Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

Yes, double the power for each 1kt increase in speed.

Current (and power) depend on prop loading---go slow, use small or use shallow pitch prop or use a pack voltage that is too low and you won't reach the current limit.

I don't use a brushless motor/controller, but the physics is the same.  I first used the stock 9.9" prop on my outboard.  If I still was using that, I probably wouldn't reach 200amps (@40-48v) due to inability to spin it fast enough to load it.  Since I'm swinging a 12"x12" prop, the loading is much greater with speed and at 48v, my controller draws 200amps.  If I were still running 36v lead-acid, I'd probably only get to 120amps.  Again, not a TS brushless kit.

 

YMMV-

 

-MT

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of THOMAS VANDERMEULEN
Sent: Tuesday, January 19, 2021 8:30 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

 

Ryan and Reuben:  Has anyone reported actually drawing 200 amps with their Thunderstruck 10kw motors?
I was just reviewing the data provided under another recent topic here, "New Prop 10kw Motor", posted by Peter running his Catalina 30 tall rig, Zephyr.  His table stated that in calm seas and running in excess of 5 knots, or roughly 75% of hull speed for a Catalina 30, he was using just over 100 amps
As has been stated in various topics here on this forum, drag increases at roughly the square of speed (depending on hull form, of course), so if Peter were to push closer to hull speed, power usage would increase.  But double?
I haven't yet committed to the main battery cables I'll actually be installing on my boat, hence my curiosity: was there a reason you mention 200 amps as a maximum to think about for the T'struck 10kw motor?
[-tv]