Upgrade to Lithium Iron Phosphate on RT27-OB NW edition

[Submariner]

LaZina just published the video on why and how we upgraded to LFP on our RT27-OB NW edition.

We have a single Lithionics 320ah battery that provides us with 240ah of usable capacity. All of that capacity is at 12.0 volts or higher. We also left 160lbs of weight on the dock with this upgrade, and regained 2/3 of the center lazarette space back. The port lazarette we gained another 1/3 more space.

This was by far, the largest project I've done on the boat. The most technical and complex. I was glad I hired Bruce Schwab at Ocean Planet Energy to work with me on this. He reviewed my design, provided configuration assistance, and also reviewed the final installation.

But now I can use the hot water heater on the boat and I don't need shore power when out boating. LFP batteries have no minimum charge requirement. So when paired with solar (I have 400 watts of Solar), it's a fantastic setup. When that sun comes up in the morning, by 7 am, my batteries are often already being charged by a couple of amps. As the day goes on, the amount of amps increases. LFP also does not suffer from being in a partial state of change.

I really hate running shore power to guest marinas as it's rarely convenient. I also don't like being reliant upon a guest dock to have shore power.

If you've got an RT27-OB NW edition, you are free to use this design, as-is, without modification... same parts, same battery, same fuses, same everything... as it's been fully vetted by Ocean Planet Energy and approved by Lithionics via a paid engagement.

We upgraded to Lithium Batteries / What it took to get there and how they work for us
https://www.youtube.com/watch?v=M7Z1lVW-t-Q&list=UU2KtMh8hFWqMp17nedTw-oA

More detailed info with copies to the electrical schematics can be found at our website.
https://www.letsgochannelsurfing.com/lithium
https://www.letsgochannelsurfing.com/lithium-techtalk

 

[Annie Time]

Martin,

Your work is always impressive. I like your upgrade but what to hear more about how you believe you killed the firefly batteries. As you know I upgraded to the fireflies as well. I don’t use mine in the same rigger as you but still need to chat about this more.
Are you going to the September rendezvous? If so this would be a great time to get into more detail. If not, we may have to chat on the phone.

Perry


Sent from my iPad using Tapatalk

 

[Submariner]

Martin,

Your work is always impressive. I like your upgrade but what to hear more about how you believe you killed the firefly batteries. As you know I upgraded to the fireflies as well. I don’t use mine in the same rigger as you but still need to chat about this more.
Are you going to the September rendezvous? If so this would be a great time to get into more detail. If not, we may have to chat on the phone.
Sent from my iPad using Tapatalk

I'll be at the Rendezvous in September. Always available by phone also. I'll email you something to look at.

 

[gregc]

Thanks! Been waiting for this one.

Interesting that nobody could vouche for the Skylla.

 

[Submariner]

Thanks! Been waiting for this one.

Interesting that nobody could vouche for the Skylla.

In the data sheet for the Skylla, it says this:

Li-Ion (LiFePO4) ready
Simple charger on-off control can be implemented by connecting a relay or open collector opto coupler output from a Li-Ion BMS to the remote control port of the charger. Alternatively complete control of voltage and current can be achieved by connecting to the CAN-bus port.

My take-away, after the fact.. The Skylla was designed for LFP only when using an external BMS. The LFP battery I went with has an internal BMS, meaning, there is no external communication with the charging sources.

I also didn't initially buy the Skylla for LFP. But I did think "oh, as long as it supports LFP, I should be future-proofed", and here lies my lessons learned.

 

[gregc]

Li-Ion (LiFePO4) ready
Simple charger on-off control can be implemented by connecting a relay or open collector opto coupler output from a Li-Ion BMS to the remote control port of the charger. Alternatively complete control of voltage and current can be achieved by connecting to the CAN-bus port.

My take-away, after the fact.. The Skylla was designed for LFP only when using an external BMS. The LFP battery I went with has an internal BMS, meaning, there is no external communication with the charging sources.

Ahhhh I had it in my head that the battery + internal BMS you chose can output CanBus, which was readable by the Skylla?

 

[Submariner]

Li-Ion (LiFePO4) ready
Simple charger on-off control can be implemented by connecting a relay or open collector opto coupler output from a Li-Ion BMS to the remote control port of the charger. Alternatively complete control of voltage and current can be achieved by connecting to the CAN-bus port.

My take-away, after the fact.. The Skylla was designed for LFP only when using an external BMS. The LFP battery I went with has an internal BMS, meaning, there is no external communication with the charging sources.

Ahhhh I had it in my head that the battery + internal BMS you chose can output CanBus, which was readable by the Skylla?

Back to the fine print...
Lithionics supports "CANbus telemetry in the RVIA RV-C format (M12)"
A quick search through Victron's community forum yields this response (copied from the Victron forum).

"Is it possible to connect the GTX12V315A CanBUS connector to a CerboGX?"

The short answer is no, not until Victron updates the Cerbo to understand RV-C. If that happens then yes.

Keep in mind the Lithionics internal BMS used in the GTX12V315A is their standard BMS providing limited data, useful with a charge profile. If you are also looking to display data on a Cerbo remote display similar to what the SmartShunt provides you would need the Lithionics external BMS which is not compatible with their GTX12V315A. Their external BMS provides much more data.

But at this point it's academic since Victron seems to have no interest in incorporating RV-C.

 

[gregc]

Back to the fine print...

Goood lord... ok.

Yeah, "Drop In"... surrrrrreeee......