"No Load" current draw?

[TheShaughnessy]

I was setting up an eagle tree logger for use in a boat of mine and during the testing I noticed that just to turn the flex and prop the power system pulled about 10 amps, there are no binds and the flex spins freely by hand, also the set up ran without any heat issues the last time I ran it.
This particular set up was a PB1800 motor T120 esc and a 4s 5000mah 50c lipo.

Has anybody tested their current draw on any of their boats without them being in the water? I was expecting a couple amps but 10 just seems like too much.

What would be the best ways to lessen drive line drag? Currently i'm running .150 flex without a teflon liner, flex shaft was polished with 2000 grit wet/dry and then polishing compound. Bushings in strut were "broken in" with some oil and using my drill to turn a flex in there. Stuffing tube bend is as gradual as is practical.

[Tamelesstgr]

Before I had my EagleTree units I had a Watts Up meter. Newb that I was I didn't realize that the recordings I was seeing on the bench would be far different when the prop was actually in the water. Pretty similar results found in this video. I would assume the "load" would be higher actually running on the pond versus holding the boat in the tub.

https://www.youtube.com/watch?v=HrC9oVTBIM0

I think your driveline setup is fine, very similar to what many folks do.

[runzwithsizorz]

Before I had my EagleTree units I had a Watts Up meter. Newb that I was I didn't realize that the recordings I was seeing on the bench would be far different when the prop was actually in the water. Pretty similar results found in this video. I would assume the "load" would be higher actually running on the pond versus holding the boat in the tub.

https://www.youtube.com/watch?v=HrC9oVTBIM0

I think your driveline setup is fine, very similar to what many folks do.

Might not be true, for on the pond nothing is holding the boat back???

[Fluid]

An electric motor with little to no load is very inefficient, and converts virtually all its energy to heat. Much of the amperage/wattage the OP saw the motor drawing is being converted into heat, not mechanical energy.


.

[srislash]

Well I just went out and tested my Pursuit with CC 1515 and got 11.5'ish amps. Then I tested the fresh S bend in my rigger with CC 1415 and at first spiked 38 amps but at a steady throttle it was 3.97amps. Both on EagleTree and 4s pack

BTW: I think I'll be testing a few more, just cause I can.

[TheShaughnessy]

I did some messing around today. The motor without a flex or anything attached pulled about 2 amps. I cleaned up the flex one more time and made sure it turning freely by hand. I tested again and it spiked to 10-11 but then settled down to 4.5 ish. Only problem was i noticed there was some cable whip going on. I ended up shimming the stuffing tube with next smaller size k&s tubing I drilled a bunch of 1/16 holes in it to uhhh hold grease better? not really sure why but it seemed like a thing to do. I only went in as far as the bend and then put a short piece of teflon the remaining length. What I noticed was the amount of grease would also affect the current draw, freshly packed with ProBoat grease the draw went up, I thought something was binding so I took the flex back out, wiped it off and checked "freeness" by hand again. Next test the draw went down.
I have now decided that it's as good as it needs to be and I may possibly switch to some thinner lubrication for race weekends.

[srislash]

In my fast boats I put a few drops of Duralube in the end of the stuffing tube with a hobby syringe, this loosens/thins the grease.

So how was the cable whip after? Your findings ring true with the rest of mine today but I found my one DF had some nasty cable whip too.

Shawn