HobbyKing Turnigy 20C lipo after 1 year, 200+ cycles

[electr0n]

In July 2012 I received an order of 9 packs of 6s, 5 amp hour, 20C Turnigy's, plus some cables and connectors at a cost of $580 shipped.

The packs were mostly run at 24s 2p, 88.8v 10 amp hours. Current has been between 40 and 90 amps. However past few months I've been running 24s 1p, again between 40 and 90 amps. So these packs have seen their fare share of high discharge rates. I keep the cells between 4.16v and 3.7v and try to keep them fairly balanced.

The cycle analyst says I'm at 170 cycles, however I've also run several dozen cycles without the cycle analyst so I estimate I'm around 200 cycles now, over 1000 amp hours delivered, over 4600 km.

Out of the 9 packs, 1 pack was damaged by a fire (my fault, cell punctured), so I've got 4 spare cells from that. I've found 3 bad cells in 3 other packs. The other 5 packs are in decent shape.

I've reconfigured my pack into 12s 3p, 44.4v 15 amp hours and set the controller limit to just 20 amps to be kinder to the batteries and also extend my range. I charged to 4.16v and discharged down to 3.7v and I got 10.8 amp hours, 500 watt hours which is 75% capacity. Most cells were between 3.7v and 3.8v after a brief rest. A couple cells were in the mid 3.6v range and one cell was down to 3.4v and needs to be replaced.

Once I replace the 3 bad cells and put all 8 packs back to work I expect I'll have greater than 80% useable capacity remaining after 1 full year of hard use. I'm hoping to get 2 years out the packs, but at a much lower C rate in the 2nd year of use.

 

[davec]

sounds like a good value out of these
im tempted but cant take the risk unfortunately...

 

[electr0n]

I just spent the last couple hours trying to repair one of the packs. I managed to desolder the outside cell with my small 30 watt iron but I had to cut out the next cell (the bad one) with a small hack saw. I replaced the two cells I removed with good ones and put it back on the charger and it looks like it was a success.

Regular solder worked fine for me. I saw many references to using a big soldering tip like a hammer head and a higher wattage soldering iron and I came across someone making their own soldering tip with a brass nut and bolt, I didn't have one that fit so I had some 12 gauge solid copper wire I cut to size and jammed into my soldering iron and wrapped additional wire around that for more mass, it actually worked pretty good even with my low wattage iron. Worth a try before buying another iron or tip.

 

[dogman dan]

Cool trick. My big iron is not so high wattage, but it has a huge tip intended for stained glass work. Takes forever to really heat up, but once it does, it melts the big solder blobs great.

I found my lipo capacity dropped a lot by two years, used much or not. Two years and 300-400 cycles would be doing good IMO. If you can stand low capacity, I have three year old lipo that has horrible capacity, but still stays balanced nice. Sags like crazy, and only 50% capacity, but still quite usable on a 20 amps bike.

 

[electr0n]

The copper tip seemed to lose some ability to heat up the more I used it, need to play around with it a bit more to figure that out but it got the job done. It was easier to just use a hacksaw and saw the cells apart anyway and only use the iron to it back together.

I read around some people are storing their lipo in the fridge or basement in cool temperatures and getting extended shelf life from them. Some people reported a couple years with little to no degradation of capacity maybe worth some investigation, although I'm not sure how practical that would be for lipo that was being put to daily use since they operate better at warmer temperatures.

I'm looking into other options aside from lipo too. I don't like the idea of having to buy new batteries every two years. I'd really prefer something that can last several years. I've been looking at headway, a123 and ping batteries, but the weight and bulk is a bit of a put off for a bicycle application and I see reports of expensive a123 and headway batteries failing early, for the price they are they really need to last significantly longer than lipo to be economical and make up for the extra weight and bulk.

By the way I appreciate your offer dogman, I've already got a pile of packs old packs here. In fact it'd be interesting to do a capacity test on my 2+ year old 8 amp hour zippy packs. They've been sitting around unused for a few months in the oven. Gotta take out the bad cells and see what they've got left in them.

 

[Eskimo]

My other four TGY 5A/5S/20C-packs are now one and half years old. Now done 87 cycles, first 15 of those on RC-plane with 18C high discharge.
Every cell is still above 4.19, capacity has degraded only very slightly, couple %. Stored six months during the winter in the fridge +4C. They approach 100 cycles in very good shape. My bike"s max is only 22A.
I run between 3.70 and 4.20.
I buy four new packs every year, it"s only little over hundred euros total shipped, no big deal.

 

[ddk]

I have 28 Tunegy 5S 20C 5Ah cells in service,also I used to have an additional 6 Zippy 5S 15C 5Ah cells but more on that later...
I have over 1000 cycles on 16 5S Turnegy packs- They still show no sign of capacity loss from after cycled about 5 times.
I only discharged 2 of the batteries to 3.5V once, and have since never discharged the packs below 3.75V.
I feel testing for capacity damages a battery so the way I chose to test is:
When the batteries were new, I traveled from A to B to A and would test the battery's resting voltage and how much power it took to recharge it.
I wrote this info in a small notebook. After three months or so of keeping tract of this info I stopped adding new information. I made graphs of the averages of the batteries 'in use' and sometimes refer to those graphs if it seems that Ive had to use more power to recharge a battery than previously.
Obviously this information is only applicable to me.
I've yet to see a reduction in range, but I have no idea if the total capacity has changed, as I never discharge below 3.75V and I only go that low a few times a month on a particularly long ride I like to do. And that only happens if it's a particularly windy day.
-Other than those few rides a month, I rarely discharge below 3.85-3.9V before recharging.

...
I found my lipo capacity dropped a lot by two years, used much or not. Two years and 300-400 cycles would be doing good IMO. If you can stand low capacity, I have three year old lipo that has horrible capacity, but still stays balanced nice. Sags like crazy, and only 50% capacity, but still quite usable on a 20 amps bike.

@dogman... so you're implying this capacity loss is related to age?
bummer- my batteries aren't quite two years old![

 

[electr0n]

Wow 1000 cycles is impressive. What size pack and how many amps do you run? The shallow cycles probably help a lot. I never did any capacity tests when I first got the batteries but I will on the next ones. I tend to agree draining the batteries right down for a full capacity test may not be the best practice for longevity. I usually stop somewhere above 3.7v but have gone slightly lower the odd time.

I have 2 packs of zippy 8 amp hours that are 2 years and 4 months old, they were abused and probably over discharged a couple times at least since I didn't have a watt meter at the time. A few cells have gone puffy and split at the seams. I pulled out some of the good cells and I'm using them to power a heated shirt I made with magnet wire. I need to give those cells a proper capacity test down to 3.7v to see how much they've got. I know at least one of the cells from 4.16v down to 3.7v gave me close to 5 amps for an hour, which isn't too bad considering the age and the abuse I've put it through.

 

[ddk]

Wow 1000 cycles is impressive. What size pack and how many amps do you run? The shallow cycles probably help a lot. I never did any capacity tests when I first got the batteries but I will on the next ones. I tend to agree draining the batteries right down for a full capacity test may not be the best practice for longevity. I usually stop somewhere above 3.7v but have gone slightly lower the odd time.

I'm assuming shallow charge-discharge cycles ARE indeed the reason I've haven't experienced much by way of battery issues except for...

I have 2 packs of zippy 8 amp hours that are 2 years and 4 months old, they were abused and probably over discharged a couple times at least since I didn't have a watt meter at the time. A few cells have gone puffy and split at the seams. I pulled out some of the good cells and I'm using them to power a heated shirt I made with magnet wire. I need to give those cells a proper capacity test down to 3.7v to see how much they've got. I know at least one of the cells from 4.16v down to 3.7v gave me close to 5 amps for an hour, which isn't too bad considering the age and the abuse I've put it through.

...of the 6 zippys, one shorted cell four, not catastrophically, mind you, as it didn't catch fire or even get too hot. That pack was configured 10S 3P and the cells are paralleled at the cell level so when the one cell failed, it took it's neighbors with it.
I've since cut up those 'failed' packs and made 4 each 3S packs, paralleled again at the cell level to run lights.

I had 4 packs configured 10s 6P and two packs 10S 3P, as I was making a setup for long distance touring.
-All my trikes take two packs for 'normal' running, as I use a redundant system utilizing two motors, controllers, etc. This also means that one motor is never overstressed on hills.
...Before that failure I was building most of the packs at 10S 30Ah (12 5-cell battery packs in 10S 6P per case) After the zippy failure I reconfigured 2 packs to 10S 20Ah and two packs 10S 15Ah. One of those packs uses 3 zippys and 3 turnegys*
Due to elements no longer in my control I can't ride much more than a couple of hours, so I've given up the touring thing and only ride locally. So I haz all deez HUGE battery packs...Heck, I didn't even mark the smaller packs
-so by default I don't need to discharge the batteries too deeply.
Additionally-
Previous tests by me showed that discharging any of my 5S battery packs below 3.7V can cause serious cell balance issues.
Balance charging battery packs takes like, forever when battery cells are mismatched a couple of hundred millivolts.
I bulk charge my battery packs. I used to check individual pack balance every time before recharging.
I (now) check my batteries for balance irregularly (only when something seems abnormal) They've never gotten out of balance. *knocks on wood*

*externally they all look the same, but a couple of them weigh a bit less-lol

edittttted for elementary school failure

 

[electr0n]

Nice battery boxes, should be well protected in those, although they do look on the heavy side. I've dropped both my zippy and turnigy packs a couple times with poor mounting, I'm not sure how much of an effect it had but those packs are still in use today. Although I'm getting better caring for my batteries I've still managed to short them, drop them and hammer them with high C rates more frequently than not. My goal was more fun and performance when I got this pack running last year than longevity.

It'll be interesting to see if these batteries do indeed degrade over time as has been suggested. In the case of my 2+ year old zippy packs I suspect my abuse had more to do with their decline than age but I couldn't say for sure. If time degrades the lipo more than just a minor percentage then it might be more cost effective not to over size the pack after all.

One other thing I've noticed and seen mentioned in another thread was that the last cell goes bad more frequently than others, kind of odd, but at least it makes for easy replacement.

 

[dnmun]

not really when you consider that it is the outside pouches that are the ones that are distorted by the shrink wrap. the same thing happens with the ping packs too.

 

[electr0n]

I agree that the cells being on the outside are more likely to get banged around and distorted by the shrink wrap but in my case at least I haven't noticed any effect on the first cell, admittedly I've only had to replace a couple cells yet so maybe the next couple to go will be cell one. This is probably less likely but I was thinking the way the current flows through the pack may have something to do with the last cell going bad but that's just a guess.

 

[ddk]

oops Just noticed I incorrectly typed that cell 5 failed.
It was actually cell 4 (of 5) that failed.
That's because I never experience 'average' anything

-it's a karma thang

 

[electr0n]

My batteries are almost at their two year anniversary and still giving me satisfactory performance. It's got to be over 300 cycles by now. CA stats indicate over 1300 amp hours used. I'm down to 6 of 9 packs being useable. I'm pretty satisfied with the longevity of these batteries and I plan to keep on using them until their capacity drops below a useful level for my needs. I would consider buying these again when the time comes but then again I'm open to alternatives.

How many of you are still using Hobby King lipos these days? Is there anything else as cost effective with the light weight and performance the hobby king Turnigys offer? My understanding is that people seem to be getting around 3 years from their ping batteries but they are bulky, heavy and offer limited discharge current comparatively.

What has your experience been with batteries, which do you prefer and why?

 

[wesnewell]

I'm now at the 2 year mark on my 10ah 24s2p of 4s 20C Turnigy hardcase packs. All still original. I've never pulled more 4C from them and most time was at probably no more than 1C. I charge to 4.2V every time but have never run them below 10% soc with my LVC set to 88V. Most times I recharge at 20-30% soc. I checked capacity a couple of weeks ago and still had 90-95% based on rated capacity. I didn't check actual capacity when I first got them, so I'm not sure of the actual loss in capacity. I do know that I've put close to 8000 miles on them now. I hope to get at least another year or two out of them but would be happy with just the 2 years and 8000 miles I've gotten from them so far. Original cost was ~$275, and could replace all of them now for about the same price. Don't keep track of charges, but I'd guess no more than 200 at this time.

 

[motomech]

My daily driver doesn't have a CA, so I don't know the number of cycles, but I can add some empirical info. on storage.
Bought my first Lipo pack 2 1/2 years ago; 4) 6S, 25C Zippy Flightmax. Various cells puffed(I probably made some Lipo noob mistakes)and today I have two bricks canibalized from the 4, that I use as the "extra pack". Still strong, maybe 90%.
4) bricks of Turnigy 6S. 20C, purchased 2 years ago. Used gently for a year then stored a year while while I worked in Mexico. Stored at 3.75V, in the fireplace of my Tucson home. The AC was NOT on, so for at least several months the inside temps had to be in the 80'sF. Got back last week and ck'ed the cell V's first. Right at 3.75V. Been using them for a week and seem as good as when I stored them

As a side note: My LVC is a little low at 3.55V amd I have hit it several times. At that point, a couple of cells are starting to nose-dive, down in the 3.20's V. But they come right back with no appearent bad effects.
Interesting to note, the price of the Tuyrnigy's has only gone up $2 a brick in two years.

Love my Turnigy's.

 

[electr0n]

That's pretty impressive wes, specially since those were with the hard case packs. I got the impression the quality on those were a bit spotty.

My first batch of hobby kings were zippy's and they lasted about a year before puffing and dropping capacity. I prefer the turnigy's now. I've been pretty hard on mine. They've been dropped, shorted and run above 10C at times. I've also had some issues here and there with my wiring harness connecting intermittently. I need a better soldering iron or more practice. I haven't capacity tested mine recently but they are getting me where I need to go for now. It does seem like I get pretty big voltage sag but then I'm running 24s 5 amp hours. I'm more interested in utility than hot-rodding these days any how.

moto, interesting to know your batteries still seem to be working despite the lengthy storage. I always thought these had some shelf life built into them where they'd degrade somewhat regardless of use after a certain amount of time. I know there's a handful of us out there that have gotten extended time from these batteries.

 

[Ohbse]

I've got 10x 4s 5ah Turnigy hardcases configured as 20s2p. Batteries are permanently paralleled as pairs at output and cell level then connected in series. I have done 1200km running up to 65a battery peak, but generally <30a/3c. I charge at each end of my journey of 13km, so I have approximately 90 charge cycles. The majority of my cycles have been charged at 1-1.5c immediately prior to departure to 4.1v, discharge to 3.75-3.8v and left at that level until following day. During recent test to establish true battery capacity I ran from 4.2v to LVC of 3.5v and had 720wh out of the pack, or ~9.6ah. Given that discharge testing using my powerlab8 immediately after pairing the batteries showed 9.5ah capacity, I am very pleased with no degradation.

From everything I have read, shallow charge cycles are key for longevity. While I could (and have a couple of times) complete my return journey on a single charge, it would be consuming 90% of the capacity of the battery. Instead I just leave chargers at both work and home and keep my cycles below half of capacity and have no range anxiety.

Total cost for this pack was $230US and it sags ~1v under full load (5.5kw). I think that this longevity/$ and performance/$ is untouchable currently. I would not hesitate to buy more Turnigy or Lipo in general. Even if I have to purchase a new pack every year I would do so gladly, considering a return journey is costing me ~10c in power compared to ~$25 per day to drive or $9-12 per day to use public transport. I might not be so pleased if I had sunk $600-700 in a 18650 pack with equivalent performance and capacity.

 

[zener]

Ohbse:
Can u show video from the 1V drop at 5.5KW ? or is this a typo ? becouse i can not belive that.

 

[Ohbse]

Not easily as I don't have a suitable camera currently. I will pay closer attention on my ride home and confirm.

Last time I looked I dropped from 83v to 82v as reported by Adaptto display under full load of ~60a. If that level of sag is unusual, perhaps the V reported by the controller is calculated from cell levels not pack output?

I have never paid all that much attention to sag as I have to capacity as it's never been an issue. Likewise I've never managed to get wires or batteries warm enough to detect with a bare hand, though they are all in direct airflow.

 

[Ugrd]

I have a 18s 12ah Turnigy battery purchased in June of 2013 with about 250 cycles on it. I pull alot from it (10kw) and even though im probably going to replace it sooner or later, it still runs fine. 8ah from 75.5v to 67.5 right now. My voltage drop at 10kw with a 20c right now is about a 5-6v drop.

 

[Eskimo]

170 cycles now from a two years old 20C/10Ah pack. Still delivers 400 usable watthours. Always charging them full, and mostly using full capacity, not shallow. Discharge rate is very low though, around 2C max. My other packs are less old. With usual 15Ah pack discharge is 1,5C, stays totally cool all the time. They do 200 cycles nicely. Them nano-packs are crap, what i have seen.

 

[Ohbse]

Not easily as I don't have a suitable camera currently. I will pay closer attention on my ride home and confirm

So sag accelerating from standstill to 60 kmh pulling 60a is apparently 2v, 81-79. That's not very accurate as the voltage reading on Adaptto main screen doesn't report anything other than rounded voltage. It's low enough I'm not bothered. Perhaps different story pulling 10kw+, though I would probably just add more packs.

 

[electr0n]

Good to hear others are also having these batteries perform well after many cycles.

When I first bought these a couple years ago their longevity was a real question but they have proven themselves to be a fairly good value. My battery setup which was 100v 10 amp hours of 20C Turnigy, plus a spare, originally set me back $580 two years ago. So the cost to have this setup has been $290 per year, not too bad for the light weight, high performance I've gotten from them. Although now I'm down to 48v 15 amp hours after having lost the use of 3 packs in that time span.

Still I like the idea of having a battery that can last 5 years or more. I know lifepo4 has been advertised as having that kind of longevity but from the real world reports I've read it seems like people are getting 2 to 3 years from them which is not much more than I'm able to get from lipo.

 

[oatnet]

Because of the references to cycleanalyst's count of resets, it sounds like you guys are calling each charge/discharge a cycle; this is accurate of you discharge the cells to their full rated capacity. However, if you only discharge half of the capacity before recharging and resetting your CA, then you have only used half a cycle, not a full cycle.

A cycle is a discharge that uses 100% of the cell's rated capacity - otherwise manufacturers could discharge 1/5 of the cell in each cycle, and claim a cycle life 5 times reality. This standard is just the metric for comparing cells, because in the real world a 100% discharge would prematurely age most cells.

ddk, on your 1000 "cycles", how many amp-hours are you using between recharges, and how many amp-hours does HK rate your pack for? Also note that charging is a lossy process, so when you measure the KWH coming out of the outlet during a recharge, this does not equal or even approximate the KWH used on your last discharge. I've worked with cheap chinese chargers that were only 60% efficient so 40% of the measured kwh was wasted, and that is before considering the charging losses within the cell itself.

-JD