HDS7 or HDS9?

[Jxjones]

Originally Posted by JohnMckroidJr

Pretty cool to multi-purpose the high-end lithiums. Ever try any of the blue bricks off ebay? Must be using a different battery than the one in the photo or keeping the brightness super low. 10A @ 2A/hr = 5hr battery life.

Haven’t tried the blue bricks, but have to look into them...thanks! The battery in the photo is a 6 cell, 10 ah battery. Each cell charges to 4.2vdc, so a total of 25.2 vdc. This gives a total of 252 watt-hours. Plan to step this down to 12 vdc. With about 96% efficiency on the voltage regulator, this will give me around 242 watt hours. At 2 amps/hour, this should give me around 10 hours (242 wh/12 vdc/2 amps/hour = 10.08 hrs). Thinking about building a 441 watt-hour battery using 33, 35a-h 18650 Li-ion cells. This should give me around 16-18 hours on the water.