Hi,
Yes Li-ion cells are lighter but we were shooting for 30 watts which as im sure you know is 10 amps at 3 volts, 5 amps at 6 volts. With a 18650 cell setup, the run time would be less than 20 minutes for two cells in series. Maybe buy four cells and boost that up to 40 minutes, six cells maybe 60 minutes. Maybe someone has a sale.
Also, 5AHr should be the same as 4.5AH.
More ideas:
Insulating the cup would help reduce heat loss. Using a top cover would help too. Once all the heat loss is eliminated it takes only a few watts to keep it hot. That could make all the difference in a battery operated cup warmer (one that keeps the cup warm that is, not heats it up).
That also means it would be nice to have a way to adjust the power in the resistor, as with a pulse width modulator. That way if most of the heat loss is eliminated the power could be kept low and that means longer (much) battery run time and battery cycle life.
Yes Li-ion cells are lighter but we were shooting for 30 watts which as im sure you know is 10 amps at 3 volts, 5 amps at 6 volts. With a 18650 cell setup, the run time would be less than 20 minutes for two cells in series. Maybe buy four cells and boost that up to 40 minutes, six cells maybe 60 minutes. Maybe someone has a sale.
Also, 5AHr should be the same as 4.5AH.
More ideas:
Insulating the cup would help reduce heat loss. Using a top cover would help too. Once all the heat loss is eliminated it takes only a few watts to keep it hot. That could make all the difference in a battery operated cup warmer (one that keeps the cup warm that is, not heats it up).
That also means it would be nice to have a way to adjust the power in the resistor, as with a pulse width modulator. That way if most of the heat loss is eliminated the power could be kept low and that means longer (much) battery run time and battery cycle life.