I need a 12V motor that will allow me to raise and lower a 40kg weight over a height of approximately 1.2 metres, over a duration of around 10 - 20 seconds. When lowered, the weight is fully supported externally, but when raised it needs to remain raised without drawing current so as not to flatten the battery source. I was thinking something like the150:1 Metal Gearmotor 37Dx73L mm 12V with 64 CPR Encoder. I would hook this up to a h-bridge controlled by an Arduino. The power supply is a 12 volt Lithium 126AH battery. It is envisaged that the weight only needs to be raised and lowered once each day. Would this motor suit the application?
Just confirming were you looking at this motor here? 150:1 Metal Gearmotor 37Dx57L mm 12V (Helical Pinion) | POLOLU-2829 | Core Electronics Australia
If you were to balance the object with another 40kg mass that means that you only have to overcome the friction in the system (and any momentum in the system) - this also keeps the object still when raised.
Do you have a pulley in mind? All ‘levers’ are multiplied together to get your final torque and speed.
Without jumping into the math there is always the buy-and-try technique!