I'm investigating options to power a small trolling motor, which is designed to be used with a 12V lead-acid battery.
My main constraint is weight, and from the research I have done so far it looks like Li-ion batteries have the highest energy/mass ratio, so this would potentially be the best option for getting the most power in the smallest package.
So I am comparing to a commercial LiFePO4 battery with the following specs:
- Voltage: 12.8V
- Continuous Discharge: 40A
- Capacity: 40Ah
- Weight: 5.9kg
So for instance, if I look at a Panasonic NCR18650B, with the unit specs:
- Voltage: 3.6V
- Continuous Discharge: 4.9A
- Capacity: 3.4Ah
- Weight: 47.5g
Then I have calculated that I should be able to configure these with 4 in series, and 12 in parallel to achieve:
- Voltage: 14.4V
- Continuous Discharge: 58.8A
- Capacity: 40.8Ah
- Weight: 2.28g
So it looks as if this battery would achieve more power than the commercial version, with the same capacity at less than half the weight.
So my questions would be:
What will happen if I connect a 12V motor to a 14.4V power source?
Is there some way to regulate the voltage coming out of the battery? I.e. can I have the battery output at 12V somehow?
If it is possible to convert the voltage, then is there a drawback to this approach? I.e. am I going to lose efficiency? Or what effects does this have on the system?
edit: The motor takes max 17A (204W) at top speed.