Slow build from Sweden

I’ve finally somewhat finished the mast and the battery build is up next. The battery will probably be LiFePO4 for safety reasons and I’ve choosen to use rather thick board, Lethal FSP PRO 5’3.

The mast clamping is made up of aluminium blocks which have been hand filed, stainless steel screws and stainless steel threaded bars with pipes to be able to apply a high tightening torque. The plastic covers are 3D printed with PETG with a coarse layer height and screwed in placed in tapped holes.

The cooling of the ESC have been modified like others where the two meanders are joined and the two back outlets have been closed. I chose aluminium screws and some high temperature/pressure plumbing thread paste to avoid any galvanic corrosion.

I’ve gone the pumpless route for watercooling. Instead the water is supposed to scooped up behind the front wing and travel up within an aluminum pipe and into the ESC via a plastic tube.

All stainless steel and aluminium contact have been treated with either silicone or Tikal tefgel to again avoid/minimize galvanic corrosion.

Thank you all for the inspiration and knowledge that continuously is spread in this community. I hope this can inspire others !



lycka till med bygget! Hopefully you finish it before the water freezes :crossed_fingers:I’m from Strängnäs (more correctly living rather than from… i’m French) would be good to meet for a ride if you also live in the neighborhood.

Merci beaucoup ! I plan to have it finished by next summer as I am currently designing the battery and I’ve not bought the cells or bms yet so we will see how long it might take… et moi je suis moitié français

Moitié Français c’est mieux que rien ! … just kidding sorry guys us French simply can’t resist a bad joke. my kids also half french :grin:
i’m curious about your battery design if you don’t mind sharing since I dropped my idea of powertools batteries I’m trying to research the best/cheapest/safest/lightweight/most simple solution. I really like the battery builds of Flightjunkie.

I dont think my battery will be either of the things you seek unfortunately, except maybe somewhat save. I’ve choosen to go with the iron phosphate chemistry as it has a high thermal stability as well as it can discharge high continuous currents. With some quick calculations I assume that with 16s8p, 51 V nominal, 3000 mAh per cell with 30 A continuous I would get roughly 35 minutes of ride time. I plan to 3D print the holders for the cells as well as a thin casing which will be laminated with aramid and glass fiber, probably with vacuum bagging. As for the BMS I’m thinking of using one from heltec 4S 8S 10S 12S 13S 16S 24S Lifrpo4 ternary LTO smart bms balance APP LCD RS485 – Heltec BMS but I’m not sure yet. Connectors will probably be amphenol surlok with some antispark switch to the ESC. I still have a lot to make decisions about. I will provide images and more info when I’m more close to done with the battery.

Hi, I’ve seen your build list and I see one thing that might be good to know and it’s the batteries. LiFePo4 they are very heavy and often have a low voltage and low max discharge current.
My diy battery is built from…

Hello. There is a big difference in weigth between regular Li-ion an LiFePO4 I agree. The cells alone for my battery will weigh almost 11 kg and a battery build with your suggestion with 14s6p would weigh almost 6 kg. I have a hard time weighing the additional safety with LiFePO4 opposed to a reduction of 5 kg… The suggested cells would also make the battery quite smaller which ofcourse is a good thing. How did you build yours, with BMS, thickness of nickel etc.?


Hello Pierre,
how is it possible that you enter the wires in the mast on the fron side and exit on the back side?
Is your mast completely hollow inside? I guess no, because of your picture with a cut of the mast where you tested your clamp.



The mast is a Gong V2 mast which is hollow. I’ve shortened the mast 150 mm, from 850 mm to 700 mm, and used that left over piece just to test fit the clamp. I wanted to reduce the bending moment on the mast and therefor I shortened it.

That is already the back side where wires go in.
You can see the end of the green strpe is actually in the middle of back void.

ahhhh :slight_smile:
Yes, now it makes sense and I see it.
There was some perspective missmatch in my brain…

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