Headway 48v 10ah - EVcomponents.com

[Ypedal]

Regarding SLA, it's called the " Peukert effect " .. a 12ah sla battery pushed hard will only give you about 6~7ah.

Lithium does not exibit this behavior..

Now let me be clear on something as it seems i may have been mis-understood earlier, the Headway cells WILL dish out 5C ie: 50 amps, no question about it, but they will heat up in the process. At 3C they remain relatively cool and this can only be a good thing for service life of the cells..

Even at high C rate, LiFePo4 still delivers it's rated capacity but it does it at a lower voltage as the V sag is proportional to IR, Internal Resistance..

 

[davespicer]

Even at high C rate, LiFePo4 still delivers it's rated capacity but it does it at a lower voltage as the V sag is proportional to IR, Internal Resistance..

...and if I remember correctly the heat from this resistance increases as the square of the current: twice the current will result in four times as much heat.

One way to remember this aspect of Ohm's Law might get you some odd looks from friends, but:

"Twinkle, twinkle little star,
power equals I-squared-R."

Use with discretion

 

[dogman dan]

Yes, 5c for the headways, though perhaps, not yet with the bms you recieved Ypedal. But I would not expect a long cycle life if used at 5 c a lot. So like you, I figure 3c would be a reasonable rate if you are looking for it to go 1000 cycles. Just like I consider 1.5 c a reasonable rate for real world use of a ping.

But if you are into speed, and have money, put a high amp bms on em a go crazy.

Interesting the lifepo4 has no peukerts effect, I thought it still happened, but just a lot less. A voltage sag could be confused with less capacity if the voltage sags enough to trip the bms while the battery still has some charge left. So maybe that's where I got the wrong idea.

 

[Russell]

Regarding SLA, it's called the " Peukert effect " .. a 12ah sla battery pushed hard will only give you about 6~7ah.

Lithium does not exibit this behavior..

Now let me be clear on something as it seems i may have been mis-understood earlier, the Headway cells WILL dish out 5C ie: 50 amps, no question about it, but they will heat up in the process. At 3C they remain relatively cool and this can only be a good thing for service life of the cells..

Even at high C rate, LiFePo4 still delivers it's rated capacity but it does it at a lower voltage as the V sag is proportional to IR, Internal Resistance..

I disagree with the statement that lithium does not exhibit the Peukert Effect as it was my understanding the ALL batteries will deliver less total capacity as the discharge rate goes up. The effect isn't nearly as great with lithium but it's still there. The curves in these discharge plots clearly show reduced capacity when the cells are discharged faster.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=7655&start=45#p118836



-R

 

[DerekG]

So Lithium packs should deliver "almost" the same amp hours but less watt hours when discharged quickly due to more energy being wasted as heat.

 

[redorblack]

My pack after charging and resting for 12+ hours seems to have settled on 56.4v, 3.525v per cell. Does that sound appropriate? Like a fully balanced pack with good cells? Ypedal... any reason for me to pull this apart and measure each cell at the BMS or anything? Or just be happy as a clam and ride? With my motor, I'm not seeing any sign of a cutout, so as long as I'm truly balanced and correctly charged, I'm happy.

 

[patrickza]

I want one of those 72 volt 20 amp headway packs from (EVC) to run my 72 volt 50 amp crystalyte controller with a new x5306 but now i am worrried about their BMS.

The cells would only be at 2.5C maxed out using a 20 amp pack with that controller. I suspect that since the 10ah packs are cutting out in the 35 amp range, that a 20ah pack bms would probably be cutting in around 70 amps, more than your controller can/would deal with.

Sounds like a fast and powerful combo, but that is 37+ pounds in battery, not bad if your replacing lead acid or are building a small electric motorcycle... bit heavy for a bike.

I run 72v10A on my 5305, seems to handle it fine. The 72v headway BMS is 100A continuos, so that won't be a problem. Mine has never cut out, and I've seen peak amps of over 90.

I had balancing issues, but now they are solved and my BMS seems fine. I'd recommend getting a single cell charger just in case you need to assist the BMS to catch up with a cell.

 

[patrickza]

I am defiantly not getting full capacity out of the pack I built from headway cells. I tested the bike today and it cut out at 8.5Ah. I ordered some single cell charges and intend to charge each cell individually to see if that will make a difference. I have tried two different BMS’s and neither seemed to balanced the pack.

Which BMS and charger are you using? Have you looked for individual low cells in the pack? How many amps do you pull from your pack on average?

I originally used a Signalab BMS I purchased from All –Battery.com. While trying to sort out a previous problem (bad cell) I changed to a BMS I purchased from Kennedy Alternative Energy which I believe is a Headway BMS. At cruising speed I am using around 15 amps, my CA shows a maxA of 30. The bike has a 30 amp controller. The charger I also purchased from KAE. The charger has no brand name on it but it does put our 58v when charging but it does not seem to balance the cells. I have looked from low cell while trouble shooting my previous problem and found just the one. I am going the pull the pack off the bike and start testing for weak cells again. The BMS shuts down the pack at 48v which I think is high. Any suggestions you have would be appreciated.

Is the 48v under load or a resting voltage? If you have the headway BMS they cut out when one cell reaches 2.5v. I'd run it to cutout, and then measure each cell. Find the cell or cells which caused the cutout. Then charge up and again check each cell. In my case I had one which wouldn't charge up correctly and that was causing the cutout. I fixed it by discharing the whole pack, then swapping the low cell with a spare, but I think if you have a single cell charger you can charge up the low cell and it should sort things out.

 

[dnmun]

why do you say you 'think' you have headway BMS? not really fair to say your pack won't balance when the charger doesn't put out enuff volts to balance it either. maybe you should put off taking the pack apart until you know a little more. can you post up a picture of the BMS and what the voltages are?

 

[velowatt]

I got my 16s1p 10Ah Headway pack earlier this month and have finally got it installed in a rear rack-mounted case. The pack looks just like Ypedal's- inside the black box, the battery and BMS had broken loose from the glue on the bottom. I put a strap around the battery and attached to the case to hold the batt in place and avoid smashing the BMS.

It is pouring rain today, but I hope to get the wiring harness to the bike finished so I can try it out!

I kept the box to hold the battery in place but took the top off to save space. It sits on the front half of an Octivia box which is divided by a wooden partition that leaves about half the box available for storage space. The partition is reinforced with fiberglass laminate and the battery box and wood/glass frame are bolted to the rack through the case, which also holds the controller and a DC converter for lights and a small cooling fan for the controller.

I have the 3A charger from EVC. The pack came with all cells balanced at 3.31V/cell exactly th same. Pack voltage just under 53V. When the charger is hooked up, the flashing red light on the charger comes on. On my SLA and NiMH chargers, this means an error; but according to Watts up meter, charge flows into the battery. I have not topped it off yet.

This is my first experience with lithium batteries (I have been using SLA's and NiMH until now).


Anybody have advice for me regarding....

1. I understand that the first few cycles should not be very deep discharge to let the cells 'break in' gradually. Is it important to top up the pack before using it?

2. The charger has a cooling fan, but it does not turn on when the charger is plugged in and working (at least not yet- I have only had it on for about 10 min).

3. If the BMS board or he batteries get hot during charging or discharging, does it make any sense to put a cooling fan near the BMS/battery? I have a couple of computer power supply fans lying around and a 15V DC current source right next to the battery (actually Velcro'ed onto the box), so it would be really simpy to bolt one on the box.

I will try to get some pix posted (camera battery is dead)!

Thanks all, this group has been incredibly educational for me!

 

[redorblack]

1. I understand that the first few cycles should not be very deep discharge to let the cells 'break in' gradually. Is it important to top up the pack before using it?

2. The charger has a cooling fan, but it does not turn on when the charger is plugged in and working (at least not yet- I have only had it on for about 10 min).

3. If the BMS board or he batteries get hot during charging or discharging, does it make any sense to put a cooling fan near the BMS/battery? I have a couple of computer power supply fans lying around and a 15V DC current source right next to the battery (actually Velcro'ed onto the box), so it would be really simpy to bolt one on the box.

I will try to get some pix posted (camera battery is dead)!

Thanks all, this group has been incredibly educational for me!

You sound just like me a week ago

I let mine charge overnight, after listening closely to the charger I could hear that the fan is spinning, it's just quiet. You can feel the air moving.

http://picasaweb.google.com/Scott.McElhiney/HeadwayLiFePo4Battery#5403047630794840034

This is what my SnapOn Vantage was showing the first time I hooked up the charger and the lamp had gone green, but I could here a quiet clicking from the charger. It appears that was it balancing the pack, it was pulsing as high as 63 volts on those spikes. After I let it balance overnight and then ran it for about a 1/2 hour while calibrating my CA in the kitchen, I charged it back up and it hit 58.4v and just stays there. That matches the top of the 2.5-3.65v range Headway gives for the cell. Since then, I haven't caught it doing any balancing, at least not long enough that I've seen it happen... just charges to 58.4v and stays there until I disconnect the charger. As an experiment, I just checked pack voltage, 55.4v after being off the charger for 2 days. Plug in the charger and it went up to 58.4v in a matter of 10 seconds and is now balancing some, I've left the charger on with my meter graphing if out so I can see how long it does that balancing.

Well, that didn't take long... less than 40 seconds. Personally, unless something is wrong with your pack or BMS, I don't think you need to worry about heat if you are using the 3A charger. I thought I saw a rating somewhere for charging at 1c, which would be 10 amps, so 3 amps shouldn't get it very warm. I might pick up a cheap thermometer and leave it in the box while charging, just leave the screws out of the top and check it on occasion, but I really don't think it's even getting warm.

 

[velowatt]

thanks- I will give it a try tonite.

 

[Ypedal]

Ok, so far so good..

regarding comments above and voltage, it all depends on your charger and what the BMS is doing.

If any single cell trips the HVC ( high voltage cutoff ) the BMS will disconect the charger, depending on if you are checking pack or charger voltage you may see 63v(charger's no load voltage ) or 58v(pack voltage at BMS cutoff ) .

In a perfect world, the charger's CV ( constant Voltage ) stage will have a charge rate low enough that the BMS can keep the highest voltage cell below the set BMS limit and charging/ballancing happens normally.. IF the charger is still in CC mode ( 3 amps, or whatever your charger is ) the BMS canot drain fast enough to prevent HVC and has to disconect the charger until that cell is drained down to 3.6xxx volts..

Problem here is that once the BMS trips due to single cell HVC, the cells that were almost full and in the 3.5v range will start to drop down to 3.4~3.3v mark so that when the charger kicks in again it does so at full amps and not throttling and the cell that caused the HVC on the BMS shoots up quickly again, BMS shuts off the charger.. rinse repeat..

My pack has been showing 53.3v after an overnight rest, and so far so good on cycle 20 or so, i'm reasonably happy and it's going to my customer tonight if he shows up and still wants it..

otherwise keep an eye open in the For Sale section ! :wink:

 

[Lock]

I am too lazy to read this whole thread but now I am told by evcomponents that Headway packs are supplied w/out a BMS? Anyone else in this ES world buying Headway pre-made packs that lack a BMS? Suggestions for any/all suitable and available options for 48V 10Ah BMSs suitable for Headway LiFePO4 chemistry most appreciated...
Educate me pls...
tks
LoKK

 

[Ypedal]

No BMS ?? yikes..

So far i'm really liking this one !

Our very own Fechter and Ggoodrum www.tppacks.com

Built for me by AndyH :
http://www.rechargeablelithiumpower.com/oscommerce2/catalog/index.php

[youtube]nkQQyi89Bzg[/youtube]

 

[dogman dan]

24 channels, yeah baby!

 

[redorblack]

I don't quite get the video... are you not using the whole board due to a smaller pack? A lot of LEDs not lighting at all in the video.

That puppy is pretty expensive, 1/2 again over the price of the battery pack and only a 30 day warranty (about $200 for the 48v version). Have you gotten any runs in on it to see if it's handling the load better than Headway's BMS?

And finally... how much work is involved in wiring the fully assembled board to the battery pack? Your Headway pack is a perfect example since that's what I have

 

[Lock]

24 channels, yeah baby!

Hehe.. well, I believe I only need their 16 channel board as I only need 16s cells...

So Ypedal, yer right. I'm cancelling my order w/evcomponents and will buy cells and BMS and charger from the Lone Star State. I hope others here have better experience dealing with evcomponents than I have had.
Tks
Lock

 

[Lock]

Built for me by AndyH :
http://www.rechargeablelithiumpower.com/oscommerce2/catalog/index.php

Done deal Ypedal... I`ve given up on evcomponents and expect will have an order and payment on AndyH`s system in a day or two... cells, BMS and charger...

Questions please? From here:
http://www.rechargeablelithiumpower.com/oscommerce2/catalog/pack-accessories-c-24.html

Why the choice(?) of either nylon acorn nuts or insulator cap and regular nuts? Is that a choice? What's best? Washer plus nut plus acorn?

Also, what are the pros/cons of the two different "pitches" of cell connecting straps (sold at the same price)?

Tks
Lock

 

[Ypedal]

That video is from my 72v PSI pack / Chopper build :
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=11410&start=60

The 24 LED's don't light up in the video, yet, my charger is not putting out quite enough voltage but the pack is like 95% + full at this point ( confirmed with volt meter probing each cell )

Any long time ES member should know this, but i will repeat : The G/F bms does not prevent over-current, it only monitors voltage of each cell and will use the controller's " E-BRAKE " signal to shut down the controller if any cell voltage goes below it's set limit.

Lock, don't rush this, take the time to read up carefully and understand what you are getting into !!! :wink: A few hours of reading now will save much frustration later !

Regarding the 2 different kind of straps for the PSI cells, the copper one's will not fit into the lego blocks, if you get the lego's, get the brass straps ! ( holes further apart ) .

regarding nylon vs SS nuts, the threaded studs on the PSI cells are hollow aluminum, fairly fragrile, if you don't have a 1/4" torque wrench that goes really low on the in/lbs scale you may want to use the nylon nuts to prevent breaking a cell stud ( I recommend buying an extra cell if you are building your own pack.. )

 

[Lock]

Thanks Y... Yes I will read more.
I have a team of process control engineers who work with hydraulics and pneumatics and electronics including custom programming, and the shop guys are pretty state-of-the-art with CNC machines and work with food-grade metals and plastics. So the plan is to just hand over all components to them 8)

And yes, hand over some useful links as well

Pack will be assembled into a cassette w/BMS and charger that can be plugged/unplugged into the scoot so the scoot can be plugged in anywhere but also left outside and pack removed to indoors for charging/security/warmth.

I am desperate to get this show on the road (literally) to experience things in this winters temps and snow and ice... Even w/out the LiFePO4 in my hands it has been an interesting "ride" so far just reading about others experiences!

Lock

 

[Lock]

BTW, I have an odd Chrystalyte 600W 16" brushed cast hub motor/wheel to play with. Only two were ever imported into NA... Not sure if the controller even *has* an e-brake signal! So now might be in the market for a new controller as well. EVentually another controller too as the next motor will be brushless.
Lock

 

[Barry]

Problem solved

I previously reported on this thread that the 48v 10Ah headway pack I built was cutting out at 8.5Ah. I suspected the pack was not getting fully charged.
I decided to remove the pack from the bike and charge each cell to 3.6v with a single cell charger. The pack was fully charged according to green LED on my 58v charger before I started this process. I was surprised to find how unbalanced the pack was even after charging through the BMS. Some cells were fully charged and other cells took 10 to 30 minutes to reach 3.6v.

When I originally built the pack, I naively thought the BMS would balance the pack. Apparently, the BMS’s I tried were not up to the task. Also, at the time I didn’t have a single cell charger.

After charging each cell individually, the resting pack voltage was 56v. I did a couple of light cycles of 3Ah and recharged each time. The pack maintained the 56v resting voltage. I also cut the charger amps from 4 amps to 3 amps with the intentions of giving the pack more time to balance. Don’t know if this has any real effect on the charging process.

The last two times I took the bike out I got 10Ah’s from the pack, so I consider the problem mitigated. Although I still notice, quirks in the charging process. After the charger LED turns green I can get another 10 to 15 minutes of charging if I unplug the charger and then plug it back in.

I still don’t trust the Chinese BMS I am using so I bought the parts to make a Fechter BMS. I’ll let you know if a novice can successfully build and test a BMS from scratch.

 

[Speedfreke]

In my thread 'Retaillers as members?' about whether to allow them to join ES, I was blasted by several members who said that if retaillers ever 'done us wrong' they would be put through the wringer, then drawn and quartered. I'm waiting......

 

[Lock]

Hehe... Speedfreke... Not sure if you are referring to any supplier problems I may have alluded to in this thread, but just for the record I start with dealing with suppliers I already have a lot of respect for and if for any reason things "fall through" and I take my biz elsewhere it's not to give them a bruise... more of a love tap. Kudos to anyone jumping into the EV biz world right now `cause it's still very bleeding edge and for biz folks that want to profit from only quality product and service there is a lotta educating to do to rise above the fast buck artists out there offering cheap prices (and poor value.) One of the hardest things for co's to handle well is rapid growth. EVerything I hear is that EV co's can't get enough (quality) product to keep up with rising demand. I am only a very small fish and I consider myself fortunate I can buy some of this stuff at all - see for example the "disappearing" 15Ah Headways...
I don't know of any EV parts suppliers these daze that are not running their as*ss off and if they don't stumble sometimes they probably are not running as fast as they could (smile.) Any EV biz noobs that think they can jump into this fray by posting to ES inflated claims about inferior product will be back to selling vibrating armchairs or whatever in pretty short order.
There are many ways to "profit" and many here "profit" from the EV biz folks that contribute here as much or more than most! AFAIK the only biz folks here are pretty much all World Class.
Sorry if I helped get this Headway 48V 10Ah - EVcomponents.com thread off its rails. BTW, did ya know we write "v" as a Capital "V" to honour Mr. Volta? ...and "a" as Capital "A" for Mr.Ampère ..."w" as "W" for Mr.Watt ...and so on? Fun eh?
Lock