Finishing Lithium Conversion on 450 Passage

[Nauticlops]

I'm at the last step of figuring out how to deal with lithium battery shutoff after charging is complete and need some advice.

Boat is: 2000 Hunter 450 Passage.

Status Complete
-12v 400ah lifepo4 house bank on bank selector one. Bank two currently unused.
-Xantrex Freedom XC Pro 3000w
-450w solar and 60amp charge controller and Solar Panel DC Isolator switch.
-Replaced all Studs and Buss Bars on 12v side and added conformal coating to all exposed connections.
-Rewired all pos/neg wires with 2/O AWG wire from batteries to bus. Also greatly shortened the wire run by moving batteries under port settee, and rerunning wires through shorter pathing to DC Panel.
-Added Victron Smart Shunt with bluetooth for battery monitoring.

Pending Items (Ready to order)
-Balmar XT-DF-170a alternator and MC-618 Regulator
-Balmar K6 Serpentine Conversion Kit (I could go with the smaller alternator and not use the serpentine conversion kit but the belt dust on the current V belt is driving me mad.)

-Need to Finish
-Add fuse to Solar Charge Controller lead to battery bank (Panels are currently off)
-Route and mount solar charge controller remote panel
-Relocate T-Fuse to safer position away from top of battery.
-I can further reduce battery wire run from battery to selector switch, I made them a little long.

Items that need identification for potential replacement
-Battery Isolator and Solenoid behind DC/AC Panel

What I'm confused on is how to deal with the Battery Isolator and Solenoid, and how to prevent lithium battery shutoff and Alternator current being redirected to my 12v systems. Do I remove it and wire the alternator directly to the starter battery then use a DC to DC charger wired to the 12v bus for charging the house bank? What does that look like?

 

[Johann]

Since you are installing an externally regulated high output alternator you would typically connect the alternator to the LFP house bank and charge the start battery with a small DC-DC charger. Then the solenoid and battery isolator can be removed. As far as BMS disconnects the two main types you can avoid are HVC (high voltage disconnect, either pack or cell), and FCP (full charge protection). Do the batteries have Bluetooth access to the BMS? Do you know if they have FCP? Some do and some don’t.
Absent any details you should be safe setting the MC-618 absorption voltage at 13.8V, float at 13.4V, and adding an APM.

Balmar Alternator Protection Module APM12 - 12V

Alternator Protection Module APM12 - 12VAlternators can be subjected to voltage spikes caused by lithium battery shutdowns, intermittent connections, and other over-voltage events. Balmar has introduced a robust Alternator Protection Module which helps to protect the alternator’s diodes and...

theyachtrigger.com

 

[dlochner]

What I'm confused on is how to deal with the Battery Isolator and Solenoid, and how to prevent lithium battery shutoff and Alternator current being redirected to my 12v systems. Do I remove it and wire the alternator directly to the starter battery then use a DC to DC charger wired to the 12v bus for charging the house bank? What does that look like?

Get rid of them. Wire the alternator to the house bank and use a small DC-DC charger to keep the start battery charged.

As for charging voltages, Rod Collins does a deep dive in a recent video.

 

[Nauticlops]

No Bluetooth access to the batteries themselves unfortunately. The BMS charge voltage cutoff seems to be 15v, no mention of full charge protection.

This is the information provided by the place I bought these batteries like 4 years ago. I can not find any additional information on these cells at all.

Triton Lithium Deep Cycle Battery for RV, Sprinter, Trailers and Motor

Affordable, Long Life Deep Cycle Battery for Trailers, Van Life and RV's. Triton Brand Lithium Iron (LFP) Deep Cycle Battery in Group Size 24 On Sale for $750 plus tax12 volt 100Ah 1280Wh Capacity and 3-5000 cycles at 50% depth of discharge Triton LFP - lithium iron phosphate chemistry Five...

deepcyclebatterystore.com

If i can't determine FCP, do I scrap the cells and find something that doesn't have it? Or does the APM solve this issue for me regardless of having FCP on the battery?

 

[dlochner]

If i can't determine FCP, do I scrap the cells and find something that doesn't have it? Or does the APM solve this issue for me regardless of having FCP on the battery?

The APM does nothing for the batteries, it protects the alternator in the event of a load disconnect on the alternator output. Load disconnects can happen because the BMS shuts the battery down, which is the load or the main battery switch is turned off while the alternator is producing power.

 

[Johann]

No Bluetooth access to the batteries themselves unfortunately. The BMS charge voltage cutoff seems to be 15v, no mention of full charge protection.

This is the information provided by the place I bought these batteries like 4 years ago. I can not find any additional information on these cells at all.

Triton Lithium Deep Cycle Battery for RV, Sprinter, Trailers and Motor

Affordable, Long Life Deep Cycle Battery for Trailers, Van Life and RV's. Triton Brand Lithium Iron (LFP) Deep Cycle Battery in Group Size 24 On Sale for $750 plus tax12 volt 100Ah 1280Wh Capacity and 3-5000 cycles at 50% depth of discharge Triton LFP - lithium iron phosphate chemistry Five...

deepcyclebatterystore.com

If i can't determine FCP, do I scrap the cells and find something that doesn't have it? Or does the APM solve this issue for me regardless of having FCP on the battery?

FCP is a recent “feature”, I doubt anyone had it 4 years ago. The datasheet says balancing voltage is 14.0V so you should be fine with 14.0-14.2V absorption.

 

[Nauticlops]

awesome, thank you everyone for the insight. i feel better about completing this project now. Big thanks to dlochner for the APM, the load disconnect issue was my biggest worry.