To nano-tech or not to nano-tech

[mauimart]

The recent "Farfle is an evil person, don't talk to him!" thread about nano-tech batteries got me thinking... I was just about to pull the trigger on 6 pieces of the Turnigy 5000mAh 6S 20C battery when the discussion of the Turnigy nano-tech 6000mAh 6S 50C came up.

So at this juncture I am trying to justify the added $200 (or $0.20 extra per Wh) for the nano-tech's over the 'generic' turnigy's for my current bike. I am hoping that it's perhaps possible that the nano-tech's will offer greater cycle life thus offsetting some of the added cost over time. I will configure the packs as 18S2P. My typical daily commute consumes roughly 500Wh of energy.

My thinking is that since the nano-tech pack offers roughly 800Wh vs 666Wh for the generics, my average depth of discharge will be less therefore increasing cycle life. Also since the discharge rate as a percentage of max C-rating for the nano's will be less than half that of the generic's (50C max vs 20C max) I could again expect increased cycle life for the nano pack. And maybe, just maybe the nano's inherently offer better cycle life than the generic, all things being equal. Are the nano's less likely to suffer from failure modes such as "puffing" than the generics?

Anyone care to comment on cycle life for the nano-tech's vs. the cheaper battery? What do you think? Sale or no sale?

Martin

 

[neptronix]

Depends entirely on your current draw and amp hours, which will determine whether you need it or not.

On my MAC bike, i like to run about 20AH of 20C stuff. Pulling a maximum of 36 amps continuous, i only get about 0.75V drop on 36v. On 72v that would be doubled to 1.5v.

On 10AH, i'm getting double that on 36A; so 1.5v for 36v, 3.0v for 72v.
Not so bad for cheapo 20C?

Now when you start getting into 100A territory, nanotech does make more sense. But you could add more amp hours if it would fit on your bike. For the same price, ya get more distance.

Middle of the road would be Turnigy 30C.

 

[Arlo1]

You should add the 4s hard case pacs to the spread sheet.

 

[dogman dan]

It's a total no brainer if the extra $200 is only a days pay to you. If it's a weeks pay, then the obvious choice is the cheapest possible thing, such as the 4s packs have been lately.

Just glancing at the bike thread, it looks high performance enough to justify nanos. Especially since the nano's are simply bigger.
For sure you want the nanos if you are going to be running 6 ah. 20c packs run in really small 5 ah batteries have a way of not lasting so many cycles. Since you are buying 6 of em, I'm assuming you will run 18s 12 ah? Even the cheap stuff would do fine in 12 ah configuration. at 10c, you'd still have 120 amps avalaible.

But the nano's will sag less, which is real nice. 8) So if the money won't bust your chops, get the nano's.

I don't run such a hot bike, only 40 amps. But I still definitely notice a difference between 20c batts and 30c batts. And that is with 10 ah size too. Even a 40 amp draw likes the higher c rate best.

 

[texaspyro]

A lot of people around here have been having AWFUL luck with the latest NanoTech cells... to the point of tossing them and swearing to never buy them again. The first batches were great. The current ones seem to puff and die after a very few cycles. These are people that are very well skilled in proper lipo management that I trust to know what they are doing (been flying jets and helicopters since day one). YMMV...

 

[nicobie]

I had some trouble with the 6 Ah nano packs. I bought a couple of 4s ones for a boost pack and the #1 cell on both kept screwing up. It would always be about .06V low after charging. I tried 3 different chargers and nothing changed. After about 6 cycles with topping off the #1 cell with a single cell charger it started to get better, but I can't say everything is ok now as I took them off and went to 6s for my boost pack. (now 100V ). I gave them to my son-in-law for his new bike and told him to keep a VERY close watch on the voltages.

 

[mauimart]

Thanks for the responses everyone.

Depends entirely on your current draw and amp hours, which will determine whether you need it or not.

My typical current draw with this bike in commute mode would be in the neighborhood of 15A to 20A for 20 minutes or so. For testing I have been running 18S 5Ah of the 20C bricks and 20A translates to 4C with a fair bit of sag. A 10Ah pack would drop that to 2C with half the sag. Some periodic current draw numbers would be short bursts of 50A to 80A when I take the bike off-roading in the hills. In this respect a stiffer nano pack would be nice.

You should add the 4s hard case pacs to the spread sheet.

The hardcase 4S bricks are attractive. For these to work in my application I would have to go to 20S, which my Kelly should be able to handle (90V max). I would need 10 of these bricks for my pack. Unfortunately that will not fit in my box the way it's currently configured. I could do it but that would require moving the controller back out of the battery box and onto the seat post rack. I really like the compactness of the bike when the controller is housed within the batter box. Nonetheless I will take a closer look at how I might make this work - the price for the hardcase is definitely right.

A lot of people around here have been having AWFUL luck with the latest NanoTech cells... to the point of tossing them and swearing to never buy them again. The first batches were great. The current ones seem to puff and die after a very few cycles. These are people that are very well skilled in proper lipo management that I trust to know what they are doing (been flying jets and helicopters since day one). YMMV...

This reliability issue could be the deal breaker for me. I might just go ahead with the 20C batteries for now until I hear that the quality of the nano's has improved. I know that the 20C bricks also suffer from occasional dud cells yet the replacement costs will be less.

I am still curious to know how the cycle life of the nano's compares to the 20C cells if this data is available.

Martin

 

[neptronix]

Hm, i've not heard of this reliability problem with nanotech. But here's the thing - regardless of the RC lipo type, Hobbyking will ship out 10% of their packs having at least 1 bunk cell in them. This is why i emphasize discharge graphing all packs immediately upon receiving them. This happens across the board for Zippy and Turnigy stuff.

If you have a low constant amp draw, the 20C packs will do if put in a 15AH or higher configuration. Maybe consider 25C and cut your current limit down to about 60A.

You are verging on being a candidate for nanotech treatment though for sure

 

[bane77087]

I've looked for stats on the cycle life and calender life for the nano techs and have seen other ppl ask too, never seen an answer though, well other than a vague "double the cycle life over standard li-poly". Double what exactly the 200 something the regular turnigys are supposed to get or double something else. If it is really double the cycles of their standard cells then you come out ahead money for cycles plus you have another AH per pack.
It would be really nice for some1 to post the cycle info for the nanotechs I don't think its on here anywhere

 

[dogman dan]

Any particular run of cells can be great stuff, or trash. In my case I had a somewhat different experience. About 10% of packs I bought to date were bad, but all were in the same batch of soft 4s turnigy packs that puffed immediately or after less than 20 cycles.

So when you go to buy lipo, you just close your eyes, cross your fingers, and click buy. I now like to buy a couple from a given "batch" in stock in the USA. Once I get em and the first two are ok, I may buy more from the same lot of packs. Won't work of course, if the stock is low when you buy the first ones.


The is no reason to expect better c rate lipo won't last longer than 20c cheap stuff. But for most 1000w street legal use, the 20c lipo is under so little strain at 10 ah that it may not matter as much as it would if you compared 20c stuff and 50 c stuff when discharged at 10c. At 2c even the cheap stuff is not taking much of a beating.

Lots of other factors for cycle life too. DOD, temperatures, top of charge voltage, state of charge in between rides. For many, just buy affordable stuff and don't sweat the cycle life could be a good enough way to go. I break many of the rules to make your lipo last, and still get more than a year of use, perhaps 100 cycles and still working ok. Even on my budget, buying 8 lipo packs a year is not too hard to tolerate. Not when balanced against the fun it bought me anyway.

 

[neptronix]

The reason is probably because most lipo packs are heavily abused in the RC world. Most of these guys don't have real time amp meters that they can watch. and/or they don't care and see lipo as disposable so they'll buy a 20-30C pack and try to dump 100's of amps out of it. No wonder that it gets puffed and useless within 50-100 cycles.

RC Lipo can easily last 300 cycles if treated well. Up to 600 if you really baby it and run it less than 1/4th under the C rating by using a lot of amp hours in parallel like i do.

I'd like to see hobbyking's claim verified, but i'm sure they're talking out their ass as they typically do

I've looked for stats on the cycle life and calender life for the nano techs and have seen other ppl ask too, never seen an answer though, well other than a vague "double the cycle life over standard li-poly". Double what exactly the 200 something the regular turnigys are supposed to get or double something else. If it is really double the cycles of their standard cells then you come out ahead money for cycles plus you have another AH per pack.
It would be really nice for some1 to post the cycle info for the nanotechs I don't think its on here anywhere

 

[liveforphysics]

The most recent Nano-Tech's are not the same product they once were.

Whatever they changed, it was not a change for the better.

 

[neptronix]

Luke; what's the reason? bad cell rate getting up there with the Non-nano, or worse? higher IR?

 

[liveforphysics]

Luke; what's the reason? bad cell rate getting up there with the Non-nano, or worse? higher IR?

Failure rate used to be very low, now it's poor. Cycle life used to be very good, now it's poor. They used to very very rarely puff or self-discharge, the recent batches seem to frequently puff or self-discharge.

They used to be the best of the RC LiPo, now they still have killer performance, but I've seen poor reliability and cycle life, where as the early ones would last for years of hard abuse.

 

[zombiess]

Luke; what's the reason? bad cell rate getting up there with the Non-nano, or worse? higher IR?

Failure rate used to be very low, now it's poor. Cycle life used to be very good, now it's poor. They used to very very rarely puff or self-discharge, the recent batches seem to frequently puff or self-discharge.

They used to be the best of the RC LiPo, now they still have killer performance, but I've seen poor reliability and cycle life, where as the early ones would last for years of hard abuse.

Not what I like to hear considering I just purchased 10 6s 6AH packs. I don't think I'll make it to the abuse category though since the most I'll ever draw from my 30S2P pack will probably be 150-200A for a 15 second burst if I can keep the front end down on the bike (working on that now).

I haven't charged up my new packs yet to play with them (damn pneumonia), but they all came in within 10mV balance around 3.8V, none were puffed upon delivery.

 

[Arlo1]

Luke; what's the reason? bad cell rate getting up there with the Non-nano, or worse? higher IR?

Failure rate used to be very low, now it's poor. Cycle life used to be very good, now it's poor. They used to very very rarely puff or self-discharge, the recent batches seem to frequently puff or self-discharge.

They used to be the best of the RC LiPo, now they still have killer performance, but I've seen poor reliability and cycle life, where as the early ones would last for years of hard abuse.

So how do we move forward. I mean can we tell them to fix this issue? Or... We are about due for the next type of better cheaper batteries to come out. I have not seen a drop in price for a year and it was the 4s hard-case packs that were the last drop....

 

[neptronix]

Not what I like to hear considering I just purchased 10 6s 6AH packs. I don't think I'll make it to the abuse category though since the most I'll ever draw from my 30S2P pack will probably be 150-200A for a 15 second burst if I can keep the front end down on the bike (working on that now).

I'm repeating myself again here, but a discharge with a balancing charger is going to help you sort out the duds and prevent problems down the line. Since there is a 10% dud cell rate with non-nanotech, you most likely have at least one pack with a funky cell in it that should be set aside.

 

[sangesf]

Not what I like to hear considering I just purchased 10 6s 6AH packs. I don't think I'll make it to the abuse category though since the most I'll ever draw from my 30S2P pack will probably be 150-200A for a 15 second burst if I can keep the front end down on the bike (working on that now).

I'm repeating myself again here, but a discharge with a balancing charger is going to help you sort out the duds and prevent problems down the line. Since there is a 10% dud cell rate with non-nanotech, you most likely have at least one pack with a funky cell in it that should be set aside.

I'm still amazed that people are still "allowing" ANY kind of "dud rate" be it, LiPo or LiFePo4..

"Oh, it's 'normal' to have a 1 out of 10 failure rate with LiPo"..
OR
"Yeah, it's rated as a 48v 20Ah LiFePo4 battery, but it's really only 15Ah usuable"

NEITHER of those two statements are acceptable in my eyes...

Imagine if the post office said to everyone, yeah only 1 out of 10 peices of mail get lost..
It would be a riot!

 

[zombiess]

Not what I like to hear considering I just purchased 10 6s 6AH packs. I don't think I'll make it to the abuse category though since the most I'll ever draw from my 30S2P pack will probably be 150-200A for a 15 second burst if I can keep the front end down on the bike (working on that now).

I'm repeating myself again here, but a discharge with a balancing charger is going to help you sort out the duds and prevent problems down the line. Since there is a 10% dud cell rate with non-nanotech, you most likely have at least one pack with a funky cell in it that should be set aside.

I've purchased 21 new packs from 3 separate orders several months apart of 20C 6S, one pack came puffed, other 20 were fine, they refunded me the dud pack and let me keep it which I then fixed with a replacement cell, probably one I got from you.

None the less I always check my packs, especially new ones for the first few cycles.

 

[neptronix]

That's the state of lithium manufacturing today.

When you buy lithium batteries cheaply from China, you often get the duds thrown in. The price definitely factors into this. I'd also rather pay a slightly higher price to be not shipped some duds.

I believe this is part of China's 'junk offset' environmentally minded recycling program - ship all the broken stuff to the USA :lol:

 

[sangesf]

I've seemed o have lost 1 % of this essage fro my "made in cina" iPhone

 

[mauimart]

I've purchased 21 new packs from 3 separate orders several months apart of 20C 6S, one pack came puffed, other 20 were fine, they refunded me the dud pack and let me keep it which I then fixed with a replacement cell, probably one I got from you.

None the less I always check my packs, especially new ones for the first few cycles.

As long as Hobby King will give you credit or a refund for a defective pack without you having to pay shipping to send it back then I guess the "dud" issue is not that big of a deal. About two years ago I tried their 100A current controllers with the 80-100 outrunners and they failed soon after I hooked them up. I did have to send the controllers back to get store credit, which was no big expense because of the small size and minimal weight. The long wait in receiving credit was the real bummer. What are their current return/exchange policies for defective batteries shipped from the USA warehouse? Is it now standard that they don't require battery returns for credit?
Martin

 

[zombiess]

I've purchased 21 new packs from 3 separate orders several months apart of 20C 6S, one pack came puffed, other 20 were fine, they refunded me the dud pack and let me keep it which I then fixed with a replacement cell, probably one I got from you.

None the less I always check my packs, especially new ones for the first few cycles.

As long as Hobby King will give you credit or a refund for a defective pack without you having to pay shipping to send it back then I guess the "dud" issue is not that big of a deal. About two years ago I tried their 100A current controllers with the 80-100 outrunners and they failed soon after I hooked them up. I did have to send the controllers back to get store credit, which was no big expense because of the small size and minimal weight. The long wait in receiving credit was the real bummer. What are their current return/exchange policies for defective batteries shipped from the USA warehouse? Is it now standard that they don't require battery returns for credit?
Martin

Mine was puffed, I even cut the wrap of fit to inspect it which violated the warranty, but they still made an exception and honored the warranty. Due to the puffed cell they didn't want it sent back to the USA warehouse. Process took about 2 weeks.

 

[neptronix]

Same failure i had on a random Turnigy 20C 5S pack. I didn't know that they accepted returns to the USA warehouse. That's really good to know.

 

[zombiess]

My NanoTech packs showed up late last week but I've been unable to ride due to being sick. Hope to charge them up and test them out later this week. Got my BMSBattery bulk charger too.

I'll post a review later once I test them out.