Hobbyking LiFeP04 ?

[auraslip]

lifespan of the pack is exactly why i was interested in these. :?
if this was good stuff, you could get 7ah(%80 dod) out of it day to day and it'd last for years
I understand you can't do that with lipo

still, if their was a bms solution that could do lipo for me, the cost would definitely be worth it

for now i'm gonna plan on headways.

 

[MitchJi]

Hi,

How come no one talks about hobbyking lifepo4?

They have talked about them. About their shortcomings at which point the discussion ended:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=14143

Actual experience starts here:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=14143&start=15#p226162

I have these battery packs ( 4 X ) since end December and I am not satisfied about them and especially not about the claimed 30c cont. and 40c peak power output.
They do give me more than 4500mAh but this is the only plus for me
I want to make 2X2 packs or 39,6 V and 9 Ah.

Here are my findings written in the "local" forum:

" I recently ordered and recieved 4 Turnigy 6S2P lifepo4 4500mAh flatpacks for my 500 watt electric bike.
These batteries are fairly new items available from Hobbyking with practically no reviews or real-time experience from buyers, so maybe I am one of the first to have some experience with them, and let me tell you, before you make the same ( expensive ) mistake I did.


They are CRAP and DO NOT even come close to their rated 30C cont. - 40C peak discharge rating, which means that theoretically, you could discharge these batteries in about 2 minutes.....or put a 2500 + watt drain on them, which is definitely A BIG LIE. and would probably ruin them in a few cycles.
Furthermore these batteries behave more like NIMh cells than lifepo4 cells running from full until empty like, strong-good-fair-tired-coma, instead of strong-strong-strong-good-tired,
I just tested one of these on my electric bike and a WATTS-UP!!! monitoring device, firstly balance charged the battery until all 6 cells read 3,6 volt.
It was the 4th charge on this turnigy, so he ( she ) should be virgin-like.


Connecting it to the bike and just free-wheeling it with light braking applied until about 150 - 200 watt was consumed,i quickly noticed after about 10 minutes that the cells became handwarm ( 30 to 35 celsius ) in a +5 degree enviroment and there is a rather large voltage drop until 16,5 to 17 volt, at this point there was about 40 % of rated mAh drained from it, and I stopped for a minute, slowly seeing the voltage come up to 20,4 volts again.
Now for the test I applied some harder braking and let it freewheel off and on for about 6 minutes ranging the load from 100 until 350 watts,
the voltage drops were severe under the higher loads, one time reading only 12,7 volts, this can not be healthy for a battery which has 19,8 volts nominal and has a "30C" discharge rating, with the 350 watt load applied this is only about 15 % of what the battery " in theory" could handle......
The lifepo4 was now warm ( about 40 to 45 degrees ) warmer then I ever felt from a Lipo from turnigy with a lower C-rating and capacity after some hard flying.....
Then I stopped again, and saw the voltage creep up till 19,1 volt, according to the watt-up there was 3400 mAh consumed, and tested some more, with the last 25 % battery mAh left I let it just drain at 50-60 watts for about 15 - 20 mintutes until 4600 mAh was reached.
Again voltage dropped until 14 volt under this slight load and no-load voltage was 18,2 some 3 minutes after the end of the test, suggesting there was still some life in it yet. ( like a 90 year old smoking alcoholic with diabetes )

I did this test because with all 4 packs on my bike it felt sluggish in preformance when climbing slight hills which raised some question markes in my head because they should preform flawless untill about the last 10 % just like lipo's do
All in all: Hobbycity should remake/rename the labels on this battery and discard the "zero" in the C30 rating and making it 3C instead, and even this is IMHO on the high side, the voltage drops under load are unhealthy for a long and happy battery life.
On the bright side, they do meet their rated capacity of 4500mAh, but only if you are willing to drian them slowly in like 30 minutes.
I just hope that the 1000+ cycle life is anything they say it is...........
Its not that I don't like hobbycity products, of the many $$$ spend here this is the first time I'm really dissapointed in a product.
350 Watt should be a walk in the park for these turnigy's but PLEASE BE WISE and keep the $69,99 w/o shipping and customs in your pocket.

Sorry for the big write-up, any comments/suggestions are welcome.
CDM, Belgium."

 

[neptronix]

^--- lol, maybe Turnigy is fishing out of PINGBattery's dumpsters for cells :lol:

 

[Rollodo]

I've posted this in my other thread about prospective purchasing. As part of my everlasting search for a perfect LiFePo4 pack, I looked at HobbyKing collection (I always thought they only carry LiPos) and came across a ZIPPY Flightmax 8400mAh 4S2P 30C LiFePo4 Pack (ID Z84002S-30). Weights about a kilo, 150x52x70mm, ~$70. Get 3/4 in series = 39.6V/52V 8.4Ah, 3 or 4 kilos. Sure, they're back-ordered, but how is the concept?
Or a Turnigy 4500mAh 6S2P 30C LiFePo4 Pack (ID T4500.6S.30F)? Same kilo, 141x43x75mm. Get 2 in series = 39.6V 4.5Ah, 2 kilos. Sure it isn't much, but it's 30C-capable and for a short 5-mile trip + another 2 bricks in a backpack for more juice - doable?
I looked at these connectors - I've never dealt with Anderson's. How would I go about connecting them in series/parallel? Though I understand that these packs are 1 kilo each, having 4 little packs sounds more logistically feasible to me than having 1 big pack.

 

[Kin]

HK LiFePO4 is a lie, they do not deliver remotely their rated parameters. Evidence: Some of that stuff says 30C. The industry standard of excellence, a123, is like 20C. EDIT: Actually, a123 is 30C. I am wrong.

For this reason alone I run away from that stuff and remind people to know what they're getting into. There's fudging, and then there's flat out lieing; i'm not sure why HK goes for lieing on these packs. *Edit: While I was wrong about the rating, the more reasonable and gentle response of mine would simply be to caution you that a lot of people have had bad experience with HK LiPO4.


That said, there might be useful characteristics and capabilities in these packs. I'd wait for people with experience on them to respond, as well as do some good searches on the hobbyking LiFePO4.

 

[Brentis]

I've posted this in my other thread about prospective purchasing. As part of my everlasting search for a perfect LiFePo4 pack,...

For a pack that size look no further than
http://www.emissions-free.com/catalog/c1_p1.html

$405us + shipping. for a 39v9.2ah pack & 5a charger.
add $88 for a 80amp BMS & you have 3000+w on tap.
Trustworthy, knowledgeable man, building quality packs with top quality cells.

Stop your search :wink:

 

[Rollodo]

HK LiFePO4 is a lie, they do not deliver remotely their rated parameters. Evidence: Some of that stuff says 30C. The industry standard of excellence, a123, is like 20C.

For this reason alone I run away from that stuff and remind people to know what they're getting into. There's fudging, and then there's flat out lieing; i'm not sure why HK goes for lieing on these packs.

That's a negative - continuous 70A / 2.3Ah each cell = ~30C; 120A pulse discharge / 2.3Ah = ~50C. Check the specs here:

http://www.emissions-free.com/id47.html

I've posted this in my other thread about prospective purchasing. As part of my everlasting search for a perfect LiFePo4 pack,...

For a pack that size look no further than
http://www.emissions-free.com/catalog/c1_p1.html

$405us + shipping. for a 39v9.2ah pack & 5a charger.
add $88 for a 80amp BMS & you have 3000+w on tap.
Trustworthy, knowledgeable man, building quality packs with top quality cells.

Stop your search :wink:

Not really - that link contains BMS, chargers (which I may look into), and huge batteries. That pack (39V 9.2Ah A123 Pack - the smallest) is measured at 160x110x140mm as a two-level 4kg brick, the same one-level configuration is 320x110x70mm and the same 4kg.

I know Cellman does great things, but the search continues...

 

[Kin]

Ok, just to clarify, what you objected to was not my comment about Hobbyking "LiPO4" but rather about a123 batteries. They are indeed 30C, it seems. I don't know why I mixed up 20C and 30C. I'm sorry.

The complaint about HK LiPO4 being very sketchy still applies.

 

[dogman dan]

Kind of a moot point eh, If they are backordered at HK.

Fact remains, genuine A123's are as good a lifepo4 cell as can be obtained. Tell Cellman what size you need, and He'll make it for you. The usual wait of course for a custom job.

 

[Rollodo]

The usual wait of course for a custom job.

And possibly a custom-job premium as well. Have you or anyone else here ever had Cellman do a custom job? If yes, how much more was it compared to a regular pack?

 

[OlderThanDirt]

Cellman built some custom batteries for me last year (51 V, 11.2 Ah) in a longer, narrower configuration than the usual size so they would fit beneath the seat of my recumbent. Additional cost was $50 per battery.

 

[Rollodo]

Cellman built some custom batteries for me last year (51 V, 11.2 Ah) in a longer, narrower configuration than the usual size so they would fit beneath the seat of my recumbent. Additional cost was $50 per battery.

I emailed him and asked about the feasibility and additional cost - will update when I get a reply back.

 

[chisixer6]

I have been riding my ebike since last summer, with 4 of those turniqy 4.5a 6c batteries, 2 in parallel and then 2 in series resulting in a almost 40v nominal at 9a. It is nice and compack fit in a Blackburn back trunk bag 2 on top of 2. cost just under $300. I know it doesn't compare in performance with a123's, but there is difference in cost, but this is my commute bike, with pedaling I can get to work and back with no recharge, want more power get 50c lipo's.

 

[jonescg]

Cell_man stocks the cylindrical A123s as well as the 20 Ah pouches. He builds them into packs as well, and does a quality job of it too. From memory the premium on a custom job was really very cheap. Two thumbs up from this end!
CHRIS

 

[cell_man]

If a pack is a straightforward build even if it isn't something I list, I don't generally charge any extra fee for it. If it requires quite a lot of work over a simple rectangular layout, then yes I may charge some additional fee, but not so much more and definitely less than what i would consider to be anywhere close to worthwhile for the effort involved in many cases If the layout is stacks of work, like a completely custom triangle battery layout, I may decline if it's just a 1-off. Building special layout packs is hugely time consuming and stressful, working things out as you go along, re-doing things that don't work out as you had though, trying to keep everything as small as possible, big headaches believe me.

Right now I don't keep stock of built packs, they are pretty much all built to order. The packs I list are just examples of what can be done and what to expect, don't take it as that is all I can offer, these things aren't set in stone right now.

 

[999zip999]

You to pay for a good working battery or roll the dice and. buy a fleabay. What ever happen to Codd a123 they just disappeared. No new reveiws

 

[neptronix]

You to pay for a good working battery or roll the dice and. buy a fleabay. What ever happen to Codd a123 they just disappeared. No new reveiws

We found out they were selling packs full of defective cells.. that's what!

Sure, you can get 10AH if you parallel 2x the bad cells to get the same amp hours.. ya'll wondered why they almost weighed as much as SLA..

 

[999zip999]

Cost money to get it right.

 

[Rollodo]

I don't mind spending money on something that I plan to use every single day - I see it as an investment that may pay for itself within the first few months. ~$1000 for the bike + ~$400 motor + worst case ~$600 for the battery = $2000. Monthly MTA fee = $100 + time lost due to construction, general lateness, daily hassles of crowded trains = ~$150. Yes, 2000/150 = 13, which is a year, but that's the worst case. Ideally, my configuration should be less expensive and more portable, making every ride more enjoyable and, therefore, more cost-effective.

I can practically imagine myself waking up on any given early weekend foggy breezy morning, getting out on my bike, blasting through the empty streets of Brooklyn on 48V at 45 mph and crashing into a guido-pimped-out CL class, the driver of which failed to stop at a nearby stop sign due to the naive thought that bicycles aren't fast enough... Jk

 

[SamTexas]

I have almost ZERO experience with LiFePo4 battery. I would like to buy either one the following packs to play with:

1) ZIPPY Flightmax 8400mAh 4S2P 30C LiFePo4 Pack (USA Warehouse)
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=20645

or
2) ZIPPY Flightmax 4200mAh 4S1P 30C LiFePo4 Pack (USA Warehouse)
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=20644

Please share your actual experience with either one of the above:
a) Can I expect half the advertised C rate for 60 seconds? ie can I pull 15C for 60 seconds? If not, what is highest rate I can do for 60 seconds? How long do I have to wait before I can do it again?

b) This is supposed to be a LOT MORE STABLE and a LOT SAFER than the typical RC LiPo. Is it "relatively" true? ie overcharge or overdischarge will kill the battery, but minimal chance of fire, correct?

c) What is the voltage sag at 15C? 5%, 10%, 20% or what?

d) Any reason why I shouldn't even bother with this chemistry or this battery?

Thanks.

 

[amberwolf]

I haven't used them, but there is a little existing discussion on them. I could have sworn I actually read a discussion with actual usage data, but I cna't find it now.

Best I could find is this:
ZIPPY Flightmax 8400mAh 4S2P 30C LiFePo4
link in this thread:
http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=38634
leads to:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=23560
which leads to:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=23523
which has at least some discussion, but no useful info. Another thread I somehow can't find now has Neptronix replying to someone else about them suggesting they look at existing discussions and reviews and see if they still want to use them; from the tone it was derogatory of the packs. So Neptronix might have data or knwo where to find it.

Then this thread:http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=33452
mentions your other choice, and again Neptronix posits that they aren't any good, but no links to the data itself.

So the best I can tell you, is that:

--HK is known for over-rating some of their cells/packs for C-rate even for regular RC LiPo types.

--HK is known for a fair percentage of dud cells and/or packs (often DOA), and at least sometimes being problematic about getting them replaced under warranty.

--Typical LiFePO4 is only good for maybe 2C max. Even the large format commonly-used-in-EV project cells like Thundersky/CALB/etc. are typically only that, and they may sag quite a lot under that kind of load. A123 is the only LiFePO4 I would expect anything above 2C from, realistically. I wouldn't honestly expect the HK stuff to deliver even a tenth of it's advertised C-rate for a minute without heating or extreme sag or both (or worse), and probably couldn't be repeated very often.

--Risk of fire is probably less with *good quality* LiFePO4, but that is also true of good quality LiCo or other Lithium chemistries. If they make it right int ehfirst place it's unlikely to die in flames without severe abuse. With cheap stuff (i.e. often poorly-made like the HK stuff can be), it doesnt' matter which chemistry it is, as a defect or contaminant could result in dramatic failure. Watch Liveforphysics' battery destruction videos to get an idea of what it took to actually get fire out of some cells. (he used to have a link in his sig, so unfortunately I don't have a link to it).

 

[neptronix]

Yeaaahhh i've trash talked them quite a bit, going off what i read in the hobbyking and rc-groups reviews about how they underperform in C, and often enough, cells seem to just suddenly die for no reason..

I'd love to see someone here on the forum formally check them out, but for around double the cost of RC Lipo, your money is best spent on some other type of higher quality battery/battery pack.

Price comparison:

Hobbyking lifepo4: 12S ( ~38.4v nominal ) 4.2AH pack = $45.97 x 3 = $138.91

Hobbyking RC Lipo: 10S ( ~38.5v nominal ) 4AH pack = $29.99 x 2 = $59.98

 

[JimW]

Interesting that you should mention this. I was just testing an HK cell over the weekend. My test objective was to see what kind of performance the cell had at max C discharge.

Turnigy 2200 mah 40 C cell - testing at max C

Starting voltage was 4.2 (unloaded)
Load is 250 watts of .05 ohm resistance (about a 60 amp load)
Cell provided 66 Amps (measured), initial voltage drop to 3.8 volts
This was a timed test - 2 minutes max duration
At the end of 2 minutes, the cell was still producing 66 Amps, voltage was at 3.4.
For the first minute (after the initial voltage drop), the additional voltage drop was pretty much straight line to 3.5 volts.
For the last minute of the test the voltage was essentially flat at 3.4 (actually rising slightly at the 2 minute mark).
At the end of the 2 minute test, the cell temperature was 134 F. ( ! ) Cell rebounded to 3.6v unloaded.

Cell fully recharged, 2 hours at 0.5 amp, plus one hour and a half at 1 amp (declining amperage through an intelligent charger)
I have not re-tested this cell, but intend to. At least a handful of cycles.

Of note for me was the rapid increase in cell temperature (from a starting temperature of 70F). This may turn out to be more of a limiting factor than the energy density. Cell cooling at this discharge rate certainly needs consideration.
Yes, the load became fairly hot (will measure load temperature on the next cycle - but it was certainly too hot to touch, much much hotter than the cell).

I have a few of these cells to test. Will post more results and a discharge curve.
Your mileage may vary.

Thanks,
Jim.

P.S. This exceeded my de-rated calculated estimate of 1 minute 30 seconds of 60 amp capacity. I was prepared to terminate the test early on low voltage, but the voltage did not drop to my 3 volt cutoff point in 2 minutes. Cell temperature became my area of biggest concern.

 

[gblast123]

I ordered a couple. The problem was that about 1 out of 4 came in with low to zero voltage.
Quality control is crap. I posted a review in the HK website... I am the one complaining about the crappy packs.
Someone else I know ordered 8 of the 8400 mA packs, got 4 out of 8 with low voltage, ie 10v, 8v, 3v and 2v (yes, that low)
Had to send it back on his own dime.
HK allowed an RMA in both cases but it was a hassle. and I had to pay for the return postage.

I have since gone to the 5000 mH, 4s lipo hardpack for less than $25 per pack. (in Stock NOW) - http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html
4 of these are less than $100. 8 for less than $200. (for 36 v, use 3 in series X 2 = 6 pcs = $150)
You are getting a 10 AH, about 56V Nominal, 65.1V fully charged pack (@ 4.1V per cell, it is better to undervolt the charge) for that price.
slapping these together takes about an hour.

Use a balancing charger but set the full charge voltage to 4.1v, instead of 4.2.
balancing charger is about $70, not including shipping - http://www.hobbyking.com/hobbyking/store/__16374__HobbyKing_ECO_4_x_6S_Lithium_Polymer_Multi_Charger_.html
a couple of these, when they are in stock (about 3-4 @ $3 each)- http://www.hobbyking.com/hobbyking/store/__21933__Multi_Adapter_All_in_One_Balance_Board_TP_HP_XH_EH_.html
cheap power supply - $15 - http://www.hobbyking.com/hobbyking/store/__20971__Hobbyking_105W_15V_7A_Switching_DC_Power_Supply.html
Better power supply - $40 - http://www.hobbyking.com/hobbyking/store/__9205__25A_14v_DC_Power_Supply_for_Chargers_350W_.html

For faster charging, you should get a 48v, 4 or 6 AH lithium charger... I know, I know.. it is not the same voltage.. but it will get the voltage of the pack over 58V for a quick charge, or about 3.7V per cell, then use the balancing charger to top it off.

65.1 is the max for the caps for most of the 48 V controllers out there commercially, ie Amped bikes, and ebike kit... but a big YMMV, as if you fry ur controller, u buy a new one on ur own dime.

So u get better performance, lower weight and pay a lot less.
Total for all the above is about $300 +/- 10....not including a 48v Li-Ion charger... these run about $50-100 depending on source and Amp rating.
For a 12 s set up, you save about $50, but use a 36v Li-Ion charger. Will work fine with most 36v kits out there.

Seems like a winner to me but there is the following. NO BMS so NO LVC. But I use a little beeper which works great. Here is how you use them.
Price about $4 each, but get 3. http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=18588
you can set the LV alarm for different voltages, so put 4 of them on different 4s packs in seriew.

Set one for 3.5/3.6v, one for 3.3/3.2, one for 3.0 and one for 2.8/2.7. (Label each one)
When the 3.6 goes off, you are about at 60%, (Pull it off and put it away to stop the beeping- that is why you should label these)
When 3.3 goes off, you know that you should start heading home and start to "nurse your pack". .
When you hit 3.0, then stop using the battery except for slight uphill, etc. When u hit 2.7/2.8, stop using the pack. In reality, I try never to go below 3.0 v, and immediately recharge once you get home.

I find this works better than a bms in some respects as you don't have to worry about the whole pack dying on you when you have to get someplace in an emergency.
Hope this helps

 

[x88x]

Even if it weren't for the reported crap QC, the price (IMO) makes them ultimately pointless unless they could actually deliver on that claimed C-rate. I plugged them into my battery stat spreadsheet (sig), and they come out to $0.86/Wh, 96.34Wh/kg, and 185.51Wh/L raw (ie, ignoring packaging). That's about what you get with Headway 38120P's, in terms of cost and specific energy/energy density. So unless they could actually do their stated C, have minimal sag, and last for over a thousand cycles without babying, I really don't see the point in them.