A123 20AHr Pouch Cell Battery Build & Info Thread

[999zip999]

With the drutledge build you use 4 long treaded rods and 8 nuts. Not a lot of loose nuts bolts and washers to drop in the middle of things Not 75 bolts 75 nuts and 150 washers to drop in the middle of the pack. Rivets are hard to remove if lets say the cell is a couple cells down. You can easily short a cell when playing aruound. I do like the pcb board for seperation from OSN but not a fan of the 150 nuts and bolts.

 

[Michall2008]

Hi,

Made some progress on the pack build, in fact the pack is done at last

Found some electrical rail (don't know the real name for that) in the trash, cut it to 4.5 cm (1.77')
pieces and it slides on like a glove, no more exposed terminals

Reinforced with some more tape

I know what you thinking: why didn't you cover the main terminals with the same rail ?
A: I have 10.5 cm (4.1') high clarens for this pack, so if I cover the mains it will exceed that.

Also I had to raise the pack of the ground so it will not rest on the main terminal.

Did a short road test with my 1Kw stand up scooter (brushed motor), I'm hooked, this power is crazy. R.I.P SLA's
I used turnigy watt meter, got 3Kw picks and about 1.1Kw continuous. Although the motor wires and controller go hot,
the main pack terminals wasn't even slightly warm, I guess it means I did a good job ?

The pack after the test

Michael

 

[megacycle]

Duct here in Australia & UK, not sure about elsewhere, that' a neat solution must be the 16mm x 16mm, you working near comms techs or Electrician's.
Good to see that pack pumping some good numbers sweet.
Got any picks of the scooter?

 

[megacycle]

With the drutledge build you use 4 long treaded rods and 8 nuts. Not a lot of loose nuts bolts and washers to drop in the middle of things Not 75 bolts 75 nuts and 150 washers to drop in the middle of the pack. Rivets are hard to remove if lets say the cell is a couple cells down. You can easily short a cell when playing aruound. I do like the pcb board for seperation from OSN but not a fan of the 150 nuts and bolts.

Yeh that's neat build zip, still looking for Drutledge's actual build info, assuming there's a plastic insert through the tabs and then the rod goes through the lot.
Yeh crap falling in between cells is a worry, especially metallic stuff and swarf, your build probably helps stop it, as there's no gaps between cells.
I'm just trying to get my head around something with the forces applied in this build.

 

[Michall2008]

Yes exactly 16mm * 16mm. On electrician's near me, the neighbors doing some renovations at their place.

Got any picks of the scooter?

What do you mean ?

 

[ambroseliao]

I see you're using lock washers. It might be good to add a drop of Loctite to each nut just as a belt and suspenders insurance policy against what 999zip999 was saying...

 

[999zip999]

Megacycle I just copied The Drutleght build - He the man - Thanks Drutleght ! It can be found in this thread on page 3 I suguess you go thrugh the Big Moose thread and check it all out. So just follow in his foot steps my thing is the 12s plastic case (recycled ) I added the end termanials 10 or 8ga. silicon wire sandwiched between 2 16ga. coopper shite. He has a McMaster parts list don't use some parts. The blue plastic is the hardest to source
Michall I put Plastic wrap around the cells before taping and ping puts some black like door insalation foam below the the tab connections. I guess for vibration. You can also glue the white rails togethere or the tape is strong and will froze it.
Ambro bro - for not against. I like the lazer welder but can't be undone clean simply as not all these cells are made equal and mat have to be exchanged.

 

[RayGo]

Just got some new info on the latest assembly kit from Nancy at OSN Power. For those of you with A123 cells with full tabs, this is the way to go. Totally simple mechanical, safe and professional build and NO holes to drill in the tabs. This is a DIY kit version of the packs built by A123. Still waiting on more info, specifically the cost, availability and max cells supported. Only bad news is that I do not think this kit will work with cells with short tabs.

 

[megacycle]

Yes exactly 16mm * 16mm. On electrician's near me, the neighbors doing some renovations at their place.

Got any picks of the scooter?

What do you mean ?

Sorry pics= photos, predictive text

 

[megacycle]

Just got some new info on the latest assembly kit from Nancy at OSN Power. For those of you with A123 cells with full tabs, this is the way to go. Totally simple mechanical, safe and professional build and NO holes to drill in the tabs. This is a DIY kit version of the packs built by A123. Still waiting on more info, specifically the cost, availability and max cells supported. Only bad news is that I do not think this kit will work with cells with short tabs.

If they're the really short tabs could put copper strip across the gaps before clamping.

 

[megacycle]

My last 24S pack I made with agniusm's kit has only given me 15ah and today 14ah

Did you find the problem ohzee?

 

[ohzee]

My last 24S pack I made with agniusm's kit has only given me 15ah and today 14ah

Did you find the problem ohzee?

Yea sorry for the lack of updates.. I charged the pack and I am able to put 15ah back into it and all the cells look fine voltage wise.
Right now I am only able to put a slight load on it about 5 amps with what I have.. So my plan is to wire up some cell logs and take a
ride so I can see which cell is giving out.. otherwise not sure what to do.

I have a 2nd battery I carry with me so it's not a huge issue , but I want to get that last 4 ah back I had before.

I really need a better way to load my batteries.. right now I just hook them up to a old electric heater or ride the bike.

 

[megacycle]

Got this quote about 6 months back.

If its similar to OSN build at these prices, reckoning on $20 +or-2ish per cell, gonna get some minus bms & chargers, they might be happier to supply naked packs as they dont have to fiddle with bms and wiring.

How are you ???
We are so happy to hear from u on weiku
About 48V20AH(16S1P) lifepo4 battery pack with BMS(20-40A) with aluminum charger(48V5A)
----Will use A123 20AH lifepo4 cell to assembly It's 16s1p
Working current :20A
Peack current:40A
Aluminum charger:48V5A
Quotation:411.0$
Quantity:10pack
We are professional for e bike battery pack ,100% guarantee products quality
And also can customized according to customer requirements
Delivery :UPS EMS DHL FEDEX etc.
Delivery Time :3-5working days
Payment:T/T
If u r interested in those information,pls contact with us in time
P.S.above parameters need change ,pls point out ..
We are gonna wait for ur reply

Best Regards
xin wang
Shenzhen Victpower Technology Co., Ltd.
T: 086 0755 89635916 | F: 086 0755 89635636 | M: 15810120194
E: victpowersales@victpower.cn
W:http://www.victpower.cn
Products Showroom on Alibaba.com

 

[agniusm]

Just got some new info on the latest assembly kit from Nancy at OSN Power. For those of you with A123 cells with full tabs, this is the way to go. Totally simple mechanical, safe and professional build and NO holes to drill in the tabs. This is a DIY kit version of the packs built by A123. Still waiting on more info, specifically the cost, availability and max cells supported. Only bad news is that I do not think this kit will work with cells with short tabs.

It does look nice but that is the least of the worries. The reason of drilling cell tabs is pressure to clamp tabs properly. In this case only sides are clamped while the middle is loose + thin bar adds to the issue. My second concern would be modular design. OK to try and glue sections but will it hold under vibration? Overall it looks good but i would like to see it in real world application.

 

[megacycle]

Yeh good point, a hardened strengthener under the clamp bar might fix it.
Doesn't have thermal management, aluminum, like yours does either for the big A's.

 

[amberwolf]

I really need a better way to load my batteries.. right now I just hook them up to a old electric heater or ride the bike.

Auraslip built a halogen load; it's simple enough. Can be adapted to a number of possible loading methods.

Can also just string up a bunch of car headlights, or household incandescents.

Electric stove elements can work, too, but you usually need a hefty parallel stack to make a good load. Mine are about 1.5A each at 48.0V (loading a meanwell for testing); two of them parallel loads my 350W MW exactly to it's 3A limit--but they make decent space heaters with a fan on them. :lol:

 

[ohzee]

Thanks Amber.. I may try to pick up some of those old style bulbs at home depot today.

Like a lot of people I assume Xin Wang emailed me last night about 2-3k stock of new full tab's 20ah pouches..
She even stated (MADE IN THE USA) which I guess that's just what is printed.

Anyway cost is 20$ each said it went up some.. guess they know people want the full tabs and will pay a bit more.
If this has been reported already sorry for the extra spam.

 

[ambroseliao]

I took inspiration from YPedal to come up with my LBD.

http://ypedal.com/Lbd.htm

http://ebikerider.blogspot.com/2010/06/lbd-light-bulb-discharger.html

 

[megacycle]

Thanks Amber.. I may try to pick up some of those old style bulbs at home depot today.

Like a lot of people I assume Xin Wang emailed me last night about 2-3k stock of new full tab's 20ah pouches..
She even stated (MADE IN THE USA) which I guess that's just what is printed.

Anyway cost is 20$ each said it went up some.. guess they know people want the full tabs and will pay a bit more.
If this has been reported already sorry for the extra spam.

Got this quote from Wang xin yesterday.
Good morning I'm so happy to hear from you About A123 48V20Ah(16s1p)battery pack without bms with charger That's possible .Qty:10packsQuotation:235.0USDNow I don't have connect or welding pics Delivery: UPS or FedEx Delivery time3-5 working days arrive AU)Payment:T/T or Paypal I'm waiting for your reply P.S in future I will use the email address Best regards

That's <$15 per cell in a 16S pack, though it is quoted for 10 packs and it does say with charger and i asked without, i'll ask again

 

[megacycle]

With the load testing, Ive used little 50W halogen buds, but it was for 12V server PSU testing.
Halogen lamps are generally a lot more discrete and like 1or $2 in a pack quantity.
Getting burnt or setting fire to gear can be an issue and also there to be banned here soon same as the old incandescent's, i'd better stock up only got 12.
I used 2 parallel copper strips and formica insulation in between and had the 12V lamp pins straddling the strips so it was really easy to modify load, if doing higher volts could series strips or use lampholders, but then pricey.
There is higher voltage halogens and they're good because Ive used up to1500W single tubes before, in about a 6" long by about 1/2" dia package, though they were 240V.

 

[Michall2008]

Yes exactly 16mm * 16mm. On electrician's near me, the neighbors doing some renovations at their place.

Got any picks of the scooter?

What do you mean ?

Sorry pics= photos, predictive text

Pics are no problem for me

Nothing special (well, not yet :lol: ) about my scooter, cheap china one.

I see you're using lock washers. It might be good to add a drop of Loctite

I had this in mind, if the loctite can get between the bolt and the nut, it will get between the tabs also ?


All this discharge bulb talking got me to this http://www.ebay.com/itm/PHILIPS-A1-...y_VintagePhotoAccessories&hash=item27ca7dbc75
those are perfect for 12s packs discharge, two bulbs in parallel will draw 800W (22A)

 

[ambroseliao]

I had this in mind, if the loctite can get between the bolt and the nut, it will get between the tabs also ?

It won't if you use just a bit which is all it takes...

 

[megacycle]

Because 110V is standard, Found these 1500W@110V lamps be good for high load testing @ eg 72V+ packs. Says £5 for 7.
http://item.mobileweb.ebay.com.au/viewitem?itemId=261095502149

 

[RayGo]

agniusm wrote: It does look nice but that is the least of the worries. The reason of drilling cell tabs is pressure to clamp tabs properly. In this case only sides are clamped while the middle is loose + thin bar adds to the issue. My second concern would be modular design. OK to try and glue sections but will it hold under vibration? Overall it looks good but i would like to see it in real world application.

I wholly agree with agniusm's concerns. Someone needs to buy one of these kits and actually build a pack with it and run tests. I got the info and thought I would pass it along to other members planning their own builds. I did not even notice the modular design. I have taken a closer look and think I have some work-arounds to some of the concerns.

To improve the clamping pressure, you could probably just drill a hole through the middle of each clamping bar, tab(s) and board and then add a nut and bolt to securely fasten the tab(s) together. I just like the idea of minimizing or avoiding drilling holes in the tabs particularly with the cells I have with the short tabs and holes. Thicker bars, that don't flex when bolted down, would be a good idea for those with heavy duty applications drawing high amps but might be sufficient for most e-bike applications. Finally, I think there is enough room to drill a hole in the first and last module along each side. Then you could fasten a thin steel bar down each side to clamp the whole modular board together. For a real heavy duty application, you might even drill and add nuts and bolts to each module and the clamping side bar. Maybe even one clamping bar down the middle of the board. Perhaps these ideas can be included in the next version of OSN's assembly kits.

I am not planning to use the OSN kits. I have my own build planned taking ideas from all the other builds on this forum and using the cells with the short tabs with holes.

I did hear back for Nancy with additional information. The 12S kits is $40 and the 16S kit is $50 not including shipping. She stated that these kits will work with the short tabs for Korean made A123 cells which I believe to be 12mm. My guess is that full tabs would need to be folded or trimmed to work with this kit although folding might help add to the tab connectivity and pressure. I would not plan on using short tabs with holes which are only 10mm long. I hope someone will be checking out this kit. I know ambroseliao will be giving some feedback on the previous OSN assembly kit shortly.

 

[amberwolf]

Simple fix for the thin bars...make thicker ones out of stiffer material. I couldn't tell how thick they are exactly, but IIRC some pics that used to be up of those EIG cells showed what looked like busbars that clamped the cell tabs down, of 1/4" thick copper. You wouldn't need to use copper since they arent' conducting anything on these; you could use aluminum, stainless steel, or basically anything you could machine that would be stiff enough at the thickness you want it at.

This does depend on the stiffness of the plastic bars, though. I think on the EIG cells they use a full tray, so it has vertical stiffness from the plate on the back of the cell, so it can't bend in between the bolt holes like the simple bars above.