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I see similar price at BatteryFinds:



$65/cell but that includes shipping.? Good energy density at 170Wh/kg.

But it look like those cells are coming from China at BatteryFinds.? So likely more than one month shipping time.
If your Georgia company has them in stock and shipping isn't too bad, that probably makes more sense.

I personally haven't ordered from BatteryFinds yet, but I've heard good things about them.

Maybe browse through BatteryFinds' USA stock to see if you can beat the Georgia company price-wise (including shipping)?

Bob, I was rewatching your video assembling your 48 volt pack on your boat and had a question regarding the 12 volt cell grouping. I see blue stripes on one end of each 4 cell group. Are those in place to reduce swelling and is swelling something I need to be concerned with?

Those are lashing straps, to help keep the cells together when moving a four-cell module.? Without them, just the bus bars hold the cells together, and the two end cells can move a lot relative to the center two cells (when lifting the module).? The straps are on the edge of the cell block where that happens (where the two terminals for connecting to other modules are, as they have no bus bar on them).? Then another (black) strap with just a plastic buckle is run under the bus bars to facilitate lifting the modules by hand.? I'm sure I'll get questions about trusting the terminals to not pull away from the cells when being lifted, but "so far so good".

On bulging, once I ran the pack down 'all the way' intentionally, to be able to observe the motor controller behavior.? I believe that caused once cell to bulge somewhat.? I ended up enlarging one bus bar's holes to allow that connection to remain flat (instead of splaying out the cells towards the bottom).? In hindsight, this situation could have been helped by a BMS.? I basically identified the weakest cell the hard way.? It also has more self discharge now, so I have to work a bit harder at getting the pack full and balanced.

I've built a second pack since then (Gotion 105Ah cells), and use small rubber bumpers between the cells.? One reason is to better accommodate bulging, the other is because I learned that the blue plastic covers live metal (the alumunim case is at the same potential as one of the terminals).? If that blue plastic were to have its insulative properties compromised, I'd be looking at a catastrophic fault for at least one cell.

The expert sources I've encountered say that prismatic battery cases must be constrained and prevented from bulging.? I've divided my pack into 4 boxes of 4 so that I can take the batteries off the boat seasonally.? The boxes are built with stiff sides along the long dimensions of the interconnected batteries.? The boxes are interconnected in series with flexible connectors rather than the copper bars used within the boxes.
My belief is that a prismatic battery with a bulging side is a suspect battery.
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