I’m still learning as much as I can, but need your help deciding on the right battery set up for my next surfboard build:
due to late night purchases, i’m stuck with the FS65161 100kv motor with the 10mm shaft, and will be using @superlefax’s prop (3D-printed folding propeller)
my goals are to provide maximum torque to help boost me from sitting still in water to catching up with a wave.
I also need to limit the amount of li-ion cells due to weight. I plan to use samsung 30T cells, which have a discharge rate of 35a.
With this motor and prop, would it be better to go 10s4p or 14s3p? or some other combo? due to balance issues, I need to distribute the batteries on the board:
Hi, i think 14s3P is optimal for the following reasons:
the propeller may have a higher rpm
the board can reach higher speeds
in the future you can replace the propeller with a propeller with higher efficiency (prolongs the sailing time) or with a higher thrust (when your weight increases)
I think you want a boost on start , top speed isn’t look for , any prop will take the motor to 100-140A for a good punch ( so discharge batt would be 100A ) 10s should be enough , after with cavitation on start , 14s isn’t needed I think ( not looking for a burst off rpm but more a nice torque )
Any prop past 2800rpm will pull nice
I guess 10s 4p better than 14s 3p , but the vesc will go with duty converting all that … both would work
What you want :
More than 2800rpm full throttle ( not 5000 as well )
Count on 10-30% rpm drop under load
Check voltage drop of cell under high amp
can you recommend another configuration with a smaller prop? I’m trying to get my shaper to mount the motor in the middle of a 3 inch deck with a small hump on the top. The motor/shaft would be angled downward slightly so the propeller doesnt come above the top of the deck.
I would consider dual motors with tiny props if absolutely required
A folding propeller can be designed in any diameter and with different characteristics as I stated in the first post …for speed, for efficiency, for thrust, or compromises thereof. The angle of inclination of the shaft determines what the maximum diameter of the propeller can be to fit into a given space.
In the first post I explained the advantages of the 14s3P battery (compared to the 10s4p). Now it remains to explain the main disadvantage of the 10s4p battery. This can be explained most clearly with this example: At the same surfboard speed, 40% more amps will pass through the wires between the battery and the motor than would be the case with a 14s3P battery. The 40% higher amps require larger diameter wires, larger interconnecting connectors.
Considering that most of the available suitable propellers are in the range of 6-7 pitch, and the target speed is probably rather moderate, can not see much point in going over 10s, actually 6s would probably be fine, its proven to work even in e foils to fly.
