New Boat System Design - Help!

[SolarSail36]

We are setting up solar panels and lithium batteries on our Lagoon 52. Overall, the plan is to start with 5 x 400 watt bifacials and 4 LiFe 460 Ah batteries (currently the boat has x6 210 Ah SLA and 360 w solar). I have a diagram (below) and a bunch of questions. Would love feedback, answers, and input.

• No. 1 from the Diagram: 200 A T-fuse for each pair - is that okay?
• No. 2 from the Diagram: The boat is configured with two parallel bus bars. I would like to bridge them with the smart shunt there instead of putting the smart shunt on negative, as all the batteries and all the other systems come together on one big negative bus bar. Will that work? Any issues? Show stoppers?
• No. 2 from the Diagram, again: would this be a good position for a 300 A kill switch?
• No. 3 from the Diagram: I assume all the MPPTs can be dropped right into the priority bus bar. Do these have to have a kill switch? Can it be a single switch for MPPT or does each one need their own? This would mean having to place a new bus bar for the MPPTs, however.
• No. 4 from the Diagram: The boat as configured has a 12 V kill switch in the saloon. This one gets quite warm and is a long run in and out of the salon. Is there a good way to upgrade this? One thought I had was to move the inverters to the priority bus but have a kill switch behind each one. This would decrease the current through that kill switch. Thoughts?
• No. 5 from the Diagram: The alternators are also tied to this priority bus. Given the change to LiPo I assume these will need to be disconnected?
• No. 6 from Diagram: The boat currently has a single Chargemaster 12/70-3. Obviously, not enough for LiPo, but we do want to keep it. However, how can I configure this for LiPo charging instead of SLA? The manual is not helpful.

Thanks all. Much appreciated. And if anyone is in the Fort Pierce, FL, area, let me know.

 

[robbob2112]

We are setting up solar panels and lithium batteries on our Lagoon 52. Overall, the plan is to start with 5 x 400 watt bifacials and 4 LiFe 460 Ah batteries (currently the boat has x6 210 Ah SLA and 360 w solar). I have a diagram (below) and a bunch of questions. Would love feedback, answers, and input.

• No. 1 from the Diagram: 200 A T-fuse for each pair - is that okay?

Better if it was a class T on each battery.

• No. 2 from the Diagram: The boat is configured with two parallel bus bars. I would like to bridge them with the smart shunt there instead of putting the smart shunt on negative, as all the batteries and all the other systems come together on one big negative bus bar. Will that work? Any issues? Show stoppers?

A few things, the shunt will indicate reverse current. Second is you need to make certain all power flows through the shunt. This would monkey with the way you hookup and switch thihgs. Not insurmountable but simpler to follow practices.

You need to draw your diagram showing both positive and negative to make it easier to understand.


And the last is I am not sure how the rest of the equipment will react, @sunshine_eggo is the King papa smurf and can answer that.

• No. 2 from the Diagram, again: would this be a good position for a 300 A kill switch?

Not really, same problem a kill switch needs to turn off batteries, solar panels, scc, and inverter.

• No. 3 from the Diagram: I assume all the MPPTs can be dropped right into the priority bus bar. Do these have to have a kill switch? Can it be a single switch for MPPT or does each one need their own? This would mean having to place a new bus bar for the MPPTs, however.

With three strings to three mppt you can bring them together in a combiner box and the have a single disconnect in there.

• No. 4 from the Diagram: The boat as configured has a 12 V kill switch in the saloon. This one gets quite warm and is a long run in and out of the salon. Is there a good way to upgrade this? One thought I had was to move the inverters to the priority bus but have a kill switch behind each one. This would decrease the current through that kill switch. Thoughts?

Simplest would be normally open contactors across the various sources of power and the switch on the dash just connects those coil positives to a battery. So the kill switch would be on for power to contactors and off removes it. You can have multiple kill switches by wiring them in series so they all have to be on to have power and if any one gets turned off and it kills power.

• No. 5 from the Diagram: The alternators are also tied to this priority bus. Given the change to LiPo I assume these will need to be disconnected?

The alternators will need to connect to a dc-dc charger for the lfp chemistry

• No. 6 from Diagram: The boat currently has a single Chargemaster 12/70-3. Obviously, not enough for LiPo, but we do want to keep it. However, how can I configure this for LiPo charging instead of SLA? The manual is not helpful.

no idea on this one

Thanks all. Much appreciated. And if anyone is in the Fort Pierce, FL, area, let me know.

The ABYC has a lot to say about power on boats, best to be familiar with it and understand the rules you should play by

Marine Electrical Certification - The American Boat & Yacht Council

abycinc.org

 

[Rocketman]

With the alternators…

The cheap answer is a Dc-Dc charger… but that will not charge very fast.

The charge fast answer is a dedicated regulator that can handle lithiums - Balmer, Zuse, and there is another that I can’t remember the name of. The issue is the regulators needs to keep the alternator from working so hard it burns up and safely keep the voltage in the proper range and prevent the alternator from dying if the bms cuts off.

Good Luck

 

[TimE]

With the alternators…

The cheap answer is a Dc-Dc charger… but that will not charge very fast.

The charge fast answer is a dedicated regulator that can handle lithiums - Balmer, Zuse, and there is another that I can’t remember the name of. The issue is the regulators needs to keep the alternator from working so hard it burns up and safely keep the voltage in the proper range and prevent the alternator from dying if the bms cuts off.

Good Luck

That's a whole extra level of expense and complexity. With 2000w of solar, engine charging won't be a big issue. With a Victron Orion xs on each engine alternator, 100A charging will be available in a simple, relatively low cost way, allowing the use of simple lithium batteries with Bluetooth BMS.

 

[TimE]

We are setting up solar panels and lithium batteries on our Lagoon 52. Overall, the plan is to start with 5 x 400 watt bifacials and 4 LiFe 460 Ah batteries (currently the boat has x6 210 Ah SLA and 360 w solar). I have a diagram (below) and a bunch of questions. Would love feedback, answers, and input.

• No. 1 from the Diagram: 200 A T-fuse for each pair - is that okay?
• No. 2 from the Diagram: The boat is configured with two parallel bus bars. I would like to bridge them with the smart shunt there instead of putting the smart shunt on negative, as all the batteries and all the other systems come together on one big negative bus bar. Will that work? Any issues? Show stoppers?
• No. 2 from the Diagram, again: would this be a good position for a 300 A kill switch?
• No. 3 from the Diagram: I assume all the MPPTs can be dropped right into the priority bus bar. Do these have to have a kill switch? Can it be a single switch for MPPT or does each one need their own? This would mean having to place a new bus bar for the MPPTs, however.
• No. 4 from the Diagram: The boat as configured has a 12 V kill switch in the saloon. This one gets quite warm and is a long run in and out of the salon. Is there a good way to upgrade this? One thought I had was to move the inverters to the priority bus but have a kill switch behind each one. This would decrease the current through that kill switch. Thoughts?
• No. 5 from the Diagram: The alternators are also tied to this priority bus. Given the change to LiPo I assume these will need to be disconnected?
• No. 6 from Diagram: The boat currently has a single Chargemaster 12/70-3. Obviously, not enough for LiPo, but we do want to keep it. However, how can I configure this for LiPo charging instead of SLA? The manual is not helpful.

Thanks all. Much appreciated. And if anyone is in the Fort Pierce, FL, area, let me know.

Each lithium battery needs a class T or NH fuse and isolator prior to the busbar. Each battery need it's own dedicated connection to the busbar.
To measure SOC, the smart shunt needs to be on the main negative busbar connection to pick up the total battery load.
Unless you are going after market external regulator for each alternator with wakespeed or similar control and BMS interface, alternators need to connect to the engine batteries only. I am not a fan of alternator charging lithium but that's my choice.