A123 32113 Ultra-B cell, cycling so far

[zeropointbug]

32113 M1 Ultra-B cell
180g.
4.4Ah
40C rated Cont. discharge
Considered a 'high power' cell

Just thought I would share how testing of this cell is going so far. I am manually cycling it through my 720i NET charger using 10amp (maximum 80watt/10amp) and a 20amp charge rate. Since the older 720i can only go down to 2.5v/cell on discharge (not sure on new ones) it will have to do, might only miss a few 10's of mah anyways...

So far, all I have to say about it is that it's a BRUTE of a little bastard(32113 little?) Pounding 20amps into it and it is just bagging for more, my guess it could handle 30+amps, judging by the cell iR and voltage fluctuation (very little). At 20 amps, there is roughly only 0.08 volts between ON and OFF current. Charger is reporting a 1-2 mohm cell iR, very nice. Check out the pics.

Notice how the cell will take 20amps charge rate all the way to 97% SOC (don't mind the 89% as the 720i miscalculates the SOC), after that the currents falls pretty damn fast too, doesn't mess around with too much time on CV stage, maybe 1 min out of the less than ~15 min charge.

Cycling is done under a 100% DOD. Currently on discharge cycle #85

[zeropointbug]

photos 1-4

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photos 5-8

[zeropointbug]

photo 9

[mistercrash]

Since you have the cells and you started this thread then you are now obligated to find out what voltage these hold with a load of 150Ah. How hot they get also. Get to work

[zeropointbug]

Hmm, I don't have a way to actively measure current above 10 amps besides my eagletree which I could try and find and rig it up for PC use. I would have to come up with a discharge source, maybe a steel rod comes to mind? I could use the hand clamp I am using now, compressing some copper mesh wire onto the cell ends, while using booster cables to make a lead to the discharge source, whatever it may be.

I will have to do some searching, I will try and make this happen though.

[zeropointbug]

I can't find my Eagletree for actual amperage rates, but...

I have been rigging up some discharge wire coils,first made out of 16 ga. wire, then I used to 12ga. wire to spread the heat out more. For the last test I did was 8 ft of 12ga. wire (0.013 Ohms load) wrapped around a 2" 1/16 aluminum tube for heat dissipation. I was using booster cables before for connection, but took them out of the equation, and instead soldered some bare 4ga. FLAT ribbon cable onto the wire and sandwiched two of them onto the cell terminals using the clamp you saw in the previous picture. I then made connection by clamping the two ribbon cables together using clamps.

Now, I only tested it for 32 seconds as the electrical tape on the wire coil was melting and burning pretty quick and things were heating up all around very fast, the cell, on the other hand, was warm, hitting 102 F after 32 seconds of discharge.

Discharge voltage was 2.75 volts instantly after I made connection, but quickly climbed to ~2.83+ volts for the entire discharge.

In those 32 secs. I discharged 1298mah (charger put thtat amount back in).

If you calculate the amperage rate using the discharge load in Ohms (0.013 Ohms), you get 215amps:

2.8volts / 0.013Ohm = 215 amps

But, if you go by the actual mah put back into the cell and multiply by 32 second discharge, you only get 146 amps:

32 sec / 60 = .53 mins x 60 min/hr. = 112.5 x 1.3Ah = 146 amps
Obviously, you have to go by the rough calculation of 146 amps.

To me, 146 amps @ 2.8 volts plus looks to be very nice for an A123, and I would hope to see a good number as the cell weighs 180grams for 4.4Ah.

I also did a quick calc, when charging the voltage increase ~0.06volts at 20amps, so going by that, 150A / 20A = 7.5 x 0.06 = .468 3.3volt cell subtract 0.468 = 2.83 volts, exactly what I saw when discharging.

2.8v x 4 cells = 11.2 volts..... at 150 amps, that would be able to start a small car engine I would think, damn near anyways.

I will look for the eagletree so we can get some real discharge tests going. I will also make a more robust discharge coil, one that won't melt and fall apart...

[mistercrash]

Thank you very much for this, and like you said, the cell performed rather excellent. 146amps that's something like 33C for that cell which kept a pretty low temp. Where can we get those cells if you don't mind saying? Or maybe I should stop being such a lazy bastard and find it myself

[snellemin]

Nice!!! I had been looking at those cells myself to use in something. But I never figured what that something could be.
Did you ever try those A123 32157 size cells?

[zeropointbug]

Yeah, those are rough estimates, but should be within 5% I would say.

The ribbon cable I am using for cell connections are about 6 inches long and they get very hot pretty quick, after 10 seconds I can't hardly touch them. I thought I remember the package saying it was 6ga. or maybe 8ga. equivalent, so you would think it could handle the current no problem?

Have you guys checked my math by any chance? 8ft of 12 ga. cable is the discharge load, 0.013 Ohms.

Snell, I would like to buy one of those 32157 cells to test as well, should buy one soon. They don't make them anymore do they? Same with the 15Ah prismatic cell.

I think the 32113 is a very good dragster cell, maybe or maybe not for racing, but for drag racing where Power/weight is the name of the game. a 5s pack would do nice for a 20 min race in a truggy, but where to put them, and how to arrange them might be tricky. Might be better off using a 8s 26650 pack instead, 4s saddle on each side...

[snellemin]

I believe that 123rc website still sells those various A123 cell formats. Dunno if they B-grade stuff though. That 32157 would be nice for a dragster, but I'm thinking more of a dragracing electric bike

I think I should build me one heh.

[BrianG]

FWIW, I would use an ammeter to accurately measure current. Calculating current by using resistance of a given gauge wire assumes that wire is exactly that gauge (and is that stranded or solid), and doesn't take into account contact resistances. Using the wire as a load is fine, but wrap a few more turns to keep the current a little lower and you could use an Eagletree to measure the current since it uses a HE sensor with minimal parasitic insertion resistance.

[zeropointbug]

Sorry I forgot to mention where you buy them, yes A123rc.com sells them, and that's where I got this one.

Brian, I do have an Eagletree, I just don't know where I have (mis)placed it. It is an older 100A model so yeah the continuous current should be around 100amps ideally.

Snell, isn't the 32157 an HD electrode chemistry geared more for energy denisty rather than power?

[zeropointbug]

Snell, did you mean an electric bicycle or electric motorcycle?

[mistercrash]

Well according to some emails I made to A123 Systems, A123RC is NOT an official distributor of A123 Systems and does NOT sell genuine A123 Systems products. According to A123 Systems, every so called A123 cells of any format sold to the public from online sources is either scrap cells or counterfeit cells.

Well if the cells I have seen perform in a couple forums are scrap or counterfeit, I say keep em coming. They do pretty darn good. IIRC I have seen in a Jack Rickards video someone who pulled close to 1000amps from a prismatic 20ah cell (surely a scrap or counterfeit one if you listen to A123 Systems) with the voltage staying well above 2V. I'll try to find it again, it was cool to watch.