'Good' lipos vs others - RC-Monster Forums

Sammus · **'Good' lipos vs others -** 03.21.2008, 08:40 AM

Hi, does anyone have any FIRST HAND experience in comparing cheaper chinese Lipo packs with the brand name korean packs?

I ask because I am currently running 3s 4000mah 20C HECELL packs (same as 3E packs) - and was thinking of upgrading soon. They still have excellent capacity - usually charge to around 4200mah on my ICE.

I can get some 3700mah polyquest XP (25C) packs for ~$80 each and was wondering if they really would perform much better (read cooler), even though theyre are comperable capacity and discharge rating.

My HECELL packs are getting pretty warm in my CRT.5 conversion and wanted something that I could run without worrying about pack temp...so does anyone have any first hand experience/evidence from 'upgrading' from cheap packs to the the big $$ packs?

Cheers

Sam

Sammus · 03.22.2008, 04:40 AM

Surely someone must be able to justify a $390 6000mah 6s polyquest pack over a $130 Zippy-H pack of the same specs?

I don't want to go and spend a heap to get something not noticeably different.

nativepaul · 03.22.2008, 07:12 AM

I've not used any Chinese LiPo co compare them, but if you are worried about pack temperature in a crt.5 I will say they are probably well worth the difference, in my 1/8 scale buggy I run a flightpower 4s 20C 4350mah pack down in 10 mins of oval running, it gets my 8XL too hot to touch and my MM too hot to hold for long but the cells although warm to the touch are no warmer than my own armpit.

Sammus · 03.22.2008, 08:03 AM

Well I kinda imagine oval running as driving at a pretty constant speed - how close am I? Only my motor gets warm at a constant speed. Constant speed has pretty low current draw, I think your going to stress the batteries a little more in high current draw applications, like constant hard acceleration and hard braking (if using esc brakes), which is why I'm hoping to hear a comparison from someone who has tried both in similar driving situations.

I've got plenty of speed out of the thing, I kinda like it how it is, but I might try dropping a tooth on the pinion and see how it goes.

nativepaul · 04:04 PM

Hehe sorry, my mind was in english mode not thinking I was posting on an american forum, I forgot that in the states if I say oval racing you probably think of nascar with mile+ long ovals where they take the (banked) corners at 200 mph with no braking and little acceleration required, in europe full scale oval racing is done with stock cars on a flat track of similar size to a running track with hard breaking to slow and sideways corners and hard acceleration to about 100 down the straights.

A two pin oval the size I run is not constant speed but hard acceleration followed by hard braking and a sideways corner repeated at very short intervals, I doubt there is a way to punish your gear more than doing the same with traction compound on your tires, my peak amps are around 120 under acceleration but runtime is a better indication of how hard you are pushing things, 10 mins from my 4350mah pack is 4.35x60/10=an average current of 26.1 amps, what runtime do you get on your 4000mah packs? If its more than 9.2 mins my average current draw is higher.

johnrobholmes · 03.22.2008, 07:22 PM

The question is how much amp load you will really be putting on the car, and how high the voltage of the battery holds under load. Are you going to be using a 6s 20C pack to the fullest?

Personally, I doubt the HECELL packs are true rated. So far I have found lots of cheap packs and plenty of expensive ones that do not hold satisfactory voltage under the rated discharges. The question is whether the HECELL packs are rated true- could they be 15C cells just rebadged? Are they still a good deal as 15C cells? Maybe even 12C?

The last "bad" pack I tested was rated 15C continuous 20C burst. The pack hit voltage cutoff at 19C and was hovering at 3.4v/cell at 9C discharge. Obviously not true rated, especially considering that the 9C discharge was a burst and not even a continuous load.

Sammus · 03.22.2008, 08:24 PM

Quote:

Originally Posted by nativepaul

Hehe sorry, my mind was in english mode not thinking I was posting on an american forum, I forgot that in the states if I say oval racing you probably think of nascar with mile+ long ovals where they take the (banked) corners at 200 mph with no braking and little acceleration required, in europe full scale oval racing is done with stock cars on a flat track of similar size to a running track with hard breaking to slow and sideways corners and hard acceleration to about 100 down the straights.

A two pin oval the size I run is not constant speed but hard acceleration followed by hard braking and a sideways corner repeated at very short intervals, I doubt there is a way to punish your gear more than doing the same with traction compound on your tires, my peak amps are around 120 under acceleration but runtime is a better indication of how hard you are pushing things, 10 mins from my 4350mah pack is 4.35x60/10=an average current of 26.1 amps, what runtime do you get on your 4000mah packs? If its more than 9.2 mins my average current draw is higher.

Cool that sounds fun, surely there are better suited cars than a buggy for it though?

I havent yet put a whole pack through the crt, the one's I have just got warm in short bouts of testing. Will have to time it soon though.

Sammus · 03.22.2008, 08:33 PM

Quote:

Originally Posted by johnrobholmes

The question is how much amp load you will really be putting on the car, and how high the voltage of the battery holds under load. Are you going to be using a 6s 20C pack to the fullest?

Personally, I doubt the HECELL packs are true rated. So far I have found lots of cheap packs and plenty of expensive ones that do not hold satisfactory voltage under the rated discharges. The question is whether the HECELL packs are rated true- could they be 15C cells just rebadged? Are they still a good deal as 15C cells? Maybe even 12C?

The last "bad" pack I tested was rated 15C continuous 20C burst. The pack hit voltage cutoff at 19C and was hovering at 3.4v/cell at 9C discharge. Obviously not true rated, especially considering that the 9C discharge was a burst and not even a continuous load.

Cheers for the info. The 6s (2 x 3s) would probably not be being used to its fullest. The hecell cells I have now dont even get slightly warm in my revo. but running them seperate as 3s packs in my rustler and my crt.5 conversion.

I've only just built the crt.5 and rebuilt the rustler so havent got any proper running done yet. But the rustler is running sidewinder, ammo 36-50-3300, 14/40 gearing.

The crt.5 is running sidewinder, feigao 9L (2731kv), running 18/46.

The the battery in the crt.5 gets quite a bit warmer than in the rustler under punishment, still not too hot though - but thats after only 5-10min hard 'testing' :P I'm thinking either to pick up some 3700 polyquest's (which I understand a pretty good quality) or some PQ 5000's to be safe. My brother runs the same cells as I do, as well as the newer copper tab Hecell cells, and says they run a LOT cooler than the older cells I run. I'm thinking I might invest in some of them too.

johnrobholmes · 03.23.2008, 02:20 AM

I have really enjoyed my 3700 PQ packs. They have a ton of punch for the weight. I have also been playing with X-Caliber batteries and they have been showing excellent numbers and weight- true rated too.

That is really the biggest difference I find in good packs, they are lot lighter for the watt/hour and discharge abilities.