solar + lifepo4 on sailing boat

[Athena119]

Hi guys
I am planning a 12v system on a sailing boat. It should be simple, reliable and redundant - to ensure that it continue to function if one component fails.
The maximum power consumption will be 1500 w (via inverter) = 125 a (peak 200a ?) + max. 50a board
I chose one relay each: Kilovac EV200: 500ah - only 1.7 w hold power. BMS I probably to use the Ant. Not sure yet, maybe Chargery or Electrodacus.
What do you think?
Suggestions for improvement are welcome
Regards
Martin

P.s. sorry for my english

 

[newbostonconst]

Most people keep the starting motor not connected to the invertor/battery bank or use a switch when needed to connect them together.....I would advise leaving them 2 different systems but I am not a expert. I am guessing you want to be able to charge battery bank by running the motor?

Not sure why you are using a relay? (the ones you show draw a lot of power to just be enabled). They make many large switches that would do it. Unless you want to remotely control it, then the relay may be needed.

Good luck..

 

[Athena119]

the starter motor is connected to a lead acid battery. The alternator is connected to lifepo4 but there is a switch. I have to test it if it gets hot while loading.
I don't trust the ant bms to stand strong currents, thin cables and no heat sinks. I think it is safer with a relay.

 

[mndare]

Hi guys
I am planning a 12v system on a sailing boat. It should be simple, reliable and redundant - to ensure that it continue to function if one component fails.
The maximum power consumption will be 1500 w (via inverter) = 125 a (peak 200a ?) + max. 50a board
I chose one relay each: Kilovac EV200: 500ah - only 1.7 w hold power. BMS I probably to use the Ant. Not sure yet, maybe Chargery or Electrodacus.
What do you think?
Suggestions for improvement are welcome
Regards
Martin

View attachment 8554P.s. sorry for my english

The solenoid cannot be controlled by that type of BMS. Whole other thread about this issue

 

[Itsasprinter]

Why use 60 amp BMS's with these huge batteries? I'd try to get appropriately sized BMS's and then you won't have to worry about things overheating. I'd get rid of the relays and switches and instead use circuit breakers on the batteries.
Redundancy and fault tolerance are great but simplicity is nice too. If you use one charge controller you simplify things considerably. Carry a spare. If the active CC fails it will take you about an hour to swap it out and you end up with your full power generation.
Make sure your alternator can deal with the LIFEPO4 batteries!!
Are you planning to install the panels over the cockpit or hanging over the transom? Make sure you take boom and sail shading into consideration when doing your math.
Good luck! I hope you plan some fun cruising!

 

[mndare]

My BMS's handle 150 amps.

 

[Athena119]

I want redundancy to avoid a power failure if one component fails. This is important so that the autopilot runs and the beer stays cold
To operate this small bms with a relay, so i have all features of a smart bms which can be load / unload up to 500 a for about $ 100
Will shows in a video the same principle for a small bms with operating a large inverter and I think if the bms is not loaded with high current, it is better for longevity.
2 small solar controlers cost the same as a large one but so I don't need a reserve device.
I’m planning to install the panels over the cockpit and on davids. Sometimes there will be shadows on the cockpit. I have to use every free space.

 

[aybabtme]

To connect your alternators to the LFP batteries, you'll need to be careful. You need something like the Balmar external regulators to prevent the alternators from burning up. Better keep the alternator disconnected if you don't want to change/upgrade them (it's at least 1000$ a pop), or use a battery-to-battery charger like the new Orion Tr "Smart" (Smart is important, the old models don't support charging LFP) but then this b2b charger maxes out at 30A. The Sterling Power battery-to-battery chargers can push more amps but are also a lot more expensive (and not as cool as Victron).

 

[MisterSandals]

Why are you running your panels in parallel? Shading?
If you run each of your arrays as a series of 3 panels, your voltage will be much better for the MPPT function of the 100/30. They are optimized for high voltage.

Just a thought.

 

[Athena119]

there will be a switch between the alternator and the Lfp battery. Then I will test how strong the current and whether the alternators will be hot.
Then I can decide to use a b2b or not.
The panels running parallel because somtimes there is shadow but it's 24v panels

 

[DeValency]

there will be a switch between the alternator and the Lfp battery. Then I will test how strong the current and whether the alternators will be hot.
Then I can decide to use a b2b or not.
The panels running parallel because somtimes there is shadow but it's 24v panels

I’m doing the same upgrade on mu cutter 43’. However, quickly realized that I must separate completely the cranking and backup batteries that will stay AGM - especially the alternator charging from the house bank. LFPs love using almost all the current possible and create an overload or worse on a standard alternator without a heavy and expensive external alternator regulator etc etc. Way too complicated and calling for trouble.

So the solution I’m looking at is keeping the present system as-is. Add a modest DC/DC charger controller (can actually even use a good solar MPPT charger controller) to separate the two banks. All the charging sources will only be connected to the existing cranking/backup AGM array, as well as the bow thruster and windlass. The new house LFP array will be fully separate and independent of the former, except the DC/DC setup, including the full BMS, temp controls etc. Simple and (at least to me) looks more reliable.

Comments are more than welcome!

 

[Athena119]

I don't want to change everything to 48v. The electrical system runs on 12v. It is a catamaran: 2 engines - 2 alternators. The space for solar panels is limited. I want to use these panels: 6 x 150 + 1 x 100 = 1000w. That is the maximum possible. I would like to get by without a generator.
The biggest consumer will be the washing machine: 1500w / 220v, watermaker 50 A / 12V and windlass. These will not run at the same time.
I agree: it should be simple. So I will do it without relay but 2 batteries with a 120 a BMS each as shown here.
Maybe i will change this plan again. It takes another year, unfortunately....