I built my eSkate with a 6374 and a pack off lipo 2x4s 5,3A
For this battery it was a 12s8p of 30q running 90A (vesc max setting) constant discharge
Could record pack temp during load , but after back to shore it was hot to hold and switch the packs
Module are professionally made in Petg and fully tested under high load and vibration but NOT mid load and hard crashs, i believed that was the problem, heat building up over 10-15min
Clearly overheated and melted , always better than my lipo taking fire and pushing the top of my case …
Hi OKP, I am struggling with my 75200. Everything fine in air with no load 16000 ERPM but Impossible to get more than 50 Amp in water ( Flipsky prop) and 5000 ERPM only. As it is the potted version I can’t see whether I have one of the bad resistors serie ( purchased on BG). I should have bought a non potted version to have acces to the resistors and immerse it in Corrosion-X as recommended by @Flightjunkie ( potion magique ) Some succeed with this ESC but I am near to give up and move to another ESC…
The primary parts of the battery box are done. They are PETG with fast printing quality and I will just use them for the structure and thickness. I will epoxy glass fiber inside and carbon fiber outside. This will bring the strength of the box. I could even go for Aramide.
To ensure I’m bulletproof with the battery pack. I will make some drills between each cell (on the PETG cell holder) and fill with high temperature silicone. This will make the pack ROCK solid… up to 1100°C.
not sure it’s necessary but I have as well another option which is to pot the battery with molding silicone that can last up to 250°C and up to 350°C. It’s not so expensive for 1kg. This may bring more heat than anything else at cell level; that’s why I’m not 100% sure about going this route.
Hello Cedric,
Nice progress on your project. Personally I think that the potting of the battery cells can be a source of heat rise…
Concerning the propeller : can it be mounted without modification on a Flipsky 65161 ? Can you tell us the outside diameter of the propeller base?
Thanks
moving ahead, I’ve drilled small holes and started to pour some high temperature silicate & silicone. This will ensure strength in the pack and avoid any cell collision should things go mad.
following a PM, I decided to stop putting the silicate as this would act as a heater. I will finish to weld the pack with the nickel as I believe, it will be strong enough anyway. Using silicate/silicone was just a bad idea.
Hey @jeffM Jean Francois, do you have any insights about my battery pack structure? do you think it will handle shocks fine once fully welded? For the box, I’m also thinking about building one in AIREX that I will full reinforce with composites (carbon/GF) and that will be probably stronger. Not sure I’m overthinking here.
For all, as a side note and ass I’m outsourcing the BMS; I plan to add an adhoc temperature monitoring by drilling the battery box and to see how high the temperature went after a ride.
However, enlarging the 12mm shaft hole requires a slow and careful procedure to ensure that the enlarged hole is not crooked or off axis. I think it is better to use a cutter instead of a drill (the cutter has a larger number of cutting edges). If a crooked or off-axis hole is still created, this defect can be corrected with additional modifications.
I am going to measure the propeller and publish its actual parameters (efficiency, thrust, …). Now I am waiting for a motor suitable for testing. I hope to be able to make the measurements before Christmas. Then I will refine the hydrodynamic shape of the propeller a bit, then measure the efficiency again. There is some hope that after increasing the efficiency it will match the hydrodynamic parameters of the FR propeller. Increasing propeller efficiency is a great hobby of mine.
Do you have the internal dimensions of the box? I only see external dimensions
This is the raw dimensions my pack; but I would need a bit more of course to accommodate the Amphenol connectors and RS232 cable… and also the 200A fuse; but that’s not such a big deal (let’s say +3 cm on any side of the box). For the height. These are 21700; so 7cm and a bit of extra space for the welding and wires.
@Thom I believe your box may fit if I go for 14S8P (instead of 9P). That would save me A LOT of time but I’m going to loose 1P (4000mAH) but still it’s going to be a tight fit. I may need the same box, but a little larger (or longer) while still having 9mm height.
My Battery is a 12S10P and fits inside.
I had to cut some plastic parts inside the box bot overall it fits OK, with a Bluetooth Daly BMS + Antispark switch + fuse.
Also, to make sure everything is perfectly IP68 rated, I poored some Dielectric Gel inside.
yes but I believe you are using 18650 cells and not 21700 right. I know aluminium is conductive at a certain extend but I also think it’s a good heat dissipator. I could get this 400x300mm box and ensure everything is well isolated inside and at the very same time have more room for more air than just an ultra tight box.
what’s everyone view on using this IP40 box? I will make sure it’s waterproof with SIKAFLEX 11FC that will work perfectly on the joints.
It’s either this one in aluminium or this one but I will need to move from 14S9P to 14S8P
I could do a square box with airex and put composites or just use the 302x232 box and go for polycarbonate instead of ABS but I still don’t know its weight.
Internal size is limited to 273x198mm so even a 14S8P will not fit adequately.
ABS or PC should be lighter. If you don’t find one that fits, airex and glass is also an option but more work. It’s also safer to use an non conductive material for the battery box, just in case.
) Some succeed with this ESC but I am near to give up and move to another ESC…
