HK hardcase packs preferred direction

[powersupply]

I there a preferred direction for HK hardcase packs?

I searched and could not find anything, not even a specsheet for LiPo hardcase packs.

Something like these:
http://www.hobbyking.com/hobbyking/...P_14_8v_20C_hardcase_pack_USA_Warehouse_.html

I see that the cells (pouches) are resting horizontally on top of each other, how fluid is the stuff inside?

Would the stuff in the pouches flow downwards if I'd mount them vertically?

It would be better for heat management and the cables would be much mor accessible.

Thanks!

 

[dogman dan]

They can go any direction you like. There is electrolyte inside, but mostly the insides are many folded layers of foil and plastic.

 

[powersupply]

Thanks, Dogman

Had seen manufacturing processes, that stuff which was spread between the foils looks like some dark paste and looks quite fluid.

Read that when heated, it gets even more fluid, just didn't know how much.

 

[friendly1uk]

Mine are on their side. I didn't think about it at first, and I'm not 'entirely' happy about it. I was more concerned about disturbing their shape though. They seen fine though and I never found any warnings about orientation anywhere

 

[Toorbough ULL-Zeveigh]

any 'dry' cell (i.e. sealed) is or should be free from orientation.

 

[dogman dan]

What you need to worry about is excessive vibration. Even inside the hard case, packs can get damaged. For that issue, lying on their sides, flat side of the pouch horizontal should be best. Upright, they will put all downward forces on the pouch ends.

I don't think the fluid moving is an issue. Running at a c rate that heats a pack too hot to hold onto would be a problem in many ways though. This is why I consider a 20c hobby king pack to be usable at 5c at most, and preferably less.

 

[DAND214]

I have mine, laying flat and standing up.

My only worry at this point is, That they are going the same direction I am!.

Dan

 

[dnmun]

i don't think the lipo has a liquid electrolyte like the lifepo4 pouches. i think it is a solid polymer that is in contact with the separator, but not sure since i have never seen them manufactured.

i do recommend removing the shrink wrap and the plastic stuff and putting them into a single pack with the hardboard end plates and wrapping with duck tape to keep them in compression. along with using a BMS to protect them which i think is more important than the orientation.

 

[friendly1uk]

I have mine, laying flat and standing up.

My only worry at this point is, That they are going the same direction I am!.

Dan

Whats that? They are swelling a bit in the middle? lol


Dnmun, why would you strip them? I'm quite committed to using nothing but hard case batteries because they're designed for crashing and are easy to tie down.

I won't call the bricks firewalls, but the separate cases could offer a small delay between one set of 4 cells going up, and the other sets following. Especially if you keep some distance between them, or an actual firewall.

It is a pity the cases are not fire retardant. Then we could pipe from them to a suitable exhaust point. Perhaps under the seat so you can do a rocket-man impression lol

 

[dnmun]

i am not like you guys. i do not consider there to be a risk of fire if the pack is being protected by a BMS. without the risk of balance wires shorting there is no reason to think a cell can overcharge to the point it becomes a risk.

i take the shrink wrap off because i feel that the distortion of the corners of the pouches is a risk to the life cycles of the pack. i already covered how i build the lipo packs up on the other threads. http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=54257

i consider the hardboard end plates to be superior protection to the shrink wrap.

 

[powersupply]

I so totally agree with you on the LiPo hype here. From buring down the house to killing Grandma and the kids.

Hinsightful/thoughtful engineering can avoid all that.

Interesting idea with the "distortion of the corners of the pouches is a risk to the life cycles of the pack". I thought those folded sides/corners were only for emergencies, in case the cell blows.

But what about the warranty?

 

[amigafan2003]

But what about the warranty?

Warranty? On a chinese lipo pack?

Haha, good one

 

[powersupply]

Now that they are present here in the US, I got mine from HK.
And I do have one pack with a bad cell.
If they won't take it back/exchange it, I'll withdraw the funds via CC.

 

[dnmun]

how do you know you have a bad cell? did you charge it up and it won't hold a charge?

 

[powersupply]

Yes, I did exhaustive research before getting them and followed the suggestions of going easy on them in the beginning.

I noted serial# of the packs and recorded their volrtages when I got them.
That one cell was low from the beginning, around 2.8V vs 3.8 to 3.9V from the rest.
There was another cell low, too, but that is OK now.

Then I manually charged just that cell slowly up and then paralelled all and charged the whole pack, again, slowly and not too high.

Discharged slowly also, not too low.

rinse&wash with slight upping the limits.

After 3 cycles separated all packs and checked individual cells, all within a few mV.

Except that cell, it dropped to 3V just by sitting there.

Even after individual pack discharges, all cells were below 10mV.

 

[friendly1uk]

i am not like you guys. i do not consider there to be a risk of fire if the pack is being protected by a BMS. without the risk of balance wires shorting there is no reason to think a cell can overcharge to the point it becomes a risk.

i take the shrink wrap off because i feel that the distortion of the corners of the pouches is a risk to the life cycles of the pack. i already covered how i build the lipo packs up on the other threads.

i consider the hardboard end plates to be superior protection to the shrink wrap.

Oh, I did hear you say shrink wrap, but these are hardcase packs.

 

[dnmun]

inside the hardcase packs there is a space between the pouches and the plastic shell and they use strips of foam tape to fill the space between the pouch and the hard case.

add up four walls of this type and you have added about 1 1/2" to the length of the pack along with all the loops of conductors that have to loop up over the top of the pack and back down to the next one in series. and the super soft silicon sense wires with 6A of charging current on some types of balancing chargers.

to me it just makes sense because that is how i rebuild the ping packs to keep them alive. makes it so easy to replace an individual pouch that way too.

but i did build the 24S lipo pack and left them in the shrink wrap too but it is not my battery.

 

[friendly1uk]

It is interesting to hear how the manufacturers packaged them. Perhaps a little room to breathe is a good thing?
A quick search tells me it is normal for some to expand. Worry if it pushes the lid off.


Balance chargers are for models, where every gram counts. I'm surprised to hear you say such a thing

Edit: I got the spec. These lipo cells can expand 15% while discharging.