New member systems questions.

[TBAILEY83]

I am having a 27 foot aluminum pilothouse boat built and in the process of designing my electrical systems. The following is an over view.

PROPULSION
300 hp main outboard, 25 hp kicker motor, 36v bow mounted trolling motor

BATTERIES
2x 230 ah lithium house bank
1x lithium starting battery
1x 36v lithium for bow mounted trolling motor

SOLAR
4X 319 watt 29v mounted on top of the cabin

12V electrical load
Lights, stereo, electronics, bilge, livewell.

120V electrical load
6 or 9k BTU mini split heat pump.

COMPONENTS
Victron 150/35 charge controller
Stealth charge on the run 12 to 36v charger for bow mount battery.
Applicable high quality inverter.

Couple of questions.

1. How long is 460ah lithium going to last when fully topped up with the mini split assuming it is running at an average consumption?

2. What is the best way to apply my power sources to all batteries? If I am running my motors main or kicker I would like to be able to apply that voltage to my starting battery, then house, then bow mount battery. The stealth charge unit will handle the 36v battery its a voltage sensitive unit that converts 12v to 36v.

I would like the solar and alternator voltage to be applied to my house bank even if both are providing power.

3. What is the best way to bring my motors alternator voltage through the starting battery eventually into the house bank?

4. Should I forgo the smaller starting battery and just add another 230ah lithium to the house bank? Protecting the motors alternators is a concern. Many people use a lead acid in line as a buffer but I do not want to deal with multiple battery chemistries if I can avoid it.

5. I will be camping with the boat in late fall, sometimes it will be below freezing. In the interest of not harming the lithium batteries I will purchase with low temp charging cutoff. Will the batteries still provide power to run the heat pump and warm the cab? In turn heating the batteries enough to safely accept charging voltage?

Any input on run time, components to add, or issues with the system input is welcomed.

Thank you.

PS I live in New York to give an idea of solar energy and will be using the boat from early spring to late fall.

[skipperpete]

I’m hoping 27’ is a typo..... and what’s a “kicker motor”?....are you talking about outboard motors on a trailerable tinnie? I’m unable to answer your electrical questions but would suggest that you’re going to need to wire the complete vessel with insulated earth, that means the engines need to be specially wired too . Apreamare made a 24 footer with more or less what your proposing, twin 200hp Yanmar 4LH inboards and a NL673 genset so its possible to cram all that stuff into a little boat BUT....if that 300 hp engine is an inboard diesel have you considered the amount of fuel required for even a short trip.
I’m sure the electrical questions can be answered by the members here but this is a cruising yacht forum, maybe try a fishing or powerboat forum for advice more relevant to your project.

[TBAILEY83]

This is indeed an outboard powered boat. The kicker motor is a small motor used to troll very slowly and save fuel and wear on the main motor. The reason I came here for answers is my build is more akin to a larger cruiser than an outboard aluminum boat. I also know that this crowd is the most knowledgeable when it comes to these types of systems. Most go fast powerboats do not have this type of install nor do the owners typically get their hands dirty for something like this.

[skipperpete]

Originally Posted by TBAILEY83

This is indeed an outboard powered boat. The kicker motor is a small motor used to troll very slowly and save fuel and wear on the main motor. The reason I came here for answers is my build is more akin to a larger cruiser than an outboard aluminum boat. I also know that this crowd is the most knowledgeable when it comes to these types of systems. Most go fast powerboats do not have this type of install nor do the owners typically get their hands dirty for something like this.

Yeah , I noticed too late that you mentioned outboards... and I’m sure the guys here that have hands on experience with complex electrical systems and recent technology battery installations can provide you with good advice.

[TBAILEY83]

Originally Posted by skipperpete

Yeah , I noticed too late that you mentioned outboards... and I’m sure the guys here that have hands on experience with complex electrical systems and recent technology battery installations can provide you with good advice.

Thank you sir! That’s why I turned to this community.

[NorthCoastJoe]

How much power does your mini split draw. In a residential version it's quite a bit of juice, 6.8 amps at 120 volts for 9K.

[TBAILEY83]

Originally Posted by NorthCoastJoe

How much power does your mini split draw. In a residential version it's quite a bit of juice, 6.8 amps at 120 volts for 9K.

From what I am reading it will average around 600 watts of current draw. I am assuming if I don't try and change the temperature of the cabin by a lot in relation to ambient temperature I can mostly stay below that. I am guessing another 230ah lithium is a wise idea. I am hoping in a marine environment never shrouded by trees the solar panels will have close to 1000watts of output on a sunny day. So if I up my house battery bank to 690ah of lithium I should get a good 8 hours plus out of the bank with no solar gain and no voltage input from the outboards.

[TBAILEY83]

I also have a honda eu2200 that when camping with the possibility of less sun or extended run times I can supplement with that.

[Pete7]

Originally Posted by TBAILEY83

I am having a 27 foot aluminum pilothouse boat built and in the process of designing my electrical systems. The following is an over view.

Couple of questions.

1. How long is 460ah lithium going to last when fully topped up with the mini split assuming it is running at an average consumption?

Totally depends on how much power you are using. 460Ah of LFP has a nominal 5980w available (13v x 460Ah). You don't want to really go below 10-15% and try to stay out of charging up the last 5%. This will give you the power available. Now calculate all your likely total loads on board.

2. What is the best way to apply my power sources to all batteries? If I am running my motors main or kicker I would like to be able to apply that voltage to my starting battery, then house, then bow mount battery. The stealth charge unit will handle the 36v battery its a voltage sensitive unit that converts 12v to 36v.

Keep the 36v separate. Use a DC>DC charger to back charge the engine start battery from the LFP.

I would like the solar and alternator voltage to be applied to my house bank even if both are providing power.

No problem, you just need to ensure there is some sort of external regulation on the alternator or you risk burning it. Wakespeed 500 is one such device.

3. What is the best way to bring my motors alternator voltage through the starting battery eventually into the house bank?

Don't back wire as above, if you want to charge the LFP from the outboards alternator.

4. Should I forgo the smaller starting battery and just add another 230ah lithium to the house bank? Protecting the motors alternators is a concern. Many people use a lead acid in line as a buffer but I do not want to deal with multiple battery chemistries if I can avoid it.

LFP isn't great as a starting battery. Stick to a sealed lead acid instead. You don't have to worry about cold temperatures then.

5. I will be camping with the boat in late fall, sometimes it will be below freezing. In the interest of not harming the lithium batteries I will purchase with low temp charging cutoff. Will the batteries still provide power to run the heat pump and warm the cab? In turn heating the batteries enough to safely accept charging voltage?

All drop in LFPs from the better makes will come with this. Consider heated LFPs if operating in cold conditions and intend to store or move it on a trailer.

Any input on run time, components to add, or issues with the system input is welcomed.

An aluminium boat is going to be a huge heat sick sucking any heat inside the boat away in double quick time. There is a reason tank crews sleep outside in a tent rather than in a tank particularly in winter. It sucks the heat away. So you need to consider lots of insulation at the build stage. Closed cell foam and lots of it. Also keep you cool in the summer.

Add some sort of battery monitoring would be nice. Consider Victron Cebu system. Pico Sigmarine is another. May as well include tank sensor monitors for fuel and water etc.

Thank you.

PS I live in New York to give an idea of solar energy and will be using the boat from early spring to late fall.

This will give you the solar yield for each month anywhere in the world. Worth playing around with so you know what to expect. In southern UK we see 75% of the average due to less than ideal panel angles, clouds etc.

https://en.sunware.solar/systemsize/daily_yield#tabelle