Small Boat Setup

[Czy_Horse]

I'm getting stuff together to install a system on my fishing boat boat.
Each summer, we do 2 or 3, 7 to 10 day boat camping, fishing trips off grid on a lake in Northern Ontario, Canada. I want to be able to use the Electric Trolling Motor more often & longer.

I have the following:
-1 - Eco-Worthy 100ah LiFePO4 battery for Electric Trolling Motor & Electronics. From the BAT-BMS APP, the BMS Over Voltage trip is 15vdc, Recovery at 14.4vdc. I kept an eye on the Intial Charge, the charger stopped at 14.66-14.67vdc
-1 - 20ah 330CCA AGM Cranking (motor cycle) Battery for the 30hp 2022 Tohatsu c/w electric start, power tilt/trim. Outboard has a 15amp alternator output. Highest voltage I've seen on the old Deep Cycle battery was 14.6vdc. Outboard can be pulled started.
-2 x 100 watt solar panels on the Bimini Cover. Hoping for 8-10amps in full sun.
-20amp Renogy 'Voyager' Water Proof Solar Charge Controller. 'Default' setting is 14.2vdc. Adjustable from 12.6-16vdc in 0.2vdc increments.
-1 Voltage Sensing Relay, Fixed Settings - On @ 13.3vdc, Off @ 12.8vdc.
-1 Orion Tr 12/12 9Amp DC-DC Converter/Isolator. 'Default' setting of 12.2vdc. Adjustable approx. -15% to +25% with the adjustable potentiometer.

Theory of Operation:
-The Solar Panels willnot be used around home for day trips.
-Store LiFePO4 battery at 50-80% SOC. Charge to 100% SOC before heading out fishing. I have a LiFePO4 battery charger.
-When Outboard starts, the Cranking Battery Voltage drops.
-With Motor running, when the Cranking Battery voltage rises 13.3vdc, the Voltage Sensing Relay turns On.
-When the Voltage Sensing Relay turns On, the Outboard Alternator current charges the LiFePO4 via the Orion 12/12 9Amp DC-DC converter and continues to charging the 20ah Cranking Battery. VSR has a 1ma Standby Current draw on the 20ah Cranking Battery.
-When the Outboard is shut down, the Cranking Battery provides charging current until the Voltage Sensing Relay shuts off at 12.8vdc, disconneting the power to the Orion Tr 12/12 9amp DC-DC Converter.
-The Output of the Orion 12/12 9 DC-DC is connected in parallel with the Output of the Solar Charge Controller to the Eco-Worthy 100ah LiFePO4.
-Not counting trolling motor, I estimate the Max Continous Load on the LiFePO4 Battery, at 8amps (2- fish finders, 5- USB plugs Phone charging, 24/7 aerator, navigation lights, etc). Trolling Motor draws approx. 50amps at Max. Will not be used much or very long at Max.


Question
- What should I set the output voltages of the Renogy & Orion at?

 

[AnarchyJet]

I would skip the DC-DC charger. The charging system of small outboards are not very robust. Your 9amp charger will pull 11-12 amps plus other loads of the boat. The motor is only going to make that kind of power at high rpm. So if you do use the DC-DC, I would just put it on a switch and manually turn it on when longer runs are made at speed. Even then, a 30 min run will put 4a into your battery.
Try and add a couple more panels or a ground array to add when at camp. Do you have room for a second lfp battery? You could keep one at camp charging from a couple 100w panels setup while out fishing. Swap the batteries every day or as needed.