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Jan 21, 2020, 06:46 PM
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Scaling measurements I have taken from 1600mAh and 2200mAh 75C Panthers at 25*C gives a figure of 5.2m.ohms/ cell which ties up with Rick’s figures. The readings were taken after a few cycles and at 100% charged.
As delivered and non cycled would be a little higher; perhaps 10% or so.

Wayne
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Jan 22, 2020, 03:23 AM
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thank you both
Feb 24, 2020, 08:36 AM
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current Panther without PCB (same as original Graphene)?


Hi,
I need to reassemble 3 pieces of Panther 1600mAh 4S 75C into two 6S packs ( with 3 stacks of 2S side by side).
Are current Panthers without PCB (same as original Graphene)?

I have performed such procedure in the past for low current applications by simply splitting the solderable surface of cell joiners. Obviously this will not work well for high currents. Rampman described the correct procedure in this post https://www.rcgroups.com/forums/show...postcount=1719

It would help to know whether I have to deal with a PCB or not.
Thank you
Feb 24, 2020, 11:02 AM
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Quote:
Originally Posted by hamburger
Hi,
I need to reassemble 3 pieces of Panther 1600mAh 4S 75C into two 6S packs ( with 3 stacks of 2S side by side).
Are current Panthers without PCB (same as original Graphene)?
...
Thank you
Yes, they are assembled the same.
Just last week I split two 6S 1300 and two 6S 1200 packs into 2 and 3 cells and they were built the same as the link you put in your above post.

Just make sure you cut the tabs apart as tearing them apart sometimes results in the tab tearing next to the cell rendering it useless for air but maybe salvageable for ground use. I also try to make each tab as long as possible so I have more area to work with.

Rick
Mar 25, 2020, 06:43 AM
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acceptable cell IR variance for Graphene Panther?


I did 2 cylcles (3A charge, 5A discharge), then charged again and rested.
Measured with original WGmeter :

4S 1600 Graphene Panther ( to be split and repacked as two 6S packs)
I ... 3.24 . 3.32 . 3.40 . 3.20
II .. 3.36 . 3.32 . 3.24 . 3.16
III . 3.40 . 3.40 . 3.28 . 3.56

3S 1500 Graphene Panther ( to run in series as 6S stick pack)
I .. 3.24 . 3.36 . 3.48
II . 3.44 . 3.24 . 3.36

These packs will see loads of 50A continuous with peaks of 120A.
To me, the variance in cell IRs is too large - iI had expected something better or is this normal with Graphene Panther?
Last edited by hamburger; Mar 25, 2020 at 06:58 AM. Reason: typo number
Mar 25, 2020, 01:57 PM
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Quote:
...To me, the variance in cell IRs is too large...
You're kidding, right?

These are extremely consistent and FOM is over 2 for all cells. Amazing packs!
Mar 25, 2020, 03:15 PM
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Quote:
Originally Posted by mrforsyth
You're kidding, right?

These are extremely consistent and FOM is over 2 for all cells. Amazing packs!
+1

Average variation is around 5% with one worst case of 8%. Way better than most lipos + high FOMs

Wayne
Mar 26, 2020, 03:22 AM
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Quote:
Originally Posted by mrforsyth
You're kidding, right? These are extremely consistent and FOM is over 2 for all cells. Amazing packs!
Quote:
Originally Posted by Wayne Giles
+1
Average variation is around 5% with one worst case of 8%. Way better than most lipos + high FOMs
I have little experience with good lipos in demanding applications and this time wanted to do it right. thanks for the thumbs up.
Mar 27, 2020, 08:46 AM
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Quote:
Originally Posted by rampman
Just make sure you cut the tabs apart as tearing them apart sometimes results in the tab tearing next to the cell rendering it useless for air but maybe salvageable for ground use. I also try to make each tab as long as possible so I have more area to work with.
Rick,
the two corresponding tabs are lying flat over each other (like two pieces of paper) and have been bonded/welded over a large area. When you say 'cut tabs apart' do you mean to separate the two sheets (like cutting trough the entire area between the sheets) or do you mean to cut the welded-double-tab into two smaller area pieces (one half hanging to each cell)?
Mar 27, 2020, 01:40 PM
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Quote:
Originally Posted by hamburger
Rick,
the two corresponding tabs are lying flat over each other (like two pieces of paper) and have been bonded/welded over a large area. When you say 'cut tabs apart' do you mean to separate the two sheets (like cutting trough the entire area between the sheets) or do you mean to cut the welded-double-tab into two smaller area pieces (one half hanging to each cell)?
No, you will need to make a choice to cut the joint on one cell side or the other rendering one tab shorter than the other. I usually cut the longer tab a bit so it it easier to fit after wires are re-attached.
You will also then need some special flux to allow you to solder to aluminum for the shorter tab; maybe both but usually you will have some solder on the longer tab that you can solder a wire/wires to.

Rick
Mar 27, 2020, 06:09 PM
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Quote:
Originally Posted by rampman
No, you will need to make a choice to cut the joint on one cell side or the other rendering one tab shorter than the other. I usually cut the longer tab a bit so it it easier to fit after wires are re-attached.
You will also then need some special flux to allow you to solder to aluminum for the shorter tab; maybe both but usually you will have some solder on the longer tab that you can solder a wire/wires to.
ok, got it. Still waiting for the flux to arrive. Thank you.
Today, 01:12 PM
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If you have a bottle of Tabasco, empty the contents, clean and dry it. Then put the liquid (if a liquid and not a paste) into this so if it falls over your only lose a drop or two.
I lost a few bottles of that precious stuff due to the bottles breaking due to being so thin, even tightening the lid broke one bottle.
I also cut a 1x4 board to a 1x3x3 square with a hole in the middle of it an glued the bottle into it to prevent it from tipping over.

Rick


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