oOple.com Forums - lipo swelling

oOple.com Forums (http://www.oople.com/forums/index.php)

- Electrics (http://www.oople.com/forums/forumdisplay.php?f=26)

- - lipo swelling (http://www.oople.com/forums/showthread.php?t=87892)

Quote:

Originally Posted by discostu (Post 594054)

dont get me wrong darren vampire products in my view are very good except the lipos i can name at least 5 drivers who have bought these and within a month or so they are showing sign of swelling ive also had some in the past, no reason for it as they were charged corretly and all the rest of it.
i will never buy a vamprire lipo again sorry this is my opinon.

i have also used track power,ip,demon,turnigy and never had swelling issues and unfortuantly due to my experience with these lipos i would not recomend them to anybody

diff grease on the other hand and dms service second to none.

stu

Stu, thanks for the honest and constructive feedback. As the distributor of these we genuinely have had very few back, less than 10 in 3+ years, which is all we can ever go by. As a "retailer" we have had LIPOs returned from ALL brands at some stage with swolen or split cases, some through faulty product and others through misuse.

However one thing we have seen on ALL the more recent high "C" rated packs (ALL brands) is that there is far less room inside the case to start with, wheras on the earlier 25-40C packs there was spare space a plenty inside the casing (and the cases were thicker too). According to the factory (a VERY well known LIPO manufacturuer) nearly ALL LIPOs swell ever so slightly when first used (almost un-noticebale in some cases) and with the more recent 60C+ versions this is more noticeable as the case will move ever so slightly causing concern the pack is "swelling up". This has come direct from the factory and has proven to be solid information. It is also why when you look at many of the soft case LIPOs they are rarely flat, they take up a natural slight curved shape which is exactly what is going on inside our hard cases of today.

But please dont anyone misunderstand what I am saying here, there is a huge differance with a minor distortion on a case that causes it to "rock" on flat surface by tiny (almost zero) amounts to LIPOs that have been harmed or gone faulty that are "obviously" swollen badly or splitting the case apart, the two should never be confused

Quote:

Originally Posted by Darren Boyle (Post 594063)

...According to the factory (a VERY well known LIPO manufacturuer) nearly ALL LIPOs swell ever so slightly when first used (almost un-noticebale in some cases) and with the more recent 60C+ versions this is more noticeable as the case will move ever so slightly causing concern the pack is "swelling up"....

Wasn't there a big problem with swelling at the world's this year, with many top team racers having their lipos 'failed' due to swelling up beyond legal size?

I have a year old Orion pack that I have looked after very well, always balanced and never let go flat, which has swollen up a bit but it seems to work just fine.

On the other hand, I have an old Core RC pack which I connected the wrong way round, and that has swollen up to the point that the case has split open by about 10mm!:woot:

Quote:

Originally Posted by F1END (Post 594237)

I think the problem at the worlds was due to the case size and not Lipo's swelling. Alot of the guys at the worlds take brand new cells with them, in fact I heard that a couple of people used budget club packs with a low 'c' rating for 2wd.

A template was used, and if the lipo did not fit (therefore not meeting the size guidelines) the drivers were allowed of sand the case down until it fitted (madness is my opinion)!!

Regarding Lipo cells in general, like servo's, esc's and most probably motors there are only a few companies in the world who manufacture lipo's. The majority of the different cells come from only a few manufacturers.

Darren is correct, with the latest high performance lipos there is no space in the cases for the cells to expand - and all lipo cells will expand slightly when first used to reach their optimum performance. Very minor swelling on these kind of packs shouldn't be a problem - providing it doesn't get any worse and performance doesn't drop off.

I'm not convinced there are only a handful of lipo manufacturers in the world - I think there are a lot more than people think. Based on the number of e-mails I receive every week from Chinese lipo manufacturers trying to sell me cheap packs there are quite a few in China alone - and there are also a number of Korean and Japanese manufacturers. I think there are only a handful of case manufactuers - hence the reason why packs look quite similar. To give an example, take a look at this pack and this pack - apart from the lables they look exactly the same - but the Vampire is listed at 304g and the SMC at 322g according to the BRCA Homologation list. So despite them looking the same they do not have the same cell inside, so probably don't come from the same factory. Please note I've used these packs as an illustration of a point - this is in no way me bashing any pack in particular, the two packs shown are different even though they may look the same and have the same performance specs - this is all I am pointing out.

I still believe there is a big quality and performance difference between established r/c brands - who have high levels of experience of batteries in r/c applications and reputations to protect - and cheap lipo suppliers who are only interested in a race to the bottom on price. This is without even touching on the fact that there is no standard capacity or C rating calculation methodology, so all there is to go on when trying to judge the actual performance of packs is the brand reputation for stating true and accurate figures that relate to real world performance.

Quote:

Originally Posted by discostu (Post 594003)

and that is why you shouldn't buy vampire lipos sorry mate get your money back if you can.

i have been running the vampire cells for about 2 years they are very good.

stu you follow me most of the time, they are vampire cells

Quote:

Originally Posted by university_dave (Post 594423)

:woot:connectors are at different ends :thumbsup::lol::woot:

Have to say that I was going to point out that those cases are clearly different!!

That said, I have reasonable good insight that even if a case is different, the cells can still originate from the same place.

any comments on this question?

what rules/advice would you guys say is the best way to charge/store/use etc lipos........:confused:

Quote:

Originally Posted by TARTMAN (Post 594060)

what guidlines would you say, ie balance/fast/charge/storage etc as a guide for lipos............... In your opinion........... Curious.......:eh?: