A 1st Timer's Headway Pack Build

[The Journey Guy]

Well, I'm about to take the plunge and build my 1st ever battery pack, and I've chosen Headways to do it with. I have been running Ping type packs for the last year or so, and I've become somewhat dissatisfied them because of the effort level that it takes to repair a pack when/if a cell or cell group goes bad. I know that for some it's no big deal to unwrap the pack, un-solder a bunch of little pcb connector boards, remove the delicate tabs, and then fit a cell into the middle of a pack... etc etc...

I have been wanting to run packs that I can easily repair if needed, without having to jump through hoops to do it. I've settled on Headways for several reasons. They are light weight, easy to work with, and have a great C rate. My first pack build will be an 8s 10ah string, and should end up weighing just under 5 lbs. I like using packs that are 24v because I can carry one on each side of the bike for better balance.

I started a thread in the "Wanted" section looking for Headway cells, but all in all the result was not that good. So, I went looking for a company in China
that had what I consider to be a good price, good selection, and more important, had a sales rep who was responsive and seems like he really cares about customer service. His English is very good also, which makes for easier communication.

Now right from the gate, I must say that I am not yet ready to share my source with all you great members just yet. The reason is that there are still a few
procedures that this company and the sales rep need to iron out before I can feel confident enough to say to you all " Hey, this is a GREAT place to get your Headways!" By that I mean this: The actual website I ordered from does not update their Customer Account section. Every time I logged in to see the progress of my order, it would only say " Processing" . Personally I would rather it provide more information, like "order in warehouse for packing" or "order packed and waiting for shipping" or just anything that lets someone know what the progress of their order is. Not just "Processing". It stayed that way until
yesterday when the package got delivered.

Another thing the sales rep said he would like to work out better for us USA customers is the way they do their shipping. He said that their current way of doing things is to charge the shipping fee at the time the customer places the order. Nothing unusual about that to my way of thinking. But then after that, and what I think he is working to streamline, is the actual way this company ships. They have a Shipping Agent located in Hong Kong that sort of acts like a broker, in that his job is to find the cheapest way to ship the package to the US. So, the company sends my package to the Agent, which then finds a company to ship to the US. Personally I find this to be surprising, because I have bought many things from China, and never has any company said that they do shipping like that. The really big problem was that I don't think the Shipping Agent communicates well with the Sales Rep, because I had the package in hand about 5 hours before my sales rep sent me an email with the tracking number. LOL

So, all in all there are only a couple of things that this company needs to address before I believe they will be a very good source of Headway cells. Of course, they have available other form factors of Lithium cells also, but I only have experience with the Headways from them. Matter of fact, this company sells many chargers, cells, and other goodies that are to me, at a great price. What I am going to do is give the sales rep a couple of days to work on those small issues stated above, and then I will be placing another, larger order with him. If that whole process goes better and smoother, then I will have full confidence to be able to share with you all who the company is. I actually checked with a prominent member of this board before I placed my first order, asking if he knew of this sales rep, but the member had never heard of him before. From all I see on the website, this is a new company because my order# was 6.

I think this company has great prices. They were $17 each for the 38120S cells, of which I kept this first order small at only 9 of them (one for a spare). I realize that $17 each is nothing to get too excited about, except for the kicker.... For each cell purchased, you get a free buss bar and a free plastic building block included. Now that sweetens the pot for me, and was the deciding factor in me ordering a test shipment from them. So, 9 cells at $17 each and a total shipping fee of $56. I don't think that's too bad!

My 1st shipment of Headway cells arrived yesterday from China. I ordered and paid for the cells on the 15th, and got them yesterday - 13 days total. When the package actually got to the shipping agent and he gave it to UPS, the time from Hong Kong to my home in the US was only 24 hours. Don't know how they did that for only $56, but I'm not going to complain!

OK, so I'm ready to open the package, and the first thing I notice is this large warning label on the box. Check out what is says:

I swear I remember reading something about UPS won't ship dangerous lithium batteries or something like that, but there it is in huge letters that can't be missed about the dangers of the contents. But anyway, it got shipped and delivered, so maybe policies have changed.

I open the top of the box, and see this:

I was impressed with the packing and the overall condition of the box when it got to me. I have had packages from Ping that were just beat to crap by the time I got them.

I peel back the first layer of padding, and see this:

Oh yeah, I like blue!! :wink:

Under the first layer, was this:

They could have packed the building blocks a bit better, because as you can see in the photo, one of the little legs snapped during shipping. No biggie this time for me, because I will not be using them anyway. The buss bars were wrapped up good, I just unwrapped them for the photo. They weren't loose like that for the shipping. :lol:

Each cell was exactly 3.3v when they arrived. So, at this point, I'm going to put a single cell charger on each of them to bring them up to aprox 3.65v and see if any of them are going to be runts or anything. I'd like to get a CBA to test them with, and it might happen if I can get a CBA-I to work with Win7. I posted another thread about that, tho.

So, that's where things are at for now. I'm very much looking forward to placing another larger order to see if things improve as to notifications and such as that. Then I can give back to all you members who have helped me, by sharing another source for Headways, Thunderskys, controllers, and other goodies.

I'll update this thread when I start assembly of the pack. If anyone has any pointers for a 1st time Headway builder, bring 'em on!! :lol:

TJG

 

[scoot]

Happy days for you Journey Guy... I can just imagine your feeling of excitement. I recall how I felt about 6 months ago :wink:

Since then, I have been testing and building 8s Headway packs for my scooters, and have managed to play with a total of 36 cells so far. I have learned a lot on my own in that period and would be happy to share some of my experiences thus far.

The first thing I would suggest is in regards to conditioning and balancing the cells is this... in order to speed things up a bit, I would suggest that you connect them all up in parallel using your bus bars. Then charge them up together that way. It will ensure they become perfectly balanced. You will also be able to slowly discharge them down to about 2.5 volts with your CBA (at about 25 amps with a CBAII, and possibly more amps with a CBAIII). After cycling them a few times that way, you should be fairly confident they are mostly conditioned.

 

[The Journey Guy]

Thanks scoot! PM sent.

 

[Steff]

I too can recall the excitement... got my package yesterday!

I had a good laugh reading your post since I thought I had it bad when the status for my order only said "sent", without them ever providing me with a tracking number. It would have been so frustrating to just see a "Processing" every time I logged in.

However, I am now the proud owner of 12 blue ones myself. I ordered from within Europe since I didn't find any Chinese suppliers willing to deal in such small quantities. Had to pay a whopping 22 Euro per cell though, but then at least I didn't have to worry about customs. Please PM me with where you got your cells if you don't wanna post here. Would be nice to know for any possible future purchases.

I guess I can skip posting my pictures of the lovely Lithium Polymer Battery warning label and my newly opened package now, since they look almost just like your pictures. Almost thinking about getting them framed though.

As for my build, it's to bad I couldn't get a hold of the 3-position cell blocks instead. I really can't use the ordinary ones either since I need to reduce the height of the pack. As you can see by my first attempt at an own cell holder out of MDF, it's not going great. But I'm already in way over my head when trying to build an own headway pack at all, so only time will tell if I actually manage.

Thanks for the inspiration all you Headway pack builders out there!

 

[The Journey Guy]

Please PM me with where you got your cells if you don't wanna post here. Would be nice to know for any possible future purchases.

I'm glad you're doing well with your new Headways! It's nice to be able to experiment with a new form factor!! If you run into any probs along the way just post to the forum, and I'm confident that someone will aid you.

Regarding your request to PM you with the source, as I said in my OP, when I feel confident enough of this new company, I will certainly be more than glad to share the information, not only with you, but with the entire forum. Not that too many people comment within any of my posts anyways, but that's alright.

Have fun building your pack!

TJG

 

[patrickza]

That is nicely packed. I had a similar experience with ecitypower. They told me the package was on the way when I had it in my hands!

I see the endcap holders are yellow, do they still crack when connected to the +ve end of the cell?

 

[The Journey Guy]

I see the endcap holders are yellow, do they still crack when connected to the +ve end of the cell?

I really don't know. I have no intention of using them, so I just put them away for another time. I've read others who say that the plastic blocks do crack over time, so that is why I will not be using them.

 

[wookey]

They only crack if you don't cut off the 5mm of blue plastic covering the slightly fatter ring at the top of the cell. But yes it would be nice if they couyld make the + and - ends of the cells the same diameter, so we didn't have to hack them about.

 

[The Journey Guy]

UPDATE: Well, I've finally found some extra time on my hands (read recoup time from minor operation) to finish up an idea or two I had. I think the finished product will work very well for what I have in mind.

The way that I've been carrying my two 24v battery packs on 'The Falcon' has been one on each side of the rear of the bike, in hard panniers. While I liked the look of the panniers, in real life, they are just a bit bulky for me to use for everyday commuting. So, since I used the rear rack off an Ezip bike for this build, I thought that it would be nice to be able to use the original Currie Battery Pack case, and put Headways into it.

After much trial and error, I have finally got the result I'm looking for. Now I can slide the packs into the rear rack, nice and neat.

I'll use a CellLog 8s on each pack to monitor cell levels, and to use as a Low Voltage Alarm if needed. I'll set the max amps out with my CA. And as I said, it
is still the stock form factor, and will slide into the rear rack just as originally designed.

When it comes time to charge, I'll use the original port to charge with, which is hidden under the handle when it's folded down and on the bike. I will do the cell level balancing as needed (read at least once a week, probably twice) using the balancing lead you see that comes out the front of the case. I just unplug the CellLog 8s, and plug in my bank of 8 VoltPhreaks. I have made a custom harness which will also have the correct balancing plug that comes off the charger circuit so that I can monitor with the CellLog 8s as the pack charges.

So, now all that is left, when I recover from this surgery, is to remove the hard sided panniers with the Ping style packs in them, and replace them with a modded case on each side of the bike.

For 85% of the time, the two 24v10ah cases, run in series for 48v10ah will be more than enough to get to work and back. For those times when I want to travel more, I will be making two additional cases to use to increase range. When the first set of two get low, I simply remove from the rack, and replace with the two backup cases, which will be in my trailer.

So, for now, that will be my new power system on The Falcon. If a cell goes bad, I can replace it much, much easier than on a Ping style pack. Less weight, less bulk, and will probably end up looking better on the bike. When I get better I'll actually install on The Falcon, and post the updated photos in the build thread.

Anyone out there riding Ezips interested in a mod like this?

TJG

Note: Yes, I see that the cells are way out of balance right now. I'm waiting for my two Power Strips to get here via USPS, so that I can actually balance the cells. I will not be using the pack until then. :wink:

 

[The Journey Guy]

I received another shipment of Headway 38120S cells today. As usual, they were packed very well, and all cells, and I mean each and every cell, was balanced to a uniform 3.33v each! To me that's a sure sign of quality and quality control. To me this is no surprise, as all the other cells I have gotten in the recent past have performed very well, and not a runt in the lot!

When I opened the large shipping container, I found inside my cells, boxed into groups of 8.

Now I can finish making a few more 24v10ah packs for myself, and I went ahead and ordered some extra, on the off chance that someone here might be looking to purchase some fresh Headways, which are already in the US. If anyone is interested, I'll be putting a thread in the For Sale New section of the forum. If no one wants the extras, I'll keep them for future use, as I intend to use these type cells for the duration.

 

[cell_man]

All cells at 3.33V doesn't mean they are balanced. You'll only know they if they are balanced when it comes to charging them in a series string. I would say with almost 100% certainty that loose cells wouldn't be balanced and it is up to the user to charge them to 3.6V or so before building the pack. That packaging is the standard Headway packaging as it leaves the factory, it's quite neat I agree.

 

[The Journey Guy]

Thanks for the insight, cell_man! As I always charge (first I do a group in parallel) then in series to condition my cells, I forget to pass that information along when I post sometimes.

However what I meant by my statement, is that I have gotten a group of cells in the past that were all over the place, referring to their resting voltage.

Yes, great packing. I have no complaints about 'em at all.

TJG

 

[scoot]

Probably one of my most enlightening learning expereinces for me was when I assembled some of my first 8s packs of Headways. All of the cells had a resting voltage of 3.32 to 3.33 volts. Then I decided to try topping of each cell individually with my hobby charger... it provides me a read of the amphours for the charge cycles. This was a very lengthy process using a small 1 amp charge rate :| , but I was keenly interested in finding out for myself what the relationship between rest voltage and the state of charge was really like. You can achieve similar data by timing/recording when those single cell chargers switch over at their end of charge... just start timing when the first one completes its charge cycle if your there to observe it.

What I discovered in my case was that there was as much as 10% variation in the state of "fullness" of my cells, and that the cells had arrived with about an average of 80% state of charge. All in all, I thought that was a good sign. It did lead me to more fully appreciate just how relatively flat the charge/discharge curve was for this cell chemistry... especially compared to Lead acid batteries. And even with Lead acid batteries, trying to determine the state of charge by voltage measurment alone is also very problematic... for a couple of reasons though.

 

[cell_man]

And only 1% difference in SOC makes a massive difference to the charge voltage when the cells are almost fully charged. I'm told you can parallel a group of cells together and they will slowly balance, but my personal preference is definitely to charge them all all to say 3.6V (LiFePO4) or so and let the current taper off to virtually nothing. It's a much better bet than building the pack and then trying to balance the cells.

 

[The Journey Guy]

And only 1% difference in SOC makes a massive difference to the charge voltage when the cells are almost fully charged. I'm told you can parallel a group of cells together and they will slowly balance, but my personal preference is definitely to charge them all all to say 3.6V (LiFePO4) or so and let the current taper off to virtually nothing. It's a much better bet than building the pack and then trying to balance the cells.

So, even tho I'm using 8 VoltPhreak LifePo4 single cell chargers, going thru the 8s balance plug, are you saying that this method is not advisable? It is my understanding that the VoltPhreaks do exactly that, charge up to aprox 3.6 and then taper the current down to 0 for the remainder of the charge cycle.

So, do I understand you to mean I should have done that with the VoltPhreaks before I assembled the cells in series?

 

[scoot]

Using your single cell chargers with your power strip array for a series connected pack accomplishes the same thing as parallel charging them all at once. It's like having your cake and eat it too. :wink:

The only reason I charged them indivually when series connected was for the sake of leanring what i could about it... I only have one charger . No point for me to do again that way, as I have learned what i wanted from the excercise.

Frankly, now that all of my packs are pre-balanced (some the tedious manual way and some by bulk parallel charge), I either just bulk charge them, or use the hobby charger to balance charge them once in a while. Your set up will perfectly balance charge them every time. Your golden. 8)

 

[The Journey Guy]

Phew!

For a moment there, I thought I had invested in all this equipment for nothing.. Thanks scoot, I can smile once again!

TJG

 

[scoot]

We want only guys on happy journies right?

Suggestion: when you set up your single cell chargers in their array, I would make darn certain that your negative and postive wires are spliced together correctly before plugging them in. The voltphreaks chargers are not reverse polarity protected

 

[cell_man]

And only 1% difference in SOC makes a massive difference to the charge voltage when the cells are almost fully charged. I'm told you can parallel a group of cells together and they will slowly balance, but my personal preference is definitely to charge them all all to say 3.6V (LiFePO4) or so and let the current taper off to virtually nothing. It's a much better bet than building the pack and then trying to balance the cells.

So, even tho I'm using 8 VoltPhreak LifePo4 single cell chargers, going thru the 8s balance plug, are you saying that this method is not advisable? It is my understanding that the VoltPhreaks do exactly that, charge up to aprox 3.6 and then taper the current down to 0 for the remainder of the charge cycle.

So, do I understand you to mean I should have done that with the VoltPhreaks before I assembled the cells in series?

No, if you've got a proper balance charger like that, it's as good as parallel charging them before assembly. A normal charger with BMS on the pack or an RC type charger take an awfully long time to get a pack balanced if any cells are more than just a little out plus you'll likely put some strain on the equipment and hit HVC on some cells. With individual chargers on every series cell it makes no difference if the cells are a little or a lot out of balance, they should still get fully charged and balanced in no time.

 

[The Journey Guy]

We want only guys on happy journies right?

Suggestion: when you set up your single cell chargers in their array, I would make darn certain that your negative and postive wires are spliced together correctly before plugging them in. The voltphreaks chargers are not reverse polarity protected

Believe you me, I checked and double checked my connections and schematics before final soldering and heat shrinking all the wires that go into the charging 8S balancing plug! I'll post a photo in a while so you can see the final product. What with being sure of the splices from the 8 VoltPhreaks, and the two 8S balancing leads, I did have a great deal of fun that day!

 

[The Journey Guy]

No, if you've got a proper balance charger like that, it's as good as parallel charging them before assembly. A normal charger with BMS on the pack or an RC type charger take an awfully long time to get a pack balanced if any cells are more than just a little out plus you'll likely put some strain on the equipment and hit HVC on some cells. With individual chargers on every series cell it makes no difference if the cells are a little or a lot out of balance, they should still get fully charged and balanced in no time.

That is good news indeed! So, you have just enlightened me as to the fact that I can bypass doing all that parallel charging from now on, since I now have the single cell charger array. Good news indeed! :lol:

Thank's for sharing your knowledge and advice.

TJG

 

[scoot]

I am very much looking forward to the day when somebody comes up with a rugged BMS design that more closely emulates those single cell charger arrays. I think Goodrum was working on one, but I lost track of that thread... so much of the discussion was so far over my head

I know of only one charger that can actually charge at about 2 to 3 amps directly through the balance leads (FMA is the brand), but I am not sure if they also use a bleeding resistor setup like most BMSs and balancing hobby chargers, or not. If so, I wouldn't see any advantage to it. Oh well... lots more research and waiting to do I suppose :|

 

[The Journey Guy]

It would be nice to get a charger like that, at a reasonable price. Here are a couple of shots of my homebrew array. Nothing special, except maybe where I ran two balancing plugs in parallel so that I can charge and keep track of values with the CellLog 8s. It works great as on OV alarm too!

Notice this pack being charged is my V1 model, with the balance leads exiting from the back of the case. Not the best spot to do that with, but this will be an extra pack, so no biggie on this one. I also like that I can record with the CellLog as I charge, to see the different profiles of each cell during the charge cycle.

TJG

 

[scoot]

That is excellent thinking. In fact, been considering doubling up on the balance leads on my next assembly ever since you mentioned it earlier. 8)

Also, sure am glad you passed on that source for the Headways. They are the first/only ones I have found that offer the 12 ah cells. I have 16 of them now, but need some spares just in case. :wink:

 

[The Journey Guy]

Yep, Michael has come thru for me every time now.


But I understand that some people are uncomfortable sending their money to places like China. There is no way to know for sure that you will ever get what you order.

So, you have the 12ah cells, eh? Nice! Those will be my next build, sometime in the late Fall.

TJG