Followed some of the assist builds for a while and decided to build one as well. I first intended to build an FD under the board stile assist, inspired by Bzhwindtalker.
Finally I changed my mind and went for a hip pack assist.
Components:
Motor: saite 6384, 130KV ~ 160$ incl. ship.& tax
Prop: FD 3 blade, 300ā¬
ESC: Harry VESC 18S, 140ā¬
Waist harness from ali:
https://a.aliexpress.com/_Eybhspu (I paid less)
Box: diys printed from foaming HT PLA, laminated over with carbon
Battery: diys 12S3P and 12S2P Reliance RS50 Tabless, around 400ā¬ for both
Charger: iChargerX12 200$
Cable: 3 core awg 13 coiled cable from ali
Remote: Bremote V2nano
Box
I designed a box in fusion 360, the sidewall part was printed in LW-PLA-HT to reduce weight. The top part which mates the seal is from ASA, as well as the bottom with the heat sink. I also put spaces for square M4 nuts into the part to be able to fix the buckles. Laminated the bottom separately from the sidewalls and glued them afterwards. I also added carbon strips for stability and to get the box waterproof. I had to add a layer of glass at the inside as one of the screw holes was leaking.
The Heatsink was laminated into the sandwich of the bottom.
Lid
The lid was built from a 2mm carbon board and the inner part was printed in LW HT PLA (for the seal grove). Then glued and laminated. Inserts for the buckles were also linated into the printed part.
As a seal I use a 3mm epdm cloased foam sheet.
VESC mount
I put to 10x10 mm angeld aluminium profiles to the sides, close to the bottom. The are also screwed with M4 to Nut inserts. The VESC is clamped with M5 grub screws to the heat sink with a 5mm carbon frame that is held against the angeled profiles. It was tricky to install the vesc, I had to put the screws first on one side, install the VESC and frame, then slide in the profile. I could only righten 1 screw to fix the profile.
Connector
Designed and built a compact connector inspired by @hangloose. The contacts are 5.5mm, printed in cc3d pbt pro fibreglass filament, filled woth epoxy.
Battery
The battery was the hardest part as the box is a bit small for 12S3P battery. I used fishpaper between the groups to separate the cans and save space at the same time. The cells were glued with hot glue and taped before spotwelding.
Due to space consteaints I had to route back battery plus with a copper bar. To avoid a short, I put a 0.5mm fibreglass board between the cells and this bar. To connect the groups I used nickle plated copper feom ali express, the weld @25J with kweld and handle 200A.
I also added a ntc temp sensor which I connected to the VESC motor temp input. Like that I can log battery temp to metr.
![IMG_9679|375x500, 75%]
Remote
Bremote nano. I only wired ppm, water sensor and analog voltage as I used the single uart of the vesc to connect my old metr pro.
Pod
Pod was printed in PC-ABS.motor is a Saite 63100 with an original FD 3 Blade.
Harness
To fix the box to the harness I sewed hook and loop bands to a poece of 3mm neoprene whoch I wrap around the harness. I put my phone on top of the box to het the metr logs. I put some additional hoock and loop bands around to secure the box.
Tried it for 3 Seasions last weekend and Iām quite hapy with it, no water ingress, plenty of power and the batter does not get hot.
The box coul be a little bit bigger, it would be easier to fit everything in.
