Recycled Batteries

Two packs made from old (well - they were physically old but never used, so the cells should be in good shape) laptop batteries.

Not for the feint of heart... harvest the cells (by ripping the laptop pack apart while trying not to short it out!) and solder together. The larger of the packs is made from two 'slabs' of 2S2P (2 cells in series connected in parallel) cells that are rather convenient to use because only one wire connecting the 2 'slabs' was required.

For those not familiar with tinkering with batteries the multi-wire connector is a balance lead so that a fancy charger can ensure the voltage in all cells in the pack is equal (unlike non-balanced in which the charger only knows the overall voltage of the entire pack and can lead to some cells degrading faster than others).

Weights are around 205g and 385g and capacity is 2350mAh for the small and 4700mAh for the large. This gives around 2 and 4 hours on full power for lights such as my Hedgehog or a SquidLED.

For racing I'll probably use the large pack for headlight and small for older bar light (which requires about half the power so run times in this setup should be matched).