Turnigy 5000 mah 6s 20c any regrets

[Emoto]

Im about to order my batts and am considering as above but 30c instead. main consideration is because of sag , mainly because there is a cromotor involved in this.
ill be going 18s 2p/10ah to start with, anyway give me your latest thoughts.

 

[wesnewell]

I'm running 24s2p 20c for over a year and 4000 miles. No problems. Max sag is 3.6V from dead stop to wot at 96V, but comes back pretty quick. IIRC the Zippies sagged considerably more, but they were only 15C. With normal riding. sag from stop is less than 1V.

 

[neptronix]

Zippies tend to have double the internal resistance of turnigy batteries, so if you read that a zippy battery is 20C, then it's really 10C.

A realistic use case for these batteries is to cut their maximum C rate by 1/3rd-1/4th to get the continuous C rating that they can really tolerate.

So if you have a 20C 10AH pack, 20 x 10 = 200 / 3 = 66A continuous, or / 4 = 50A continuous.

If you go to 15AH, then that 20C pack at 1/4th it's C rate gives you 75A continuous, which is a pretty good figure for a cromotor.

18S x 13.7v = 66.6V x 75A = 4995 maximum watts.

 

[Ykick]

If only a few bucks more go for higher C rate but don't get too carried away chasing those ratings. I've got 3 yr old 20C 5Ah Turnigy's handling 10A loads and still doing quite well on +600 easy, shallow cycles.

 

[Ypedal]

i've been having good luck with the 25~30 C rated packs in the QC dept vs the 20C... no DOA cells yet.. and out of a few dozen packs only a couple have higher self discharge but still usable.

the 20C packs i got back in 2009 or so were pretty crappy and often had 0v cells on arrival... hopefully they have improved since..

 

[dogman dan]

I recently bought turnigy 20c , and having used 30-40 c ones in the past, was somewhat disappointed. The sag, defined as you are at say 54v, and accelerate resulting in a lower voltage, is not so bad, 2-3 volts. But I was used to a half to one volt less of it. The pack works fine, I had no defects, till I screwed up and dinged a pack. They seemed hard to keep balanced at first, but seem to have finally settled into a more even state of charge. That may be a result of getting a second pack, and not discharging quite as deep.

A second, but smaller pack ended up being zippies, and they do sag more. But then, it's half the size too.

 

[neptronix]

^-- you should mention the amp hours and amperage when talking about voltage sag.

If i told you that my 20C turnigy pack only sagged 0.5v under peak load, would you wonder if i had a magic pack or was just putting a ~2C load on a 20AH 36v battery?

 

[Emoto]

Thank's all great info
My gut feeling before hitting the order button was leaning toward the 30c , from my rc experience 25vs30c the 30's are not puffing and sag noticeably less. im way above the recommended discharge ratting,
but as you know a ebike pack is a sizable investment compared. if i was going 3p/15ah i would go the 20's but this is my first ebike so who knows.

The point of less duds in the 30's is interesting, one other consideration is as the pack ages [ie charge/discharge cycles] the pack will be more prone to sag, so the the 30's should be more resilient there.
.

 

[GMUseless]

For what it's worth, I've bought the 20c versions at about an 80% good quality rate. Which I feel rather sucks...but you could consider that in the price difference.

I had one pack with the 'missing cell' syndrome (one cell goes to 0v, and overall pack voltage measures 5s for a 6s pack.) I've also had one pack show up a with high self discharge cell (.2 votls per day). Both of these don't belong in a commissioned ebike battery.

If you go with the 25/30c, please update back with the quality of the packs you receive.

 

[dogman dan]

The pack I was whining about more sag with, is 10 ah. used with a 48v 40 amps controller. Adding 5 ah more, to have 15ah total helped a lot.

 

[Emoto]

For what it's worth, I've bought the 20c versions at about an 80% good quality rate. Which I feel rather sucks...but you could consider that in the price difference.

I had one pack with the 'missing cell' syndrome (one cell goes to 0v, and overall pack voltage measures 5s for a 6s pack.) I've also had one pack show up a with high self discharge cell (.2 votls per day). Both of these don't belong in a commissioned ebike battery.

If you go with the 25/30c, please update back with the quality of the packs you receive[/color].

Will do im still on the fence atm --- i contacted hk on the 30c dimension's/weight and there response was" order them and when you get them let us know" :| right te ho

The pack I was whining about more sag with, is 10 ah. used with a 48v 40 amps controller. Adding 5 ah more, to have 15ah total helped a lot.

Ok so im guessing from now on you will order 30c yeah

 

[corim123]

Why would he need to order 30c in the future? You don't need as high of a C rating if you have more capacity.

 

[jonescg]

I built a pack for Rodney using the 20C cells and they are plenty good. Still have to see how they go in terms of cycle life, but they are very energy dense and even if the C rating is more like 10 C max, 5 C continuous, that's heaps for an e-bike. We built it as a 15 Ah pack though. I wouldn't think that 10 Ah is enough for anything over 48 V.

 

[dogman dan]

I chose 20c partly based on price, (I'll never work steady again in my life) partly based on what was in stock. In general, I tend to pull about 20 amps continuous, and my sag is not bad at all when cruising 30 mph. I just see more sag on stuff like uphill starts, than I saw with the 30-40c stuff.

Soon as I can scrape up some money, I might buy another 14s 5 ah, of whatever is in stock. That would give me lots of range, and I could just about forget about noticeable sag under load. Ideally, this cargo bike would pack 30 ah, at which point even 2c ping would run that 40 amps controller fine.

Just saying though, if sag is your concern, get 30c or better. If nothing else, you might have a nicer last six months of use, when capacity is down and sag gets a lot worse.

 

[Ykick]

I chose 20c partly based on price, (I'll never work steady again in my life) partly based on what was in stock. In general, I tend to pull about 20 amps continuous, and my sag is not bad at all when cruising 30 mph. I just see more sag on stuff like uphill starts, than I saw with the 30-40c stuff.

Soon as I can scrape up some money, I might buy another 14s 5 ah, of whatever is in stock. That would give me lots of range, and I could just about forget about noticeable sag under load. Ideally, this cargo bike would pack 30 ah, at which point even 2c ping would run that 40 amps controller fine.

Just saying though, if sag is your concern, get 30c or better. If nothing else, you might have a nicer last six months of use, when capacity is down and sag gets a lot worse.

Also cold weather. Dunno if higher C rate helps with that or not but probably doesn't hurt? Warm weather is the best for RC Lipo performance, btw. Saggy, saggy when cold....

 

[mvly]

nanotech 25C sags 0.1V per cells under WOT(around 2-3C) when new. Now it's 0.5V per cells under WOT after 2 years of use and 305 cycles babying them.

So if you have what some members are saying now for turnigy 20C... like 0.2V or more per cell, expect them to be shit when you hit my cycle numbers.

 

[Emoto]

Jonescg good to know

Just saying though, if sag is your concern, get 30c or better. If nothing else, you might have a nicer last six months of use, when capacity is down and sag gets a lot worse.

Thats what i think, 20c @ 15ah would be ok but 30c will be a better investment imho - still might get 15ah of them, and if i want a 10ah lighter pack for just a quick fun blasts around the block....
And less worrying about puffing....., and human nature to start tinkering for more performance later too. bottom line is if money was no object we would all get 40c minimum i spose.

Ykick i have to say man i liked your old avatar of- larry i think- made me smile.
Mvlv thanks interesting, the confusing thing is some have had worse results with nano. but the 25c constant to 50c burst nano's are close to turnigy 30c pricing

 

[corim123]

Pretty much hit the nail on the head there. If money were no object, I'd have a hub monster and wouldn't be using recycled li-ion batteries.

 

[Emoto]

^^^ yeah i wouldnt mind adding a stealth bomber just for something to ride while working on my current project but back to the real world .
In a bit of a twist i found a local rc shop selling a brand of lipos that come from Singapore, now wot would you say if you could get $ return for duds and local shop Convenience [or direct manafacturer online ordering ] they make em fresh to order and check the cells before shipping. and close to hk prices. i may have to start a new thread with info links to tests done ect.
EDIT i have seen a graph and are matching nanotec's performance.