Switch from AGM to Lith-ion

[tanglewood]

Dockhead nailed it.


Lead acid is very complicated. We talk endlessly about how to charge and maintain our LA batteries. But it's all familiar to us, so we accept it as normal and "simple".


LFP is totally different, so seems complicated because we don't understand it. Once you get your head around it, it's really quite simple. And once you have a monitoring and protection system built around them, they just work like a charm without any of the day to day attention that LA requires.


And for what it's worth, I think the only BMS action that is safety related is guarding against over-charge. All the other protections are about protecting your wallet by making sure you don't trash the batteries. Interestingly, we could have all the same protections on our LA batteries, but don't. Instead we happily murder them on a daily basis, swallow hard, and buy new ones. All the fuss over lots and lots of BMS protection is really just because LFP cells are expensive, and we don't want to break them.

[Pelagic]

WOW! .....thank you for putting things in an easy to digest perspective Dockhead and Tanglewood.

I guess it's the devil we know versus a new one promising salvation at a much higher price IF we only read the fine print "very carefully"!

It is easy to get intimidated by those who stand so tall above me in electrical theory and its holy properties.

Kinda reminds me of the story of Issac. [emoji4]

Story of Isaac https://g.co/kgs/UXs4Yn

[jkleins]

Thanks Dockhead. Most of the major motorhome manufacturers sell a stock lithium setup with solar panels, etc. It is basically just like a boat setup and must be further along then a “science experiment” in this crowd.
I have to agree that if you start with a clean slate it does take some of the intimidation away from trying to “integrate” it into your existing systems.

Jim

[Dockhead]

Originally Posted by Pelagic

WOW! .....thank you for putting things in an easy to digest perspective Dockhead and Tanglewood.

I guess it's the devil we know versus a new one promising salvation at a much higher price IF we only read the fine print "very carefully"!

It is easy to get intimidated by those who stand so tall above me in electrical theory and its holy properties.

Kinda reminds me of the story of Issac. [emoji4]

Story of Isaac https://g.co/kgs/UXs4Yn

Well, my theoretical electrical knowledge is limited and probably not a bit better than yours. I am sure you are just as capable of understanding all these things -- by studying the issues carefully, and by asking questions to the Cruisers Forum brain trust when you need to.


It's not actually rocket science and advanced electrical theory is not required, to get a handle on this one.


And one important thing -- there is a popular misconception that lithium is much more expensive than lead. In fact it's not. You need first of all to separate the cost of the installation and infrastructure, from the cost of the cells. The installation and infrastructure, including modifying what you already have, plus BMS and other devices, may or may not be fairly expensive, but it's a one-time cost. The cells themselves are much cheaper than lead, measured in terms of REAL CAPACITY, not nominal, and considering the real life cycle life.


The whole cost for me, for example, including a fairly expensive fixed installation and infrastructure cost (because my existing system is complex), is still only maybe double or 2.5x the cost of a set of quality lead batteries of the same real capacity. So even the conversion cost will pay itself back over a certain period of time. And if you are starting out from zero, with either an obsolete charging and management system which needs to be replaced anyway, or building a new boat, then lithium in my opinion is an absolute no brainer.

[a64pilot]

Nothing could be simpler than lead.
You can feed a constant charge voltage to it, and that’s it, think automobiles and how boats were until recently, just throw 14V ish at a bank forever, don’t monitor anything and it will work. That ish isn’t even a tight number something between 13.5 and 14.5 will work.

I do know and understand Lithium, used to have kilowatt hour Lithium banks to run my dive scooter, at $5,000 a piece, you learned to take care of them. Yes they were Lipo, nothing else has that kind of energy density.
For Lithium you have to ensure you don’t run them down too far, which is easy, but they real Key is you have to make sure you don’t overcharge, that is death and is dangerous, I’m sure even LFP can thermal runaway, all battery chemistries can, even lead.
Then there is the alternator disconnect, cause you don’t float Lithium, take that out of your thought process.
But the real key that most want to just feel isn’t important is you need a BMS that has thermal cut outs and that will monitor and balance each cell every time it’s charged.
Most want to believe that if I do an initial charge to .001 decimals in voltage that the cells are magically identical and won’t drift in charge, that’s wishful thinking.
Of course you will have several that say well I do it, and it works so how do you explain that. I do they same way I tell a life long smoker that they don’t have cancer because they are lucky is all, but them not having cancer doesn’t prove that smoking isn’t harmful.
So yes its simple I guess if you compare all of those safety features and required electronics, their expense and expertise to install, better carry a spare everything though, cause your not finding this stuff out cruising, so double your install estimate price wise.
I call it a science experiment, cause for one, where do you source all of that stuff? You just call Balmar and ask for their lithium box that has all of these features built in right?
No, you don’t cause that doesn’t exist yet, you source and or build it all yourself, and that makes it an experiment.

Same thing with a Watermaker actually, back in the day I’m sure you had to gather all the pieces yourself, that came with no warranty or customer support and you had to muddle through how much pressure, how much flow per output etc.
Now you can pick up the phone, call Tellie or Rich and after deciding which one have all the parts delivered, that has a warranty and customer support is available for when it does something you don’t understand.

I’m waiting until I can call Balmar or another company and order their box or kit if you will, and have a warranty and support.
I’m not saying Lithium is bad, I’m just saying it’s not yet ready for prime time is all, not until a major, respected manufacturer sells a kit or a drop in battery, cause I firmly believe all the electronics could be put in the battery, it would I believe take a different alternator controller controlled by the bank though, but Balmar could easily implement that.
Actually now that I think about it, it wouldn’t, it could connect to and control an existing Balmar alternator controller.

But from a simplistic standpoint, nothing is simpler than AGM, drop it in and forget it, then two years later when it slowly becomes apparent that the bank is dying, replace it.
Nothing bad happens, no equipment is damaged and you had to put zero thought and attention to the bank, and it dies a slow death, so you have warning.
It’s how the overwhelming majority of boats are operated now, and you know what? It works.
Last boat wasn’t a cruising boat, it was a dive / fishing boat, but every two years I bought new batteries at Walmart and took the two year old batteries out of the boat and put them in the RV, ones from the RV were turned in to recycle, never had a failure.

We make lead complex trying to eek the absolute longest life possible out of it, but don’t have to , and in truth it’s not at all complex.
Automatic three stage charging is all that is needed, nothing more.
The difference is that lead is rather tough, it will tolerate things like being overcharged and or killed near dead flat than Lithium will, and if it doesn’t, it’s a whole lot cheaper and easier to replace.
Does Costco, and Walmart or auto stores carry Lithium? They carry lead.

[jkleins]

Are you sure you are not forgetting something? Every battery discussion on this forums discusses how you can kill lead batteries by discharging them below 50%. Charging them too high can have the same effect of decreasing life. Letting them discharge significantly will kill lead or at least damage them enough that they are pretty useless for a house bank.
These things can all happen to AGM’s and gels and you have to integrate the system if you want to keep the life span of lead just like Li (charging with good output in the middle with a trickle on the end to get to 100% and all that nonsense)
Balmar doesn’t sell a complete system to handle every charging situation. They sell an alternator and regulator. If you set the regulator to a low enough voltage it will work the exact same way for Li as for an AGM. If you just buy a 12v charger you don’t even need to do that. Just hook it up to your engine start battery and charge the Li from that.
You may be correct that you can, theoretically, kill Li a little faster by ignoring the high and low cutoffs of a BMS but ignoring high and low cutoffs on lead can have a pretty damaging effect as well if any of these battery discussions are to be believed.
The lead situation is just more familiar to us and therefore we are fine saying just drop it in and use it and I will replace it in a couple years.
You can do that to Li as well at just a greater cost.
Do you buy your batteries at Costco or Walmart?
Several major? companies sell BMSs (Mastervolt being a common one in the marine area, BattleBorn is a common on in the RV world) They both sell packages not unlike the Watermaker analogy you used. Multiple components that work together to acheive your desired results.
Your statement on lead about “eaking out” the longest life possible is exactly the rational some lithium users use to just keep the charging voltage low enough to be safe and not worry about every amp you are getting out of the battery. Just make it easy and accept a little less then perfect.
Most of us know way more about Li then we need to use some of the commonly purchased systems and if we just are a little careful (like we are with our AGM’s) they will last a long time and be very serviceable.
It is why I have to reject your “science experiment “ label. Most cruisers put as much thought into their lead system as you would have to to go to Li. They just already have put that thought into it so don’t want to do it again. :-)

[FlyingScot]

No one has yet mentioned Firefly Oasis as a choice. I have them and consider them a great step above AGM and one step below LiFePO4.

The only real concern I have with Lithium is having to have ALL charge sources updated to properly care for them.

For me that would be two alternators and one combo inverter/charger.

Weight and voltage sag are the only reasons I would want them, but truthfully, voltage sag hasn't been an issue for me yet, even pulling 145 amps at times on my 12v nominal system. (FF Oasis 450 ah). So weight savings would be nice.

I can't charge more than 100 amps maximum and almost exclusively charge from solar. So typically charge 50-80 amps. My bank will happily accept this even well past 80% SOC.

[a64pilot]

The people that would benefit most to switch are those that only charge with a generator or while motoring, the Solar guys would benefit, but not as much.

If you think lead is complex, I don’t know what to say, lead you set absorption voltage and float, thats it, then years later you buy another bank that’s pretty easy to me.
Lithium is far easier to kill than lead, lead is for dummy’s, you usually can keep knocking it down, deep discharges and overcharging and it keeps on coming back.
6 years ago when I first got my AGM bank, I did something stupid, I set the Magnum to equalize where it is supposed to hold 15.5 V for 5 hours them back to float.
That was on a Sun, I came back fri night and guess what, it was still outputting 15.5 VDC. I don’t know how, but the batteries survived, they were accepting no current and weren’t even warm.
Do that to an LFP bank and see what happens.
I never have figured out what happened, since then the charger drops to float at the set time, just now of course I don’t trust it.

Now I’m not saying you should do this, but some how mine survived.

Then about a year later I came back to the boat one weekend and the bank was stone dead, the dock circuit breaker had gone bad and there was no charger power for a week, and this was before I had Solar.
Somehow the bank survived and now we are on year 6, they may die tomorrow, I hope not as lead usually dies a long slow, painful death and gives you plenty of warning. Lithium? Not so much, often they die pretty suddenly, or are dying and it’s masked by their ability to hold even voltage during discharge maybe.

Lead is a known quantity, take care of a Lifeline bank and you’ll easily get six years from it.
A home brew, cause that is all there is so far LFP bank? Maybe, maybe not, we don’t know yet and likely won’t until there are systems sold.
It’s coming, just it’s not here yet, and it will cost more than a home brew, initially costs will keep the average Joe like me from adopting, like it does now, but costs will come down.

Now my lead bank does everything I want it to do, if I had an LFP bank all that would change for me is that I wouldn’t have to run the Honda for 30 min in the morning is all. And I likely don’t have to do that now, it’s just Insurence at this point.

[Seawindcruiser]

I’m with Dockhead, lithium’s are great. Yes any LiFePo4 installation needs ‘idiot-proofing’ but it’s not that hard. The best part is they accept all the charge you can throw at them. No more running a generator for hours just to get that last 15% into an AGM bank. No more losses due to crappy Peukert factor or charge efficiency losses. With only limited sun light hours in the day you need to make the best use of it. LiFePo4 allows you to get the best out of any charge sources you have.

[cuffy]

My LFP installation is as Dockhead describes, 2 small LA for starting to which all the charge sources go and then b2b to LFP. As a full time liveaboard the new install is proving very good with no worries re fully charging LA bank. I harvest much more from my solar each day (400w), due to no tail current, and make hot water on demand via the inverter. We have added a freezer and watermaker this year all running of the solar, she loves it!!

[hellosailor]

"If you think lead is complex, I don’t know what to say, lead you set absorption voltage and float, thats it,"
Yes and no, actually. If you recall the Solarstick threads from years ago? I was monitoring charge voltage and current from the panels versus the MPPT (Blue Sky) controller, and noticed that the controller, which had been "simply" programmed with battery specs, was not putting out bulk/absorption voltage. I checked with BS and then amazingly got a lead engineer from one of the top battery companies on the phone. He told me, back then, that this was already old news. The best way to charge lead acid batteries, especially wet ones, is to charge them at slightly higher voltage than they are at--not at "full" absorbtion voltage. That allows you to push more amperage into them while at the same time reducing microbubbling at the plate surface, which keeps internal resistance down and gives you higher charge acceptance rates and lower electrolyte evaporation. As the battery voltage rises, you keep ramping up voltage to match.
And similarly, charging with PWM (which MPPT does too) is actually MORE effective than charging with pure DC, for the same reason. The pulsing means less bubble formation and more effective charging. Who knew?
Since Blue Sky and others use a computer and a look-up table, they can do this very easily. Three stage, four stage, all obsolete and old news even ten years ago.
So yes, you might "just set" a modern computer controlled charger, but it is going to be doing way more than just pumping out fixed voltages if it is a truly "smart" charger.

[Dave9111]

I'm a EE.
Unless you are very familiar with electricity and electronic technology, don't go to Lith batteries. YOU will be the tech guy for your system. If you have issues YOU will have to figure it out. If you pull into a marina to have your boat serviced they will likely RUN away from your boat.


IMO, there are almost zero reasons to put Lith batteries on a boat. They are used in cars because weight is a huge issue. Weight on a displacement boat is not a huge issue.



Stick with Lead Acid or go back to school so you can support your Lith Battery Marine system.



If you want a cheap, high capacity battery system - consider banks of 6V golf cart batteries. Cheap, common, and relatively long lasting.

[Dockhead]

Originally Posted by jkleins

Are you sure you are not forgetting something? Every battery discussion on this forums discusses how you can kill lead batteries by discharging them below 50%. Charging them too high can have the same effect of decreasing life. Letting them discharge significantly will kill lead or at least damage them enough that they are pretty useless for a house bank.
These things can all happen to AGM’s and gels and you have to integrate the system if you want to keep the life span of lead just like Li (charging with good output in the middle with a trickle on the end to get to 100% and all that nonsense)
Balmar doesn’t sell a complete system to handle every charging situation. They sell an alternator and regulator. If you set the regulator to a low enough voltage it will work the exact same way for Li as for an AGM. If you just buy a 12v charger you don’t even need to do that. Just hook it up to your engine start battery and charge the Li from that.
You may be correct that you can, theoretically, kill Li a little faster by ignoring the high and low cutoffs of a BMS but ignoring high and low cutoffs on lead can have a pretty damaging effect as well if any of these battery discussions are to be believed.
The lead situation is just more familiar to us and therefore we are fine saying just drop it in and use it and I will replace it in a couple years.
You can do that to Li as well at just a greater cost.
Do you buy your batteries at Costco or Walmart?
Several major? companies sell BMSs (Mastervolt being a common one in the marine area, BattleBorn is a common on in the RV world) They both sell packages not unlike the Watermaker analogy you used. Multiple components that work together to acheive your desired results.
Your statement on lead about “eaking out” the longest life possible is exactly the rational some lithium users use to just keep the charging voltage low enough to be safe and not worry about every amp you are getting out of the battery. Just make it easy and accept a little less then perfect.
Most of us know way more about Li then we need to use some of the commonly purchased systems and if we just are a little careful (like we are with our AGM’s) they will last a long time and be very serviceable.
It is why I have to reject your “science experiment “ label. Most cruisers put as much thought into their lead system as you would have to to go to Li. They just already have put that thought into it so don’t want to do it again. :-)

Well said!

[CarlF]

I was planning to go from Lifeline AGM to LIbut went instead with 800 amp/hr of Firefly.

While LIon have many advantages over AGM, those advantages compared to Firefly’s are few and may not matter to you.

Firefly’s have no PSOC concerns and can be discharged almost as much as Li. 1500 cycles at 80% discharge. 5000 cycles at 50% . No need to charge back to 100% regularly. These should be 10 year batteries - probably longer than I’ll own the boat.

While LI are even better, the Firefly has much higher charge acceptance than my Lifelines. I charge at the full 300 amps my charging system can deliver to above 90%. As with LI, there’s no reason to continue charging for the last 10%. I wouldn’t charge any faster with Li

Firefly’s were less than 1/3rd the cost of switching to LIon mostly because they used the same case, same cables, same regulators and chargers, same charger settings. Even if the Li’s last longer than the first set of Firefly’s, I can buy a 2nd set in ten years and still be ahead of the game. .

Assuming the Firefly’s live up to their specs, early tests and marketing (and it’s too soon to know for sure) their major negatives are that Firefly’s are heavier and only come in two sizes. Neither of these things mattered to me but would if you had a catamaran or a battery box that couldn’t fit those sizes.

[GRIT]

Dave 9111.

As an EE, your opinion may carry some weight. But as a sailor, some of your statements ring as baloney. I think the technical term for a person who throws out blanket statements, such as those in your post is : "Negative Nelly".
I'm sure many folks back in the late 1800's had similar opinions about the automobile.

Many, if not most, of us choose lithium for it's charge/use qualities, and consider the lighter weight a bonus. I don't think blanket statements like some of what you said are true, especially to those of us using lithium.

For anyone willing to do the research, Lithium shouldn't be any more difficult than any other "newer" technology.


I don't think you have to go back to school, and become an ee, to service lifepo4 batteries. You just have to learn about LiFePo4 batteries, and their eccentricities.

For those who think boating is about turning a key, and going sailing, Lithium probably isn't what they should be using. For those who live, sail, cruise, maintain and repair their boats, it shouldn't be any more difficult than any of the other technologies we tend to have to study, and fiddle with.

Just my opinion; which is worth about as much as yours...

Cheers.
Paul.

(Spellcheck didn't like balogna...)