Cheap 6S 5000 mah lipo on ebay

[madgooner99]

Anyone using these

They look cheap but seem too small and light ??

22.2v 5200mAh 25C 6S LiPo RC Battery R/C Trex 500 600 on eBay (end time 11-Sep-10 10:15:52 BST)

[Sieze2]

You would want a higer C rating for a 550 I would have thought?

[Ashley Davis]

25C should be enough, the 550 isn't a 600E, no pack eating going on.

[Dave Rand]

I've got one coming for the Rage, mark34578 has run BQYs for the past year and they seem ok.

[Jamin_00]

In "packing content" it says its a 30c pack!!!

But I assume he is referring to the burst rate

[Dave Rand]

Yep 30c burst.
There prob 20c continuos in truth as they tend to over spec lipos.

[sacko]

I cant feel the difference in flight between 25c and 30c, other than the temperature they come down at.

In time im sure that the 25c packs wont continue to give the performance that the 30c's may.

..but by that time im sure they are both nackered anyway.

[alioth]

25c on that battery is 115 amps continous (and with a 100A ESC on the 600ESP, and probably the same on a 550) the battery has a higher continuous rating than the ESC can actually draw.

However, I do rather suspect battery makers overstate the continuous ratings. How can people be puffing 25C and 30C 5000mAh+ batteries on a T-Rex 600E if it weren't otherwise, since these batteries supposedly exceed the highest current draw the ESC can make? I suspect the 600's "battery eating" reputation has more to do with battery manufacturers lying about the real C rating of their batteries than anything to do with the heli. (Mine has never puffed a battery, I have 4100 30C batteries for mine).

I remember someone complaining about puffing batteries with only sport flying on a 600E. With sport flying (simple aerobatics, flips, loops, rolls etc, forward flight) a 600E will fly about 6 minutes while consuming around 4Ah of a battery, in other words, an average of just 40 amps. On a 5000mAh battery, 40 amps is just 8C (25C would be 125 amps). If a so called 25C continuous battery is puffing from a flight that averages at 8C, I'd say the battery manufacturer was telling tall tales about the C rating of the battery.

Part of the problem may be that these big bricks of batteries simply cannot dissipate heat fast enough, but if they can't, even if the individual cells can indeed do 25C continuously, the whole battery pack shouldn't be rated as such, it should only be rated as to what continuous current you can draw without the pack getting too hot. (I suspect this is part of the problem, the people assembling the packs take genuine 25C cells, put them together as a 6 pack which can no longer dissipate the heat - as the pack size increases its surface area to mass ratio goes down which means it's harder to dissipate heat - and then claim the whole pack is 25C when in reality due to heat dissipation issues it's probably by now only a 5C continuous battery at most.

[Ashley Davis]

continuous current is not the problem, current spiking (ie. typical heli flight characteristics) cause heat build up faster than a continuous draw. These spikes create pockets of heat in the lipo which if sustained cause damage and cause the puffing.

[alioth]

continuous current is not the problem, current spiking (ie. typical heli flight characteristics) cause heat build up faster than a continuous draw. These spikes create pockets of heat in the lipo which if sustained cause damage and cause the puffing.

The problem with the 600 is people have complained about battery puffing with just sport flying, which isn't really very "spiky". Hard 3D is obviously going to have very widely varying currents and very high peaks (possibly exceeding what the ESC is labeled up for), but "sport flying" which typically means the power doesn't change a great deal and is rather less spiky (otherwise there's no way you'd get 6 minutes out of a pack on a 600E) should never puff a 5000mAh 25C continous battery. If it does, the C rating isn't what is claimed.

[robby_121]

Be Careful

When it comes to Lipo batteries do do really get whatyou pay for. I would stick with a brand you know well. I have heard from a pretty reliable source that should you crash due to a battery failure and make a claim through BMFA you would not be covered if the battery didnt dispaly the kite mark. Obviously you would not mention the fact however kite marks are put on things for a reason. I agree Lipo batteries are extremely expensive...especially when you get up to the larger models but would you put cheap oil & petrol in your new sports car??

[alioth]

Is there such a thing as a LiPoly battery with a BS kitemark? I've never seen one. Come to mention it, I've not seen a kite mark on much for a few years (I thought it had fallen into disuse). In which case for electric flyers, BMFA insurance wouldn't be worth the paper it's printed on.

Can our LiPolys even get such markings, given that normal lithium ion/polymer type batteries are expected to come with protection circuits (which ours don't) and not be quite so accessable as our batteries?

[Rob Barnes]

Ive been using these in my Avant Aurora 90E with a 5 min flight and 24% left in each pack they dont get over warm and perform really well. Ive now run some 30+ cycles through them with no sign of fatigue balance charging them at 1C.

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[Tom Burgess]

Ive been using these in my Avant Aurora 90E with a 5 min flight and 24% left in each pack they dont get over warm and perform really well. Ive now run some 30+ cycles through them with no sign of fatigue balance charging them at 1C.

eBay - The UK's Online Marketplace

Damn, they are cheap Rob!! Gotta be worth a go those

[robgt]

Hey Rob!
Where are you hiding!!!
LOL
Cheers,
Rob