Izits
100 W
My laptop uses a standard 6-cell Dell T54FJ battery. Looking for a replacement, I was astounded to find a new one costs $140. Thanks to what I learned at Endless-sphere.com, I replaced the cells instead of buying a new battery.
Equally dismaying was the fact that my old Dell battery only uses cells with 2.7Ah capacity. I had already been buying 3.5Ah cells for flashlights so the solution seemed obvious. (new Dell batteries now use 2.93Ah cells)
Genuine Dell battery price: $140
Genuine Dell battery capacity: 5.59Ah
x7 Panasonic NCR18650GA cells: $40.75 (+one extra)
Final pack capacity: 7.18Ah
These are the stock cells. Notice the sheet metal tabs between each pair of cells for balance charging.
I don't have a spot welder and didn't really want to buy one. So I opted to solder my new cells together. The trick was to solder wires to both ends of every cell without making the cells sit too far away from each other. There is a little leeway in the plastic case for length but not much. The only available space between the cells was where the button wasn't. So I was careful to solder the wire on the perimeter of the cells.
I reinstalled the foam insulation spacer between the cell sets and added some special protection anywhere I thought there was the remotest chance of a short being created through the shrink wrap of the cells. Finally, I soldered the balance charging tails back onto the circuit board.
Here is the finished case after being snapped back together. I didn't mention what an ordeal it was to get the two halves apart in the first place. Just keep prying away at it, they do eventually come apart and with surprisingly little damage. All said and done the battery worked like a charm.
I doubt this project would have occurred to me were it not for the great sharing of knowledge here at Endless-Sphere. My humble thanks to everyone.
Equally dismaying was the fact that my old Dell battery only uses cells with 2.7Ah capacity. I had already been buying 3.5Ah cells for flashlights so the solution seemed obvious. (new Dell batteries now use 2.93Ah cells)
Genuine Dell battery price: $140
Genuine Dell battery capacity: 5.59Ah
x7 Panasonic NCR18650GA cells: $40.75 (+one extra)
Final pack capacity: 7.18Ah
These are the stock cells. Notice the sheet metal tabs between each pair of cells for balance charging.
I don't have a spot welder and didn't really want to buy one. So I opted to solder my new cells together. The trick was to solder wires to both ends of every cell without making the cells sit too far away from each other. There is a little leeway in the plastic case for length but not much. The only available space between the cells was where the button wasn't. So I was careful to solder the wire on the perimeter of the cells.
I reinstalled the foam insulation spacer between the cell sets and added some special protection anywhere I thought there was the remotest chance of a short being created through the shrink wrap of the cells. Finally, I soldered the balance charging tails back onto the circuit board.
Here is the finished case after being snapped back together. I didn't mention what an ordeal it was to get the two halves apart in the first place. Just keep prying away at it, they do eventually come apart and with surprisingly little damage. All said and done the battery worked like a charm.
I doubt this project would have occurred to me were it not for the great sharing of knowledge here at Endless-Sphere. My humble thanks to everyone.