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Old Jul 01, 2012, 07:09 PM
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Low voltage level for PL8 where it won't even see cell anymore?

Hello all

I have a six cell Turnigy pack that has been showing signs of puffing lately, so I brought it home and watched more closely the charging on my PL8 and from even plugging it in, it reads it as a 5 cell pack.

Btw I have two complete PL8's, each with its own adapter boards and tried it on both and got the same.

Then I took one of those little red multi-cell testers that plugs into the balance tap and its showing normal voltage for all cells except number 5 which is at .015

Also btw I have even tested this with a Fluke meter and some tinny pins and for sure the number 5 balance tap lead reads this low voltage so its not like there is just a break in the wiring inside the pack (I would guess).

I think I read somewhere that in general, all the Cell Pro lines have a cut off level of a about 1.5v for a cell and then after that, it doesn't even recognize it as a cell anymore?

So this would explain why it's not seeing it, but I just wonder if that number of about 1.5 is correct?


Oh one other question if someone might know.

For the IR on cells 1-4 on the PL8 read out, I get some pretty even numbers of 2-3 ohms, but then number 5 is like 23-25.

Am assuming one, as number 6 cell on my little tester is showing good, that the number 5 of the PL8 is actually this 6th cell. And as well as since with that tester and even by the PL8, is showing the same volts as the others, that this high ohm reading might be because of something where the IR runs through all the packs and back via the discharge plug. Or more simply put, the 5 cells IR reading is somehow including the 5 bad cell along with the 6th?

Basically just was thinking that this pack is probably shot and there's nothing I can do for this 5th cell. But as I have 3 others of the exact same type, and will probably now have to get a replacement for this one, that I can save this pack for the other 5 good cells in case I happen to loose one of two of any of the other I have, perhaps I can Frankenstein up a pack from spare cells from this pack.

But just want to know of which of the ones left in this pack are OK.


Thanks for any help.
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Old Jul 01, 2012, 08:13 PM
President, FMA, Inc.
Tim Marks's Avatar
Joined Mar 2008
1,059 Posts
Quote:
Originally Posted by WBFAir View Post
Hello all

I have a six cell Turnigy pack that has been showing signs of puffing lately, so I brought it home and watched more closely the charging on my PL8 and from even plugging it in, it reads it as a 5 cell pack.

Btw I have two complete PL8's, each with its own adapter boards and tried it on both and got the same.

Then I took one of those little red multi-cell testers that plugs into the balance tap and its showing normal voltage for all cells except number 5 which is at .015

Also btw I have even tested this with a Fluke meter and some tinny pins and for sure the number 5 balance tap lead reads this low voltage so its not like there is just a break in the wiring inside the pack (I would guess).

I think I read somewhere that in general, all the Cell Pro lines have a cut off level of a about 1.5v for a cell and then after that, it doesn't even recognize it as a cell anymore?

So this would explain why it's not seeing it, but I just wonder if that number of about 1.5 is correct?


Oh one other question if someone might know.

For the IR on cells 1-4 on the PL8 read out, I get some pretty even numbers of 2-3 ohms, but then number 5 is like 23-25.

Am assuming one, as number 6 cell on my little tester is showing good, that the number 5 of the PL8 is actually this 6th cell. And as well as since with that tester and even by the PL8, is showing the same volts as the others, that this high ohm reading might be because of something where the IR runs through all the packs and back via the discharge plug. Or more simply put, the 5 cells IR reading is somehow including the 5 bad cell along with the 6th?

Basically just was thinking that this pack is probably shot and there's nothing I can do for this 5th cell. But as I have 3 others of the exact same type, and will probably now have to get a replacement for this one, that I can save this pack for the other 5 good cells in case I happen to loose one of two of any of the other I have, perhaps I can Frankenstein up a pack from spare cells from this pack.

But just want to know of which of the ones left in this pack are OK.


Thanks for any help.
Hi:

Do yourself a favor and discard that battery pack. The sooner the better. Do it safely, but get rid of it. You have enough evidence to know the pack is no good. You don't want to "frankenstein up" a pack. It sounds like a good idea, but it really isn't. You never want to put old worn out cells with good cells in a pack. Any pack is only as good as the weakest cells. You'll just keep chasing your tail on this one.

My 2 cents.

Tim Marks
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Old Jul 01, 2012, 08:20 PM
Registered User
United States, CT, Stamford
Joined Jan 2007
819 Posts
Quote:
Originally Posted by Tim Marks View Post
Hi:

Do yourself a favor and discard that battery pack. The sooner the better. Do it safely, but get rid of it. You have enough evidence to know the pack is no good. You don't want to "frankenstein up" a pack. It sounds like a good idea, but it really isn't. You never want to put old worn out cells with good cells in a pack. Any pack is only as good as the weakest cells. You'll just keep chasing your tail on this one.

My 2 cents.

Tim Marks
Yeah, I'm kinda 99% leaning that way myself.

A buddy of mine just did a make up from two bad six's into one good one just this week and flew it today and it worked pretty good. Showed me all the work he did as he hasn't shrinked it yet (wrapped good with tape though just to test) and it didn't seem that much.

After this post though I took the wrap off the pack and was looking at it and was was like, hmmm, $75.00 for a new pack or the risk of having one blowup in my face and just think I might have to think about that some more.

I'm pretty fuggly enough by natural causes, don't need to help that along any.

At any rate, still might like to hear some info on the first part of this question if anyone knows.
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Old Jul 01, 2012, 08:24 PM
President, FMA, Inc.
Tim Marks's Avatar
Joined Mar 2008
1,059 Posts
Quote:
Originally Posted by WBFAir View Post
Yeah, I'm kinda 99% leaning that way myself.

A buddy of mine just did a make up from two bad six's into one good one just this week and flew it today and it worked pretty good. Showed me all the work he did as he hasn't shrinked it yet (wrapped good with tape though just to test) and it didn't seem that much.

After this post though I took the wrap off the pack and was looking at it and was was like, hmmm, $75.00 for a new pack or the risk of having one blowup in my face and just think I might have to think about that some more.

I'm pretty fuggly enough by natural causes, don't need to help that along any.

At any rate, still might like to hear some info on the first part of this question if anyone knows.

...or burning your house down, god forbid, because you wanted to save $75 on a new battery pack with fresh cells. A puffing battery is a forewarning and one you should heed. Li is not something to play around with and you should not be skimpy when it comes to respecting their potential.

Tim Marks
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