Help with motor choice for 12s setup

[StevenBryant]

Hey guys

I am planning on building a 48 inch cat for racing 20min endurance offshore racing. I’m planning on running a Cobra cat from Elson Racing, Schulze 40.304 esc, I just need help on the motor choice and capacity to get me past the 20 min mark

SB


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[fweasel]

20min, wow. That's going to be a lot of batteries. Interested in seeing this build for sure.

[photohoward1]

Hey guys

I am planning on building a 48 inch cat for racing 20min endurance offshore racing. I’m planning on running a Cobra cat from Elson Racing, Schulze 40.304 esc, I just need help on the motor choice and capacity to get me past the 20 min mark

SB


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Well I just built one with that setup with a Lehner 3080/8 on 10s. With a 40-330 Schulze. X470 prop. Set up for sprint. Expect about 70mph on 8k to 10k mah. On 12s the prop would be smaller but the system would be more efficient. I would go with a 3080/9 on 12s and I think you are going to need at least 15-20k mah to any kind of speed. What speed do you expect? You could figure an amp draw and figure how much battery you are going to use at a particular amp draw for 20 minutes. Example I think. 20k mah batts at 60 amp draw you would use 18kmah of your batts.


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[Speed3]

I think running a twin setup is your best option, as the motors will share the load.

Leopard have a 700kv 4092. You can run a twin with that kv on 12s per motor. The props would be counter rotating 50mm. This setup will not be an amp hungry set.

Batteries 15000 to 20000 mah per motor at 12s. So you need a lot of batteries.

The props should be reving close to 30000 rpm loaded. This setup should allow you to run full throttle for 20 min. Water cooling have to be good and high current connector 8 mm I can imagine will help to keep the wire at manageable temperature.

[RaceMechaniX]

The question is how many mAh are you allowed and any other restrictions on paralleling or other? HK have some decent large 6S Graphene packs with low C rating. You won't need anything over 15C assuming you can run parallel cells.

[Peter A]

I am building a 46" mono for endurance (offshore). I am competing against gassers and races are usually 20 min and 1 hour. Last year I ran an Osprey on 10s 20000mah, using multistar batts and a TP 4060 580kv motor. This years boat will be running 12s (2x6s 20000mah multistars and a leo 5692 540 kv to start with, prop will likely be a prather 245 or 250. I may change the motor later for something around 400-450 kv but will just see now things go. Speeds are around 65-70 kph range, but still competitive against the gassers, especially when the water is rough.