Emax Nighthawk 250 V1
4 x DYS 2204 2400kv
4 x DYS 20A BL Heli ESC
Naze32 REV6 6DOF version
CC3D mini Power Distribution board
Hobbywing 3A UBEC
Battery is 35C 3s 1500mah.. one cell dead now
The video below shows that the motor pulls a max of around 155 Watt on a dys 5045 propeller on bench test(don't know if it's a 2 blade or a 3 blade one).
So, if we use a 5030 2 blade prop, ESC will be safe(Some dys ESCs like XM20A V2 support 3s and 4s only. Ensure your particular model supports 2s). Worst case: 6.6V @ 155W = 23.5A. On a two blade 5030 flexible prop like the gemfan ones, max power should be well below 155W. (Do you have any 5030 2 blade props lying around?)
This brings us to 23.5x4 = 94A required current. This is the absolute max required. I expect we may not pull 94A at all. A motor on bench test pulls more current than on a quad.
Assuming that the 1500mAh 35C rating is correct(which may or may not be true), we have 35Cx1500mAh=52.5A for a "3 cell" battery. Depending on the battery brand, age, wear, etc. this number will be very less.
The numbers do not look promising. But, there are way too many factors and assumptions that we can't possibly model mathematically.
If you have plans to use the 2s LiPo for any other application, I would suggest not to try this.
Otherwise, why not give it a try? At least, now that we know you won't hurt your ESCs and the motors, you have nothing to lose either way. At max, the motors will try to spin and the battery gets killed. Just use a voltage alarm to let you know when to stop pushing it hard and you can still save the LiPo.
Regards,
Raj Gunaseelan James
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