Need a bit of help with system design/setup

sandog

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Hello. I know there is a lot of different threads trying to discuss this, but unfortunately none seem to fit my need close enough. I have a 65' power boat. It has two engines for prop power, smaller generators on them. It had one 20kw generator and one 5kw generator. Engine room is midship, and has bow and stern thrusters. The stern thruster, along with the batteries, are in the aft cabin. Bow thruster batteries are in the engine room.

All batteries need replacing. The engines and bow thruster I will run off of two 8d agm batteries. The stern thruster requires the same. Unless anybody has a better idea for this. The ship is 100tons, so the thrusters are a bit large.

Due to the need to take this on a 6000 mile journey, and just completing another 2000 mile journey on a different boat (52', 16kw generator and 2 MTU 900HP engines) I own where I had to run the generator nearly constantly, I have decided to make this boat much more self-sufficient for this journey.

I intend to add flexible solar panels to my hard bimini (16' x12') top (any good recommendations from aliexpress would be great). Also looking to perhaps add a wind generator. But looking to also add in ~20kw (+/- 5kw) worth of LiFePO4 battery banks (not looking to build from cells).

So my question is help with some of the suppliers, and any help with design considerations given I plan to have solar, wind, two different generators, plus AGm and LiFePO4 batteries.

I am sure I am missing out on a ton of details you will need to provide some feedback, but anything would be great!

Thank you in advance.
 

svsagres

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Based on the research I’ve done (looking at doing something similar, albeit for a much smaller boat), your best bet for a solid -the-shelf equipment is probably something built out of Victron components. Done right, the inverters, Solar charge controllers, batteries all talk to each other and provide you with a nice clean interface. The equipment is also pretty darned bulletproof.

I would still keep the batteries for your thrusters (and probably anchor windlass) AGM due to current requirements, but your house easily be off-the-shelf lifepo4.
 

Diysolar123

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the tricky part is always finding a "shade free" area for solar panels, some rigging, the tower, even a "little bird size" shadow seriously degrades the performance of a panel. No idea of the boat layout but make sure to take into account such things to get a better understanding how much solar you "really" can plan on.

the most efficient panels would be something like a maxeon3 at around 200W/sqm so with around (16'x12')17sqm in a perfect world you could get 3.4kW ..in, well, a perfect world hehe

as this is a marine application I would agree with others that you do not want to go for low bidder; get victron equipment which will cost a fortune...but you have a boat so you are used to that hehe
If you want to really cut down your power usage..put up a sail ;)
(of course the sails will keep blocking your solar panels because that is just what the wind wants to do)
 

svsagres

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the tricky part is always finding a "shade free" area for solar panels, some rigging, the tower, even a "little bird size" shadow seriously degrades the performance of a panel. No idea of the boat layout but make sure to take into account such things to get a better understanding how much solar you "really" can plan on.

the most efficient panels would be something like a maxeon3 at around 200W/sqm so with around (16'x12')17sqm in a perfect world you could get 3.4kW ..in, well, a perfect world hehe

as this is a marine application I would agree with others that you do not want to go for low bidder; get victron equipment which will cost a fortune...but you have a boat so you are used to that hehe
If you want to really cut down your power usage..put up a sail ;)
(of course the sails will keep blocking your solar panels because that is just what the wind wants to do)
My thinking for the shade thing is to use multiple smaller panels so that if one OS shaded, I’ve lost less capacity. Reality is, though, on a 27’ sailboat that’s setup for single handed work, most of my deck is taken up by lines and rigging. I’m looking at a pair of 60 or 80w panels on top of my dodger.

The reality is that when away from my dock, most of my stored power is going to come from hoisting the Iron Gennaker (aka burning dead dino juice). I’ll run a 70A alternator off my poor little Diesel engine.
 

sandog

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I am about done designing the system and am going all Victron. Will use multiple panels due to any shade effects. based on the two measurements, I am hoping to get about 5 kw solar. I think I am going to go and build 8 12v batteries, using 280aH cells, using Daly 250A BMS's. Batteries will be 12v, ran in series (will Daly BMS's, allow me to run them into series like that, or no?) and parallel, in two different sets, in different locations on the ship. So essentially it will allow me to have 24v, systems with a max discharge of 500 amps, in two locations (bow thruster (11kw) and stern thruster (11kw) at once. Though it makes it tricky as I really should not have the AC or induction cooktop running, as if those are running, I need to add another 12kw discharge, and at that point, it gets I think a bit trickier. Not going tricky on the inverter/chargers to auto select, as the ship is wired to manually select shore/Gen1/Gen2, and will just utilize that and save some money.
 

sandog

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It appears as though it is not a good idea to run BMS's in series. So I will convert it to a 24v 250Amp BMS, and run two packs in parallel in one section for a 500amp load and another 3 in parallel for a 750 amp load. This should give me enough power to run the bow and stern thrusters. Though if the AC units are running or the induction cooktop is running, power would still be an issue. If I run 5 packs, that is 36kw of storage capacity. I could run 7 packs and have everything easy but that gives me over 50kw, and seems a bit overkill. Any thoughts?
 

Adamberti

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You mentioned two things that seem to be opposing and might need some clarity to help others give advice.

1. You don’t want to build your own batteries from cells.
2. You want to use a Daly BMS

I’m a bit new around here (my system is designed, half purchased but not built), but my understanding is off the shelf LiFePO4 batteries will include their own built in BMS and you wouldn’t use an external one like Daly.

Please someone else correct me if I’m wrong!
 

jbird526

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I too am confused on the initial comment of NOT building battery packs and then speaking about DALY BMS's. Not sure I want to venture on the high seas with high amperage DALY BMS's as my main source of power.

I do agree going all Victron is a good idea as it is available worldwide and highly used in the marine community so support and replacement should be less of an issue.

Wonder though @sandog with the 5k in solar that you are contemplating if purchasing prebuilt 48v batts would be an option. https://shop.signaturesolar.us/products/48v-100ah-water-proof-battery-by-eg4

From the 48v house battery, you could run buck converters to step down to 12v where needed. 48v would be more efficient converting to AC and require smaller wiring. I saw another thread, I thought in the Marine forum, where someone was outfitting with 48v and stepping down where needed. For the thrusters perhaps localized 12v AGM batteries that are charged off the inverter with smart chargers? Not sure that last item is the best solution going from 48v DC to 120v AC back to 12v DC, just throwing it out there. Edit: Perhaps a Victron Orion 48v to 12v converter would be a solution to charge the AGM batts in remote locations.
 
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sandog

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I originally was looking at off-the-shelf LiFePO4 solutions for batteries, but it seems they add a decent markup over the DIY solution. Second, I would love to go to 48V solutions, but the DC-DC converters to run two 11kw loads @24v gets expensive, and space-consuming, quickly. If you have a good source, please share. For those heavy loads (bow and stern thrusters, and engine starters), as well as for cooktop (7.2kw, 220V), and the three AC units (2.4kw, 220v each) all cabling is already run for those. Though it is for a boat, it does not necessarily need to be rated for a marine environment, as it is a 20M boat and has areas that if water enters, there are bigger issues than the batteries getting splashed.

I looked at doing the AGM's for the thrusters as well, but they each require 2 sets of 8D, and they run about $750/battery. Initially, I was looking at going that route, but looking at the cost of cells and bms's, for a little bit more money, I get a great deal more capacity.

The rack-mount 48v packs, I love and would make the install much nicer but they do not appear to work for the needs.....

I am not absolutely needing Daly for a BMS, but they seem to be reliable and affordable.

I do appreciate the feedback, advice, and suggestions.
 

jbird526

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So think I may be tracking what you are doing now from a previous post.
So I will convert it to a 24v 250Amp BMS, and run two packs in parallel in one section for a 500amp load and another 3 in parallel for a 750 amp load. This should give me enough power to run the bow and stern thrusters.
Are the thrusters 24v? Sounds like they are.

You want to run 500amps through 2 250A DALY BMS's. I would want someone like @sunshine_eggo to chime in as to running that much power through FET based BMS reliably and often, as opposed to wiring direct from battery or high amp relay.
 

sandog

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So think I may be tracking what you are doing now from a previous post.

Are the thrusters 24v? Sounds like they are.

You want to run 500amps through 2 250A DALY BMS's. I would want someone like @sunshine_eggo to chime in as to running that much power through FET based BMS reliably and often, as opposed to wiring direct from battery or high amp relay.
The thrusters are 24v, Vetus, 110kgf, so about 11kw of current each. Though connecting them to the battery cells, rather than through a BMS for the short amount of use, sounds brilliant.
 

jbird526

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Though connecting them to the battery cells, rather than through a BMS for the short amount of use, sounds brilliant.
There are posts where others have done this. Have not done it myself as have not had to pull that much amperage. You should be able to find multiple instances and experts on the matter.
 

sandog

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Power System 01.12.21.jpgHere is what I have come up with so far for system design. I think, for the time being, I am going to go with dual AGM's, type 31 for the high-current loads to help simplify everything.
 

svsagres

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View attachment 79465Here is what I have come up with so far for system design. I think, for the time being, I am going to go with dual AGM's, type 31 for the high-current loads to help simplify everything.
Looks alright. The one thing I would change is to put a 24V|24V DC:DC charger between your LiFePO4 bus and your two sets of AGMs. You don't want to hard-wire the AGMs in parallel with your LiFePO4 except, maybe, have the option to do that in an emergency. The DC:DC charger will properly charge and maintain the batteries, as they should spend most of their time idle.

As far as BMS goes, check out the following thread on the Victron Community: https://community.victronenergy.com...nusos-driver-for-serial-connected-bms-av.html as you really do want your BMSs linked in to facilitate charging/management, and to make them available.
 

jbird526

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Looks alright. The one thing I would change is to put a 24V|24V DC:DC charger between your LiFePO4 bus and your two sets of AGMs. You don't want to hard-wire the AGMs in parallel with your LiFePO4 except, maybe, have the option to do that in an emergency. The DC:DC charger will properly charge and maintain the batteries, as they should spend most of their time idle.
Agree. Would think that while have seen many charge LFP with AGM charge profiles, the charging of the AGM batts by dedicated "chargers" would be more efficient and charge at the correct stages based on batt voltage.

As far as BMS goes, check out the following thread on the Victron Community: https://community.victronenergy.com...nusos-driver-for-serial-connected-bms-av.html as you really do want your BMSs linked in to facilitate charging/management, and to make them available.
There is also a conversation over here talking about BMS's that communicate with the Victron Cerbo GX. https://diysolarforum.com/threads/bms-recommendations-advice.33187/#post-407760

Would it also make sense to, when on shore or generator power, have dedicated AC to 24V DC chargers to the AGM's since those are for the thrusters? Maybe overbuilding? Just feel that the bow and stern thruster power is so important over whether you have LFP power for the microwave. :)
 

jbird526

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What LiFePO4 Alt Reg are you specifying here? Would the LFP 2 stage charge profile here be charging the AGM batteries be an issue? Assuming this is a 2 stage charge profile.

Screen Shot 2022-01-13 at 10.38.31 AM.png
 

sandog

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Why would I want a bms to talk to the cerbo, or what benefits would that offer me?
 

sandog

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Does anyone have thoughts on using the growatt 5k charger/inverter, 2 of them, rather than 3~4 of the victron 3k multipass charger/inverter?
 

svsagres

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I was looking at the wakespeed ws500 for this. Unless you have a better recommendation.
IMHO, those are the best available, especially in your configuration with two engines. It will allow the loads to be well balanced between the two engines.
 
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