"Drop In" LiFePO4--My Case Study

[Dave_R]

I'm planning ahead for a house battery replacement in November. I sail seasonally, and am away from the boat right now. So I'm working from memory, but will answer questions wherever possible. I'm in my 2nd year of boat ownership, and pretty new to all the electical components.

My existing house batteries (3 of Victron's 12-230 AGM batteries) are end of life. The main charge controller/inverter is the Victron 3000. Batteries are charged by either shore power, 1080W solar or a 6.5kw generator (rarely needed.) My start battery and alternator are isolated from the rest of the system. Typical "automotive" start battery and stock alternator on the Yanmar engine.

I'd 'like' to replace the 3 AGM house batteries with 2x 280AH LiFePO4 batteries. That would give me similar useful storage.

Can I "drop those in" and re-program the Victron 3000 for LiPo charge profile? Or is it a lot more complicated than that?

I asked this on the Victron Energy Facebook forum, and respondents said that, as long as I reprogram the Victron 3000 with the absorb and float voltages and absorb time I can set the Victron 3000 for the LiFePO4 batteries.

[GILow]

Can’t comment on reprogramming the Victron, but I do suggest you investigate extra fuse protection for the batteries.

LiFePO4 batteries need a MUCH higher AIC rated fuse than conventional lead/agm batteries. I went with a class T fuse for my bank but there are other technologies that might be more available/popular depending on your location.

If you haven’t done so already I suggest a bit of a read on the whole AIC rating thing. It’s scary stuff.

[shimari]

Here's a good video that covers many of the issues you'll need to think about.

You can have the alternator charge the start battery and then use a DC-DC charger to charge the house LiFePO4 batteries to keep things simple.

https://youtu.be/2r6NbG73qZg?si=cTRS-_6WIUc6cVDW

[newhaul]

Originally Posted by Dave_R

I'm planning ahead for a house battery replacement in November. I sail seasonally, and am away from the boat right now. So I'm working from memory, but will answer questions wherever possible. I'm in my 2nd year of boat ownership, and pretty new to all the electical components.

My existing house batteries (3 of Victron's 12-230 AGM batteries) are end of life. The main charge controller/inverter is the Victron 3000. Batteries are charged by either shore power, 1080W solar or a 6.5kw generator (rarely needed.) My start battery and alternator are isolated from the rest of the system. Typical "automotive" start battery and stock alternator on the Yanmar engine.

I'd 'like' to replace the 3 AGM house batteries with 2x 280AH LiFePO4 batteries. That would give me similar useful storage.

Can I "drop those in" and re-program the Victron 3000 for LiPo charge profile? Or is it a lot more complicated than that?

I asked this on the Victron Energy Facebook forum, and respondents said that, as long as I reprogram the Victron 3000 with the absorb and float voltages and absorb time I can set the Victron 3000 for the LiFePO4 batteries.

Set charge controller to lifepo4 profile . Set float time to absolutely the minimum victron will allow lifepo4 don't like to be floated. Myself I Set my mppt to bulk to stop at 14 and to restart when voltage drops to 13.4.iirc might be 13.5.
You have more solar than you need for 560ah of lifepo4 but thats not a problem just run your most power hungry appliances in the afternoon off of your solar. .

[donradcliffe]

Sounds like you have a Victron inverter/charger. What's controlling your solar panels?

[Dave_R]

Originally Posted by donradcliffe

Sounds like you have a Victron inverter/charger. What's controlling your solar panels?

Victron MPPT controllers on the solar panels. I can program those with the Victron app, too.

[Dave_R]

Originally Posted by newhaul

....You have more solar than you need for 560ah of lifepo4 but thats not a problem just run your most power hungry appliances in the afternoon off of your solar. .

LOL, that's exactly what we do. When the battery bank hits 100%, usually early afternoon, we make ice, vacuum the boat, cook dinner on the induction surface or make rice in the insta-pot, do any reparis that require power tools, etc.

Save the battery for TV, Starlink, and a quick warm-up of dinner.

[newhaul]

Originally Posted by Dave_R

LOL, that's exactly what we do. When the battery bank hits 100%, usually early afternoon, we make ice, vacuum the boat, cook dinner on the induction surface or make rice in the insta-pot, do any reparis that require power tools, etc.

Save the battery for TV, Starlink, and a quick warm-up of dinner.

Exactly for me it's watermaker rice cooker and deep cool my holding plate fridge system.

[CaptainRivet]

Originally Posted by Dave_R

I'm planning ahead for a house battery replacement in November. I sail seasonally, and am away from the boat right now. So I'm working from memory, but will answer questions wherever possible. I'm in my 2nd year of boat ownership, and pretty new to all the electical components.

My existing house batteries (3 of Victron's 12-230 AGM batteries) are end of life. The main charge controller/inverter is the Victron 3000. Batteries are charged by either shore power, 1080W solar or a 6.5kw generator (rarely needed.) My start battery and alternator are isolated from the rest of the system. Typical "automotive" start battery and stock alternator on the Yanmar engine.

I'd 'like' to replace the 3 AGM house batteries with 2x 280AH LiFePO4 batteries. That would give me similar useful storage.

Can I "drop those in" and re-program the Victron 3000 for LiPo charge profile? Or is it a lot more complicated than that?

I asked this on the Victron Energy Facebook forum, and respondents said that, as long as I reprogram the Victron 3000 with the absorb and float voltages and absorb time I can set the Victron 3000 for the LiFePO4 batteries.

What yanmar engine is it exactly?
Does it have serpentine or V-belt?
If serpentine is it the 125A Valeo or the 115A Mitsubishi, most likley it is if serpentine ? If you don't know the exact alternator what its current rating.
On these answers depends what is the best solution for alternator charging of your LiFePO4 house. That's the biggest change you need to do.

As other said you need a super fast acting fuse with AIC >20kA per battery which only class T or NH fuse has. Ypu most likley have ANL or megafuse which are not sufficent for LiFePo.
You addditionally need an independent last resort shut off in case BMS fails which is best done with a victron BMV702 or 702 that steers with it's programmable relay output a disconnect relay. As side effect you have a good monitoring of your bank into your other victron equipement.
Which 280AH batteries you wanna get?


Victron Multi 3000 and MPPT can be reprogrammed to needed lifepo4 settings as others said.

[CaptainRivet]

Originally Posted by Dave_R

I'm planning ahead for a house battery replacement in November. I sail seasonally, and am away from the boat right now. So I'm working from memory, but will answer questions wherever possible. I'm in my 2nd year of boat ownership, and pretty new to all the electical components.

My existing house batteries (3 of Victron's 12-230 AGM batteries) are end of life. The main charge controller/inverter is the Victron 3000. Batteries are charged by either shore power, 1080W solar or a 6.5kw generator (rarely needed.) My start battery and alternator are isolated from the rest of the system. Typical "automotive" start battery and stock alternator on the Yanmar engine.

I'd 'like' to replace the 3 AGM house batteries with 2x 280AH LiFePO4 batteries. That would give me similar useful storage.

Can I "drop those in" and re-program the Victron 3000 for LiPo charge profile? Or is it a lot more complicated than that?

I asked this on the Victron Energy Facebook forum, and respondents said that, as long as I reprogram the Victron 3000 with the absorb and float voltages and absorb time I can set the Victron 3000 for the LiFePO4 batteries.

What yanmar engine is it exactly?
Does it have serpentine or V-belt?
If serpentine is it the 125A Valeo or the 115A Mitsubishi? If you don't know the exact alternator what its current rating.
On these answers depends what is the best solution for alternator charging of your LiFePO4 house. That's the biggest change you need to do.

As other said you need a super fast acting fuse with AIC >20kA per battery which only class T or NH fuse has.
You addditionally need an independent last resort shut off in case BMS fails which is best done with a victron BMV702 or 702 that steers with it's programmable relay output a disconnect relay. As side effect you have a good monitoring of your bank into your other victron equipement.
Which 280AH batteries you wanna get?


Victron Multi 3000 and MPPT can be reprogrammed to needed lifepo4 settings.

[Dave_R]

What yanmar engine is it exactly?
Does it have serpentine or V-belt?
If serpentine is it the 125A Valeo or the 115A Mitsubishi? If you don't know the exact alternator what its current rating.
On these answers depends what is the best solution for alternator charging of your LiFePO4 house. That's the biggest change you need to do.

As other said you need a super fast acting fuse with AIC >20kA per battery which only class T or NH fuse has.
You addditionally need an independent last resort shut off in case BMS fails which is best done with a victron BMV702 or 702 that steers with it's programmable relay output a disconnect relay. As side effect you have a good monitoring of your bank into your other victron equipement.
Which 280AH batteries you wanna get?

I'm away from the boat until November, so I can't give definitive answers on the alternator. The engine is the Yanmar 4JH3e. The alternator is the original. I think its a v belt and alternator rated for 85 amps? The key factor is, the alternator and start battery are isolated from the rest of the system, IIRC. The alternator only charges ths start battery. The house batteries are only charged by either solar, generator, or shore power.

I could be wrong, but that's how I remember the system. Thanks for the tips on fusing.

No decision on the LiFePO4 batteries, yet. Looking at the ECO-WORTHY. Its a good price, and they have the JBD (Jiabaida) brand internal BMS, which seems to be well respected.

[donradcliffe]

It sounds like a pretty good plan. I'd set the 3000 and the solar controllers to a bulk voltage of 13.8v, minimal bulk time, and float at 13.4v.

The other thing to check is the engine alternator. If you are sure that it is NOT connected to the house bank, you are done. If you want the option of using the alternator as a source for charging the house, you can always use a jumper cable or put a switch on that interconnection.

If the alternator is connected to the house battery, you will need to determine whether you need to protect the alternator from over temperature, and the battery from overcharging. If its a dumb alternator putting out 14v, the batteries can probably take that for an hour or two, but not for motoring all day and night.

If you do ever want to charge from the alternator, when the bank is at a low state of charge, you should a one-time check Put a clamp-on ammeter in the circuit and check how much current is coming out of the alternator and going to the house bank. If its less than 40 amps and for a limited time, you won't burn up the alternator. If its over 50, you may want to put a DC-DC charger between the start and house bank.

[newhaul]

Originally Posted by donradcliffe

It sounds like a pretty good plan. I'd set the 3000 and the solar controllers to a bulk voltage of 13.8v, minimal bulk time, and float at 13.4v.

The other thing to check is the engine alternator. If you are sure that it is NOT connected to the house bank, you are done. If you want the option of using the alternator as a source for charging the house, you can always use a jumper cable or put a switch on that interconnection.

If the alternator is connected to the house battery, you will need to determine whether you need to protect the alternator from over temperature, and the battery from overcharging. If its a dumb alternator putting out 14v, the batteries can probably take that for an hour or two, but not for motoring all day and night.

If you do ever want to charge from the alternator, when the bank is at a low state of charge, you should a one-time check Put a clamp-on ammeter in the circuit and check how much current is coming out of the alternator and going to the house bank. If its less than 40 amps and for a limited time, you won't burn up the alternator. If its over 50, you may want to put a DC-DC charger between the start and house bank.

Stock 85 amp alternator would be safe with the renogy 60 amp dc2dc. Just wire it up so you can energize the 50% charge circuit with a switch if you ever need to motor for long periods. ( drops the charge down to 30 amps. )
Renogy is the only one with that capability that I know of .

[sailorboy1]

there are many threads on the OP topic and lot can be saved by reading those all in 1 sitting

Heck I had a thread just like it

[CaptainRivet]

Originally Posted by Dave_R

I'm away from the boat until November, so I can't give definitive answers on the alternator. The engine is the Yanmar 4JH3e. The alternator is the original. I think its a v belt and alternator rated for 85 amps? The key factor is, the alternator and start battery are isolated from the rest of the system, IIRC. The alternator only charges ths start battery. The house batteries are only charged by either solar, generator, or shore power.

I could be wrong, but that's how I remember the system. Thanks for the tips on fusing.

No decision on the LiFePO4 batteries, yet. Looking at the ECO-WORTHY. Its a good price, and they have the JBD (Jiabaida) brand internal BMS, which seems to be well respected.

That's the dumb 85A MAE/Denso alternator, can do max 50A and has no temp protection.
If you wanna charge your lifepo4 via alternator then I highly recommend the victron Orion XS 50A DC2DC charger and you are set. In this case the orion is the best solution, is far superior and only 30Euro more expensive then the 60A renogy newhaul suggested. The alternator can only do 50A and 60A is too much, 30A too less. The victron can do 50A and can be dialed back in 1A steps via victron connect app when it's eg very hot and you motorsail with low RPMs.

For the rest you set as explained before.
Yes ecoworthy, Li-Time and power queen are the 3 moat common budget ones. Good batteries for the money.
Just get batteries with no parallel cells inside, biggest capacity single cell battery and take the amount that make your total wanted capacity.
The less batteries the better, remember every battery needs a class T or NH fuse incl. Holder and a disconnect switch plus cables and lugs, that adds up to aprox 150Euro per battery additional.
So 2x300AH (+300) is better then 3x200Ah (+450)or 6x100AH (+900Euro) as you also spent more money on capacity and less on install hardware. Also the more batteries the more failure points and therefor more potential to shut the system down. The main failure for a blackout in a lithium system is the main fuse failing (so extremely seldom and the less main fuses=the less batteries the better) while in a lead battery system it's the lead battery, that why you need multiple lead batteries.