lithium batteries or AGM

[CarinaPDX]

For the OP, it should be clear that unless you are an enthusiast and wish to spend a lot of time learning, designing, installing, and maintaining a lithium system (not to mention the extra cost) you should stick with lead technology. Also, if you are a serious cruiser you may want to stick with batteries that can be replaced almost anywhere in the world. OTOH if you are a bit of a geek and would enjoy having a state-of-the-art system to play with then have at it.

Years ago my Rolls deep cycle batteries reached end-of-life when I was in Curacao. I couldn't find quality deep cycle batteries locally, and I was told that the airlines wouldn't ship them (possibly wrong as they are shipped dry-charged but I was in no position to argue). I ordered in some Sonnenschein gel batteries, which were allowed as they did not contain liquid battery acid. Lithium? Good luck with that. Anyway, if nothing else I could have bought some cheap truck batteries to continue to a place with replacements - is it possible to do the same with a lithium charge system? (I don't know the answer, but it would be important to me.) And if specialist chargers/BMS are required, it is not likely to be able to replace them in many cruising grounds. For me, reliability and repairability trump whatever benefits the lithium batteries offer.

Of course, YMMV.

Greg

[john61ct]

It is entirely practical for an owner without special knowledge or a high level of interest to successfully manage a quality packaged $ystem.

You just need to be willing to let the pros who install it to teach you the key items to pay attention to. Won't take any extra time compared to say dealing with a watermaker, or even that flooded Rolls bank.

Their longevity means, barring disaster, they won't need replacement for 15-20 years IMO maybe longer, we just don't know yet.

And if disaster does strike, yes an infrastructure designed for LFP will just be charging normal lead a bit slower due to lower voltages.

GEL may well just slot in fine.

Long enough to get you back home anyway 8-)

Personally, I make sure all my charge sources, and other "permanent" infrastructure, have custom user profiles / full setpoint adjustability, so that I can easily swap out the banks (as a consumable item) for any chemistry.

[44'cruisingcat]

They're not as fragile as they're made out to be either. Two of my friends have had their LIFePO batteries severely over discharged. Below 2 volts per cell. Cells bulging, looking like a disaster.

But with advice from the supplier, they both were able to recover the cells, and report only minor capacity loss.

I doubt if AGMs would have fared any better.

[john61ct]

But who knows how many lifetime cycles lost?

Say in theory they'd last up to 5000 if "coddled" over twenty years, call a big $5000 system $1 per cycle, or $250 a year.

The mfg rates 2000 cycles treating them per their specs.

But damaged like this maybe only 1000, and could be far less, maybe only a few years.

The large up-front investment makes things inherently risky, few business investors would be willing to delay ROI like that.

And sometimes sh1t happens even with all the right care and protective infrastructure.

But a lot riskier with a non-tech noobie trying DIY to save money.

[travellerw]

Originally Posted by john61ct

It is entirely practical for an owner without special knowledge or a high level of interest to successfully manage a quality packaged $ystem.

You just need to be willing to let the pros who install it to teach you the key items to pay attention to. Won't take any extra time compared to say dealing with a watermaker, or even that flooded Rolls bank.

Their longevity means, barring disaster, they won't need replacement for 15-20 years IMO maybe longer, we just don't know yet.

And if disaster does strike, yes an infrastructure designed for LFP will just be charging normal lead a bit slower due to lower voltages.

GEL may well just slot in fine.

Long enough to get you back home anyway 8-)

Personally, I make sure all my charge sources, and other "permanent" infrastructure, have custom user profiles / full setpoint adjustability, so that I can easily swap out the banks (as a consumable item) for any chemistry.

This I agree with %100.... We have a very good cruising friend who has ZERO knowledge of Lithiums and has been cruising 2 years. Her system was designed and installed by someone who knew what they were doing and it has stood up to her abuse without issues. Unfortunately she does struggle with finding people to help when things do go wrong (like when her Victron charger packed it in). None of the professionals wanted to help (at least down here).

We also know another cruiser with GBS cells that were discharged to pretty much ZERO volts early in their life twice (a multimeter showed 0.5 - 0.6 volts on the bank). All loads were disconnected and those batts were nursed back to life on a power supply (both times). They have now been cruising on those batteries 4 years and just now are feeling the effects of that punishment. However 4 years of %100 full time cruising means quite a few cycles. I was certainly impressed the cells survived and lasted 4 more years.

As to the other questions.. I have spotty internet here in Martinique and am fighting with my wind generator. I will endevour to dig up my links when time permits.

One question I do have for Mainsail is on temperature. Any idea what the hottest temp your cells have experienced? Down here in the islands temperature is a big issue. Even in a well designed compartment its difficult to keep things below +40C at the height of the day!

[ggray]

I've been looking hard at LFP.

I need to replace my batteries NOW, but decided to wait a while longer on the LHP. I was thinking about Fireflies in the interim, but a friend suggested looking at Vmax Tank batteries:

https://www.vmaxtanks.com/XTR6-235-6...ry-_p_152.html

Does anyone have any experience with them? The price is certainly attractive.

[john61ct]

Just based on "informed instinct", likely not even qualify to call true deep cycling.

You should be able to get their tech support to provide a life cycles vs DoD graph.

FLA Trojans and Duracell (Deka) 6V GCs are rated to 800+ cycles at 50% DoD, and cost ~$200 for 200+AH, no shipping.

That to me is the baseline.

[200MPH]

Should be no real problem changing from Li to Pb in a situation where you need a battery quick and there is no Li replacement locally. In our case we were able to reprogram 3 out of 4 battery charging sources to suit Li. But to change them back to Pb settings would be no problem. Its only a problem if you had dedicated Li specific battery charging devices that are not adjustable....so try to avoid that and you'll not have to worry about going back to Pb battery if necessary!

As to the firefly carbon foam batteries, from memory they were not cheaper than Li. So for the money, why not go Li?

[john61ct]

Originally Posted by 200MPH

Should be no real problem changing from Li to Pb in a situation where you need a battery quick and there is no Li replacement locally. In our case we were able to reprogram 3 out of 4 battery charging sources to suit Li. But to change them back to Pb settings would be no problem. Its only a problem if you had dedicated Li specific battery charging devices that are not adjustable....so try to avoid that and you'll not have to worry about going back to Pb battery if necessary!

As to the firefly carbon foam batteries, from memory they were not cheaper than Li. So for the money, why not go Li?

The FF certainly **are** a lot cheaper than LFP, if you agree that only packaged systems including a proprietary BMS are suitable for most boat owners.

Even in a DIY context, you need to account for the (time and) money spent on all the required infrastructure, replacing existing charge sources with adjustable ones, etc all costs more than even a big bank of just the raw cells.

Firefly just drops in at $500 per 100AH.

Not all the benefits of LFP, but resistance to PSOC and deep discharges when needed is worth paying a premium for many use cases.

[CatNewBee]

There are lots of great LiFeYPO4 installs on RV's in Germany, I do know several person who use them for years flawlessly with several different BMS solution's).

The Winston Thundersky cells are very popular.

I also have seen several installations in Liveaboard blogs with the yellow cells and also have seen 1000Ah cells installed in a Lagoon 440 Fly-bridge that was recently for sale.

Also there are a lot drop-in LFP bricks installed in various vessels with internal BMS. The Wynns have such a setup for instance, but there are lots more out there too.

LiFeYPO4 is superior to any Lead Acid / AGM / GEL installation, they are smaller, lighter, charge faster, can handle higher currents, with a good BMS they are maintenance free.

Of course all the system integrator's do not like us to set up our own installations, because they want to sell their LFP for 3-4 times the price.

[john61ct]

All that is true.

And?

[CatNewBee]

Originally Posted by travellerw

Fair enough.. Not sure anything I say or post would change your opinion... Nor do I care to..

However... Can I ask.. Do you have Lifepo4 batts? Do you know anyone personally (not here on CF) that is running them in a liveaboard scenario?

Its clear our opinion will continue to differ no matter what.. My boat, my bank, my life... Take it for what its worth, or not IDC...

My post was related to this...

Well, I'll go the LiFeYPO4 path, so soon +1 user

BTW, My Installation will be 1000Ah LiFeYPO4 , cost estimate: 5.500€ including BMS and solenoids, so 550€/100Ah, quite close to the 500$/100Ah of the FireFly, but a lot better.

[john61ct]

Links please.

Yes European campervan market is **much** more developed and technically mature.

Maybe more disposable income, I guess universal free education and health insurance help.

[john61ct]

> drop-in LFP bricks installed in various vessels with internal BMS

I would avoid, for exactly that reason, except as a portable powerpack, camping, day on the beach, etc

> The Wynns have such a setup for instance

Not technical

> quite close to the 500$/100Ah of the FireFly

As mentioned, infrastructure replacements like adjustable charge sources also needs to factored in.

Not advocating one type over the other, but the "much better" prediction / opinion will IMO need more evidence.

[senormechanico]

"universal free education and health insurance"

That stuff just mysteriously drops out of the sky for free from a cloud of fairy dust?