Can Anyone Recommend A Reliable, Trusted Seller of A123?

[cell_man]

Thanks guys for all the positive comments much appreciated

I'll see if I can't get some packs put together soon. I've revised some of my earlier thinking about getting a big surface area to reduce losses at the terminations. I'm now gonna go with 6mm square aluminium bar at the rear of the termination and an insulating material at the front. This will make the machining quicker, easier and cheaper. It should also make the assembly easier. I'm a bit distracted with getting Chris's big 96 cell pack ready but I'll get something done in the next few days that people can have a look at. It's also something that you could easily tackle DIY with pretty basic tools.

 

[The Mighty Volt]

Thanks guys for all the positive comments much appreciated

I'll see if I can't get some packs put together soon. I've revised some of my earlier thinking about getting a big surface area to reduce losses at the terminations. I'm now gonna go with 6mm square aluminium bar at the rear of the termination and an insulating material at the front. This will make the machining quicker, easier and cheaper. It should also make the assembly easier. I'm a bit distracted with getting Chris's big 96 cell pack ready but I'll get something done in the next few days that people can have a look at. It's also something that you could easily tackle DIY with pretty basic tools.

Do you manufacture and sell Prismatic flat-packs?

72v 50A is what I am looking for.

Thanks.

 

[leamcorp]

I'd talk to Cell_Man about his prismatic ones.

Thanks Wolf. My only beef with the Prismatics is that I wont be able to build them into a pack with the same ease as the others.

Also, do they have the a high discharge rate??

For a newb building a DIY pack, cylinder cells are going to be much tougher than prismatics. The only right way to do it is with a tab-welder and nickle strips, then you need to come up with a solution for structural support for the cells, insulation etc. You're also going to need to make large groups of cells in parallel to get any useful capacity. The end result is something bulky and heavy with boat loads of connection points and cells to make and secure.

Using the prismatic cell_man cells, you can run 1P, and simply stack the cells with carpet tape in between, fold the tabs against each other and solder with LiPo tab solder. This would be all any E-bike would ever need for a pack, but for added durability and performance, you could sandwich your stack of cells between a couple sheets of aluminum with some long bolts on the outside to clamp the stack firmly together with. This gives physical protection, and compression on the cell's layers.

Anyway you want to stack it, prismatics are way way easier to make a DIY pack with. The end product will also have a much smaller volume, weight, and better cycle life than dealing with the outdated cylinder A123 cells.

Not true at all. I build A123 pack all the time and cylindrical cell are easiest to work with compared to those large box cells or prismatic. A123 or cylindrical cells are versatile and highly flexible due to its size - they are small so that you could build whatever size/shape pack you want. And carpentry skill needed is rudimentary at best to make your own pack. With these small cylindrical cells, you could add, subtract, take a bad cell out of pack easy, and check each cell since none of these cells are soldered down or closed off. Its easy for anyone who could cut wood (home depot sells modeling wood that is super light) or plastic boards, use drill/drill press and very light soldering (you don't have to solder but it makes it more secure but most of the time, I don't solder, I just tape it and that makes it even easier to take it off later if you want to change things).

To build it, you need to cut some thin pieces of wood or plastic, buy some battery tabs from Mouser.com, 1/8" wide copper strip from Mcmaster.com, drill some holes, and use plain old wood screw to hold everything down. No need for tab welder or soldering skill. If you're really good at cutting wood in certain shape, then it makes it even easier to make a custom shaped box using simple items listed above. I would say it should take you no more than 1 day to make a simple pack or few days if you want to make it look good. Me, I have many pre-cut boards and usually can make a pack in couple of hours. Most of the time, I just duct tape my pack as it just go into my rack bag (no point in making it look good for hidden item).

I think I have a pic of one of my earlier build from last year - I'll post that if you want.

Edit - I also didn't get your last comment - about A123 cell being outdated. Because they are cylindrical? not in a box or in a pouch?

 

[MitchJi]

Hi Leamcorp,

Anyway you want to stack it, prismatics are way way easier to make a DIY pack with. The end product will also have a much smaller volume, weight, and better cycle life than dealing with the outdated cylinder A123 cells.

Not true at all. I build A123 pack all the time and cylindrical cell are easiest to work with compared to those large box cells or prismatic. A123 or cylindrical cells are versatile and highly flexible due to its size - they are small so that you could build whatever size/shape pack you want. And carpentry skill needed is rudimentary at best to make your own pack.
I think I have a pic of one of my earlier build from last year - I'll post that if you want.

Edit - I also didn't get your last comment - about A123 cell being outdated. Because they are cylindrical? not in a box or in a pouch?

Even if the cylindrical cells are easier to work with you need to connect 7 to 9 times as many cells. I have a hard time believing they are 7 to 9 times easier to work with.

I'd really like to see a picture and an explanation of your pack build.

I think by outdated Luke meant the need to connect 7 to 9 times as many cells plus the facts that they are much bigger and heavier.

 

[leamcorp]

Here's a picture of battery I built last year. This was my 1st attemp, so its not clean but you get the idea. By the way, you remember I was making plastic battery holder last year, this was result of that effort - much simple and extremely adjustable.



As you can see, its in a wooden box (you could use plastic as my later version did). The batteries are not soldered or tied down at all- its just loose cells in a case. The cells are inserted into the box like a battery case - if I want to change anything - just unscrew the box to replace cells, add longer board or copper strip for additional voltage/AH. And if any of the cells are blown like you see so many thread asking what is wrong with their battery, you could unscrew to check each battery without worrying about soldering or where to break the line.

This is a very simple box to build and is amazingly flexible since cost of the copper strip/screw/wood is very cheap. Once you are done, you could use shrink tubing, wood/plastic board, or in my case, couple of round of duct tape for tight seal. So far, I built 24v, 36v, 48v and 72v in multiple shape (not just boxy shape). I'm am in the process of taking everything apart as I got a new bike and I will be building different shape box/pack for this new bike. When you are changing the shape, you do lose some space due to un-usable spot but because these cells are quite small, you minimize those wast.

As mention, I'm building a new case/pack and if you want me to document each proccess, I will but as you could see in the picture, there's nothing difficult about building A123 pack. My next version, I'm using a heat gun to change the shape of plastic board to fit the bike, so it will be custom fitted to my new bike.

By the way, so far only A123 or lipo was able to push my 5304 and BMC 1000w DD motor over 45+mph, no prismatic can do that. Maybe newer ones but not the ones I've tried.

 

[j3tch1u]

I would definitely stick with the prismatic cells.

second that.

 

[j3tch1u]

geometrically speaking, even if the energy density of the A123 cylindrical cells were on par with the A123 prismatics (they aren't, the prismatics are higher), you are wasting a lot of volume with the dead space between round objects and extra packaging and connections of more cells. unless your design calls for a circular battery container or you want to stuff them lengthwise in tubes, the prismatics are pretty much a no-brainer.

 

[leamcorp]

geometrically speaking, even if the energy density of the A123 cylindrical cells were on par with the A123 prismatics (they aren't, the prismatics are higher), you are wasting a lot of volume with the dead space between round objects and extra packaging and connections of more cells. unless your design calls for a circular battery container or you want to stuff them lengthwise in tubes, the prismatics are pretty much a no-brainer.

OK! Build what you want - I'm just telling you that its not that difficult to build a cylindrical A123 pack. The post I've replied was about building cylindrical A123 packs and why its not that difficult to build them (that was the counter point - not what is better).

If you want prismatic, then what do I care what you use. Hell most of time, I'm using 36v Mr. Lau's battery that is bolted on my main commuter. I use variety of battery packs (including A123 cylindrical) to play with and this is what I came up with. So if you don't like it, then don't use it - others might find it useful.

Again, its not difficult to build A123 cylindrical pack - so if anyone have these cylindrical pack... rather than throwing it out because its not "efficient as prismatic", this is one way to use them.

 

[leamcorp]

I would definitely stick with the prismatic cells.

second that.

Very helpful, thank you. By the way, I've picked up these (most, not all 200+ cells) for about $1.20 each.

 

[miro13car]

can you provide also
prismatic A123 cells?
A123 manufactures also bigger orange round cells, can you provide them ?
mc

 

[amberwolf]

We have constant supply for original brand new A123 cells.

If you have interest please contact : sales-1@yesa.com.hk

But we can not sell to USA, except USA any country is fine.

Price?
Shipping?
Other fees?

 

[miro13car]

why Yesa doesn't bother to answer.
There is nothing about A123 cells on their web site
MC

 

[CamLight]

Give him a couple of days, at least.
Many folks don't have the time to check the forums a couple of times a day.

 

[The Mighty Volt]

I would definitely stick with the prismatic cells.

With the cylinder cells you get 2.3 ah at 26v for 12 cells in series...which means to get to 20ah you'd need 9 sets of those in parallel... 12s9p. Thats 108 cells!!!

Lets see....I'ma go with the 12 flat cells!

21 flat cells, not 12.

12 flat cells gets you 40 volts only

 

[MitchJi]

Hi,

I use variety of battery packs (including A123 cylindrical) to play with and this is what I came up with. So if you don't like it, then don't use it - others might find it useful.

Again, its not difficult to build A123 cylindrical pack - so if anyone have these cylindrical pack... rather than throwing it out because its not "efficient as prismatic", this is one way to use them.

Thanks for the picture and the information. It does look pretty easy. I think a dedicated thread with a few more pictures and a little more information would be useful to quite a few people.

A couple of questions:
Do the Copper Bars require support (e.g. duct tape, shrink wrap or a housing cover)?

How thick are the bars?

Thanks!

Mitch

 

[leamcorp]

I'll be building another pack soon - I'll document that one ( got so many project, its a time issue).

The copper strip is 1/2" strip I got from Mcmaster and snip to length (I think it was 1/16" thick). You could also use 5/8" and 3/4" wide strip as well - I like 1/2". With the 1/2" strip, as long as you don't go over 7 cells per row, you're fine. Else, you could add small tension bar in the middle and that will take care of longer packs.

Good thing about this is that you could build small and modular packs to build bigger packs - so no need to make a larger pack. Make a 4-6 cell packs in 12-24v size, then use more copper strip or wire to interconnect for higher volt or amp. And no soldering or torch is required as I don't do that for my packs. Unscrew few bolts and you could remove the cells easily for whatever reason.

 

[MitchJi]

Hi leamcorp,

Thanks for the information!

I'll be building another pack soon - I'll document that one ( got so many project, its a time issue).

No hurry but I'll be looking forward to that thread.

Most people have been paying about the same per ah for the M1 cells as the larger prismatics. In that case I think due to more compact size and lighter weight they make more sense. But if someone gets a good deal on the M1's your very easy method of pack assembly makes them a very viable option.

Thanks Again!

Mitch

 

[cell_man]

You can't knock the M1 cells. I just think the guys are supporting the new technology that is now coming along. At the moment the prismatics are limited to 15 and 20Ah cells so many seem to think they are very expensive as they can't do a 6 or 8Ah pack as you can with the smaller M1, but the fact is the price is actually very similar per Ah. I'm now hoping the difficulty of building these into a pack will soon be a thing of the past. Below is a terminal I've been working on and I reckon it hits all the spots and looks pretty neat too. BTW, the ring crimps face inwards in the free space between the tabs.

View attachment 2





I'll have a pack or 2 assembled using these terminals over the weekend and if all looks good will get them machined for me ASAP The basic idea for these terminals can be adjusted to any 1p pack size/cell type just by adjusting the hole spacing on the insulating front plate. The brass terminals are common to both 1p and bigger parallel packs. I think we're almost there

 

[leamcorp]

You can't knock the M1 cells. I just think the guys are supporting the new technology that is now coming along. At the moment the prismatics are limited to 15 and 20Ah cells so many seem to think they are very expensive as they can't do a 6 or 8Ah pack as you can with the smaller M1, but the fact is the price is actually very similar per Ah. I'm now hoping the difficulty of building these into a pack will soon be a thing of the past. Below is a terminal I've been working on and I reckon it hits all the spots and looks pretty neat too. BTW, the ring crimps face inwards in the free space between the tabs.

Agree - whatever is your requirement is, if you got it cheap, then it's a winner. I just happened to get ton of it for really cheap as part of a larger business deal. I also agree, I used to build 20ah packs then realize I only use 4-5ah at the most (pedal rest of time) so I'm just carrying dead weight at that point.

Another good thing about these M1 cells are that its easy and cheap to replace vs 15/20ah prismatic. I like prismatic but it is much more costly overall, especially if you don't use that kind of capacity.

Love to see what your pack will look like - if its easier, then its merrier.

 

[cell_man]

Well there is talk of much smaller prismatics like 4Ah and 8Ah, so that should address some of the things that put people off the bigger cells like those I have presently. I should be in a good position to source these when they do start to become available. These will offer similar power and energy density to these bigger prismatics but in a more e bike friendly size. Hopefully we don't have to wait too long.

 

[The Mighty Volt]

I don't know why anyone would want to go below 10AH at all.....


Cell_Man, do you offer aftermarket support to your customers? If I buy prismatics, can you show me how to make a pack and wire in a BMS, or do you only offer the finished product? Thanks.

 

[cell_man]

I don't know why anyone would want to go below 10AH at all.....


Cell_Man, do you offer aftermarket support to your customers? If I buy prismatics, can you show me how to make a pack and wire in a BMS, or do you only offer the finished product? Thanks.

I do kind of agree. As a practical means of transport, with a high power motor and controller you really do need a few Ah.

So far I've only offered the cells, much to many peoples annoyance, but the termination parts are now very close. Of course I'd be happy to help. I have a small stock of various 12S and 16S BMS, some chargers, also have large heatshrink, a few different types of power connectors and should be getting the termination parts assembled for me very soon (put the order in this week). A BMS is pretty straightforward to terminate and with the new termination method, you've pretty much got a set of ready made terminal blocks to tie into. It couldn't be simpler IMO.

The only aspect of the termination that is a bit tricky is getting the tabs bent over equally and drilling them. I made a little tool that fits over the tabs so they are bent about 2mm from the end of the body of the cell and ensures they are bent over square. I use a couple of the brass terminals to clamp the tabs together and then drill them. The assembly itself takes a little time but really isn't so bad. I've been using a 12S pack for a few days with a similar termination to the above, but these latest terminals will be much neater IMO. 16 cells are balanced and I just need to assemble the pack tomorrow.

Cheers
Paul

 

[MitchJi]

Hi Paul,

So far I've only offered the cells, much to many peoples annoyance, but the termination parts are now very close. Of course I'd be happy to help. I have a small stock of various 12S and 16S BMS, some chargers, also have large heatshrink, a few different types of power connectors and should be getting the termination parts assembled for me very soon (put the order in this week). A BMS is pretty straightforward to terminate and with the new termination method, you've pretty much got a set of ready made terminal blocks to tie into. It couldn't be simpler IMO.

The only aspect of the termination that is a bit tricky is getting the tabs bent over equally and drilling them. I made a little tool that fits over the tabs so they are bent about 2mm from the end of the body of the cell and ensures they are bent over square. I use a couple of the brass terminals to clamp the tabs together and then drill them. The assembly itself takes a little time but really isn't so bad. I've been using a 12S pack for a few days with a similar termination to the above, but these latest terminals will be much neater IMO. 16 cells are balanced and I just need to assemble the pack tomorrow.

Cheers
Paul

I think a small video with step by step instructions, something like Doc's Makita pack disassembly would be a good idea:
[youtube]Z5taguEdlkY[/youtube]

It would help people decide if they want a DIY solution and if they decide to do it would guide them through the process.

Probably save you a lot of time, in the long run, as compared to answering a lot of individual questions.

MIght be a good idea to sell the templates and tools also.

 

[leamcorp]

I don't know why anyone would want to go below 10AH at all.....


Cell_Man, do you offer aftermarket support to your customers? If I buy prismatics, can you show me how to make a pack and wire in a BMS, or do you only offer the finished product? Thanks.

Because if you don't need that capacity, why would you want to carry all that extra weight? My regular commute is 6 miles or so. And at that distant, I use no more than 2ah and certainly less than 4ah on days I don't pedal as much, so at the most, I would build 7 or 9ah pack for this commute (I do charge at work). And I do this all without BMS. The M1 battery is very robust and you have to literally drain the crap out of it to kill it. So if you keep a watch on its capacity, its will do you fine.

Also, I enjoy riding a bike, and as I went up in weight with 20+ah packs (and heavier motor to drive them - I do have a 40+ mph bike), the less I enjoy commuting on them. To me, that extra weight made the bike feel, well not a bike. So to each his own.

 

[leamcorp]

Well there is talk of much smaller prismatics like 4Ah and 8Ah, so that should address some of the things that put people off the bigger cells like those I have presently. I should be in a good position to source these when they do start to become available. These will offer similar power and energy density to these bigger prismatics but in a more e bike friendly size. Hopefully we don't have to wait too long.

I would be mighty interested in that 8ah cells. Any hint on its size/weight or your estimate for 36v, 48v pack?