Due to shipping restrictions we were not able to purchase the battery from Blue Robotics.
If this is the case for you, do not be alarmed. Building your own is not too difficult.
Here’s your shopping list:
Heat Shrink Tubing: https://www.aliexpress.com/item/Wide-180MM-Diameter-115MM-PVC-2-1-Heat-Shrink-Tubing-Battery-Wrap/32789619207.html?spm=a2g0s.9042311.0.0.ykJ102
Heat resistant tape: https://www.aliexpress.com/item/10mm-X-100Ft-Gold-High-Temperature-Heat-Resistant-Kapton-Tape-Polyimide-BGA-Free-shipping/32780815592.html?spm=a2g0s.9042311.0.0.ykJ102
10AWG silicone wire: https://www.aliexpress.com/item/10AWG-Flexible-Silicone-Wire-RC-Cable-10AWG-1050-0-08TS-Outer-Diameter-5-5mm-5-3mm/32832064351.html?spm=a2g0s.9042311.0.0.dDg5U3
Nickel strips: https://www.aliexpress.com/item/100pcs-lot-0-15mm-x-7mm-x-100mm-Quality-low-resistance-99-96-pure-nickel-Strip/32333149144.html?spm=a2g0s.9042311.0.0.dDg5U3
Eva foam: https://www.aliexpress.com/item/5pcs-lot-50-50cm-2mm-EVA-Foam-Sheet-Handmade-Sponge-Paper-DIY-handcraft-Materials-Multicolour/32366174527.html?spm=a2g0s.9042311.0.0.dDg5U3
Spot Welder: https://www.aliexpress.com/item/Free-shipping-by-DHL-POWER-787A-MCU-Spot-Welder-Battery-Welder-Applicable-Notebook-and-Phone-Battery/32510885967.html?spm=a2g0s.9042311.0.0.dDg5U3
XT90 connectors: https://www.aliexpress.com/item/Original-Amass-10-Pairs-XT30-XT60-XT90-Male-Female-Bullet-Connector-PlugFor-RC-FPV-Lipo-Battery/32774990373.html?spm=a2g0s.90423126.96.36.199YFG8R
JST-XH 4S wire and connector: https://www.lazada.com.ph/set-of-10-30cm-jst-xh-4s-lipo-balance-wire-extension-leads-cables-681849.html
For the batteries, we purchased them from a local vape shop. We couldn’t get the same brand as the ones used in the BR battery but we got an equivalent. The one we got was LG Choco: https://www.mistwoodvape.com/collections/power/products/lg-choco
On top of that, you will need a soldering iron, glue gun and PPE.
Here is the drawing of the battery assembly:
Note that this is a 4S6P whith means that you need to connect 4 banks in series to get to the required voltage (3.7V*4=14.8) and each bank has 6 batteries in parallel to get the required mAh. (3000mAh * 6 = 18000mAh)
Here is the pattern we chose for this project:
Here are some fabrication pictures and the finished product: (be kind its our first try)
After building this first battery, I found that the shrink wrap we got was a bit too wide, I would recommend a smaller diameter to do a nicer finish.
Note that the fitting inside the 3inch enclosure is tight so you have to keep everything as low profile as possible.
If it’s of any interest, I can put a link of the final procedure and job safety analysis. Let me know.
In conclusion, it would take 3 batteries for us to break even. I would still recommend BR’s battery if you can get it shipped. There are considerable risks involved in making this. Make sure you know what you are doing, never solder directly on the batteries and protect the contacts with electrical tape when you are doing your manipulations.