Post your pack (with a difference)

[Sputnik]

Good day,

As part of a personal project, I'd like to get an idea of the construction of battery packs used by EV-ers, from e-bikes to e-cars. I have come across Fetcher's **POST YOUR PACK** thread, however, I am looking for more specific information and more results.

My request applies to Lithium ion packs only. The specific Lithium chemistry is irrelevant, but may be included. What I am looking for specifically is the arrangement of the cells in the pack, i.e. 7p12s. A picture of your pack would be enjoyed as well.

Thanks all,
Sputnik

 

[BMI]

I supply LiFeTech "engineers/designer's packs" to advanced battery users (usually to manufacturer's as prototype batteries).

The cells can be re-arranged into virtually any shape since the hexagonal cell holding blocks can be clipped together much like lego blocks to build batteries into various shapes and sizes. The BMS and VMS circuit boards are supplied on a metal panel and can be removed and the wires extended and the circuit boards can be fitted into a separate weatherproof box remote from the cells.

These packs feature complete BMS with LVC protection as well as VMS which allows the owner to check individual cell voltages, number of cycles accumulated as well as error log for overcharge, over discarge and over temperature occurances all remotely via a laptop computer.
The packs are supplied in several different voltage and capacity combinations.
A typical 24V 15Ah designers pack is shown below.

View attachment LiFeTech Energy 24V 15Ah Designers Pack with BMS.JPG

 

[icecube57]

Thundersky 20AH LifePo4
24s 1P
1.44kwh
2-3C Discharge Rate (40-60A)
10C Burst For 10 Secs
79-80v Resting Voltage
72v Under Load
No BMS
4 HK Battery Medics For Balancing
2 Sub Packs 12s Strings 44.4v
40lb Total Pack Weight.

In the picture there is a hard base. (Floor Tile Cut to Size) There are 2 rows of cells with 3 cells in each row. There is another piece of floor tile cut to size to isolate it from the next layer. Another 6 cells in the same configuration on top. There are balance leads that I installed to monitor and balance each 6s string. There is 12G wiring coming off the battery for discharge. The packs are wrapped in Gorilla Tape. The best tape you can buy. I charge the 2 packs in parallel with a Meanwell Power Supply set to 44.4v. My Meanwell is pushing about 425w. I discharge through a special Y harness that connects the two packs in series for a 72v pack. All leads are terminated with 45A Anderson Powerpole connectors.

 

[TPA]

with all the jokesters on this board, I'm surprised you haven't gotten a clever response to "Post your Pack".

 

[scoot]

Sputnik, I see you have what looks like an older electric Goped in your avatar... are you seeking to upgrade from the SLAs on that one, or a newer ESR version?

 

[Sputnik]

with all the jokesters on this board, I'm surprised you haven't gotten a clever response to "Post your Pack".

Haha, oh my! I only picked up on the alternative interpretation of the topic after reading your message

Sputnik, I see you have what looks like an older electric Goped in your avatar... are you seeking to upgrade from the SLAs on that one, or a newer ESR version?

Yes, it is rather old. I didn't get it with any batteries and so am looking into Li-ion but it is fiendishly expensive . I don't want to waste my time with SLA. NiCd or NiMH are alternatives, however Li-ion would be ideal. Even a Ping Pack is too expensive for me at the moment . I'm still looking for a place where I could ask about returned power tool battery packs in my area. Apart from energy storage, I still need to get it rolling again. What do you mean by "a newer ESR version"?

The idea is to write software that will determine the arrangement of Li-ion cells in a pack for optimal capacity and internal resistance. The idea/inspiration/interest came about after reading Doctorbass' == 2100Wh 432 kinion cells project == thread. I'm trying to get a rough idea of the average construction of Li-ion packs here to see if I could set up a cluster capable of calculating the optimal combination of an "average" pack in an acceptable amount of time. I've been wanting to setup a cluster for a long time and this would be something interesting to do. I'm keen to see what sort of performance I can achieve. I've programmed a little Python script that calculates the total number of combinations in a specific battery pack, i.e. in a 20p18s battery pack there are 69 766 089 804 140 049 584 515 714 560 186 883 459 916 816 142 584 864 496 440 323 716 294 334 435 540 818 137 130 079 946 204 103 025 141 079 665 384 886 645 695 179 195 408 829 191 593 481 609 707 077 142 697 905 345 585 391 233 440 455 821 501 152 463 497 989 229 336 176 721 631 352 093 804 089 676 065 242 630 082 798 803 453 033 361 988 427 697 501 314 794 275 858 154 516 345 000 450 051 336 385 995 393 217 364 219 651 531 110 190 753 540 077 546 392 670 447 283 080 768 211 593 612 476 605 899 250 246 764 056 313 942 646 151 024 720 000 000 000 000 possible combinations. Not sure if my algorithm is correct but it appears to be for smaller packs that I have worked out by hand. If it is correct then this example of a battery pack would never be calculated within my lifetime with mere desktop computers lol. Could start something similar to distributed.net, but this is all another topic...

I suppose this thread applies predominately to Li-ion packs with two or more cells in each parallel group.

Thanks everyone,
Sputnik

 

[def215]

ooh. i want to play...lol

so what i have is a 7s6p konion pack(sometimes i do 8s6p just because i have the spare 6p). i believe its lithium manganese chemistry. no need for balancing but theres a need for LVC. i monitor my pack with HK battery monitors and a wattmeter in the meantime. so far im liking these batteries because of them being lithium and they are low-maintenance too.

this is what i have:

i know, everything is a total mess right now. it looks like spaghetti, but i know whats going on.

 

[scoot]

Hi Def... good to hear from ya again :wink:

Based on my trials and tribulations, I found the biggest obstacle and challenge was finding a battery pack or combination of cells that would physically fit in the battery pan.... combining that with all of the other aspects such as required C rate, controller setting & limitations etc. all compounds the challenge.

Sputnik, There is a group of us who have been using headway cells very effectively in the newer ESR-ex and Hoverboards with the EX deck spacer between the deck and the pan. I think our battery pans are longer though.... 12 inches lengthwise of battery space. Suggest you pull off your deck and take/post a pic with a ruler in the shot for scale. This what the newer ones look like with four stock HR 9-12 SLA batteries and the Headway retrofit, 3rd pic shows the deck spacer.

Other options could include A123, Konion (like Def215) and Lipo hobby packs.... all depending on your skill and knowledge... pros and cons to all of the options. I would have tried the Konions if I could solder worth a dam.

If you need some information on what you actually have there, I suggest you inquire in the Electric Forum at Goped Nation. Those folks should be able to bring you up to speed on your electronics and hardware.

View attachment IMG_0460.JPG
View attachment IMG_0991.JPG

 

[Toorbough ULL-Zeveigh]

with all the jokesters on this board, I'm surprised you haven't gotten a clever response to "Post your Pack".

like this jokester.

I don't know if I could keep it "hidden" and pull it out fast enough. of course, you *don't* want to pull it out until absolutely necessary because people can be a bit more volatile and dangerous. For sure, I've never pulled it out.).

 

[def215]

Hi Def... good to hear from ya again :wink:

hey scoot. whats going on? yeah, im still around, just lurking most of the time...lol

good to see that your headway pack is still together. do you still have the PMW LiFePo4 pack?

one question sputnik? what would the application of the battery pack be that you are trying to gather information for?

 

[scoot]

good to see that your headway pack is still together. do you still have the PMW LiFePo4 pack?

Yep that's just my original 20 ah (8s2p with 10ah cells) setup in the pic. Have all of the 12ah cells from the PMW pack nicely broken in and matched up for pairing (4s2p per side), and all of the assembly parts made up. Just need to assemble the pack (so little time ), and they'll be good to go. Heavily considering the Chargery DB8 balancer w/LV alarm... although I am doing fine with the manual balancing and conservative discharge approach so far. 8) Len's PMW packs are holding up fine as well... he is getting lots of use on them. I have also been in e-mail contact with a couple other fellas' that are happy with their ESR Headway conversions too. 8)