Anyway to save a cell that's reversed pol.?
02-04-2010, 12:49 AM
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Anyway to save a cell that's reversed pol.?
Help, I need a battery guru!! 
Problem is I have afunky pack of batts and Im wonderingis there anyway to save a cell that's reversed polarity? (or reading negative volts) What happened was,I bought a 6V1100 MiMh "hump" pack for myRX, and 2 of the cells are reading negative voltage.. I'd send it back, but I've already cut the shrink off them and added a second set of leads for dedicated charging.. (All before I ever tested the pack, like a bozo) Anyway,I put it on the peak charger at 2a and it keeps peaking long before the negative cells could come back, if that's even possible..I was thinkin about cutting the pack apart and seeing if I could charge them one at a time (or at least the 2 bad ones) and then once they were back to positive I could put it back together??Any ideas, short of just tossing the thing? Thanks for any help or ideas.. It's already useless so any "theories" or experiments you wanted to try but never had a bad pack of cells to try on, lets hear it!
Thanks..
Problem is I have afunky pack of batts and Im wonderingis there anyway to save a cell that's reversed polarity? (or reading negative volts) What happened was,I bought a 6V1100 MiMh "hump" pack for myRX, and 2 of the cells are reading negative voltage.. I'd send it back, but I've already cut the shrink off them and added a second set of leads for dedicated charging.. (All before I ever tested the pack, like a bozo) Anyway,I put it on the peak charger at 2a and it keeps peaking long before the negative cells could come back, if that's even possible..I was thinkin about cutting the pack apart and seeing if I could charge them one at a time (or at least the 2 bad ones) and then once they were back to positive I could put it back together??Any ideas, short of just tossing the thing? Thanks for any help or ideas.. It's already useless so any "theories" or experiments you wanted to try but never had a bad pack of cells to try on, lets hear it!Thanks..
02-04-2010, 06:54 AM
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RE: Anyway to save a cell that's reversed pol.?
ORIGINAL: Mickstix
Help, I need a battery guru!! Problem is I have a funky pack of batts and Im wondering is there anyway to save a cell that's reversed polarity? (or reading negative volts) What happened was, I bought a 6V 1100 MiMh ''hump'' pack for my RX, and 2 of the cells are reading negative voltage.. I'd send it back, but I've already cut the shrink off them and added a second set of leads for dedicated charging.. (All before I ever tested the pack, like a bozo) Anyway, I put it on the peak charger at 2a and it keeps peaking long before the negative cells could come back, if that's even possible.. I was thinkin about cutting the pack apart and seeing if I could charge them one at a time (or at least the 2 bad ones) and then once they were back to positive I could put it back together?? Any ideas, short of just tossing the thing? Thanks for any help or ideas.. It's already useless so any ''theories'' or experiments you wanted to try but never had a bad pack of cells to try on, lets hear it! Thanks..
Help, I need a battery guru!!
Problem is I have a funky pack of batts and Im wondering is there anyway to save a cell that's reversed polarity? (or reading negative volts) What happened was, I bought a 6V 1100 MiMh ''hump'' pack for my RX, and 2 of the cells are reading negative voltage.. I'd send it back, but I've already cut the shrink off them and added a second set of leads for dedicated charging.. (All before I ever tested the pack, like a bozo) Anyway, I put it on the peak charger at 2a and it keeps peaking long before the negative cells could come back, if that's even possible.. I was thinkin about cutting the pack apart and seeing if I could charge them one at a time (or at least the 2 bad ones) and then once they were back to positive I could put it back together?? Any ideas, short of just tossing the thing? Thanks for any help or ideas.. It's already useless so any ''theories'' or experiments you wanted to try but never had a bad pack of cells to try on, lets hear it! Thanks..
What is cheaper:
1. To replace a $15 battery pack with a new one ? or
2. Replace a $200 worth crashed plane with a new one, and legal costs if your out of control plane hit someone/public/property. [sm=72_72.gif]
From a flight safety point you should not use that pack to fly with. A few years ago a boy was killed in the UK when an out of control RC plane crashed into the pit area. The police investigation and legal aftermath ruined peoples lives forever.
02-04-2010, 05:54 PM
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RE: Anyway to save a cell that's reversed pol.?
If the two cells are not installed reversed, and they still show negative voltage then they are goners.
02-04-2010, 11:35 PM
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RE: Anyway to save a cell that's reversed pol.?
OK, thanks for the info! I found a place that has 1500 mah cells that'll ship usps (ie: cheap) so I think I'll just get 2 new cells to save the pack.. It'll run me around 8 bucks for the 2 cells shipped.. Only question is, what negative effect, if any, will I have using (3) 1100 mah cells and (2) 1500mah?? Will the 1500's just act like 1100's, or will it mess up the entire pack? Thanks again!
Note: It's not for a plane.. Im not a flyer, just a rc trucker (basher), and I use a failsafe to apply the brakes if it senses less than 4v.. So, no deadly consequences will occur if I get to experimenting..
Note: It's not for a plane.. Im not a flyer, just a rc trucker (basher), and I use a failsafe to apply the brakes if it senses less than 4v.. So, no deadly consequences will occur if I get to experimenting..
02-05-2010, 12:51 AM
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RE: Anyway to save a cell that's reversed pol.?
If you mix 1500 and 1100 mah cells in a pack, the lower capacity cells (1100 mah) will overheat and short circuit......
see link for possible consequences......
http://www.youtube.com/watch?v=xAVMJ...layer_embedded
see link for possible consequences......
http://www.youtube.com/watch?v=xAVMJ...layer_embedded
02-05-2010, 02:06 AM
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RE: Anyway to save a cell that's reversed pol.?
Well, definitely dont want to burn up my truck! Guess I'll have to keep lookin for some 1100's..
Anyone know what size shrink wrap fits 2/3A "single" cells?? (My 3 remaining good ones are naked after deconstructing the pack..) Thanks again!!
02-05-2010, 02:45 AM
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RE: Anyway to save a cell that's reversed pol.?
If 2 cells in a pack is damaged, the other my have sustained some damage too.
It is not a good idea to tamper with a battery pack.
You can get heatshrink tubing (comes in all sizes) from any shop that sells electronic components. You buy it per length and should just be big enough to slide over the pack (leads sticking out one end.
Measure your pack, cut the heatshrink tube slightly longer (to allow for shrinkage) than the pack, slides it over the pack and heatshrink it with a heat gun. Be careful not to apply too much heat for too long or you can damage the battery pack. Should not take more than 15 sec to shrink it.
But by this time it is probably cheaper to just buy a new pack........
It is not a good idea to tamper with a battery pack.
You can get heatshrink tubing (comes in all sizes) from any shop that sells electronic components. You buy it per length and should just be big enough to slide over the pack (leads sticking out one end.
Measure your pack, cut the heatshrink tube slightly longer (to allow for shrinkage) than the pack, slides it over the pack and heatshrink it with a heat gun. Be careful not to apply too much heat for too long or you can damage the battery pack. Should not take more than 15 sec to shrink it.
But by this time it is probably cheaper to just buy a new pack........
02-05-2010, 03:10 AM
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RE: Anyway to save a cell that's reversed pol.?
Well, I could get a new one for 20$ or try and save this "new" one for 8$.. For what I need it to do (power 2 servos) I'll take the chance that the other 3 cells are ok.. If I was powering a high volt low turn modified motor with Lipo's or something, I'd be more concerned, but for my little nitro buggy it'll have to do.. But thanks for the info and warnings!
02-05-2010, 08:06 AM
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RE: Anyway to save a cell that's reversed pol.?
Mixstich.
Lets clarify some things. I assume you have a NiCad or NiMh 5 cell 1100mah battery. Two of the cells are bad.
You could replace the two bad cells. There will be no problem if you replace them with 1500mah cells. You will not overheat the 1100's. All that will happen is that the 1500's will still have some capacity left when the 1100's are discharged. BTW the fire in the link referenced is from a LiPo battery not NiCad or NiMh.
Glen
Lets clarify some things. I assume you have a NiCad or NiMh 5 cell 1100mah battery. Two of the cells are bad.
You could replace the two bad cells. There will be no problem if you replace them with 1500mah cells. You will not overheat the 1100's. All that will happen is that the 1500's will still have some capacity left when the 1100's are discharged. BTW the fire in the link referenced is from a LiPo battery not NiCad or NiMh.
Glen
02-05-2010, 08:03 PM
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RE: Anyway to save a cell that's reversed pol.?
ORIGINAL: huck1199
How does a cell's polarity change?
How does a cell's polarity change?
Glen
02-05-2010, 10:47 PM
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RE: Anyway to save a cell that's reversed pol.?
Thanks for the info Glen! They are infact NiMH cells.. I found another thread that said basically the same thing (that for just powering an rx., on a land based model, the mismatched mah should do fine) So I ordered the 1500's and some shrink wrap and will hopefully have it back in action here in a few days..
02-06-2010, 09:00 AM
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RE: Anyway to save a cell that's reversed pol.?
ORIGINAL: huck1199
How does a cell's polarity change?
How does a cell's polarity change?
