Help with set up for Small Express Cruiser 12V Lifepo4

Hi guys, Im so happy I found this place.. I have been watching a ton of YouTube videos and reading but I had some specific question. I wish I could talk to someone and see if what I want makes sense. this seems to be the closest thing to it.

We use our 27ft Cruiser for a weekend at a time, have been planning a few 2-3 day trips.

I want to be able to use the AC(4-6hrs at the most per day), microwave, TV and some outlets to charge phone/computer while on the water. (not necessarily all at the same time)

So since I started researching I figured I could somewhere around 400-500ah battery.

AC is a 8000btu 115v/60htz Max Cool 5.4amp Max Heat 7.0amp

My space is limited, I have some room in the aft cabin. I would like to build the batteries vs buying to hopefully fit in that space.

Charging:
Boat stays in the water, and I have access to 110v and usually have it plugged and have my battery charger running. So I was thinking I could do the same with the LifePo4 since I will be back to the dock daily. and I want in the future to add a few solar panels for those 2-3 day trips.

is it possible to tap into the Main Shore Power from the Inverter/lifePo4 since everything I want to run is already in the 110v panel?

Im looking for a simple set up that I can later modify to be able to charge from alternators and solar, also possibly to increase battery ah capacity.

looking for recommendations on:
- Cells
- Inverter
- BMS
- Charger
- etc

Sorry for the long post.

thanks in advance for all the advice and thoughts.


Dan.

OK, let's try to get you an idea of how to size this thing.

Let's say your AC want's 7 amps, at 115v thats right around 800 watts. Lets be lazy and round up to 1000w. (That'll give you a power budget for other things)
So you'll want 6kwh of usable power (at 80%DoD) that means around 7.5kwh.

I have around 14kwh in my camper, it uses 16 280Ah Eve cells. (3.25V*16*280) = 14560
I have them wired in 8s2p, so it's effectively a 26v 560ah battery.
That pack is pretty big. If you used 8 of them, you'd have 7kwh.
I will say this: if you can fit more capacity in there, go for it.

For a BMS, I use SBMS0, but I think it needs more protection to be used in a marine env.

For inverter sizing, I'd look for a 2kw or bigger unit. You want overhead for things like a/c motor startup, etc. If you try to size it for say 1000w, you're probably going to have issues when the a/c motor tries to spin up.

Thank you Willo, I like that!
Im going to order (8) 280ah Cells.

any suggestions on marine 2-3kw inverters.

I'd check the charge rate of the pronautic if you're planning to use it for a large pack.
I haven't dug into the marine scene enough yet. Keep in mind that you'll want an ignition safe unit (so it won't spark up fuel fumes)
If I had to have a unit right now, I'd probably consider the xantrex marine stuff. I love my victron but I believe that my multiplus (which is huge) isn't rated as ignition safe.
I suggest keeping an AGM on your motor - it'll act as a buffer if you want to charge off the alternator. (The cut in/out of lifepo4 is hard on most alternators otherwise.)
I'd determine if you want to run 12v or 24v. Given that you may want alternator charging, you may want to just go with 12, but 24v means smaller wiring which is easier to work with.