Battery: Expansion

The Expansion

I ordered 1000 cells that I thought would be ready to put together, but I needed to disassemble them from their prior intended purpose. They were destined to be used as packs for some sort of battery powered vacuum, but the speculation is that the company went out of business before the packs could ever be used. I'd say I got a great deal on them since they are normally (when brand new) around $8 per single cell.





Nice clean work space...or not...

These are the processed cells that are currently wrapped. This is 10001420/1960 cells that will make up the next pack(s) 14s, 200p. This will include the cells from the existing battery (840 cells, which will bring the total up to 2800 cells.

Anyone in the market for a bag of slightly used cell wrappers? We spent a day re-wrapping and processing more cells. You can see the boxes of packs that still need to be processed on the floor (~600 cells). At this point, all of the loose Panasonic NCR18650BD cells have been processed and are ready for construction.

The wall got a little too tall and I needed to get a better idea of how many cells there were remaining to process. After I took it to more of a horizontal position, it looks like the 14 pack series setup is currently close to each having 120 cells in parallel. Still need to get 120 more cells processed to reach that point. The current plan is still to get all of these cells processed to 140x14=1,960 and then combine them together with the existing packs to make it 14x200. To reach that point I still need to process about 400 cells. These will still be ~200 NCR18650BD cells remaining after completing the 14x140 goal. I'm torn on just meeting that point and building vs. processing all of the cells and replacing the lower capacity cells. I also will have ~200 other cells laying around, which I could combine to make a 14s, 240p instead, but I really want to get the new battery built and then start work on the next battery with the remaining cells. I also bought a UPS to setup with a 7s configuration @~24v.

Mini Goal Achieved

I now have enough cells processed that I can make a 14s 120p pack from these nice high capacity cells, but I am faced with a dilemma. Do I just build a new battery with these cells and leverage my existing 14s, 60p as part of it or do I wait and keep processing cells even though I am lacking motivation? The sensible part of me says that I should use as many high capacity cells as I can, so that the battery is most cost efficient and has the highest capacity, but another part of me just wants to get it into service and move on to the next thing.

Hurry up and wait...nearly 4 months after ordering more cells to complete my build, the seller still has not correctly sent my order. He has promised an extra 200 cells for the inconvenience, but I just would like my order so that I can work on assembly. I have 2,000 cells sitting on standby waiting for the remainder of their companions. I want to have a 14s, 300p battery, which means I am still a few cells short. 14 x 300 = 4200 vs. 2000 + 1700 = 3700, leaving me 500 cells short in theory. If I reuse the existing battery in the build, I will have 14 x 60 = 840 cells to add to the mix. I also can consider that there are a few hundred cells sitting around from other applications and orders that could be used in addition or instead of those from the current build. Either way, it is really frustrating to be stuck at this point without being able to utilize all the power sitting right next to me.

After a brief battle with the seller over PayPal, (they tried to lie and say that they delivered, but I provided a transcript of 4 months of lies from them to the investigators) I was awarded a refund. I reached out to someone that I knew would provide reliable, tested cells that I would be able to put into the expansion. Thank you to Terry from Powerr2Spare for helping me out after this massive headache!

For the expansion, I will be re-using the existing 14s, 60P battery and integrating the cells into the new packs. I have 4 of the new packs (pictured right-above) that are ready to receive the existing 60 cells per. I need to re-wrap many of the cells from P2S, but that is a small inconvenience in the grand scheme of things.

From design concept to reality!

Got both positive and negative sides to repeat 13 more times.

Fuse wire is 35 SWG (Standard Wire Gauge) is used here to go to each of the cells and 4 AWG (American Wire Gauge) is being used as the bus bar with the lugs crimping on the ends.