Panosonic 25ah Prismatic cells for sale $28

[eric1565]

Hello,

I am selling 25ah Prismatic cells. I will only ship to the lower 48 states.

These cells are used at 250 amps in the cars they power. They can safely do 500 amps for a 10 second burst. If you need bus bars let me know, and I can get them machined for you for 3 dollars each. They will be made out of aluminum.

Discharge Curves are in below posts

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NMC Chemistry
Voltage range 4.2-3.2V
Compression is required until you get the posts 1.13" apart. This takes very little torque from 1/4 bolts (less than finger tight while holding just the socket (no ratchet)) Once compression is acheived, the cells are pretty tight, and will not move around.
Weight approx 730g
DCIR .00165 ohm
Discharge up to 500 amps for a 10 seconds (this leads to a 1V drop in voltage of the cell), 250 amps for 30 seconds no problem
Charge between .5C and 1C (from http://batteryuniversity.com/learn/arti ... ithium_ion)
The outside of the case is energized. You MUST use seperators!!!! The center seperators are provided when you buy multiple, but you need to make your own end seperators so you don't short the pack when you compress them.
Factory end plates are 10mm thick aluminum


If you have any questions just let me know.

Thank you
Eric1565

[Chalo]

You don't specify cell chemistry, voltage range, or weight. Do they need to be housed under compression?

[eric1565]

All good points. Fixed in the original post.

Thank you
Eric1565

[Chalo]

Thanks!

[eric1565]

So I did some charge and discharge cycles, and my logview took a crap so I lost some data.

I got the charge cycle saved. The unsaved discharge had the same capacity, 23ah. I had the voltage cut at 3.2v on the discharge, and the curve had just started to arc down. So I reset the min V to 3V and am re-running.

Here is the charge from 3.2 up to 4.2V. on the discharge cycle the battery hit 3.2 volts, and the charger cut off, but then the voltage went back to 3.45V.

25ah_charge3.2to4.2.JPG (188 KiB) Viewed 3890 times

[eric1565]

Here is a discharge from 4.2 to 3V. Capacity was 24,252mah

3V looks like the bottom of where you would want to go. I did find some literature that said 2.75V was dead but I did not want to go that low.

The voltage jumped up to 3.2V after the discharge stopped.

25ah_discharge_4.2to3V.JPG (168.09 KiB) Viewed 3890 times

I plan to do some tests where I change the discharge current from 30 amps down to 1 amp to see how much the voltage increases by. From that information an IR can be calculated on the battery.

Eric

[miro13car]

why there is no Panasonic logo anywhere on those cells?

[cycborg]

Couple questions. First, the power and energy numbers don't seem to match the voltage, current, and capacity numbers. For example, 24 Ah at an average voltage of 3.6 V is about 85 Wh, but you're showing twice that. And the initial power of 275 W doesn't match 30 A x 4.15 V = 125 W. What am I missing?

Second, what's supposed to go on those posts? They're way to long for just the bus bars, and it looks like they'd cause a lot of volume to be wasted.

[Chalo]

I am in the process of testing these with an Icharger 3010. I have a 2P1S battery made up. I will log and post the results of a charge discharge cycle in a few days.

[eric1565]

Are there ever Panasonic logo's on their cells??? I don't think I've ever seen a panasonic logo on a naked cell...

[eric1565]

AH, ok, maybe I should have said I am testing a 2S1P pack... lol... Sorry about that. If I tested just one cell then the Icharger would read the voltage on the main leads and when your dumping 30 amps thru 12-14 awg wire there is a decent voltage drop, so it would give a lower ah rating.

so yes your numbers are correct. I took off the full cell voltage, and just showed a single cell.

Good catch... see I did that to see if anybody was REALLY paying attention

Eric

[eric1565]

Couple questions. First, the power and energy numbers don't seem to match the voltage, current, and capacity numbers. For example, 24 Ah at an average voltage of 3.6 V is about 85 Wh, but you're showing twice that. And the initial power of 275 W doesn't match 30 A x 4.15 V = 125 W. What am I missing?

Second, what's supposed to go on those posts? They're way to long for just the bus bars, and it looks like they'd cause a lot of volume to be wasted.

The posts are just for the bus bars. yes they consume alot of room, but that is what is on there. They have a little plastic box that goes around them to protect them.

[parabellum]

You should post some official specs sheet, model Nr/name, where they where used, how many cycles in use (assumption at least), DCR if no cycle. Your candy wrap looks cheap and I did not find any official info just by googling given parameters, which is your failure. This are my 2 cents, person that purchased batteries, of this forum, 2 times in this month.
I actually still need some high C rate cells in 3.6-3.7 nominal volt flavour with long calender life.

[eric1565]

Ok..... Candy wrap looks cheap?.... That is how they come out of the pack. It is not my cheap candy wrap.

I put an actual discharge cycle of a 2s1p battery.

Calculating number of cycles is difficult. All I can say is that I have a 2015 year battery with 15k miles on the way. The cells I tested we're from a 2013 pack with 30k miles.

I have this car, a 2013 w 100k miles and I still get full range and I have a buddy who has the same car w 130k miles and still get full range. The car runs the bat from 4.05 to 3.4. so u don't get full capacity but u get many many cycles with little degradation.

Hence the 24ah capacity on a 5 yr old bat.

Eric

[Alan B]

Looks interesting.

Which vehicle are these from?

[DanGT86]

Are those separators flat against the whole cell between them or are those something you made? I'm wondering regarding compression. Can a user just put the whole stack under compression with end plates using those separators?

[Pajda]

Looks interesting.

Which vehicle are these from?

This cells was used mostly by Volkswagen in e-Golf with 24 kWh battery, in e-UP! and in some hybrids.

[eric1565]

The plastic parts are all OEM. When I pull the pack apart I'll pay extra attention to cell compression / confinment. On the 2014 spark pack I took apart they we're COMPRESSED. But on these I think they are more confined vs compression. You can not just use these as is. You need confinment at a minimum. Plastic parts will go with cells.

Padja is correct on cars

[parabellum]

Ok..... Candy wrap looks cheap?....

I meant, you give to little information.
But now I see, this cells are like good kept secret, I could not find any official data-sheet, it is also not in Panasonic’s catalogue. Looks like exclusive OEM solution where specs sheets did not leaked to the public.
Interesting!

[Drokz]

Where you from ?

[eric1565]

I am located in houston tx.

[eric1565]

Ok, I ran some tests on my icharger. While in the process of running these tests I burnt up one of my anderson powerpole connectors that SHOULD be good for about 40 amps... but apperently not 40 continous amps... lol... so I bougth some 4mm bullet plugs to replace my anderson powerpoles.

I will wait for my bullet plugs to come in to do more tests.

So with the calcs from "www.mdpi.com/1424-8220/10/6/5604/pdf" I calculated a DCIR of about .0016-.0017 ohms. Take this number with a grain of salt. I really needed to have a high accuracy multi meter on the cell to get a more accurate DCIR.

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[eric1565]

The order of batteries has not come in yet, I will let post once it arrives, and I will take pics.

Up graded my wires on my Icharger today. I had 14 awg wires and went up to 12 awg, and changed from anderson power poles to 4mm bullet plugs.

I should be able to do more testing on the batteries tomorrow. if there is any specific tests you want run let me know.

Here is a pic of the melted powerpole

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sorry it is out of focus

Eric

[miro13car]

I understand no Panasonic word,
but any marking, numbers , etc.???

[999zip999]

These cells output 250amps ? How many in parallel ? Or 1p ?