How do you ever get those Lifepo batteries charged?

[SailingPNW]

Originally Posted by Shanachie

After reading more lithium battery threads, I've decided that most sailors with these batteries are electronics nerds/ trend-setters who thoroughly enjoy building increasingly complicated systems.



Not that there's anything wrong with that!


As someone who only wants the lights to turn on and the diesel to start at appropriate times, I think golf cart batteries with solar will fill my needs quite nicely.


Simple is reassuring to me. When the lights don't turn on, I want to be able to trace the problem quickly. Sorting through the complicated setups of lithium lovers isn't attractive.

If simple works for you and your sailing plans then that's what you should go with. Don't simply change for change.

LiPo batteries start making more sense if your out for weeks at a time, and where improvements in capacity and charging make a big difference or where you want to reduce weight.

For me when I am anchored out, I am often still working so this means I have my inverter on all day with a computer running. Adding that load to my regular load means I use a lot of power, and a few cloudy days can really have a negative effect.

[SV Confianza]

If by cruising you mean staying away from power for multiple days, I would bet you’ll be unhappy unless you upgrade that alternator.

You will probably get used to having household like power, start consuming more, and get frustrated with the undersized charging system. I’m making a number of assumptions here, of course, but I’m still pretty confident in this answer.

My suggestion would be to upgrade to the balmar xt170 and balmar regulator with alternator temperature sensor. The balmar regulators already have a built in profile that will be fine for most LFP drop ins.

Your 60 amp alternator is probably going to only put in 30-40amps once it gets warmed up, and you will probably burn it up without external regulation. They’re not continuous duty. And with its internal regulation, it will spend way too much time in absorption mode, and barely charging. Would take waaay more than you would think to charge.

The balmar xt170 averages about 100amps into the batteries.

Also be careful to make sure your wiring can handle the amount of amps that will be moving around now.

You’ll need a method to charge your starting batteries as well.

If interested, I did a full write up on our system and what decisions we made here: Connie's Lithium Powered Electrical System to WFB (Work from Boat). Goes through the various options we tried and the results.

I would go with the balmar regulators instead of the wakespeed for simplicity.

[hjohnson]

Originally Posted by Shanachie

So I've been reading all of these entertaining lithium threads as I debate what to do for new house batteries.


Generally, I think all of this is way too complicated, suitable more for the engineering geeks than the average sailor who just wants to cruise around. I like simple.



But one thing keeps bothering me: How do you ever get these huge lithium battery banks charged? I see people talking about 400, 600 even 1,000 amp hours, and it staggers me.


I have a 34-foot sailboat with a Yanmar 3gm30 and a 50 amp alternator as well as 320 watts of solar with a Xantrex MPPT. Let's say I put 400 AH of lithium batteries in and a 20-amp DC to DC charger on the start battery.



If I'm motoring on a sunny, calm day, I'll put close to 40 amps an hour into the battery bank. But that's eight hours to a full charge if I had run the bank down for some reason.


It's still three or four hours if it's a more normal overnight discharge.


Under my current 320AH of FLA, I'm generally into float in early afternoon after solar and a bit of motoring. A couple more hours, sure, but I'm topped off well before I drop the hook.


So what am I missing? What's the difference? Is getting fully charged a couple of hours earlier really worth all of the fuss with BMS, balancing cells and all of the rest? Or is it just fun to be an early adapter?



Enlighten me.

So I have 460Ah on my Ericson 27. The big win for me is I no longer have to worry about my power system.

Before I leave the dock, I’ll log in and bring the batteries up to 100% SoC (they normally live at 60% when I’m not using the boat). That’s about 6 or 7 days of running the boat with little conservation, or any charging. From there, I’ll charge up either with 320W of solar, or my engine’s alternator.

The thing is, I don’t need to make sure, or worry about fully recharging the battery. I can run a power deficit, and still have nothing to worry about for some 10 days in normal usage. Realistically, within 5 or 6 days, I’ll usually spend s night at a marina so I can do laundry and take a shower, at which point I plug in and top the battery off again. Heck, I’ll usually wind up at about 60% SoC the night before hitting the marina, so I’ll flip on my hot water tank and have a tank of water for dishes and washing up. Just because I can.

I have an 85A alternator bolted onto my poor little Yanmar 1GM10 (though I mostly limit it to 40A), but it can put out 75A continuous at the cost of significant power to the prop. I rarely run it at full power.

Between the engine and solar, typically run about a 5-10% deficit a day. Because I just don’t have to care any more. I leave all my electronics running, keep my devices charged up, leave the inverter on, and so forth.

Lastly, because of the higher voltage, a lot of things run a heck of a lot better. Lights are a little brighter, and my refrigerator (little dometic icebox conversion) cycles a lot less.

TL;DR: How do I keep my batteries charged? I don’t. They last longer than any amount of time we would spend away from the dock.

[Pete7]

Originally Posted by Shanachie

So what am I missing? What's the difference? Is getting fully charged a couple of hours earlier really worth all of the fuss with BMS, balancing cells and all of the rest? Or is it just fun to be an early adapter?

Enlighten me.

Shane,

As already mentioned don't underestimate the speed at which these batteries charge up at. I am sure you are aware that getting the last 20% into lead batteries can take time. Well the first screen shot was taken in Aug 21 at 11am. Like you, we had 300w at the time and the weather was cloudy so pretty good output from the solar. The LFP battery is 120Ah hybrid with 2 x Trojan TMX 24s. That's 15A going into the batteries and they are nearly full, 20A possible in full sun.

Equally the third screen shot shows taken earlier is the mains electric kettle being boiled to make tea. The voltage drop would be horrible and shorten the life if we tried this on lead acid.

Electric cooking is our primary reason for going down the LFP route on a 31ft yacht. Yes we could use gas, but prefer electric, handy given the fiasco in price and availability in the UK over the past 3 years. Now we have the option to choose which way we cook and upgraded to 600w of solar.

There is a some studying needed to go down this route and it may not suit some folk who perhaps only sail at weekends, which is fine. Ideally make a list of the advantages and disadvantages that LFP have and choosing if its worth the effort and cost to change.

Pete

[CaptainRivet]

On small boats with small banks I would even go LTO. Reason is that >0.5C discharge really stresses a LFP and reducing its lifespan.
Well and 100AH is just 50A and 200AH 100amps.
More then enough for a small boat in the low 30ft BUT an induction hob 2 burner is typically 1800W US and 2400WEurope, at 12V 200A draw plus the short peaks you don't see in rhe 250-300A range.
An LTO can do 10C so even a 40AH bank =400A can run that cooktop and the inverter.

Addirional advantage safest chemistry avaliable, the amount of abuse these LTO cells can take are from another universe....you can discharge to 0% SOC, high voltage cutoff is 18V for 12V system so unless your alternator regulator is faulty you are not reaching 18V.
For a small 3p4S system you don't even need a BMS, a cell Voltage monitor and an active balancer is enough.
You can also skip the starter battery, get 40AH more for your house from what you saved...even at 6V that LTO bank will start your diesel.
I can highly recommend the 40AH Yinglong LTO cells, you need 6 for 12V as they are 2,6V but the flat area is 2-2,3V where 95% SOC is. Charge efficency like LFP and -70degees celcius till +100 deegrees celcius...so even nor a problem at antartica.
30000 cycles, buy once install properly and forget. and it will outlast your boat...
Only disadvantage they are nearly as heavy as lead.
As also maine sail said, there is no reason anymore to use lead.

[hjohnson]

Originally Posted by Pete7

Shane,

As already mentioned don't underestimate the speed at which these batteries charge up at. I am sure you are aware that getting the last 20% into lead batteries can take time. Well the first screen shot was taken in Aug 21 at 11am. Like you, we had 300w at the time and the weather was cloudy so pretty good output from the solar. The LFP battery is 120Ah hybrid with 2 x Trojan TMX 24s. That's 15A going into the batteries and they are nearly full, 20A possible in full sun.

The other thing to remember is that charging LFP is very efficient. It’s something crazy like 92% of the energy pushed into the battery can be taken back out again. So 50A for two hours gives you 92Ah of usable battery power. Lead acid is lower, something like 70-80%, and that drops as you go to higher C rates.

I tend to run through about 100Ah a day, not being careful or conservative. If I’m cruising, I tend to motor probably a couple hours a day, which pushes a good 80Ah back into the battery. Add a bit of solar power and bob’s your uncle.

[FlyingScot]

Fundamentally batteries just allow you to time shift energy production.
The larger the bank, the more flexibility you have whether it be weather, generator run time, marine/dock, etc.

We upgraded out 900AH FireFly Oasis AGM bank last week to 1320 LiFePO4. We haven't switched the solar over, so we are at 1440wp for now. But I'm amazed at upgrade already.

Some important points, you worry less about the batteries when you don't concern yourself with getting them full every week.

Our primary charging source is solar. It was always an issue to try to consume the power solar could produce, but the Charge Acceptance Rate (CAR) of the FF Oasis couldn't accept.

I won't be going back to lead based batteries as a house bank.

[SV__Grace]

Takes me 3 hours of generator time to charge my 1200ah lithium house bank that required 8 hours for my old AGMs.

Lithiums accepts full current from my generator, 200amp alternator, solar and wind.

FLA and AGM have a 3 stage charging cycle- Bulk, Absorption, and Float. At least 50% of my generator time was wasted on float with almost no load but had to do it because I would degrade and eventually kill the batteries if not charged to 100% (which did happen, BTW, so I learned the hard way).

Killed me to have a 200ah charger and alternator that kicks down to 100ah absorption after 2 hours at 80% then 10ah float after 4 hours at 90%. Hated that.

With my Lithiums I don't worry about charging to 100% and have more usable battery power- 80%/960ah vs 50%/600ah

Big difference. Enlightened yet?

I would want a bigger alternator, more solar, and bigger charger in your situation to decrease charging time, but even without doing so, the above differences still apply and make Lithiums a no-brainer for cruisers (but a waste for dock queens).

Originally Posted by Shanachie

So I've been reading all of these entertaining lithium threads as I debate what to do for new house batteries.


Generally, I think all of this is way too complicated, suitable more for the engineering geeks than the average sailor who just wants to cruise around. I like simple.



But one thing keeps bothering me: How do you ever get these huge lithium battery banks charged? I see people talking about 400, 600 even 1,000 amp hours, and it staggers me.


I have a 34-foot sailboat with a Yanmar 3gm30 and a 50 amp alternator as well as 320 watts of solar with a Xantrex MPPT. Let's say I put 400 AH of lithium batteries in and a 20-amp DC to DC charger on the start battery.



If I'm motoring on a sunny, calm day, I'll put close to 40 amps an hour into the battery bank. But that's eight hours to a full charge if I had run the bank down for some reason.


It's still three or four hours if it's a more normal overnight discharge.


Under my current 320AH of FLA, I'm generally into float in early afternoon after solar and a bit of motoring. A couple more hours, sure, but I'm topped off well before I drop the hook.


So what am I missing? What's the difference? Is getting fully charged a couple of hours earlier really worth all of the fuss with BMS, balancing cells and all of the rest? Or is it just fun to be an early adapter?



Enlighten me.

[knutmi]

My alternator charges with 14.4 Volt, its a std Volvo Penta with max 125A, drops to 80-70A after short time. 14.4 volt will not charge my 200Ah LFP house bank 100% but it charge quite quick. I also have a 90Ah AGM start battery. I use a Victron Argo Fet 200A battery separator between the alternator and the two battery banks. I have used this setup 5 years and zero problems.
I do holiday and most weekend sailing. I don't need charging LFP from grid, even in winter, but my AGM do get some grid charging.
Here in Norway hundred of boats have this setup and this do not blow VP alternators, they are produced by Mitsubishi.

[Andrew Lippman]

Correct me where I am wrong... It sounds like most of you folks put in a far larger lithium bank than you need. Given the deeper disccharge avaliable in lithium you would need a smaller bank yet most seem to have a larger one. That is counterintuitive.

Besides the advantages of being lighter, reliable, deeper dischargeable, and more expensive, the more hidden good is that they can charge at a greater rate. Therefore a good alternator that can handle it (both runtime and power) is better for all: The engine is running at a higher load, which is good for it, and for less time, which is good for you and your guests.

My reluctance to date is skepticism. Salespeople tell you how many cycles and years to expect but my laptop and phones don't perform that well. (I realize it's a different chemistry.) I want to see some other people's experience. If after some number of cycles they only charge up to 80% as my computer does, then I have to think about both the size and honesty and the cost.

[rslifkin]

Originally Posted by Andrew Lippman

Correct me where I am wrong... It sounds like most of you folks put in a far larger lithium bank than you need. Given the deeper disccharge avaliable in lithium you would need a smaller bank yet most seem to have a larger one. That is counterintuitive.

Sometimes minimum bank size is driven by factors like needing a larger bank to support the desired amount of short term power draw (such as for cooking), not an absolute need for capacity. And more capacity has benefits as well, such as better being able to handle a cloudy day or 2 without having to start an engine or generator.

[hjohnson]

Originally Posted by Andrew Lippman

Correct me where I am wrong... It sounds like most of you folks put in a far larger lithium bank than you need. Given the deeper disccharge avaliable in lithium you would need a smaller bank yet most seem to have a larger one. That is counterintuitive.

Besides the advantages of being lighter, reliable, deeper dischargeable, and more expensive, the more hidden good is that they can charge at a greater rate. Therefore a good alternator that can handle it (both runtime and power) is better for all: The engine is running at a higher load, which is good for it, and for less time, which is good for you and your guests.

My reluctance to date is skepticism. Salespeople tell you how many cycles and years to expect but my laptop and phones don't perform that well. (I realize it's a different chemistry.) I want to see some other people's experience. If after some number of cycles they only charge up to 80% as my computer does, then I have to think about both the size and honesty and the cost.

So in my case, our previous FLA battery back was quite frankly inadequate for the modern systems we have installed on our 50 year old boat. Between refrigeration and modern electronics, we were working our old lead acids way too hard. So we wound up designing a modern LiFePO4 power system. Because my coowner and myself are both instrumentation and integration geeks, we went all in on the Victron ecosystem. For the battery proper, we weren’t completely made of money, so designed a DIY battery that fit into the same hole as the old lead acid batteries. When all was said and done, we wound up with almost 5x the usable battery capacity.

We also shifted the engine to its own dedicated marine Start battery which is kept constantly on the float.

[Icarus]

Originally Posted by Shanachie

So I've been reading all of these entertaining lithium threads as I debate what to do for new house batteries.


Generally, I think all of this is way too complicated, suitable more for the engineering geeks than the average sailor who just wants to cruise around. I like simple.



But one thing keeps bothering me: How do you ever get these huge lithium battery banks charged? I see people talking about 400, 600 even 1,000 amp hours, and it staggers me.


I have a 34-foot sailboat with a Yanmar 3gm30 and a 50 amp alternator as well as 320 watts of solar with a Xantrex MPPT. Let's say I put 400 AH of lithium batteries in and a 20-amp DC to DC charger on the start battery.



If I'm motoring on a sunny, calm day, I'll put close to 40 amps an hour into the battery bank. But that's eight hours to a full charge if I had run the bank down for some reason.


It's still three or four hours if it's a more normal overnight discharge.


Under my current 320AH of FLA, I'm generally into float in early afternoon after solar and a bit of motoring. A couple more hours, sure, but I'm topped off well before I drop the hook.


So what am I missing? What's the difference? Is getting fully charged a couple of hours earlier really worth all of the fuss with BMS, balancing cells and all of the rest? Or is it just fun to be an early adapter?



Enlighten me.

I agree...keep it simple.

[Ozzlawrence]

Why stick to just solar? Wind generators are available at reasonable prices, work well on overcast days (and night time), are environmentally friendly, don't care if the boat is heeled over and not facing the sun.... Get yourself some wind power. We are a SAILING community relying on wind for locomotion - use it for power generations as well.

[rabbi]

Originally Posted by Shanachie

After reading more lithium battery threads, I've decided that most sailors with these batteries are electronics nerds/ trend-setters who thoroughly enjoy building increasingly complicated systems.



Not that there's anything wrong with that!


As someone who only wants the lights to turn on and the diesel to start at appropriate times, I think golf cart batteries with solar will fill my needs quite nicely.


Simple is reassuring to me. When the lights don't turn on, I want to be able to trace the problem quickly. Sorting through the complicated setups of lithium lovers isn't attractive.

Things become complicated when trying to make the batteries go the theoretical 6000 cycles. Then it's better to stay 30-80% SoC, limit charge / discharge currents according to SoC and temp, do cell balancing at 100% every few weeks, pressurize the cells, etc.

I simply configure the charger & BMS once, accept that the cell will only do 3000 cycles, and call it a day.

"Theoretical 6000 cycles" because both me & the cells age anyway and neither of us will survive the 30+ years it takes to reach 6000 full cycles.
Replacement cost in 10 years will be much lower than today so I don't really care.

It just needs to be safe, not perfect.