Fishing boat electrifying, lead, lithium, solar, advice needed

[Maxxim]

Hello all. I'm new here on the forum, and also a newbie with lithium batteries. And sorry for my english, it's not my native lauguage.

I have a small fishing/trolling boat that runns with an 60hp outboard motor(17amp alternator) and also has a bow mounted electric gps motor. Have two lead acid batteries, one 80Ah for start and boat electronics, and a 110Ah for the electric motor.

The boat has some electronics, lights, separate Garmin sonar and chart plotter, and a Furuno radar etc.

I always try to keep the trolling motor battery(110Ah) topped up after a fishing trip with 90W solar panel(mppt contr), or with a separate battery charger. But the 80Ah start battery seems to be a little bit low on charge if the outboard alternator hasn't have much time to charge. Some fishing trips with much electric motor use and only short bursts with the outboard.

For next summer I wan't to update the system a little bit. Wan't to replace the trolling battery with lithium. Ordered cheap 100Ah LiFePO4 packs from china Aliexpress and a Overkill 120A BMS from US. But I want to keep the lead acid battery as start battery. I would like that it's possible to charge both batteries with the outboard alternator, solar panel and easily with a separate battery charger. But how is the best way to connect everything?

Would like to use existing parts and components I already have. But if they can't be used then I'm willing to make some investements. Advice on what to use and best way to connect everything is much appreciated.

- 110Ah lead acid battery
- 100Ah LiFePo4 battery
- 90W solar panel
- 10A MPPT controller
- Victron Orion-Tr 12/12-9A DC-DC converter
- Charging relay (max 125A)

My idea is to use the 110Ah lead acid battery as main/start battery that would be charged by the alternator, solar panel and an outside battery charger. And then use the Victron DC-DC converter to charge the LiFePO4 battery from the main battery. Any idea in this? I have no idea how the Victron would handle the sudden peaks that happen when the BMS shut off the charge.

Hope you get an idea of the setup, as my explanation may be little bit unclear.

 

[HRTKD]

I don't have a DC-DC charger but I do have other Victron equipment. If the Orion allows you to change the parameters then all you have to do is make sure the charge profile on the Orion is set to slightly below the charge parameters of the BMS (specifically the High Voltage Disconnect). The idea is that you want your charge source to control when charging stops, not the BMS.

The Orion may have a sensor on it that will keep it from trying to charge the LiFePO4 battery until the engine/alternator is producing sufficient volts.

 

[MisterSandals]

My idea is to use the 110Ah lead acid battery as main/start battery that would be charged by the alternator, solar panel and an outside battery charger.

If you mostly need to maintain a starting battery while in storage and can get by with a trickle, I recommend this. I set mine up 10 years ago and it just does its thing.

Wow, looks like they are making beefy ones now. Mine was small like .5 amps.

LSL Products / LSLProducts.com - Problem-Solving Gear & Gadgets

RV Battery Chargers, Boat Battery Chargers, Trickle Chargers, Sewer Fans, Battery Box Fans

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[Maxxim]

Thanks for the replies.

The boat is a trailer boat, that never stays in the water for long times. It's in water only when used. I store it in the garage normally and at winter times, but at our summer house I store it outside, so the solar panel is topping up the battery.

I would like to keep battery charging as simpple as possible, just by plugging a single powercord to the boat, and both batteries charges up.

Most need for external charging would be to the trolling LiFePO4 battery. The electric motor draw 40-50 amp at full power, but maybe something like 5-10 amp at moderate trolling speed. Or at casting fishing less than that in anchor mode or in slow drifting.

I don't even know if the Victron 12/12-9 is suitable to charge LiFePO batteries..? But the output voltage is adjustable.

 

[HRTKD]

Thanks for the replies.

The boat is a trailer boat, that never stays in the water for long times. It's in water only when used. I store it in the garage normally and at winter times, but at our summer house I store it outside, so the solar panel is topping up the battery.

I would like to keep battery charging as simpple as possible, just by plugging a single powercord to the boat, and both batteries charges up.

Most need for external charging would be to the trolling LiFePO4 battery. The electric motor draw 40-50 amp at full power, but maybe something like 5-10 amp at moderate trolling speed. Or at casting fishing less than that in anchor mode or in slow drifting.

I don't even know if the Victron 12/12-9 is suitable to charge LiFePO batteries..? But the output voltage is adjustable.

The regular Victron Orion Tr doesn't mention LiFePO4. But the Orion-Tr Smart, which is programmable, does mention charging LiFePO4.

 

[pollenface]

My brother uses a Minn Kota Ulterra motor (24v) basically as an anchor (spot lock) and an autopilot via Hummingbird GPS. He has 2x 110ah agms specifically to run the trolling motor with a 12-24v dc-dc charger and seems to never run out of power. I love his setup but he doesn't have solar.

I have no experience with programming Victron, but I could recommend a Redarc BCDC1225D as it has a selectable charging profile for a lithium aux battery and MPPT solar panel input.

 

[MisterSandals]

and seems to never run out of power. I love his setup but he doesn't have solar.

If he has enough battery and shows up on the water with them charged, he does not need solar. THIS is why its good to do the math before buying, so you end up with a solution that works.

 

[BroomJM]

I know this is a couple months old, but Neco offers a product in their "Genius" line that will charge 2 batteries, at 5 amps each, and you can specify AGM or Lithium chemistry, individually.