Adding LiFeP04 to 35 ft Cruiser

[Juanvaldez]

My system is currently as follows:

300 Watts Solar
Diesel Engine with 100amp alternator
Victron 100/20 mppt smart controller
Xantrex Freedom X 1000Watt inverter
3 x FLA house batteries
1 x FLA starter battery

Replacing the house batteries with 2 x 105 mah DYI batteries using EVE cells from Jenny Wu at Docan

From what I read so far I think I want/need:

1. Remove the Auto battery combiner and leave the starter FLA battery isolated
2. Add a dc to dc charger from the starter battery to the Lifep04 bank. Have alternator to starter battery only.
3. Add a victron smart shunt to lifep04 bank. Use the auxiliary on smart shunt for the starter battery voltage input
4. Add victron smart Battery sense to lifep04 for charge temp protection or is this redundant and covered by mppt controller or bms?
5. Run solar and shore power charging to lifep04 bank only

I have interior lighting, cell booster and a small fridge on the inverter. All the rest of the boat on 12vdc. Sail mostly weekends up to a week out at a time.

Does this seem like a reasonable way to power it with Lifep04?

Thanks for any advice

Cheers

 

[svsagres]

A few questions:

1. What are you planning on using as a BMS?
2. How are you handling charging when shorepower is available?

The system we're building out for our Ericson 27 sailboat will have as follows:

• 460AHr of LiFePO4 (230Ahr batteries in a 2p4s configuration)
• REC Active BMS to manage said battery
• Victron Inverter/Charger for shorepower charging + 120vac at sea
• 120W of 24v solar (just not much room on a 27' sailboat that's rigged for single-handing)
• 80A alternator driven by an advanced regulator, directly charging the LiFePO4.

We have 12V refrigeration (icebox conversion), so based on our current usage patterns, the 460AHr will give us 5 to 6 days of power until we run the engine again. We're not energy misers, but also not crazy users either, so your 200Ahr might be a little light.

But I also recognize that we're going whole-hog for the high end/integrated solution, which isn't suited for everyone, or for their budget.

Depending on what BMS you're using, that Smart Shunt is likely to be redundant. The main reason to keep it around is that the SoC calculations of many of the cheaper BMSs is woefully bad.

Down the road, I'd also look at converting your alternator to external regulation, then using an advanced regulator (Ideally Wakespeed, but Balmar also works) so you can push as much current as your alternator can safely generate into your batteries. For the 80A alternator on our boat, it cost us $140 to get it rebuilt and converted to external regulation (new rectifier, new bearings, and general cleanup/paint).

 

[sailingcal21]

I have a similar setup. But have only PV charging for the LFP bank and using the shore power/alternator for the FLA bank. I plan on installing a DC-DC converter to the LFP bank in the future.

 

[Juanvaldez]

A few questions:

1. What are you planning on using as a BMS?
2. How are you handling charging when shorepower is available?

The system we're building out for our Ericson 27 sailboat will have as follows:

• 460AHr of LiFePO4 (230Ahr batteries in a 2p4s configuration)
• REC Active BMS to manage said battery
• Victron Inverter/Charger for shorepower charging + 120vac at sea
• 120W of 24v solar (just not much room on a 27' sailboat that's rigged for single-handing)
• 80A alternator driven by an advanced regulator, directly charging the LiFePO4.

We have 12V refrigeration (icebox conversion), so based on our current usage patterns, the 460AHr will give us 5 to 6 days of power until we run the engine again. We're not energy misers, but also not crazy users either, so your 200Ahr might be a little light.

But I also recognize that we're going whole-hog for the high end/integrated solution, which isn't suited for everyone, or for their budget.

Depending on what BMS you're using, that Smart Shunt is likely to be redundant. The main reason to keep it around is that the SoC calculations of many of the cheaper BMSs is woefully bad.

Down the road, I'd also look at converting your alternator to external regulation, then using an advanced regulator (Ideally Wakespeed, but Balmar also works) so you can push as much current as your alternator can safely generate into your batteries. For the 80A alternator on our boat, it cost us $140 to get it rebuilt and converted to external regulation (new rectifier, new bearings, and general cleanup/paint).

Undecided on the BMS...was looking at Daly but seem to be quite a few issues reported on this forum.

I don't have shore power at my mooring so not a big concern for me just yet. Have not given it much thought and open to suggestions. I like the Victron stuff!!!

My dc to dc will be the Victron 12|12 30amp. Looked at the Renogy but like to keep as much of it Victron as I can/afford

 

[svsagres]

Undecided on the BMS...was looking at Daly but seem to be quite a few issues reported on this forum.

I don't have shore power at my mooring so not a big concern for me just yet. Have not given it much thought and open to suggestions. I like the Victron stuff!!!

My dc to dc will be the Victron 12|12 30amp. Looked at the Renogy but like to keep as much of it Victron as I can/afford

What I would look at doing is at least picking a BMS that's compatible with the Victron VenusOS, even if through the third party serial driver. This will let you integrate everything together, which has huge advantages. They've released the software for Raspberry Pi if you don't want to pony up for a Cerbo GX if you don't want to (though I did, thought it was a better deal). It basically gives you one panel for your entire electrical system, plus easy expansion to also monitor tanks/bilge pumps etc...

As far as shorepower goes, if this is something in your future, definitely look at the Inverter/Chargers. I wound up going with the Multiplus Compact 12/2000-80, mostly because that's the smallest inverter/charger they make for the North American market.