Can Anyone Recommend A Reliable, Trusted Seller of A123?

[MitchJi]

Hi,

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

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.

But the prismatic cells are more compact and weigh quite a bit less per ah than the M1's. The 15ah pack of prismatic cells are 401g per cell. The 2.3ah M1's are 70g per cell. So 4p (9.2 ah) are 280g. Maybe another 20g per cell for the extra connections and the larger housing. So roughly 100g per 15ah cell more. So a 16s pack will be about 3 pounds more which might not be a show stopper when you factor in the convenience of having a larger pack.

 

[leamcorp]

Mitch, I understand that its much lighter but that 3lb you're talking about still makes a difference. When I was building my Specialized RockHopper last year - the overall setup was so heavy, the bike swayed left and right. Granted, this was with 72v 22ah pack... when I've moved it down to 12ah, it was more acceptable but still swayed. I got tired of that so I've moved it down to 36v 9ah (from 72, then 48v) and its just about right. I think its still too heavy but I'll live. Now my other bike can handle more weight than my Rockhopper but I still choose a lower ah pack as its easier to handle, carry, and charge on the road. And that 3lb will be felt when your riding style is not to use electric power most of the time.

I also understand about having a large enough pack - but you if you don't have to carry the extra weight without jeopardizing your pack, why would you? If I want to go for a longer ride, I'll either pedal more or take a bigger pack. I think that is the parts thats not registering - I have many packs and can choose to take any one of them, but I'll choose a lighter pack that will do the job for that trip (but you have to know your pack and distant you'll be going).

Now if were' talking about 8-9ah prismatic vs 9ah M1, you already know the answer. Either way, I got these cells at tremendous bargain, so I'll play with them until they die.

 

[cell_man]

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.

You've read my mind a bit there Mitch. I'm starting to think that I can offer the parts for assembly and put together a good document or maybe even a video (but I'm a bit shy ). The assembly is a quite a bit of work. I'm not ruling it out in the future, far from it. but there's lots of other things i need to be getting on with. I'm gonna maybe get some staff to do the assembly or outsource it.

Now I've found a local machine shop that can knock up parts at reasonable prices. I mean they are machined by a person rather than a machine and not mass produced so they aren't gonna peanuts. It's not so difficult to assemble the pack with these terminals and I didn't make any sparks (well almost none) so the little dividers between the terminals seem to do the trick. The box can be improvised as required. Anyway now I've got the design pretty much nailed down I'll get some parts ordered. Will likely stick with the typical formats initially but less typical configurations shouldn't be a problem but might take a little time to get machined.

By the way a pack I've been using for a few days, 36V, 20Ah with a 30A constant BMS (no problems pulling 50A though), all in weight is 6.1kg. The termination method I'm using could be slimmed down a bit by going to maybe 3mm thick brass terminals and could go down a little on the front plates thickness or find an alternative maybe lighter material. That is not the pack I posted in the other thread by the way. That is a 48V pack with a bigger BMS (80A constant).

 

[CamLight]

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

I'm also VERY excited about the small Ah pouch cells coming to market!
A 6Ah or 8Ah cell is perfect for several applications my clients have in mind.

 

[MitchJi]

Hi 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.

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.

How are the springs fastened to the bars? Just press them in place and they stay?

Three suggestions:

• 1. You could use one wider bar that spans two rows of batteries instead of three separate bars.
  
  2. If you do that it would be easy to use bolts between the rows to "clamp" the bars to the pack. You could use wide plastic washers on the other end of the bolts to use the other end of the cells to "clamp" the bars. That would make it easy to support the bars along their length and wouldn't require thick pack end plates for bolts.
  
  3. I'd cover the (wider) bars with a piece of non-conductive plastic for support and safety.

Still looking forward to a thread on your next pack build (no hurry).

 

[monster]

i'm disapointed in my olympics2008 A123's. they are completly dead after less than a year. i was opperating them in parallel with a ping battery using the same bms to balance both. the A123's would run at 6C and the ping at 1C. i noticed that the current was nowere near 70 amps (30C) even when they were new. the voltage sag was tremendous even at 30 amps. they were only good for 15amps 6C. now they are dead. watts up reads volts but if you put any load on them the volts disapear. you can even short them and there are no sparks.

 

[webfootguy]

i'm disapointed in my olympics2008 A123's. they are completly dead after less than a year. i was opperating them in parallel with a ping battery using the same bms to balance both. the A123's would run at 6C and the ping at 1C. i noticed that the current was nowere near 70 amps (30C) even when they were new. the voltage sag was tremendous even at 30 amps. they were only good for 15amps 6C. now they are dead. watts up reads volts but if you put any load on them the volts disapear. you can even short them and there are no sparks.

All the more reason to buy the $50 toolking 8 cell tool packs. They may be older datecodes (1997 or 1998) but they are genuine tested A cells that passed all their voltage and capacity tests. I'm expecting 2000+ cycles out of mine.

 

[webfootguy]

Followup that might be of interest:

Toolking just put their 8 cell DC9280 28v packs on sale again for $39.88.

http://www.toolking.com/dewalt-dc9280-28-volt-lithium-ion-nano-battery

Get em while they're hot!
--phil

 

[ejonesss]

seeing the ebay seller it looks like he sells alot of illegal or restricted stuff.

take for example item 120526308809 they look like military technology

 

[miro13car]

monster,
that should puzzle everybody here,
one conclusion:
THERE ARE NOT REAL A123 cells!!
describew what do you mean by "olimpic"??
MC

 

[pgt400]

Toolking.com has Dewalt 28v packs on sale for $39.95 today.....free shipping over $100. I bought 6 packs last month. Comes to $5/cell.

 

[pwbset]

Toolking.com has Dewalt 28v packs on sale for $39.95 today.....free shipping over $100. I bought 6 packs last month. Comes to $5/cell.

Arrrggh!! Screw it.. I'm in. 8 packs. Sub $0.70/wh for genuine A123 shipped is way too good a deal to pass up.

 

[regmeister]

deleted

 

[pwbset]

The're 3 year old packs.

Who cares. They probably sit at a certain percentage of discharge waiting to ship so potentially there would be not too much ill effect to their age. @ around $0.68/wh including shipping and with BMS built-in to each pack (however crappy it's still better than most BMS strap-on junk out there) they could have half their cycle life and still be a killer deal.. way better than the $75 Bosch fatpacks for example... and let's be honest while the fatpacks kick ass certainly they aren't designed to last nearly as long as an A123 cells. If I even get 500 cycles outta these that's still two years of hard riding for me for $320 and by then we'll be running on antimatter power. :wink:

Think of it this way also... that EV Components 48v10ah $350 Headway pack they were doing was essentially the same watt/hrs as the 8 packs I just ordered from Toolking for an additional $30 not including shipping and with a BMS that would very likely destroy itself and with cells rated for 5C not 30C. Getting harvest konions off of Doctorbass would be cheaper, but you'd only get 100s of cycles and have to build the damn thing... over that. This was a no brainer really.

 

[The Mighty Volt]

Hi there, got a bum shipment of A123 in an old 36v DeWalt which was advertised as being faulty.

Several of the cells are 2.3v or so in charge.

Is it possible to save them?

Thanks fellas.