Minicat 420 - liquid cooled - 20S1P Eve 105ah - JK bms, Flipsky 75350 ESC and 65161 motor - IP67 Build Project

[geppogp]

Good day Gents,

This is my first post be gentle. i'm in Montreal, QC. CANADA.

I'm design/building an IP67 Battery 20S1P made of x20 EVE 105ah + ESC75350 to power a flipsky 65161 motor that will then be used on minicat 420.
I'm aiming for max 1C -> 105A at 64Vdc nominal even though setup will be mostly use for fishing/trolling at about 1/4th of that max.

These are the components i selected (almost all from aliexpress) with the help of Deepseek, CHatGPT and Grok:

1. PELICAN 1610 case
2. x20 EVE 105AH lifepo4 CELLS
3. MOTOR FLIPSKY 65161 120kv with VX3 Pro remote
4. JK B2A24S20P
5. Dc to Dc converter 64v to 24v 10W
6. 280mm copper radiator and x2 IP67 Noctua 140mm fans
7. AAVID 6-73561-01 cooling plate (ebay now out of stock) + 1.5mm Thermal pad (Aliexpress)
8. Overload breaker Earu dc-mccb 125A 2P Type C
   
   
9. Disconnect Contactor TE EV200AAANA
10. Aluminum Tubes cut in half to make contain the cells.
11. 24V 10W circulation pump (waiting for return arrived damaged)

Total budget until now is roughly 3000k CAD. I'm doing this mainly to learn LFP batteries and possibly use it in case of outage, emergency backup power.

Photos shows the final BMS and ESC setting I will try first. Planning to mount motor on the front cross member of the catamaran and the battery will be on the extra trampoline in the front.

Photos attached of components , Current status of 3d drawing and BMS, ESC parameters currently selected.-> Build in progress, it will probably take me all winter before I start testing. (see 3d drawing current status).

For the cooling, Avid cold plate will be first then the ESC then out of the box to radiator in series .
I expect the pack to be around 50kg.

• Some AI suggested 2awg cable min and some 4 awg min (even sometime 6awg. i would like your input (2awg tinned copper iscurrenty on its way from aliexpress) to make it a legal and safe as possible. is 2awg too much.
• I have trouble finding 72v rated bus bars so was going to compression crimp connections directly with reducers. 75350 has x2 8awg per input line with make it approx 5awg (where you yo find compression fitting that size? to co to 2awg, such as a reducer.)
• Do you think motor can take 105a continuous at 64V nominal?
• I am open to suggestions for the impeller (i don't have a 3d printer). I believe the one that came with the motor is mostly for efoil.Irts got the 12mm pinned shaft. I will have approx total weight of 370kg. (50kg cat +180kg x2 fat fishermans + 50kg battery +motor + extra gear)

Thanks in advance!

• COMPONENTS RECEIVED UP TO TODAY
• 

3D IN PROGREES DRAWING (i'm figuring out how to push down sells onto cool plate and avois shorts. Once i get the first draft of the cover i'll show you.)

 

[amberwolf]

If you're concerned with legality, you'll need to verify with your local marine authority but 48v is a typical maximum allowed system voltage.

As far as wire gauge goes, thicker is better for minimizing resistance to current (decreasing voltage drops within cables at high currents), but you will also require properly crimped connections that are then correcty bolted to each destination point.

When making the battery casing design, be sure that it provides proper compression across the large faces of the cell stacks, to provide the correct pressure per square unit of surface area per the spec sheet of the cells. If tehre is insufficient compression, the cells will swell from outgassing during use and charging, and the gas will begin separating the layers inside, decreasing their efficiency and capability and capacity, and causing the remaining still-connected surfaces to be more highly loaded, increasing stress on the cells more and more as time goes on and damage increases.

(the only cells that don't require this are cylindrical, as they are the only ones with this compression built into the cell structure).