Hobby King LiFePo4

Hobby King has a U.S.A. warehouse and they have a lot of LiFePo4 packs at a decent price. Not as good a lipo though but my next bike will have lifepo4 cause of all the hoopla over lipo even though mine has performed great so far. I even managed to plug a balance tap in wrong but my reflexes are still sharp so I didn't blow the interconnect or vaporize the balance tap. (just a little discoloration of the prongs) so far they still balance great on the cell level. I digress... How come HK lifepo4 has such a high c discharge rate compared to ping. Hobby King lifepo4 has a 30c discharge rate constant 40 c burst. Ping's have a 1 or 2 c discharge rate. Does that sound right? PS Can I run HK LifePo4 without a bms?


Spec.
Capacity: 8400mAh
Voltage: 4S2P / 13.2V
Discharge: 30C Constant / 40C Burst
Weight: 1026g (including wire, plug & case)
Dimensions: 150mm x 52mm x 70mm
Balance Plug: JST-XH
Discharge Plug: 5.5mm Bullet-Connector

http://www.hobbyking.com/hobbyking/...mAh_4S2P_30C_LiFePo4_Pack_USA_Warehouse_.html

The scuttlebut on those lifepo4 is the c rate is wildly inflated. Even so, should run a commuter wattage bike just fine.

They have comparable (lowish) energy density to a123 26650 but without electrical and mechanical robustness of a123 cylindricals. And the price difference is not that much either. Not sure they make much sense.

OTOH if HK offered us pre-built packs of a123 20ah prismatics that would have been a totally different story HK has probably enough market share in the hobbyist market to generate minimal order requirements for a123. Wishful thinking though...

So if I have 16ah of HK LiFePo4 will I be able to run 50 amps to the controller? That would be just over 3c discharge rate. They are claiming 30.

boppinbob said:

So if I have 16ah of HK LiFePo4 will I be able to run 50 amps to the controller? That would be just over 3c discharge rate. They are claiming 30.

Click to expand...

It will probably work but I would suggest buying a123 pack from cellman if you want lifepo4 chemistry. Much better odds of getting few years of reliable service from those cells.

curious said:

boppinbob said:

So if I have 16ah of HK LiFePo4 will I be able to run 50 amps to the controller? That would be just over 3c discharge rate. They are claiming 30.

Click to expand...

It will probably work but I would suggest buying a123 pack from cellman if you want lifepo4 chemistry. Much better odds of getting few years of reliable service from those cells.

Click to expand...

I dont want to come across as a salesman for Emissions_Free, but you will not save any $ by guinea pigging HK LiFePo4 packs.
If you have lots of disposable income then sure test away.
lets compare a H.K. 52v8.4ah pack versus Cellman 52v9.2ahpack.

H.K. http://www.hobbyking.com/hobbyking/...mAh_4S2P_30C_LiFePo4_Pack_USA_Warehouse_.html

4 x $86 = $344
BMS = ? (let' estimate $75-$100) I wouldnt run LiFePo4 without, though you certainly could with prudent use of a C.A.
Charger = You could use your Lipo charger for free, but then would have to breakdown your packs to charge.
New 52v charger say $50-$100.
So $469-$544 + shipping/taxes for a 52v8.4ah 436.8wh

Cellman a123 26650 http://www.emissions-free.com/catalog/i26.html
16s4p = $450
BMS = $55 included. 80amp upgrade is only $40. & recommended for future proofing. I wish I did
Charger = $55 4a, $72 6a. I did upgrade this.
So $505-$562. + a bit more shipping/tax for 52v9.2ah 478.4wh.

With the H.K. you get a unknown/mixed review pack of LiFePo4 cells.
Emissions_free offers a tested/matched pack of the very best, affordable, cells currently available,in 26650.
made into a functioning plug & play pack with pre-charge resistor and all.
Speaking English,communicating effectively & honestly, are major pluses
I cant recommended Paul more highly.

If you are looking for 16ah though, consider asking if he could source you some of the coveted 20ah pouches.
He has offered them in the past & sometimes has gear that is not listed on his site. :wink:
Shoot him an email with your needs, & he'll take good care of you.

That was sort of my impression too. Sure, 16 ah of it should run a 50 amps controller fine, but it's simply not that fantastic a price. And you get no bms, so you are looking at adding money for that, or dealing with human bms type arrangements.

A lot would depend on what your specific use would be. Could be a good pack for adding range to an existing battery for the weekend jaunts. Or a dirt bike ridden just weekends mostly. I'd rather just have a bms equipped lifepo4 for a charge twice a day commuting setup.

Prismatic Lifepo4 from hobbyking is not what you are looking for, A customer did buy a lot of them and after a while he had a lot of unbalanced cells, Lipo does not really need a bms but these lifepo4 zippy packs do, and even with a bms he had a lot of errors. Running 40A at a 10Ah pack. So theire 30C claim can not be true and even 4c seems not work out.

Hey, I'm no expert, but if someone has metrics to share with data - love to see it. Here's a couple experiments with these packs, what I'm doing is varying the configuration because frankly don't know what pack I want with my bike's drive system. So I am changing it up a bit, maybe go to a A123 system later (what's up with the bankruptcy thing anyway?).

So here's what I've got -
Battery performance, small inexpensive LFP HK Pack, and ‘morphed’ rear panier rack and battery carrying bag (50 grm) -

Packs arrived at 13.17v LFP storage level. Weight total of 4x 4s set w/ wires & cellmeter is 4220 grm / 9lb 4 oz (think that's right).
With internal lightweight 50 grm carrying bags, plus panniers, battery, all up is 12.4 lb (approx, bath scale).

This LFP pack (not, Li-Ion) HK battery is readily configurable as (approx) 48, 60 or 72v, and 8400 or 16800 mah. Intent is to easily change the configuration using 12v / 8400 4s cells, and runs without a BMS. Charge is done with a plain bulk lead charger and then w/ parallel board (up to 6) to full up , watch cells with a small digital 'cellmeter' & use a monitor with low volt piezo buzz alarm.

First tests are with the minimum LiFePo4 (LFP) battery a lightweight config of 48 v (4x , 4s 8400mah). Was hoping this lightweight pack would handle the draw, and so far, OK. This is a pretty small pack (as first test), but performed well on several short 3-5 mile rides and a 5 mile trail ride. There's been negative comments on E.S. Forums about these (above), but a few HK guys have used them on bikes with luck. So far, these are working to my expectation, but haven't pushed it hard yet. After my alfine shift hub is fixed, I will go for 1000' ride with a watt gage, and check the total battery sag & watt capability (future thread) - but as for the minimum 48v pack providing enough peak amp, worked OK thus far, but have to see what it can do for distance.

Today’s ride ran through 192 watt, started at 52.7 volt, ended 51.47v. Peak amp 21.5 and 1014 watt. Low sag point dropped to 47.2 with short few second alarms on 3v cutoff. Cell variance .04v
Yesterday, short rides of cumulative 1000' climb, parts at 13deg slope, shows 900-950 watt peak, about 19.1 amp peak. Pack started at 53.7v, with sag to 48.02 on steep pitches. Post ride, the cell variance was only .003-.04 volt.

View attachment 3Can't find a better place for this rack & pannier bag, so will shove it here -

A wave sailing friend runs a sail loft for small boats, windsurfers, and kitesurfers.

The battery bag carries either 2, 3, or 4 '12 v 8400 Bricks' per side and ride suspended inside the pannier. That keeps them up, and all the other crap falls to the bottom. The bag is made with flame retardant sail material that is super strong, but is absurdly light – kapton monofilm with kevlar and polyester tracers. Bag is literally 50 grms, could easily carry 50 lbs. Inside the pannier, Still enough room for rain gear & tools, and keep battery up, and out of the bottom, banging about.

Rack is a morph between a regualar seat post chinese style, married to a Nitto hard tail rack. It is laced with kitesurf line spectra 600 lb test, then a bit of epoxy to keep it tight - take 50 lb, at least rather than 20 lb limit, 2nd attach at the frame post makes it much stiffer.

A couple 8s chargers plus power supply and you got a hobby plus a spider of connections, maybe draw it out or.. How many steps.

Hey wavezz2k where you live lot's of rain ? Plug and play with one charger that shuts off with lifepo4 and bms maybe a 10amp charger ?

9 lb pack (8400 4s) has about 4x 5x @5-6 mile short runs with several steep pitch, max 1100 watt peak draw (20+amp) - about 110 to 200 watt pulled total per ride (as recalling, what the amp meter stated). For first tests, it's working fine I guess - but no expert here with Li-Po & bikes.. . next plan is up-volts the controller (soon as arrives) for 6s 82v, and hope for 2kw burst thru GNG motor drive, & no BMS (for now). will update w/ data as progresses, and record watts used vs recharge. Don't think the pack has yet been fully charged up, but will get to it. Lot's motorcycle guys are using plain 12v lead acid charge circuits on LFP, so my plan (was) for single bulk charge use a 48v lead acid, then trim once in awhile. Pack cell balance hasn't been issue so far, less than a tenth volt delta (.04 max). A canned A123 built pack might be a better plan when the end-game is figured out, but as try & fly goes, meets my purpose. These cells appear, "Largely an unknown", so starting small with these $80x4=$320 wasn't a killer; previously failed a $400 pack from china - that was a drag.. Comfortable enough at this point to push these cells further, and order a few more. Hope get a more accurate performance over next couple weeks. HK claims to honor 30day capacity & delivered storage volt level upon receipt, but dunno if they'd honor it or not, if contested. your mileage may vary. Not sure about single charge for the 82v pack, as haven't seen anything over 60v that is cheap... plan is that volt level, as the motor shows 72v+ is possible.

Now hub 8spd is working proper, feels way more efficient, so looking fwd to watt data before up-sized.

Yep it rains here, nearest landmark is Anuo Nuevo 'ride 2', see (crappy, short 1 min) video ride to the overlook at Big Basin redwood park, pg 30 of thread -
http://endless-sphere.com/forums/viewtopic.php?f=28&t=42785&start=435

nobody knows where your here is since you don't have your location in your profile.

how can you balance your pack if you never use a BMS and then on top of that only charge with a SLA charger.

@ less than $500, this woulda been cheaper, more power and last longer than the HK stuff you guys think is so cheap and great:

http://www.ebay.com/itm/LiFePO4-48V-20AH-Battery-5A-Charger-BMS-Rechargeable-Scooter-Sea-7-8Week-Outdoor-/140793235954?pt=US_Rechargeable_Batteries&hash=item20c7ee49f2

I don't think anyone said 'cheap and great', .. I think my comment was about the little $5 cell meter & peep buzzer warning ... anyway ..
simply state what it cost, volts and amps it is delivering on some rides- folks can decide for them self what to get.

The HK, supposedly will warrant for 30days, and they sell boatloads of Li-Ion (slurry, & pack in-house, Li-co / whatever the R/C flavor is anyway). I bought a nice looking psuedo-no-name pack from China $400 36v, and it pooped out. Return ship cost nearly $100 each way, so winds up that a R&R is nearly $200. Personally, not doing that again.

These HK packs show up with at least a semblance of warranty at the door, and shipped from US warehouse (lot's of HK Li-Ion off road MTB throughout this forum for sure, check the GNG thread alone there are several). To balance trim the HK pack setup, simply use a balance adapter with a RC charger once every couple weeks or so. After my 6x test rides so far, there is no evidence that these cells are going to go 'off balance' any time soon as the cell variance was 0.04v. just trying to put out 'data', if you have a bad single battery of 4s, you could use the balance on just one battery, or run with a cellmedic tap balance, of if you scrap one battery - not a deal breaker.

The most important reason to run with these HK batteries (self brew style), also, is the need to change configuration easily, trying to figure out the volts&amp ratio for my kit - so premade isn't going to work. My next configuration is, 6x (4s), with 3 'batteries' per side, providing just over 80 volts for test rides. I may end up with 8x (4s), with just over 50v pack and 16.8ah total, as a final setup (4 batteries per side), with less peak power & lower top speed, but greater distance & better pedal cadence. 60v at 5x (4s) might actually be ideal. Dunno, gonna try them each till I find what's best for my ride. Can't do the change test program, unless you are building the pack up. If it's true as stated, the LFP is a tad safer from a fire and handling perspective than Li-Ion (Li-co, whatever), possibly get longer cycles with LFP, have to see.

dnmun » I think said. "an engineer would never run a battery without a bms .. " , hmmm ... LoL.

Took couple 4s batteries apart for the heck of it, toasted balance tap with a bit of bad plumbing...
gonna fix it. cells look fine & individual voltage is still ok, yep, such a noob here. Ha.

Was checking back the Feb thread on HK LFP & $/watt,
looks like LFP has come down 25-30% in recent months (didn't know that, hadn't seen this prior, didn't know better, just ordered some). The points about A123 built up with BMS, ready to roll certainly make sense if you aren't changing your configuration about with testing...

by LegendLength »
Zippy 30C LiFePo4
Capacity: 69.3 Wh
Weight: 0.642 kg
Price: 79.88 USD
Density: 107.94 Wh / kg
Price / Capacity: 1.15 USD / Wh

Zippy 30C LiPo
Capacity: 92.5 Wh
Weight: 0.650 kg
Price: 54.85 USD
Density: 142.30 Wh / kg
Price / Capacity: 0.59 USD / Wh

Click to expand...

ZIPPY_Flightmax_8400mAh
http://www.hobbyking.com/hobbyking/store/__14074__ZIPPY_Flightmax_8400mAh_4S2P_30C_LiFePo4_Pack.html


So, HK LFP doesn't compete WH/kg against the LiPo (Cost stayed about flat), but cost are bit more competitive at $75/111 watt= $.67 /watt. Personally, would guess raw material & process are similar, perhaps delta cost may go down if demand grows? I'll post setup with a Lyen 3-spd on the GNG drive (just arrived) with higher volts later this week .. perhaps methtek harness setup would be good for configuration for 24s. .. A123 pouch, hmmm ..

Repaired the balance taps, which were toasted . hey, note am not advocating a HK or Cellman, but FWIW . bit more results on HK LFP - I've run this 9 lb , 4 pack (4x4s 8400) aprox 10 times for 50 miles. Typical cell variation is about 0.06 (hardly,' way out of balance'). I may not be getting as much total power as a LiPo, but for my current tests, works fine - able to pull a useable 275 watt from the pack (per the wattmeter), when cellmeter 'beep beep' starts to indicate 'low' (below 48v total), it is at 51.9 volt (no load), with drops to 47.2 (given 1+ kw motor load). Gonna update to another test config 6x (4s) power with new controller and will post those results (on the bench with Lyman no sensor controller). As the 4s sits, this pack is good for 5-6 miles typical singletrack with good uphill grades fine. I did ride a test ride of 1 mile after cell alarm warning going off, and ended up with a two cells 1 volt out from the rest (over discharged). I rebalanced, and don't see any degradation, but wouldn't recommend pulling down below warning setvolt. Delivers 19.5-20 amp consistent through it's discharge. For stock setup on GNG, works pretty well. Double the pack to 16ah, could give a reasonably nice range.

wavezz2k
What is your lowest and highest cell voltage after discharge in normal case? What was lowest and highest cell V in particular case of very deep discharge described?

wavezz2k said:

Took couple 4s batteries apart for the heck of it, toasted balance tap with a bit of bad plumbing...
gonna fix it. cells look fine & individual voltage is still ok, yep, such a noob here. Ha.

Click to expand...

looks like cheap 2C lifepo4 china pouches.
Really who know source of "hobbyking" cells ? its just inside of beatiful heat shrink and bright logo sticker.

ended up buying a pair of Turnigy 4.5 Ah 6S2P "30C" LiFePo4 Packs, despite some really bad reviews.

To me, it looks like three things go wrong with these:

1.) Quality control is bad on them, and they sometimes ship with dead cells. I bought cell checkers, individual cell low voltage alarm, and a charge/discharge/balancer. My thinking is I should be able to check them within days of their arrival and send them back if I get bad ones.

2.) They really can't take anywhere near 30c discharge rates. I plan, at a worst case, to run them at around 2.5C (limited by the controller shunt resister) for 12 minutes (50% depth of discharge).

3.) They get out of balance quickly (poor quality control again). I'll have an alarm for low individual cell voltage. With only 50% depth of discharge, and 8 hours of charge time, I can balance them every single time I charge them if needed.

It also looks like the wiring isn't the best in them....(didn't see this thread until after I bought them)

I bought these because I'm not sure if I will even want to use the setup I'm building when it is done, and these seem like a decent intersection between cost/weight/low risk of being out 100% of the money spent on them, and they can be pressed into service for my other 18v stuff.

I'm gambling that I'll get enough more life (time more so than cycles) out of them to justify the extra cost compared to LiPoly. Bad gamble?

Statistics says a lot, and frankly, we'll never know what sort of reject rate that they have. My belief is they sell tons. If quality suffers too much, they'll lose market share. "Who makes HK brand?" they states on their web site that the make slurry, pack electrolyte, and do final package and test. But yea, they are on the cheap side, which is why I'm experimenting with them. Once, ran more than a mile after undervoltage alarm going off, and had 1 cell on each of 2 packs which were 0.8 cell 'down' from the rest. Thought might had killed it, but recharged slowly back to full, and have since ridden another 15 miles (5 miles x 3 outings) with no noticed degradation; Perhaps if needed, it'd be easy to swap out a pouch for that matter, if one were killed by my error.. Definitely don't believe These LFP are 30c actual, but I've seen several tests run on their other LiPo packs which certainly deliver 30c with watt tests on R/C motors. Generally, when I do shut off at the cellmeter alarm, the cell to cell variance is .08 or less on each of these 6 batteries, 60 miles so far. Sorry, don't have more data on combined 72v pack with Lyen controller yet, as been busy on a multirotor bird .. plus it's been raining tons.

NOT trying to be an advocate nor a sales person, just sharing some data. Your mileage may vary.

I have about 12 HK & Turnigy batteries total, not one has a dead cell, each was shipped in a reasonably timely manner, with no damage. My experience: I can not agree that "they get out of balance quickly', as that has not shown up in any of my runs when LVC was respected. The wiring is not spacecraft grade, but works fine for 22amp 1000+ watt peak discharge using only 4 packs -

As soon as one of these LFP packs does die, I'll post it here, with circumstance and number of cycles. I truly wish someone with more miles (cycles) posted logged data, but haven't seen that anywhere. Any other reference data would be great - cheers.

Thanks for posting first hand experience. to clarify, mine have yet to arrive. I was posting my inferences from the types of complaints I've read. So by saying they go out of balance, I meant when someone has reported problems, that is one of the complaints. I wasn't trying to imply they all have that problem.

you can increase the chances they will survive by using a BMS to balance and protect them from overcharging and over discharging. cheap insurance.

dnmun said:

you can increase the chances they will survive by using a BMS to balance and protect them from overcharging and over discharging. cheap insurance.

Click to expand...

Not my thread, but I plan to use a cell level low voltage alarm in use set to something that gives around a 20% SoC under my use, a balance charger every other charge cycle, and 95% SoC on the bulk charger.