Battery selection criticism please

[dave02150]

Hello
I am in the process of building ebike # 2 and luckily there's no rush, as I have gotten a bit wrapped around the axle about batteries. I had been been leaning towards a Ping Battery LiFePo4 (more $$$ but good service, lots of cycles, etc) but now I'm over in the Lipo camp and here's why:
Based on what I've seen at Hobby King and what I've read here, I can build a 10Ah 44V Lipo pack for under $200 (+ harnesses and chargers and BMS and power supply and voltage alarms, but those costs would be applied over several years / multiple packs). In theory, that means I can get 3 or 4 packs for the cost of 1 good quality Ping battery. Which means that I can afford a bit more of a learning curve as I discover the quirks of Lipo and hopefully not burn down the garage. I have read the FAQ several times, I have read some interesting and educational threads here; there still seems to be some issues (ie. BMS or no BMS) but I figure I should just jump in and learn by experience, secure in the knowledge that all the good folks here at endless-sphere.com can keep me on the straight and narrow.<g>
There appears to be a bewildering assortment of Lipos available at Hobby King, but here is my choice of battery:
http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html
6 of those configured with 3 in series = 44.4 V, and 2 parallel sets should give 10Ah, which is enough to get me to work.
Of course, then there's a custom harness and all the other goodies mentioned above but first, I would like to see if I am headed in the "right" direction with this choice of battery. It's a hardshell case, which I think should be a Good Thing. It's only 4 cells per brick, so only 4 points of failure.
I invite one and all to please tell me why this is a dumb idea, and why I should stick with something safer and more stable.
From what I've read, things can and do go wrong with LiFePo4 or LiMnO4 packs - is there that much of a difference in quality/stability?
Will I be spending all of my time fussing over these, instead of just charging and riding?
Are Lipo suitable for commuting / charging at work?
Speaking of charging - it's 2012. Does anyone make an integrated power supply/charger for Lipo batteries? Why not?
Do other lithium types require both bulk and balance charging or is it just Lipo that requires that?
Of course, I would prefer something totally stable, safe and plug-and-play, but I don't think it exists, so I might as well go with something cheap that gives a really good bang for the buck.
Thank you
dave02150

 

[Ykick]

You seem to have a pretty good handle on things. I commute with RC Lipo and occasionally charge at work. No way I would start out doing that but once you have some Wh's under your belt you can better adapt to safely doing so and associated challenges.

Another pro is that at least with RC Lipo you actually learn about pack construction and cell balancing. An invaluable lesson for the present and future IMO. RC Charger is a wonderful thing to use and explore - many prebuilt packs could benefit from people who have one and know how to use it.

I usually estimate about $200-$250 for 10Ah worth of bricks. Add all the other stuff you mentioned but most of it will be used across many packs and bike platforms.

Hard case bricks tend to worry me because it's harder to see when you have a puffer. Due to my experience doing brick surgery I suspect many flames originate from deformed cells shorting tabs so I like shrink wrap bricks and attach my own protective covering. Which usually amounts to clear food wrap and filament tape. 6 of 1 or half dozen.... Doesn't make that much difference.

 

[fizzit]

Speaking of charging - it's 2012. Does anyone make an integrated power supply/charger for Lipo batteries? Why not?

Yes - it's called a Meanwell Power supply They require a little modification but they can work great.

And as for the viability of LiPo cells for commuting, I've been using mine to commute for over a year and I just rode 17 miles to my new job and used 14ah at 44v. I am charging them at work right now and I have charged them at my old job as well and never had a problem.

I'm using the 4s hardcase packs and they are just as good as any other Turnigy LiPo in my experience.

I don't think that LiPo is something you need to 'fuss' over. There are many people using a lot of LiPo in various configurations across the forum and overall we've had a very low number of incidents. Almost zero if you take out the ones caused by operator error. Hobbyking lithium is designed for use in high-current deep-discharge RC devices so running an eBike is really not hard on the batteries if you size your pack correctly and don't discharge it too much.

Hopefully this answers some of your questions!

 

[Ypedal]

I get the 6 cell 5ah packs in 25C or better.. *( less harnesses, less connections )

the 4 cell hardcase packs i avoid, simply due to the face of the very rare but " it happened " incidents with those specific packs.. ( john in CR had one go off while sitting on the shelf , and a few others have reported issues.. not many.. but again.. they happen )

I would build a big enough pack to avoid charging at work. personal opinion... the biggest concerns are while charging, bad enough to have it happen at home, worse to have it happen at the work place..

 

[binlagin]

Shipping from the US warehouse for Lipo is taking a long time.

I placed an order a month ago and my package still hasn't even shipped yet

 

[999zip999]

A ping is a good place to start as with the led's to tell about balance ect. As for Lipo Hk has alams for lvc, Plus a balance charger like hyperion 1420 than a power supply. Icecube57 has wiring harnesses to make it easy. But all this adds up in time with shipping and money and extra money, plus one extra pack just in case a dud ect. What is your setup now. In ebikes cheaper cost more.

 

[Drunkskunk]

Parachuting and Lipo are things you realy need to right the first time, and every time. :lol:

I wouldn't charge at work since Lipo need more attention than most people can give them at work.

Lipo aren't as long lived as LiFePo4, so for a commuter, the Ping or a battery from Cell_Man makes more sence.

 

[Ypedal]

Lipo aren't as long lived as LiFePo4, so for a commuter, the Ping or a battery from Cell_Man makes more sence.

I dont entirely agree with that statement.. it's often repeated.. but not yet proven imo..

equally treated, never drained 100%, charged correctly ( slightly lower than 4.20v ) at reasonable C rates ( half the claimed specs on HK ) .... lipo has been holding up as long as any other lithium packs i've used ( and i've used them nearly all )

 

[wesnewell]

The 4s hard case packs are the best bang for the buck, period. They configure to 12, 16, 20, and 24s packs easily. The plastic case provides good protection against mishaps with sharp objects. They also allow even stacking. I run mine as 24s2p stacked 3 wide and 4 high, which fits nicely in the triangle with just enough room for pedal clearance on both sides.

 

[Kin]

I'd say just add some money to whatever you think LiPo will cost you. Small things add a bit to the cost, and making a harness takes a bit of time.

Consider investing in a battery medic, parralel balance cables (if you like; some people recommend against), celllog(s). You really need something other than your RC charger that can quickly take a look a the voltages.

So if you want something easy, I really think a cellman pack is nice. But if you really want, you can probably get away with LiPo. The costs for me have added up, but I enjoy the learning and infrastructure I purchased because I went down the LiPo root. I have also had some packs prematurely fail, so again, do realize it might end up costing a bit more than you expect, but still a bunch less than LiPO4.

 

[dogman dan]

My first ping went 700 cycles, so I don't agree that lifepo4 is going to last 2000 cycles. I've killed some Turnigy lipo I abused in 50 cycles. So I can't say 500 cycles is garanteed for lipo. As always, "It depends" .

I stick with my choice of ping lifepo4 for commuting because when I did that commute, it was30 miles per day. At that distance, safe, easy, worry free charging at work was the whole deal.

But if you can go both ways on your commute with 500wh of lipo, then why the hell not? Surely you can get 700 cycles from two sets of packs, and still be cheaper than a big heavy 700wh ping.

But in the end, I plugged in a pingbattery and went to bed for 4 years and slept like a baby. Lipo would have to finish by bedtime. Fast as you can charge lipo, that's not hard to do.

Again, the way I see it, the advantages of lipo diminish for a bike that only needs 1000w when you still need to carry 700 wh. But if you can ride with a 500w lipo pack that really is half the weight, then of course you want to do that.

 

[Drunkskunk]

Lipo aren't as long lived as LiFePo4, so for a commuter, the Ping or a battery from Cell_Man makes more sence.

I dont entirely agree with that statement.. it's often repeated.. but not yet proven imo..

equally treated, never drained 100%, charged correctly ( slightly lower than 4.20v ) at reasonable C rates ( half the claimed specs on HK ) .... lipo has been holding up as long as any other lithium packs i've used ( and i've used them nearly all )

I'd be interested in what kind of capacity you still have in your packs. I know you were an early LiCo adopter, and have more experiance than most of us do.
My Lico from HK did great for 3 years. this is there 4th and will be their last. But I also run a bunch of LiCo for my RC Planes, and no battery made it past 3 years. I've also had a few LiCo laptop batteries, all dead in 2-3 years.

Maybe this would be a good topic for a Poll or something, and see what kind of life people are getting from LiCo, LiFePO4, and the other various forms of Lithium

 

[Ykick]

Did I miss the memo that we're now using Lico instead of RC Lipo when referring to Hobby King bricks?

PS - just finishing up a test of a full 2 year old 5Ah Turnigy brick with large amount (+500) cycles. About 3Ah is all it can muster between 4.15V-3.3V, 1C load. It's actually just one cell that's severely lacking in the brick but yeah, gonna need to replace or perhaps cull the remaining decent cells into a Franken-brick? Squeeze a few more months from it?

 

[999zip999]

Dogman didn't you forget something with your ping so it die a early dead ?

 

[motomech]

If the OP is going to go with 3)4S's to get 12S, he most likely will be grafting up balance leads to out-put 2) 6S[7-pin]balance plugs.
What he needs to understand is that last lead from cel #6[the #2 cel in the middle 4S pack]has to be parelleled to the first lead of the second 6S balance plug.
Clear as mud?
It's something that I never read here and had to figure out for myself.
I've done 3) 4S's to get 12S and frankly, with the Turnigy 6S 5Ah 20C's going for $42.66 out of the US warehouse, I don't think it's worth the extra work for the little $$$ saved.
The other thing is, 2) 6S's together leaves open charging/discharging options. For instance, if your 1420I dies or you want to use a "knock-a-round cheap 6S charger out of your work area, you have the option of breaking those packs for easy 6S charging. No can do with 4S+4S+4S.

 

[wesnewell]

I've got 12 4s packs and I charge them all at the same time, the same as I would if I had 8 6s packs.

 

[999zip999]

Still Lipo is a hard for the work place battery if you have to bring inside to charge. If a big enough pack is less worry as not the need to charge in the office ect.

 

[dogman dan]

Yes, I left my ping V1 battery plugged into the bike the day I rode home with a 102 f fever when I got the west nile virus last summer. Two weeks later I found it all puffed and resting at 1v. The bms should have cut off the battery at 36v though, so it was a fail. The lvc in the controller should have helped, but the 3w the controller draws on standby must have been enough to take it from 28v to 1v. It was parked pretty close to fully discharged too, so 72 wh per day was enough to do the trick, with just a 100wh left in the pack.

By cycle 700, it had gotten to where it would get very unbalanced every discharge, and had lost some capacity. Not 20% lost, but more like 10%.

The point is, just because a single cell of lifepo4 can do 2000 cycles in a lab under controlled enviroment does not mean your 48 cells bouncing around on the bike in the hot and the cold, getting bulk charged then balanced, AND the bms are going to last 2000 cycles. We've seen plenty of bms or cell failures by cycle 500 or sooner.

So while one chemistry or another may have a longer cycle life, it does not garantee that all of your cells will do that. That's even more true the way some kits are marketed. That is 2c batteries matched with motors and controllers that will draw 2c. I never tire of saying, " don't buy that 10 ah battery for a 20 amp controller".

RE charging at work. For many people, charging RC lipo at work would be just dangerous enough to not do it. But if you have a secure place to charge outside, that could be different. Personally, I would NOT charge lipo on my desk at work. One puffed cell venting toxic gas in the office could get ya fired. I charge my lifepo4 at work, but that is outside.

 

[deVries]

equally treated, never drained 100%, charged correctly ( slightly lower than 4.20v ) at reasonable C rates ( half the claimed specs on HK ) .... lipo has been holding up as long as any other lithium packs i've used ( and i've used them nearly all )

What is your experience with A123 batteries? Battery volts/ah? Service date/cycles?

Have you tracked your LiPo with some record keeping? Service life date, total cycles, and what do you charge your lipo to & discharge to? Metered by volts or amps used on rides? What is the maximum you will discharge to if needed, or is that something you avoid except for some "emergency" that almost never happens if ever???

Thanks.

 

[Ypedal]

http://ypedal.com/Lipo/Lipo.htm

HK turnigy lipo started early 2010 for me, my main test rig is the Norc Chaos on 100v 5ah with a 55 amp controller. That pack was used for 2 years, bulk charged with meanwell supplies to 100.0v ( giving a range of 4.13 to 4.18v per cell across 24 cells ) .. occasionally ballanced charged with an Icharger 3010B but over 2 years of this i've discovered that the icharger ballance cycle was not needed as the cells always return to their voltages pre-ballance almost right away, but it served a learning purpose.

if you have healthy cells in your pack, a BMS and ballancing is not required..

Discharges going to work and back = 9.6km = +/- 3ah average per cycle ( from 5ah cells at 10C peak, 2C +constant from 20C packs )

work 5 days a week *( and a few cycles per day on the weekends ) , 2 years, from april to dec = 500+ cycles over 2 years and the packs are still working, i have to perform a capacity test and report back but i have 1 cell that limits the others on the most + side of the pack. always that same cell that dies first.. not sure why.

I installed 4 fresh packs on the nocro this year for commuting as the 2010 cells are showing their age but still work fine and are used for secondary packs on my other bikes ( the BMX, rang extender for longer trips in a backack, etc etc etc.. )

All my bikes have Cycle Analysts, that is how i keep track of voltage, ah, etc. on the bikes, i also use CA's on my chargers to keep track of charge profiles and behavior. (no BMS on any of my packs )

my PSI cells ( 10ah Lifepo4 cylindrical cells ) have been in service since early 2009, not that many cycles on these, they have been used on the chopper, on the BMX in a backpack, various projects of the years , accidentally drained to 0v and revived, more than once, and still work...

A123 i have not used very much, only a few 26650 cell packs here and there, but no data to report on those..

i present my projects page with LOTS of data to read thru for anyone interested in knowing details of all this.... blogged as i go.

Then i add 10,000 posts here on ES, reading and writing daily other's findings and results, and imo... start with quality cells, do a preliminary QC check and make sure you dont have runts in the pack, manually monitor them carefully all the time, any lithium chemistry will work excellent for you.

Avoid, ebay, lowest priced cells, packs spot welded crappily, bad chargers, BMS's ... i hate BMS's... they have caused me more cell failures than they have saved packs.. arg..3

This pack is still in use :
http://ypedal.com/EBK/ebk.htm

been abused, lent to customers *( heavy usage from one guy for 6 months ) cold tested, heat tested, dropped, and still keeps on ticking.. i have to get it back for a capacity test from the local customer who is currently using it.

---

All that being said, you can kill a pack with a single day of bad usage, if you try hard enough.. be it lifepo4, limn, lico, rc lipo, nimh, nicad, or lead acid... no matter.. severely overcharge it, drain it flat with a hard over-discharge, and there you go .. 2000 cycle claims worth nothing if you ruin a pack by being a jerk.... like tools... use as intended..

edit " fixed typo's..

 

[pff7]

"All that being said, you can kill a pack with a single day of bad usage, if you try hard enough.. be it lifepo4, limn, lico, rc lipo, nimh, nicad, or lead acid... no matter.. severely overcharge it, drain it flat with a hard over-discharge, and there you go .. 2000 cycle claims worth nothing if you ruin a pack by being a jerk.... like tools... use as intended..

nicely said Ypedal !

 

[aixelsyd]

Parachuting and Lipo are things you realy need to right the first time, and every time. .

As a skydiver I second that notion 8)

 

[GMUseless]

do a preliminary QC check and make sure you dont have runts in the pack, manually monitor them carefully all the time, any lithium chemistry will work excellent for you.

There it is. Thanks Ypdeal. Turnigy should print that on every pack and pay you a royalty.

DIY QC...because you are about to use RC grade cells (i.e. toys) in an EV application.

I treat them like pets. They need attention. I check on them every few days. Any packs sitting idle gets a cell-log plugged in at least once a weak. I look for leakers, laggers, puffers, ghosts or MIA's. I keep a log, and labels right on the packs of which cells to watch for suspicious behavior.

And upon receiving any pack...I cycle it at least 5 times. I watch how it balances. I measure capacity. I let it sit a few days at 90% to watch for self dishcarge. I fully expect to not be able to use 10-15% of everything I get from Hobby King.

Then, I sleep good at night. And charge at work, on my desk. (But in nomex bags, and I do have a door leading outside close by...and two five gallon buckets half full of sand each in the closet.)

 

[dave02150]

Hello and sorry for the long-delayed response

Thank you, everyone, for your thoughts and suggestions.

Some of the advice I have taken to heart ie. I have purchased regular instead of hardshell batteries. (I'm all excited! They arrived today!)

Some things I guess there can be no definitive answer on - it's a matter of opinion and personal experience.

I have purchased 4 x Turnigy 5Ah 6s 20C packs - 2 in series (44V, 5Ah) for recreational rides, or 2 x 2 for the trip to work and back. I'm not comfortable with the idea of charging at work (yet)(maybe never)(we'll see...)

I have purchased 2 chargers - an iCharger 106B (from EP Buddy; not here yet) and a HobbyKing eco six balance charger. I have purchased 2 low voltage alarms.

The HobbyKing stuff was all ordered on July 25 and it arrived today August 7. It appears to have come from China via EMS Speedpost. I was able to track it online as far as "Released by Air Destination" on 1 August. No city name was mentioned, but it took a week to get from there to here. Packing was very good, there appears to be no damage.

Total cost so far: $281 + $98 = $379 (US)

binlagin: I am sorry to hear of your long wait; I was worried that mine may have been as long. Luckily, only 2 weeks. I am also in the Ottawa area (Chelsea, QC) - it's 18 kms to my cubicle downtown. I don't recall specifically choosing US Warehouse or International when I made my order, but it appears to have come from China and arrived here in under 2 weeks. If you ordered from HobbyKing, do they have online tracking for US Warehouse orders?

I have been doing more reading and I have lots of work ahead - I am going to be conditioning the batteries to improve lifespan and to get used to the charging / discharging processes.

Thanks again, we'll be seeing you on the road! More likely, I'll be back here asking more noob questions.
dave02150

 

[Jason27]

I use lipo as a backup for short distances. I just have to be very careful when charging them.