Kayak fishing fish finder battery made from portable car jump starter.

We assemble a DIY kayak fishing fish finder battery out of a car battery jump starter.
My current fish finder - Garmin ECHOMAP Plus 64cv --- amzn.to/36GvwuT
DBPOWER 600A 18000mAh Portable Car Jump Starter --- amzn.to/2Ju9mT0
OliYin 2 Pairs EC5 5.0mm Male Female Banana Connector with 12awg Silicone Wire 3.93 inch RC Hobby Lipo Battery(Pack of 2) --- amzn.to/2YiwJmB
Uxcell a12110200ux0689 Waterproof Connector Cable Gland --- amzn.to/2DYMKGU
LEDJump 18AWG Wire Gauge Male Female Plug 2 Pin LED Waterproof Connector Cable --- amzn.to/2E1J9HR
INNOVA 3320 Auto-Ranging Digital Multimeter --- amzn.to/2YlBM66
Monoprice Weatherproof/Shockproof Hard Case - Black IP67 Level dust and Water Protection up to 1 Meter Depth with Customizable Foam, 8 x 7 x 6 in (2.88 liter cube) --- amzn.to/2LH3WqK
Hopkins 47965 2-Pole Flat Extension --- amzn.to/2VbFKfB