To prevent the mis-fortune of using counterfeit or manufacture discarded cells, batches are capacity and electronic load tested at a constant 15A. Above photo depicts a sample discharge graph of a Samsung 30Q cell which is consistent with manufacture's data sheet. Cells are purchased in bulk in Samsung sealed packaging.
Single layer of 12 mm by 0.15 mm thick nickel strips equates to an 13AWG current carying capacity. This yields 0.03% power loss over 12mm length between cells. This allows for proper current flow with the ability to "blow" incase of a short, acting as a fuse. These welds are electronically timed using capacitive discharge.
Substituting Polyvinyl Chloride (PVC) insulated wire with a temperature threshold of -20C to 105C for Polytetrafluoroethylene (PTFE) which increases the threshold to 240C and decreases the overall diameter by 40%. PTFE has a much higher resistance to abrasion than PVC. PTFE is costly.
Epoxy is used on parallel cells to relieve stress from the welds. Plastic strips insulate series cells. PVC heatshrink to seal battery assembly.
Taking off the BMS from your factory battery, using a heat gun to heat three "solder sleeves", and plugging in the 11-pin BMS harness, completes the installation.
Factory (7aH): 16x135.7x335.3mm @ 1.5kg
40 Cell (12aH): 21.2x141x378 @ 2.01kg
80 Cell (24aH): 42.2x135x376 @ 4kg
Factory (10aH): 22.5x134.7x331.9mm @ 2.12kg
40 Cell (12aH): 21.2x141x378 @ 2.01kg
80 Cell (24aH): 42.2x135x376 @ 4kg
Factory (10aH): 18.2x135.1x414.1 mm @ 2.15kg
40 Cell (12aH): 20.4x133.4x378.3 mm @ 2.01kg
50 Cell (15aH): 20.4x133.4x465.5 mm @ 2.43kg
Design flaw - No Heatsink causes over heating
Size: 95x50x8mm
Design flaw - No Heatsink causes over heating
Size: 110x40x6.5mm
Heatsinked
120.5x40.3x10mm
Samsung's discharge shows the voltage sag you'll experience over load and cycle life. Street wheels on flat surface on ECO you'll see minimum load. Uphill with AT tires on GT mode you'll see close to maximum .
Recommended max output per cell: 15A
Recommended max charge per cell: 4A
Electronic load testing verifies constisconsistency with Samsung's data sheet.
Maximum Charging Current: 6A.
Maximum Output Current: 60A for 10 Sec.
22awg charging cable is another reason not to charge over 5.4A.
Cells can withstand a lot, nearing 300 degrees Fahrenheit per datasheet. Do not test these limits.
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