
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Bro, you do get the 2 cells charged and balance, but not the defective one.
The sequence is like this:
Cell 1 -, Cell 2 -, Cell 3 -, Cell 3 + which correspond to your description of color:
black, yellow, blue and red.

So you saying red one is bad, cell 3 is bad. You pull off the red, now blue becomes the Cell 2 +.
Your charger will recognize 2S. Max voltage is then 8.4V.
But your main power plug is still wired between all 3 cells and your charger will read 4.2+4.2+3.9=12.3V.
Surprise how your charger compare 8.4V and 12.3V and does nothing to cut off at some point..

There is a way to save it and make it 2S permanent but I won't tell you here. It doesn't look like you should do this operation.
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Old Jul 14, 2016, 01:11 AM
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Quote:
Originally Posted by prodriverex View Post
Surprise how your charger compare 8.4V and 12.3V and does nothing to cut off at some point..
Cheapo charger that does it through the balance taps?
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Old Jul 14, 2016, 02:01 AM
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Just wondering where you are going with this…..

Lets put the charging thing aside, it worked and your house is still standing.

You now have 3 cells connected together 2 of which are at a higher voltage than the other one. What are you going to do with the pack???? If you try to use it all 3 cells will start to discharge at roughly the same rate (experts please correct if I am way off track) and the voltage will reduce on each cell, also at roughly the same rate.

Your ‘poor’ cell will over discharge damaging it further until it goes bang (once again, experts please correct if I am wrong).

I can’t see the point in risking your house for something which you won’t be able to use afterwards with any degree of success.

Just wondering where you are going with this…..

Paul
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Old Jul 14, 2016, 12:09 PM
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Remove the dead cell from the pack, bypass it and end up with a perfectly good 2 cell pack. Leaving it in place is dangerous, how are you going to draw power out of the remaining 2 cells without going through the damaged 3rd cell?
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Old Jul 14, 2016, 12:15 PM
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no remove bad cell its still getting voltage thru it so remove and install 2 cell lipo balance plug//

unsafe
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Old Jul 14, 2016, 06:40 PM
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Quote:
Originally Posted by batata003 View Post
I know, I know... lipo is dangerous and other important things. Ok, I know it.

I just want to know this other thing: I have a lipo battery 3S and one of the cells inside is with problem, it's not charging any more.

So I decided to do this: in the "white plastic" (plug) that I usually connect to my 3S batttery charger there are 4 wires: black (gnd) and other 3 wires yellow, blue and red. I discovered the red wire belongs to the faulty cell. So I did this: I "pulled" the red wire and removed it from the "white plastic" and I connected this "white plastic" to my 3S charger in the 3S port charger (it has a 2S port charge but I cant fit the white plugin the 2S port). The charger sad to me it recognized 2 cells and it's charging right now.

My question is this: is it safe doing this way? Should I at least buy a "white plastic" (plug) with only 3 roles (gnd and 2 cells wires) to charge this battery in the correct port of my charger?
Quote:
Originally Posted by batata003 View Post
Respectfully I think you are all wrong. My charger said the 2 cells are fully charged and when I measure the voltage with a multimeter it says each cell has 4.2v. The third cell (which is the defect one) has 3.9v. I know it does not look it is defective but it is, when I try to charge that cell it takes tooooo long and it never gets to 4v. So I decided to charge 2 cells separetelly.
LOL!!!

a) why ask the question if you "know" the answer?

b) where do you live? I want to monitor your local news site for when your house burns down?
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Old Jul 15, 2016, 05:54 AM
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Have you tried charging the low cell by itself through the balance tap to get it fully charged?? I've never even took the time to remove a cell from a 3s pack to make it a 2s pack. 2s packs can be replaced for under 10 bucks so I see no point in the risk of time involved.
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