A123 20AHr Pouch Cell Battery Build & Info Thread

[josh786]

Here is what I have been working on. I have to give thanks to all the people that contribute to this forum I got all my ideas from others builds. (Long time lurker) The green stuff is urethane with copper inserts. I plan on putting a tube thru the holes before I put the bolts in. There will be a wire that will exit into the middle from the series bus bar for BMS. With this I think I will have every possible configuration covered. Feed back is welcome will start making molds next week. Still having a hard time with copper vs aluminum for the bus bars.

[bigmoose]

Josh your design was so elegant, I thought the pixs should show in line.

4S2P complete 2b.jpg (28.42 KiB) Viewed 1007 times

4S2P completeb.jpg (34.04 KiB) Viewed 1007 times

[docnjoj]

Hey Josh! That is an interessting and clever design. Will the urethane be cast, like the kind for making model railroad parts?
otherDoc

[josh786]

The parts will be made from urethane adhesive (I build the equipment at work) we have alot of left over product. Once the molds are made the cost will be just the copper + time. I am not sure about the compression strength of the modeling urethane, the stuff we have will set hard enough to thread.

[docnjoj]

Thanks Josh it sounds quite solid!
otherDoc

[bigmoose]

Josh, just a thought to not forget the balance wires. That may be what the hole for is on top of the conductor in your green molded piece. If not, we should figure out how to elegantly attach a balance wire.

[josh786]

Big, My though was to solder a wire to the S plates that will exit into the V on the top. I have some 6061-T6 aluminum (1/2 X 2 should be good to 700-1000amps?) that I can use to build the prototype but the wire attachment is what is holding me up. Might just drill and tap a hole and use a plated ring terminal but I am not sure about longevity there will no way to fix it later. I have no problem with using copper for the final product just that I have the aluminum and I am getting antsy. I am trying to extend the end plates down to contain the cells but it is getting very bulky. May need to rethink how the cell terminal sits so the end plate can be thinner. Ideas?

Josh

[999zip999]

If it's 2p can you get rid of the buss between the parelle's with it being tab to tab ? Will this srcew of the spacing ? Yes alumiun is hard to think of over copper. As in houses ect. and how hot it can get ? I guess it's all about mass. To a point of to to much heat.

[josh786]

Here is what I have currently. If the pic shows up inline.

4S2P complete 3.JPG

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Mod Edit: I resized your pix. It has to be below 800 pixels in width to show up in line. (one of the boards little quirks!)

4S2P complete 3-600px.JPG (82.28 KiB) Viewed 1008 times

I added the holes for the balance wires. The lines in the top of the plates are to mark the connections. This would have plastic or steel shipping bands wrapped around to hold the cells. Maybe getting to heavy for a bike?

[josh786]

Zip, Removing the bus from the 2P makes the S plates wider, may have to think about it more. My plan was to be able to reconfigure this to any size pack by changing out the plates. What about terminals stud vs. taped hole I can see advantages to both.
Josh

[999zip999]

I mean in a 2p pack the cells at 2p will fit togethere in one taps pressed togethere and fit in your buss bar? Only maybe. I find they fit togethere very easily as 2p. But I would like to have one in hand as to help as would you.

[megacycle]

I'm waiting for my agniusm kits to arrive but in the meantime I;'ve used my No-Ox ID-A on all my plugs and outlets outdoors and by the pool. It seems to really help conductivity since when I do a before and after with a Killowatt meter the current draw seems to be about 1 amp in 10 lower. Maybe a fluke but I will swear by this stuff and use it on my 12S battery when the kit comes. Seems like good stuff.
otherDoc

Been through this on agenius kit thread, viewtopic.php?f=14&t=38545&start=135
They ac outlets around the house
Can anybody please proof this stuff decreases resistance to dc
Other than provide corrosion protection is it that much better than vaseline.

[999zip999]

O.k. Vaseline it is. Stiil charging for days. They just look so sleepy.

[megacycle]

Aka snake oil

[999zip999]

When I took apart my ping I put a set of extra balance wires and if i put a bms on these packs I still will have a set of balance wires for checking and balance as probing the bms will mess up the wires and.

[999zip999]

O.k getting around to the drutledge build. On the end temminals I using 8ga. silicone wire between two 16ga.copper plates the same size as the alunium buss and flaten then fill the small gap with solder. Hope this is fine. Guess I have use silver solder higher temp. ?

[ohzee]

Like to see a pic of how it's going zip if you get the chance.

[999zip999]

36volts sucks MUST build another 12s, plus the yellow light on the bmc 48v throttle came on and shut me down ? It can't shut me down ? Always run at 60v now 74v and going to A123 84v ( soon ). This battery has a lot of steps as my little garage is not a battery factory. Yet. Back to the drill press.

[999zip999]

O.k. added a12s so 24s and it still a little flat. It went down to 3.3v fast. i only charged to 3.6v and hadn't cycled it. Till I tried it. So going to find out how to cycle on the 1420 as i still looking for the smallest box. This is getting evpensive. Just ribbed tape for compession ?

[ohzee]

I built something similar so if I can understand where you are I may be able to assist.

I had 2 12s 20ah packs via compression. 2 cell_man high power BMS with diodes in between to keep them safe.

You running a BMS ? I still have the 2 BMS no longer using. They worked great , but it was a pain dealing with
the wiring compared to having it all in 1 unit.

[999zip999]

Ohzee i'm just going to run bareback as I have 74v konion That works fine so as no need to rush.

[ohzee]

Cool keep us updated bud..

[deVries]

Thought this post should be in this thread too...

I'm not sure if it was this thread or another thread on 20ah a123s that I mentioned I had a spark on one pack when a metal object touched an aluminium tab and part of the plastic outer case. I've just finished off a 48v 20ahr a123 pack and I found the source of this spark.
The plastic outer sleeving of the cells appears to have a connection to the copper in the pack. There is a very very thin ( a few microns) clear plastic that is the first layer touching the the inner cells/tabs. If you interfer with the plastic outer covering when connecting cells together there is a very good chance of developing a short.
I'll give a bit of detail how I found the issue.
In my 48v pack, I needed to disonnect in the middle of the pack for charging ( using turnigy/hobbyking chargers) so that I have two 24v packs for charging.
The high amp switch inbetween the two 24v packs when 'off' I was still getting some voltage going through the pack, hence there was a short somewhere.
The source of the short was where I had punched a hole in the aluminium tab, since my tabs were very short, the hole I punched for a bolt went maybe 2mm across the plastic at the base of the aluminium tab.
After the bolt was done up tight it turns out the outerplastic ( having a connection to the copper somehow) was shorting with the aluminium tab.
With a very small screw driver i could see a tiny spark if I touched the aluminium tab and where the plastic outer casing had been interferred with by my hole punching. I think the aluminium within the plastic outer covering ( probably vapour deposited) being very thin layer of aluminium ( or similar metal) can carry a tiny current ( probably high resistance) so even though its a tiny current the voltage across the short could be quite high.
Any how if any one else has issue with some hard to find shorts, check the outerplastic covering in particular anywhere where its been cut, I landed up using nuetral cure silastic along any parts of the outer plastic that might be potential problem.
Because the plastic layer that insulates the aluminium outer plastic from the cells is only a few micron thick I suspect others will also see similar problems.
Cells that haven't had tabs cut shouldn't be a problem but any of the seconds that have very short tabs may have this issue.
A picture of what i've tried to describe would help I know, will try to organise one.

[999zip999]

o.k. charged my 24s twrice. The first run at 25amp was disapointingS. it went down fast. The second charge a little better, but. I stopped at 3.34v. They charge fast at 12a. to 3.59v then my 1420 shut off at 100%, all very even. Running bareback and all keep balance, but go flat fast. So a couple more cycles. Sorry can't down load pic's. ?

[cwah]

o.k. charged my 24s twrice. The first run at 25amp was disapointingS. it went down fast. The second charge a little better, but. I stopped at 3.34v. They charge fast at 12a. to 3.59v then my 1420 shut off at 100%, all very even. Running bareback and all keep balance, but go flat fast. So a couple more cycles. Sorry can't down load pic's. ?

How many AH or WH can you pull out of the 24s pack from full charge (3.6V) to empty (3.2V)? Is it the Victpower cells?