EcoRenovator - View Single Post - Do you own a C-Cell flashlight?

jeff5may · 06-06-17, 11:03 PM

The battery banks in laptops have a dedicated BMS board inside. It is classified by the number of series-connected nodes (3s, 4s, 5s) inside the pack. Most boards are useless for repurposing due to the fact that they are married to the laptops they serve.

Lucky for us, there are a bajillion generic BMS boards out there. You can get them long and skinny, postage stamp rectangular, round wafers, flat like paper, whatever. All the way from a single cell (1S) to 72 Volts (20S) are pretty common. I like the round wafers for single cells because they stack on top of the cell and don't take up much space. They sell on flea bay for a dollar alone and about two dollars in a kit with some heat shrink tubing, insulation, and wires.

For size reference, the Li-Ion batteries' numbers tell what size it is. A 14500 battery is the same size as a AA cell, and measures 14mm in diameter x 50 mm long. A 25500 is the same size as a C cell (25mm x 50mm). An 18650 is skinnier and longer than a single C cell.

06-06-17, 11:03 PM	#4
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	The battery banks in laptops have a dedicated BMS board inside. It is classified by the number of series-connected nodes (3s, 4s, 5s) inside the pack. Most boards are useless for repurposing due to the fact that they are married to the laptops they serve. Lucky for us, there are a bajillion generic BMS boards out there. You can get them long and skinny, postage stamp rectangular, round wafers, flat like paper, whatever. All the way from a single cell (1S) to 72 Volts (20S) are pretty common. I like the round wafers for single cells because they stack on top of the cell and don't take up much space. They sell on flea bay for a dollar alone and about two dollars in a kit with some heat shrink tubing, insulation, and wires. For size reference, the Li-Ion batteries' numbers tell what size it is. A 14500 battery is the same size as a AA cell, and measures 14mm in diameter x 50 mm long. A 25500 is the same size as a C cell (25mm x 50mm). An 18650 is skinnier and longer than a single C cell. Last edited by jeff5may; 06-15-17 at 11:51 AM..