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› Front pack in series puffs but rear does not?
11-20-2011 11:41 AM  6 years agoPost 1
LaurenceGough

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UK

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Hi guys,

I have seen on the Logo 600 that front packs puff more than rear packs, is there a reason for this?

Considering that both packs are charged/handled the same way and the leads are pretty much the same total length.

mAh draw is also the same with both packs.

Could it be because only the rear 3/4 of the front pack is supported on the tray?

As for heat that my friend says - I think at most it will only be a few degrees more than the rear pack?

I have seen around 4 sets of packs like this, but never the other way around (rear pack puffed).

Me and my friends are really confused over this..

Cheers,

Laurence

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11-20-2011 11:50 AM  6 years agoPost 2
MrMel

rrProfessor

Gotland

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Could be, or tight straps, or just unlucky.
I use a U shaped alu piece and lockstraps, minimum tension on the pack yet secure.

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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11-20-2011 12:06 PM  6 years agoPost 3
kiksko

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San Lorenzo, CA

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+1 Thanks MR Mel

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11-20-2011 04:52 PM  6 years agoPost 4
LaurenceGough

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UK

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Thanks, I was thinking of using a battery tray - this would also prevent the pack from sliding forwards.

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11-20-2011 05:26 PM  6 years agoPost 5
Gregor99

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Western Wa

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What brand and C rating are the packs?
Considering that both packs .... the leads are pretty much the same total length.
Are you sure about that? Most stick packs I've seen have short extentions from the rear pack to the front, where they connect to the ESC. Whereas the leads for the front pack are often shortened.

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11-20-2011 05:36 PM  6 years agoPost 6
MrMel

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Gotland

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To be honest, I've been at this before, ever since I started with Helis (pretty much when Lipo started to make it), when a failure occur of a pack its often outer cells, I mean probably 90% of all my pack failure over the years has always been the outer cell of a pack.

I even asked the factories if they could say, if its the pressure or if its the microbursts from the heli, but they cannot say either, simply put they do not know.

However, don't know if its just me being lucky with my last set of packs, or if its just this change (lock straps + tray) but my Logo 600 packs are from 2009-05 all of them, and I have had ONE pack failure, and it was a pack that I had crashed once.

So if that just pure luck or not, I do not know, takes too long to do real tests, but I figure it cannot hurt if you can strap them down not so tight.

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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11-20-2011 06:34 PM  6 years agoPost 7
Gregor99

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Western Wa

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Agreed. Excessive presssure on the packs is not good for them. As the pack may expand slightly during flight, there should be a little in the straps to accomodate.

Regarding failurem, I've the same experience. Failing cell is using the outside one. I most cases its the cell exposed to the strap vs the cell sitting on the tray. Concentrated pressure from the strap may be contributing, vs uniform pressure from the tray.

But its been a very long time since I lost pack due to puffing or failing cell. These days most of my packs are retired because they are tired, uniformly across all cells. Or I want to move on to a better quality, higher C rated pack.
I use a U shaped alu piece and lockstraps
Do you have a picture of that?

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11-20-2011 06:43 PM  6 years agoPost 8
PC12DRVR

rrKey Veteran

USA

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Couldnt it be from temps, the front packs are under the canopy on most helis and the rear are a little more exposed to airflow.

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11-20-2011 07:29 PM  6 years agoPost 9
LaurenceGough

rrElite Veteran

UK

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The packs have always been of a high C rating and I'm talking about two 6 cell packs, the leads make an identical length from the pack exits. (i.e series pos and neg is the same length direct to ESC).

As for straps, well the rear one has always been the same tightness in the models. I know packs can be damaged by micro crystals on physical pressure/impact so I tend to keep them untouched other than by velcro under and the anti slip mikado straps.

Possibly the front pack is moving around a little more but I find it very hard as it's well strapped on, with velcro under and joined to the rear pack by lots of tape.

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11-20-2011 08:26 PM  6 years agoPost 10
MrMel

rrProfessor

Gotland

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Do you have a picture of that?
Check metalic's picture in this thread, he used my version as template.
https://rc.runryder.com/t651716p1/

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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