The other way around


Weight is 5086 grams.


Thats great. Not long ago i was looking at 15-16 20Ah lifepo4 pouch cells, i had a good deal on them. With around 315g each, thats about same weight as yours at half the capacity. Price for new was not much under 400€ if i recall well.


The good thing about these cells is that they are rated for automotive use. We will never find that quality in rc cells.


Update! The 100kv Alien is now ”shrink to fit” mounted in the all tube. Sits firmly. I added x layers of alu tape to the motor to get a dia that’s slightly larger than inner dia of tube. Then add fire to tube :slight_smile:


First spin!


Hi, Riwi put it in the water and you will see there is not enough torque. Also the max Amps I can achieve is around 15 Amps. I have 2 motors like this( Aps 56115 100kv from Freerchobbies-Mark Tan is the seller) and I tried them with 14S and 22S Liion battery. The Esc is Flier up to 22S 400A.
Please report if your motor works different.



What happens after you reach 15A?

What prop diameter and pitch do you use? Any pictures?

I will report as soon as I hit the water.

Br Rikard


The propeller stops. I can quite easily hold propeler with my hand. The proppeler is 4 blades prop from Pacificmeister and I tried also others.
I thought the problem is in Esc but I’ve realized there is a motor problem. I bought Sss motor 56114 360kv, there is no way I can hold the shaft with my hand. Also the current flow on sss motor bursts up to 30A for a second and then I cant hold it anymore. My next step is to measure exact max Rpm and torque of the motors and then I will decide for planetary gear ratio, because I am planning to use 22S battery. I build the hole hydrofoil on my own, and I had a plan of using direct drive, but I didnt manage to suceed.
I’ve posted some pictures few months ago, Rikard please check my previous posts if you are interested.


Battery update. Did a stress test of the batteries today. Got a 2,5kw pure sine inverter for 48V. Hooked up my heat gun and the vacuum cleaner. Maxed out on 2000W while monitoring the temperature with my FLIR. Excellent setup :slight_smile: wife loves it to since the apartment gets warm and clean.

These cells are amazing, VERY stable temperature. I pushed 50A out of a 42,5ah pack.

Cables reach approx 30 degrees Celsius. Might do an upgrade to 8awg.


30 degrees on 10AWG? Wonder what they will get up to with at around 80A…


Yes, guess that’s why people are seeing melted connectors. The FLIR is a good tool.


I noticed that my connectors get hot, but the wire is not nearly as hot. Never really bothered measuring it though. I have moved to crimping more now though so as to avoid any solder melting and shorting…
I’m also going to install a few temperature sensors to shut things down if they get too hot.


What connectors do you use? I use the xt150 and noticed that it needs some adjusting after a while to get max conductivity. The connector should feel really tight when connected/removed.


For testing up to 5 minutes, I was just using 4mm bullet connectors and HST connectors. For my large battery I have crimp connectors that bolt onto the busbars and then I will most likely use either Amass XT150 antispark or the amphenol surlok. I know that fliteboard is using the amphenol surlok on their battery (


exactly, i add this problem with my xt150 from hobbyking (see my post), plug unpluged, not adjusting: connector soldered under high amp on the last ride (last a couple months …)


i try to understand: room 20°C cables 30°C so +10°C for 50A that is not bad no ?
can you do the same with the cables twisted on each other (suppose to lower induction) ?


If it’s stays on 30-40 I guess I’m good. I need a new charger before I can run a longer test. The plan is to run through 80% of the capacity and measure temp during the test.


Thrust test one is done.

Everything works but I need a prop with higher pitch and/or bigger blade area.

140mm maxed out at 14kg of thrust using 35 phade amps (amps measured on one of the three phases of the motor). I used a digital fish scale to measure the thrust.

The fish-scale was connected to the torpedo using a rope. The rope was tied to the slot where the mast normally goes.

Video on


Has anyone done similar thrust tests using a scale? Can anyone verify that a measurement of approx 25kg is “correct”.



I used a digital crane scale to measure thrust- more than 30kg. With a 6384PG 100Kv and a 138mm prop cut down from yamaha. Direct drive with direct cooling. At around 3000W.