Where to Get Clear Shrink Wrap for LiPo - Endless Sphere

El_Steak

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• Jan 2,

• #1

After finding a few damaged cells in my Turnigy LiPo packs (1 busted at the seam and a few more leaking/puffy), I'd like to visually inspect the cells in all my turnigy pack. I will have to re-shrink wrap the packs afterwards and was thinking it would be neat if I could do it with clear shrink tube. That would allow me to regularly check for any sign of physical damage on my cells without having to open them up.

Anybody know were I can find clear (see-through) shrink wrap large enough for a turnigy 6s 25c 5ah pack? The pack has a perimeter of about 200mm so shrink wrap with a diameter of 75 mm would be fine. Or if the shrink wrap width is measured flat, then something around 115-130mm would work as well.

x88x

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• Jan 2,

• #2

Well, there's always mcmaster, but that gets pretty expensive with the large diameter stuff. One neat tip I found a while ago is to just use soda bottles. Since they're expanded plastic, when you heat them they contract. Plus, they're tougher and a lot cheaper than similarly sized heatshrink.

El_Steak

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• Jan 2,

• #3

x88x said: Well, there's always mcmaster, but that gets pretty expensive with the large diameter stuff. One neat tip I found a while ago is to just use soda bottles. Since they're expanded plastic, when you heat them they contract. Plus, they're tougher and a lot cheaper than similarly sized heatshrink.

Interesting idea, any preference on the type/size of bottle ?

texaspyro

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• Jan 2,

• #4

search for: battery shrink wrap on Ebay. 24 feet of heavy 5" for cheapish (12 bucks)

Also search for: battery heat shrink

x88x

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• Jan 2,

• #5

El_Steak said:

x88x said: Well, there's always mcmaster, but that gets pretty expensive with the large diameter stuff. One neat tip I found a while ago is to just use soda bottles. Since they're expanded plastic, when you heat them they contract. Plus, they're tougher and a lot cheaper than similarly sized heatshrink.

Interesting idea, any preference on the type/size of bottle ?

Just whatever size is a bit larger than the battery pack you want to enclose. At the price texaspyro mentioned though, it's a toss up. The stuff I saw on mcmaster was more in the range of $50-60 per foot.

EDIT:
Here's where I first saw soda bottles used (halfway down the page).
http://www.etotheipiplusone.net/?p=837

El_Steak

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Gatineau, Quebec

• Jan 2,

• #6

Thanks for the link texaspyro. This is really cheap ! I had searched ebay before posting, but I used the wrong search criteria and didn't see it.

I contacted the guy for a shipping quote to Canada.

I'll also give the x88x soda bottle idea a try.

• Jan 2,

• #7

Have you looked at a good hobby shop? I used to sell it buy the foot, all colors as well as clear. This was back in the Nicad rc car days.
A shop that is into rc cars would be a the best shot.
Dan

spinningmagnets

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• Jan 3,

• #8

This spring I will build a pack from Doctorbass cells, and I also would really like clear shrink-wrap/heat-shrink. Just to have the links in the same thread, ebikes.ca sells 20cm and 28cm wide dark shrink-wrap for $10 per meter of length. (bottom of link page).

http://www.ebikes.ca/store/store_connectors.php
View attachment ebikes.ca_heatshrink.jpg

McMaster-Carr also has clear heat-shrink in rolls of flat sheet. (instead of the common tube-style). You cut off a length, wrap the item, bond the edge with a heat-bar and then heat it up to shrink. (I've never tried this) Page "Heat-Shrink Film Spools & Tubes"

10" wide, X 500-foot roll, part # T6, listed as "CLEAR", 0.75-mil thickness. $30 for PVC, $38 for Polyolefin

"...Unlike stretch wrap, which utilizes the elasticity of the film to keep it tight, heat-shrink film contracts when heated to create a form-fitting barrier..."

Attachments

• clear_heat_shrink.gif

El_Steak

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Gatineau, Quebec

• Jan 3,

• #9

I ordered a roll of 4" and one of 5" from the ebay guy. Free shipping to the US and only 5$ to Canada.

Thanks texaspyro

ambroseliao

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Washington, DC, USA area

• Jan 3,

• #10

El_Steak said: I ordered a roll of 4" and one of 5" from the ebay guy. Free shipping to the US and only 5$ to Canada.

Thanks texaspyro

Yo, Steak...

Do you have the URL of the seller or to the items you bought?

Thanks,
Ambrose

El_Steak

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• Jan 3,

• #11

Here is the link

The same guy sells 5" wide as well.

I ordered both 4" and 5" (not sure which will better fit the Turnigy 6s packs, 4" might be a bit tight.)

ambroseliao

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Doctorbass

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• Jan 3,

• #13

El_Steak said: Here is the link

The same guy sells 5" wide as well.

I ordered both 4" and 5" (not sure which will better fit the Turnigy 6s packs, 4" might be a bit tight.)

Thanks for the link El_steak!
This guy is also selling this great nano pocket Scope for 54$ !! not bad for quick test!
http://cgi.ebay.com/ARM-DSO-Nano-Po...s=63&clkid=#ht_wt_905e

Doc

El_Steak

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Gatineau, Quebec

• Jan 11,

• #14

Got the shrink wrap today, it took 8 days, which is pretty darn fast using USPS to Canada!

Guys, this stuff is perfect, get some while you can!

In terms of thickess and texture, the wrap seems identical to the original blue wrap on the turnigy packs... except is clear !

The 4" wrap fits like a glove on my Turnigy 6s 25C mAh packs. It would probably be fine on 5s packs as well. The 5" wrap also fits, but its a bit too large and leaves a few wrinkles.

Since I got 24 feet of the damn thing, I TRIPLE wrapped my packs ! They feel real tight and rigid now.

Even with 3 layers of wrap, its still perfectly see-thru. I think this is essential to let you periodically inspect packs for leaking/busted cells. Having had that last season, I would have quickly detected my busted cells and would have prevented further damage to their brothers and sisters.

Big thanks to texaspyro for the find !

Here's some exciting shrink wrap pictures

texaspyro

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• Jan 12,

• #15

Damn nice shrinkage ya got goin' on there... also a great idea to keep some history data with the packs.

Doctorbass

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• Jan 13,

• #16

Elsteak,

is it really mAh out of a mAh after 100 cycles?

That is like 9-10% lost after just 100 cycles!..

do you use them at high C rate? or... maybe tested them at high C-rate?

Doc

El_Steak

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• Jan 13,

• #17

Doctorbass said: is it really mAh out of a mAh after 100 cycles?
That is like 9-10% lost after just 100 cycles!..
do you use them at high C rate? or... maybe tested them at high C-rate?

Yes and no

The number is not a full discharge cycle (4.20V to 3.0V). It is a more realistic real-life cycle (4.16V to 3.6V). My load of 2 x 12V 50W halogen bulbs in series is not very high so I only discharged at around 4.2A.

Still, I did lose some capacity but I can't say exactly how much because I didn't test the packs when they were new. I also had some weak cells, some puffy ones a even a completely busted one. You can see the discharge curves of all my packs after 100 cycles here: http://endless-sphere.com/forums/viewtopic.php?f=14&t=&start=240#p

I had to replace some individual cells in some packs and I am completely replacing 4 packs with new ones (they had busted/puffy cells).

All in all I'm really happy about the performance of the cells, but no so much about their durability.

Things I did right:
----------------------
-Never charged over 4.16V
-Never discharged under 3.65V (resting voltage)
-Never charged/discharged under 8-10 Celcius or over 30 Celcius
-Never discharged at over 7C (I run 3 x 25C packs in parallel)
-Never charged at over 1C
-Provided good physical protection for the packs, no bouncing around in a bag


Things I did wrong:
----------------------
-No cell-level LVC. Eventhough my cells are at 3.65V at resting voltage, some weaker ones might have dropped under 3V on heavy loads at the end of the ride (100A)
-Ran packs with puffy/busted cells in parallel with healthy ones (didn't notice)
-Charged the packs to a full 4.16V every evening after my commute. Left the pack fully charged for the weekend.

Corrective measures:
-------------------------
-Got some LVC adapters from geoff for next season
-Building a dashboard with multiple cell logs and buzzers to monitor my 24 individual cells while riding.
-Got some clear wrap to be able to inspect my packs for physical damage
-Buying 2 Hyperion i (W) so I can charge the entire pack in series in less than an hour in the morning, just before riding instead of the day before). Will never leave the packs in fully charged state for more than an hour.

I will run the same discharge curve tests at the end of next season to see if there was any improvement

texaspyro

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• Jan 13,

• #18

Storing the packs fully charged for the time intervals is no problem at all. The ditty about storing them half charged applies to very long term storage (months)... and even then the benefit seems to be minimal.

El_Steak

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• Jan 13,

• #19

texaspyro said: Storing the packs fully charged for the time intervals is no problem at all. The ditty about storing them half charged applies to very long term storage (months)... and even then the benefit seems to be minimal.

I based my assumption on a this paragraph in the Hyperion i charger manual:

Lithium Care
To maximize your investment in Lithium Battery packs, do the following: * ALWAYS Store your packs at 60%~70% capacity. After a day of flying, use STORE Mode to achieve this. It is especially harmful to store lithium packs fully charged, and should be avoided for more than a few hours at most. *
NEVER discharge cells beyond 90% of capacity (plan for 80% max).
NEVER fully discharge lithium packs.
* STORE your packs in a cool, relatively dry location.

itchynackers

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• Jan 13,

• #20

This doesn't bode well for those of us charging packs at a very low C rate (ie 0.1C). It takes many hours to charge up, thus the packs are above storage voltage for hours. Hmm. Is there an ideal charge rate that takes this into account? Sounds like some life cycle testing may be in order.

texaspyro

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• Jan 13,

• #21

El_Steak said: To maximize your investment in Lithium Battery packs, do the following: * ALWAYS Store your packs at 60%~70% capacity. After a day of flying, use STORE Mode to achieve this. It is especially harmful to store lithium packs fully charged, and should be avoided for more than a few hours at most.

Something tells me they are trying to FUD you into using their chargers that have the magic STORE feature. Just about every cell , laptop, or camera would be toast if it were true. I think that the extra discharge/re-charge cycles of doing the store would cause a lot more wear on the pack.

amberwolf

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• Jan 13,

• #22

I guess if their chargers are pushing the cells into absolute max charge states, then it could be bad for them to stay that way for long, but if they are charging to typical levels, then it shouldn't hurt a thing.

spinningmagnets

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• Jan 14,

• #23

I have read that charging to 4.1V per cell will significantly extend pack life, rather than the common 4.16V. I have no long-term experience with either.