Recommendations for Group 31 AGM replacement with LiFPO4

[newhaul]

Originally Posted by john61ct

What about the 20-30 years I'm striving to get out of mine?

ok what bank do you have please post the specifics for everyone . Either here or on the build thread . Would be nice to see what you have finally decided to do and why you chose the specific equipment .

[CapnBazza]

Originally Posted by john61ct

One would hope so.

If you are happy with the 2-3000 cycles the vendor promises, then by all means, most not-rip-off LFP will indeed deliver that, barring any catastrophic care failures.

But will they do the 12+ years a good FLA bank can? Has the price difference delivered good ROI at that point?

What about the 20-30 years I'm striving to get out of mine?

I won’t know for another 8 years if they’ll last 12 years, let alone 20 or 30. But, like solar panels, the technology advances and there is a good chance that in another few years I’ll be happy to replace them with something newer and hopefully better. It’s like evolution, it’s how we advance.

[swampbush]

Originally Posted by newhaul

ok what bank do you have please post the specifics for everyone . Either here or on the build thread . Would be nice to see what you have finally decided to do and why you chose the specific equipment .

I have already got three extra years out of mine by not buying them yet

[CapnBazza]

Originally Posted by john61ct

Putting more than 2-3 series strings (as each 12V unit is, 4S) in parallel can lead to shortened lifetimes from balancing issues.

I am very skeptical that drop-ins have the same quality of manufacturing, purity of chemicals etc.

Who is the actual manufacturer of the cells internally?

It is a very dicey market, thousands of small Chinese companies competing in sometimes shady ways, very little transparency no decent word of mouth.

I think very unlikely they will have the lifespan of Winston/Thundersky/Voltronix, CALB, GBS, Sinopoly. And so little collective experience has accumulated wrt drop-ins, this factor won't be know for decades

They may even mask the fact that the batt is LiPo or NMC rather than LFP, very very short-lived.

Drop-in 12V interior BMS is opaque, can't be adjusted or disabled, no communications to the outside, and they can suddenly isolate the battery with no warning.

Special steps must be taken to ensure this can't damage charge sources or sensitive load devices.

Terminating charging when full, or when temps get too low or too high, should be able to signal other*gear, or controlling generic relays.

As opposed to simply taking a batt offline without warning, which load dump can cause damaging spikes/surges.

The BMS can't be bypassed, even to check on the cells' voltages, and often drastically limits charge / discharge C-rates to a tiny fraction of LFP's capabilities.

LFP is usually capable of accepting very high charge rates, no problem. To the point that 2-3 day's worth of energy can be pumped back into the bank in an hour or two if you have a high-current charge source available. But the cheap included BMS in drop-ins prevents that, restricts you to a slow charge (and discharge) rate.

Check to see if they even allow serial or parallel connection into a bigger bank?

Allowing the "Full" or "Too Low" setpoints to be adjusted by the user to extend lifespan. The balancing function may require a charge voltage that is higher than what you want for longevity.

Allowing the user to even **see** the state of cell balance, verify that BMS function is working.

Allowing a cell to be swapped out if one proves faulty.

All impossible with drop-ins.

You have to understand, the whole "drop-in concept" is a lie if you want longevity, you need a ​good system, all the infrastructure designed for LFP from the ground up*

not just BMS
over-current protection
LVD and HVD safety cut-offs
temperature protection

but also
100% PROGRAMMABLE charge sources
IMO a separate charge and loads bus

Finally for a large bank, they're rarely cheaper, might as well get a packaged system from OPE-Li3 (Lithionics/Ocean Planet), Victron or MasterVolt.

Super B looks worth checking out also.

Geez mate, that’s a lot of adjustments you want to be able to make on a battery. How do you satisfy your need for so much intervention on a lead acid battery? Try a pair of these, you can suck 500 amps out of 2 x 120ah batteries and the price is in cheap Australian dollars. You’ll spend less time adjusting your batteries and more time enjoying your sailing. https://itechworld.com.au/collection...ithium-battery . Fair winds to you.

[Inkog]

Battleborn promises 3000-5000 cycles before capacity drops below 80%. Their batteries are also 100% rated capacity useable. Mine are actually over 105Ah usable from my testing. Their 100Ah packs are in realty closer to 120Ah internally.

One of my favorite things about LiFePo4 drop-ins is that you can add or replace batteries at anytime without needing to replace the entire bank. You can add a brand new pack to a healthy 5+ year old bank and they'll be perfectly happy together.

BattleBorn is a U.S company with a 10 year replacement warrantee. Will they be around in 10 years? Who knows, but they are huge in the RV world right now and are selling a sh*t-ton of batteries.

[newhaul]

Originally Posted by CapnBazza

Geez mate, that’s a lot of adjustments you want to be able to make on a battery. How do you satisfy your need for so much intervention on a lead acid battery? Try a pair of these, you can suck 500 amps out of 2 x 120ah batteries and the price is in cheap Australian dollars. You’ll spend less time adjusting your batteries and more time enjoying your sailing. https://itechworld.com.au/collection...ithium-battery . Fair winds to you.

remember one little detail all of his Lfp knowledge while now days rather extensive ( he is a quick learner) it is all theoretical and not real world actual personal experience.

[eMarineSystems]

A lot of good information from valid field experience here. We do not recommend putting that many batteries in parallel unless you have an external BMS that can communicate with all the batteries in the bank (Victron as an example). With individual batteries in parallel you are not able to see collectively what all the components of your battery bank are doing and therefore it could lead to problems with one battery turning off, the second following, etc. (cascading turn-off )until the bank is completely shut down and you have no concept of what happened. Please be sure you got an external BMS to integrate to all your batteries in the LiIon bank. You will thank yourself for spending the extra money to get there.

[john61ct]

Originally Posted by Inkog

Battleborn promises 3000-5000 cycles before capacity drops below 80%.

Yes, and were for a long time unable to keep even a small DC compressor fridge running, supposedly "too much current draw"!!!!!

Not even fully fixed yet, the special proprietary adapter cable often out of stock.

So when you have a windlass, bilge pumps, watermakers, bowthrusters any of which can demand 20x that much peak current loads, what do you do, parallel thirty of them?

Do you know how fantastic (and bigger) a proper packaged system you can buy for that money?

Then look at fast charging options off DC sources. . .

Sure for running a 20' minimalist boat, lights & nav off a few panels, maybe.

But not the kind of needs most members here have.

And BTW, that's not what I consider a long lifespan for LFP.

[Inkog]

Originally Posted by john61ct

Yes, and were for a long time unable to keep even a small DC compressor fridge running, supposedly "too much current draw"!!!!!

Not even fully fixed yet, the special proprietary adapter cable often out of stock.

So when you have a windlass, bilge pumps, watermakers, bowthrusters any of which can demand 20x that much peak current loads, what do you do, parallel thirty of them?

Do you know how fantastic (and bigger) a proper packaged system you can buy for that money?

Then look at fast charging options off DC sources. . .

Sure for running a 20' minimalist boat, lights & nav off a few panels, maybe.

But not the kind of needs most members here have.

And BTW, that's not what I consider a long lifespan for LFP.

I don't know what your talking about, and I question if you do either. This thread is about replacing a few old lead acid with LiFePo4, with specific questions about Drop-ins. His bank is currently <300Ah Usable. You can do that with 12v drop-ins for well under $3k, swap them out and be sailing in an hour.

I run my Battle Born bank at close to 1C discharge daily when I'm traveling, and the batteries don't break a sweat.

Why do you need an adapter for a two post drop-in battery?

[CapnBazza]

Originally Posted by john61ct

Yes, and were for a long time unable to keep even a small DC compressor fridge running, supposedly "too much current draw"!!!!!

Not even fully fixed yet, the special proprietary adapter cable often out of stock.

So when you have a windlass, bilge pumps, watermakers, bowthrusters any of which can demand 20x that much peak current loads, what do you do, parallel thirty of them?

Do you know how fantastic (and bigger) a proper packaged system you can buy for that money?

Then look at fast charging options off DC sources. . .

Sure for running a 20' minimalist boat, lights & nav off a few panels, maybe.

But not the kind of needs most members here have.

And BTW, that's not what I consider a long lifespan for LFP.

I must be luckier than you because 500 amps out of 2 LiFePO4 batteries is more than plenty for my needs.

[newhaul]

Originally Posted by john61ct

Yes, and were for a long time unable to keep even a small DC compressor fridge running, supposedly "too much current draw"!!!!!

Not even fully fixed yet, the special proprietary adapter cable often out of stock.
.

sounds to me more like a Lipo battery not an Lfp bank
Are you sure of the battery the guy you are referring to was actually using???

[john61ct]

Wow what a brainfart, completely different product, my apologies to all especially the folks at Battle Born

[newhaul]

Originally Posted by john61ct

Wow what a brainfart, completely different product, my apologies to all especially the folks at Battle Born

after all of the negative posts by you concerning them . You might want to start verifying before you repost specific data

[senormechanico]

Wow, that was a first, actually admitting he was wrong about something.

[Trimaran Ken]

Originally Posted by svspirited

Is the idea of a simple drop in replacement reality or marketing hype?

I just replace my FLA Group 31 with a 105 AH LiFePO4 drop in.

This was one of the best boat upgrades I have ever done. I would only consider batteries with a built in BMS. My battery protects against everything and does not require any other changes. It is happy to charge off my solar charge controller (on FLA setting), my Yamaha 9.9 outboard, or a small 110 volt charger I carry in case I'm at a marina for an extended time. Mine has a Bluetooth connection to read various status items.

This is a battery I imported directly from China that can not be ordered by the general public, but there are similar batteries available from suppliers in the US.