Motor:
A brushless no smaller than 540-size should work fine on Paula 3. In-runner should have a proper reduction gearbox for higher torque output and power efficiency.
Battery & ESC:
You can use NiCd, NiHM or lead-acid battery to power brushless motor. Li-po is not the best choice for heavy duty application because its discharge rate is usually lower than NiHM or lead-acid. For instance, 4400mah implies the battery can discharge at the rate of 4.4A for an hour. If it is a 15C battery, the maximum discharge rate would be 4.4 x 15 = 66A for 4 minutes (60/15=4). 20C would be 4.4 x 20 = 88A for 3 minutes. If your motor (brush or brushless) drains more current than the Li-po can handle, the battery would be cooked. In the worst case, it would burst into fire and toast your boat. Therefore, the choice of Li-po and ESC is highly dependent to your choice of motor.
Besides, Li-po would be permanently damaged once they're shorted (the risk is high in case of boating). Since Paula 3 is not such a tiny boat, it should not have weight problem that requires the use of Li-po.
Although I'm a Li-po supporter, I must admit that the use of Li-po requires extra caution. |