LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[john61ct]

Originally Posted by Pelagic

I will start a new thread:
"Lithium Ion for Dummies"

Which will then spin out of control 8-)

But hey, new threads cost nothing!

Personally, better to start one that is just for **your** setup and needs, lay out the details, and ask Qs as specifically as possible.

Anything goes over your head, you google and ask for clarifications

you can then send OT too-techie arguers back here 8-)

[newhaul]

Originally Posted by john61ct

I did not realize Lithionics sold **any** drop-ins, much less that big.

don't know about orthodontics but here is a drop in 400 ah from Vasworld Power

[Hoopla]

Originally Posted by jkleins

Thanks. It is clear that you are not impressed with the current crop of drop in batteries. The question that I am asking is not about that but more about the concept of the drop in. It seems that each of the points you make are not related to the concept but the actual implementation. i.e. #1 proper fusing is needed but normally not related to the actual batteries we have now why are they the responsibility of the battery now?
#2 this is marketing, not anything about the actual product. If they were more clear about charge current,etc would the product concept still be bad?
#3 doesn’t the whole concept of the BMS being built in mean that each battery might shut down if there were a BMS malfunction but it is not guaranteed that all the batteries would shut down at once unless the charge source was indeed faulty. Wouldn’t that be a problem related to the charger not the battery? Don’t they come back online as soon as the charge source is removed and a load applied?
#4 this seems to be a real issue but it seems that many just put a lead acid battery in the charge circuit to accommodate this. Is this a bad idea?
I have read this entire thread as well as many related to electric cars and RVs and I am just as confused as you think I am. I am just trying to sort between bad implementation/instruction/marketing that some of the manufacturer are clearly guilty of and bad engineering. It seems less clear to me that a good drop in battery and a good charge system installed correctly with clear settings designed for LFP batteries wouldn’t be an advance rather then a setback.

Jim

Jim I see what your asking being ignore anything the manufacture says and if you implement and operate properly do you have a functioning, reliable and safe source of energy storage using a LFP battery that incorporates an internal BMS without any external communication?

However before answering the fact is once you do that, you no longer are installing a "Drop In" battery. That concept ceases starting with changing existing primary fusing to that with high interrupt capability and then addressing a myriad of issues down the line beyond that.

It ceases in terms of operation when saying a float or maintenance charge is avoided for all but short periods and only when someone is on board to hear a pack voltage monitoring alarm. Or if unused for extended periods the SOC is below 50% to counter capacity shrinkage.

Those things are all being done to both preserve the investment and insure it is safe but are ignored by the manufacturer because to reveal them their offering is no longer a "drop-in" replacement of LA.

The answer to your question is dependant on the product and questions you would need to put to the vendor. For instance what is exactly being monitored and how is it managed. Is it a pack or individual cell voltage? What are the high and low voltage cut offs? Is temperature monitored and if so what the high and low temp cut offs? Does it incorporate cell balancing and if so how does it operate? If the BMS is faulty does it automatically shut down? How can you determine if the BMS is operating to specs? If the BMS activates does it have to be manually reset or in the case of a low voltage event will it keep cycling on and off not allowing voltage to bounce up from the zone of death? Does it have an audible alarm?

Then there are questions the vendor can't properly answer
For instance the quality of the cells themselves so you can be assured they will have retain some semblance of balance, bearing in mind there is no means to return them to balance if they are not.

After doing all that my guess is if you are prepared to accept some risk and operate well within the accepted voltage ranges for LFP you may have a reliable, functioning and safe energy storage platform.

That risk is attached to high and low voltage events that if they were to occur at the voltage levels the BMS kicks in you can be assured the battery bank has suffered and that injury can't be reversed. That risk is magnified on account avoidance relys on human intervention, but where humans are known to forget and for high voltage events, chargers that have a history of misbehaving and when they do the battery takes a hit and maybe a fatal one.

So the bottom line is that it is no longer about "investing" but "placing a bet" and one arguably against the odds.

[Delfin]

Originally Posted by john61ct

I did not realize Lithionics sold **any** drop-ins, much less that big.

In any case, yes, large amp hour LiFePO4 batteries are available, and yes, they are available as "drop-in", whatever the heck that means. If it means removing LA batteries, replacing them with Li batteries and using precisely the same regulation, alternator and charger, then assuming said equipment allows setting max charging current, allows detuning the alternator so it doesn't burn up trying to keep up with Lithium batteries ability to suck down current, and assuming you can eliminate or dramatically minimize absorption period and float, then yes, Lithionics and others make "drop-in" Li batteries.

Since many install smart regulation and chargers for their LA batteries, the same equipment can be used for Li batteries. Given the cost of the darn things, one would probably want to use the same care in managing a Lithium bank that you use to avoid running over rocks or burning up a $30,000 diesel engine, but that's boating for you.

If you want to build your own you can save a lot of money, and then threads discussing the complexities of Lithium batteries on dude boats will be helpful. However, if you want to purchase a Lithium bank and BMS from a reputable supplier like Bruce Schwab, and you already have good regulation and a programmable charger, then drop-in and go, just as I did. Just don't try to manage them like a LA bank, anymore than you would change out a gas engine for diesel and manage the diesel like it was gas.

[Hoopla]

Originally Posted by john61ct

I did not realize Lithionics sold **any** drop-ins, much less that big.

They have from the beginning but I think at first was for small capacity and start batts only. Now some larger capacity in different formats.

Comparing their internal BMS/Switching, HVC and LVC voltages and cell quality etc to that of typical "drop-ins" is like comparing chalk and cheese. They also don't market them as a "drop-in do nothing else" replacement for LA.

They are probably the premium Marine LFP supplier in the world today IMHO.

[Hoopla]

Originally Posted by Delfin

In any case, yes, large amp hour LiFePO4 batteries are available, and yes, they are available as "drop-in", whatever the heck that means. If it means removing LA batteries, replacing them with Li batteries and using precisely the same regulation, alternator and charger, then assuming said equipment allows setting max charging current, allows detuning the alternator so it doesn't burn up trying to keep up with Lithium batteries ability to suck down current, and assuming you can eliminate or dramatically minimize absorption period and float, then yes, Lithionics and others make "drop-in" Li batteries...

.

The term "Drop-In" is clearly not understood.

It refers to LFP batteries incorporating an internal BMS that can't communicate externally AND incorporates high and low cut off voltages beyond the range recognised as being acceptable for LFP.

With those out of range voltages it can then be marketed as a "drop-in" substitute for Lead Acid WITH NOTHING ELSE REQUIRED.

Lithionics also in addition to their external BMS line have a self contained offering utilising an internal BMS but fully featured and with correct HVC and LVC's and so they DON'T market it as a "drop-in" substitute for LA.

Your belief that most people already have programmable charge sources and or an understanding of things battery in my experience is far from correct.

Three decades of seeing GEL batteries marketed as "drop-in" replacements for FLA and murdered and likewise AGM's burning up small case auto style alternators or being killed with excessive DOD's and or not being regularly returned to 100% SOC confirms that belief.

The marketing of LFP as "Drop-In" simply shows this same path is being travelled again where wallets will be emptied and the reputation of another battery chemistry trashed by the people selling them with no disclosure.

[Hoopla]

Originally Posted by OceanPlanet

I hope that readers on this forum realize they are getting access to some very smart and experienced contributors here (John61ct, MaineSail and Hoopla being prime examples). I've been in the Li battery game for a long time and don't know where else (aside from an ABYC Standards committee meeting) where one would find better info.

Bruce very kind of you but I just soiled my pants being put around the same table as you guys.

[john61ct]

I think the term Drop-In has now been well-defined wrt the characteristics of the battery sold.

If someone wants to add their own infrastructure for charging monitoring and BMS functionality,

I say excellent!

ignoring maker specs to give LFP proper care is of course required with all types of LFP implementation once you decide to strive for maximum longevity.

By saying "that is no longer a drop-in system" you are giving a compliment.

[Hoopla]

Originally Posted by Pelagic

This has been a fascinating technical thread but at 6000 posts is it beyond most cruisers who are just now considering the battery change?

I will start a new thread:
"Lithium Ion for Dummies" and hopefully the fantastic gurus on here would advise the less specialist captains on here with a redesign solution for their own boat's needs?

My own boat is not unlike the Delos 24v system / 8 x 8D 12v batteries connected series- parallel who have just released a video of their electrical changes.

https://youtu.be/GvDCLtN22jY

It would be interesting to hear the critiques from the knowledgeable contributers on here

I will still follow technical one, but maybe the Dummies one can answer more basic user questions.

Pelagic my only advice is buried within those 6,000 posts you will discover pure gold and as OceanPlanet says above found no where else. It is worth the dig. As outlined below the Delos guy should have spent some time here digging

As for the Delos video about their swap to LFP. All I can say is wow.

There is also a blog that accompanies it.

https://svdelos.com/sailing-tools-software/lithium/

When Social Media "Influencers" like Delos endorse something people start lining up to buy. They have 280,000 UTube subscribers, many more lookers but more importantly around 2,000 Patreons who kick in money in the order of USD$100k+ per year. They are very professional albeit the vlog genre is not to all tastes. It is also a full time job so they earn every penny of that income.

This is actually an excellent Case Study regarding the current discussion about "Drop-Ins" as I have defined above. I see you have a similiar system?? if so please don't construe what I say here as critisism, just hopefully an objective review of their approach, as best as can accertain.

1. Background.

This Vlog and Blog have been made in relatively real time so post LFP experience is happening right now. To explain these UTuber Vloggers upload everything via WiFi not Sat so to maintain continuity of income pre-make episodes that are automatically uploaded when not within WiFi range

They are big energy users on account up to 6 people on board, large loads particularly with Microwave and all the video and editing demands etc.

The AGM's (Lifeline I think so not cheap and chearful) are around 6 months old and replaced in Cape Town. I suspect the LFP vendor has either donated or provided a deal to good to refuse, so this obviously has some bearing on system selection. I note they go on about Propane/LPG versus Induction Cooking, but think their reasoning a bit shallow so more a case of hey we have LFP, let's go Induction.

They have four(4) existing charge sources, namely

a) Solar utilising Victron regulator(s) that are LFP programmable.
b) Wind with a proprietary regulator of a vintage I doubt LFP programmable.
c) 2 X Existing AC Chargers (large AC Generator) one definitely not LFP programmable the Masterbolt a maybe depending on vintage. A new Victron Charger/Inverter LFP programmable and with potential free contacts to accommodate a LFP BMS with external communication capability.
d) A 80HP diesel auxilarry with twin small case OEM alternators incorporating internal regulation I think.

I should have been a detective :-)

2. Delos LFP Installation

a) A collection of 12v (wired in series and parallel to produce 24v) to furnish a real AH capacity far in excess of the AGM's. These are 12v packs containing an internal BMS and contactors with no external communication. Note at this point having regard to both existing charge sources and their vintages/features plus a new Inverter driven high load source with an existing Microwave alarm bells are going off in my head.

b) A Victron BMV battery monitor that does include a relay feature but did not see that included in the install.

c) There was no modifications made to existing infrastructure other than you would presume charge sources which in all but Solar and one AC charger at best plus incorporating a LA Start battery as a "load dump" but no details on how that was to be achieved with no mention of say a DC/DC Charger or diode isolator or there being no BMS controlled external high current contactors to control the enivitable voltage spikes associated with a high voltage cutoff etc?

3. Critique of Delos Instalation

Firstly to be fair to the Delos crowd in the aim of uplifting a
video quick smart to keep the dollars rolling in they may already have planned modifications to existing infrastructure where they can to accommodate LFP to be the subject of another episode. However as they make no mention of that and are on the move, bearing in mind they are in the Caribbean where even the most simplistic of gear is hard to procure one would think they would stay put and implement a holistic approach to dealing with their LFP conversion.

That aside my critique assumes the worst and that is not the plan, but more importantly I'm viewing this is the eyes of their fan club who will go out and copy what they do without reservation.

The specs of their LFP batteries are as follows.

https://www.transporterenergy.co.uk/...technical-data

So the things that jump out in those specs.

a) Charge voltage 14.4 - 14.6v. This exceeds the maximum LFP cells can tolerate by 0.2 - 0.4v at best with the most sophisticated BMS cell balancing available today and even then chasing individual cell voltages is like herding cats, or my analogy upthread of 100 people trying to get out of a bedroom. There is no mention as what the internal BMS HVC is so I'm assuming in LFP killer land approaching 15v pack voltage and as for individual cell voltage who knows. It may not even be monitored.

Conclusion: This Charge Voltage spec is designed to attract the 'Drop-In replace LA with nothing else required crowd.

b) Load Voltage. No voltage nominated for LVC other than stating "discharge up to 100%". That is nonsense on account at around 25% SOC LFP cells turn into cats each with their own voltage and when measured on pack voltage basis that is irrelevant. Cell damage is about to occur.

c) Stored Voltage. The Delos guy with his LA brain engaged along with the pale skinned LFP Vendor marveled as delivered each pack (not individual cells as impossible to measure) was sitting at 13.3v or 100% SOC. Another alarm bell, stored voltage should be 50% SOC max. To do otherwise invites capacity shrinkage with LFP.

d) The BMS. In the blog the new Victron Battery Monitor is described as being integral to the new LFP instals BMS. That is nonsense on account it provides no automated pack voltage security other than being an alarm and a display the human eye can observe if they are all sober. Having a Still on board and watching some of their Vids brings that aspect to mind

e) The Cells. The Vendor says their system is US made obviously to avoid connotations attached to things China. I have already described upthread the principal source of LFP cells to the western world being reliant on China and quality an issue. For example Tesla sick of China supply problems have built their own battery factory. Genasun who had very sophisticated cell balancing equipment gave up on being in the LFP business, not withstanding insisting individual cell supply from CALB had sequential build numbers.

So to this crowd advertising a US made product. My guess take a hammer to it one will find a 100% US made and assembled product, save for the China cells having absolutely no provenance or guarantee on quality. My apologies to the vendor if I'm wrong.

4. Conclusion

It is quite clear this is a "Drop-In" solution as I have defined being an internal BMS with no external communication and having a BMS speced to suggest it is a LA replacement with no modification to existing infrastructure solution.

However having regard for maybe some WIP by Delos not yet revealed, not mentioned or even without it, I suspect the Delos crowd will dodge most of the bullets attached to their discounted/free LFP instalation for these reasons, bearing in mind they are not typical users.

a) They are onboard all the time and at least half the crew are energy savy and the Skip is no idiot.

b) They consume a lot of energy and despite all the charge sources, the prospects of them having a HVE where they are most at risk is more remote compared to other users. At sea their principal charge source is AC Chargers via an AC Generator courtesy of fuel tankage and not withstanding that tankage are very cognisant of what they consume so prospects of an HVE are low.

c) That said you would think they are least at risk when at sea even with multiple energy sources driving LFP and even inexperienced people switching things on and off, However with the introduction of large Inverter/Charger with a "pass through" facility not contemplated by their boats 2 decade old electrical distribution and switching suddenly high load AC devices come into play like Hot Water, Air Conditioning and now an Induction Stove. The prospect of a LVC has just increased, but without a LFP BMS that can't do anything other than shut down all power long after it should be.

d) Their next greatest risk is being on "Shore Power" in ydtms of an HVE. They need to get a handle on that prospect quick smart.

e) The most annoying thing is Delos being a major social media influencer will tip people into "Drop-In" LFP nonsense. ABYC need to get cracking to stop this happening.

End of sermon and I hope some can expand upon my agricultural analysis of this Delos instal as a "Drop-In Case Study".

[OceanPlanet]

Originally Posted by Hoopla

They have from the beginning but I think at first was for small capacity and start batts only. Now some larger capacity in different formats.

Comparing their internal BMS/Switching, HVC and LVC voltages and cell quality etc to that of typical "drop-ins" is like comparing chalk and cheese. They also don't market them as a "drop-in do nothing else" replacement for LA.

They are probably the premium Marine LFP supplier in the world today IMHO.

Note that the Lithionics "internal BMS" modules that we sell ALWAYS come with an external charge control circuit that we call the "FCC". We insist that the FCC must be able to turn off all charge sources that could:

1) Be ruined by running without a battery connection (alternators!), and/or

2) Any charger that isn't rated as a stand-alone power supply that won't spike the voltage and kill all the electronics that would be connected to it if the battery had to disconnect itself.

All that said, note that over 90% of the Lithionics we sell use external BMS's and set up for "dual-channel" systems...that is, with separate charge & discharge channels. This makes for much more elegant operation at HVC (loads stay connected) or LVC (source stay connected), etc. Also makes for better automatic system restarting if the boat is unattended. See attached sample diagram.

In any case, whether internal single-channel (using FCC) or external dual-channel (also using FCC), all the chargers must be programmed to the correct parameters.

[Pelagic]

Originally Posted by Hoopla

End of sermon and I hope some can expand upon my agricultural analysis of this Delos instal as a "Drop-In Case Study".

Thanks for that detailed analysis and having read this whole 6000 post thread, I've actually managed to follow most of your notes on Delos.

On the Dummies thread I will endeavour to get a consensus on supplier and system to replace my 24v x 1040Ah AGM batteries

[Hoopla]

Originally Posted by john61ct

I think the term Drop-In has now been well-defined wrt the characteristics of the battery sold.

If someone wants to add their own infrastructure for charging monitoring and BMS functionality,

I say excellent!

ignoring maker specs to give LFP proper care is of course required with all types of LFP implementation once you decide to strive for maximum longevity.

By saying "that is no longer a drop-in system" you are giving a compliment.

I hope to God the terminology "drop--in" is now understood, but my guess if this thread hits 12,000 posts it is still being debated. Nature of the beast.

Spot on, ignore "drop in" maker specs as you say as a decent LFP system can still be built using it, but with the overider being subject to existing infrastructure and application.

That said for a vast majority of applications and uses I see, I recommend Flooded Lead Acid.

No wonder the kids didn't go to College :-)

[john61ct]

For any DC charge source without user-adjustable setpoints, output can be routed through Sterling BB line DC-DC chargers.

Putting the lead batt load dump on the same circuit as the LFP bank will indeed help buffer spikes from unexpected cutoff events from the internal BMSs.

Cheap, even sacrificial, no need to ensure a proper charge profile for that.

Originally Posted by Hoopla

Charge voltage 14.4 - 14.6v. This exceeds the maximum LFP cells can tolerate by 0.2 - 0.4v

No, any LFP 4s pack can tolerate those levels just fine.

It's just that this high charging voltage will only get the customer past the warranty period, or maybe the batt's rated lifetime cycles,

not the **much** longer life it would have at lower voltage, avoiding the shoulder.

> "discharge up to 100%"

My 100% DoD is defined as 11.9V, just as my 100% Full SoC is defined as 13.8V. Assuming low current rates.

These are arbitrary choices made by the owner.

The vendor LVD cutoff may be lower, but it certainly is not at an instant & permanent death-level low voltage,

> at around 25% SOC LFP cells turn into cats each with their own voltage and when measured on pack voltage basis that is irrelevant. Cell damage is about to occur.

Not so. Depending on discharge rate, 11.9V is around 10% compared to vendor zero, and still well above the immediately dangerous low-shoulder area of the SoC/voltage curve.

Yes, lifetime cycles are reduced by higher DoD, as with any batt, but that is a decision for the owner, not a hard bright line, but a smooth greyscale curve,

and so, if a higher cutoff is automated, that is more "user level" protection, not BMS functionality. The Victron BMV relay could be well used for that, as well as user-adjustable LVDs at higher setpoints fronting specific non-essential load devices or circuit groupings.

What are:

WIP
ydtms

?

[jkleins]

Originally Posted by Hoopla

Conclusion: This Charge Voltage spec is designed to attract the 'Drop-In replace LA with nothing else required crowd.

b) Load Voltage. No voltage nominated for LVC other than stating "discharge up to 100%". That is nonsense on account at around 25% SOC LFP cells turn into cats each with their own voltage and when measured on pack voltage basis that is irrelevant. Cell damage is about to occur.

c) Stored Voltage. The Delos guy with his LA brain engaged along with the pale skinned LFP Vendor marveled as delivered each pack (not individual cells as impossible to measure) was sitting at 13.3v or 100% SOC. Another alarm bell, stored voltage should be 50% SOC max. To do otherwise invites capacity shrinkage with LFP.

d) The BMS. In the blog the new Victron Battery Monitor is described as being integral to the new LFP instals BMS. That is nonsense on account it provides no automated pack voltage security other than being an alarm and a display the human eye can observe if they are all sober. Having a Still on board and watching some of their Vids brings that aspect to mind

e) The Cells. The Vendor says their system is US made obviously to avoid connotations attached to things China. I have already described upthread the principal source of LFP cells to the western world being reliant on China and quality an issue. For example Tesla sick of China supply problems have built their own battery factory. Genasun who had very sophisticated cell balancing equipment gave up on being in the LFP business, not withstanding insisting individual cell supply from CALB had sequential build numbers.

So to this crowd advertising a US made product. My guess take a hammer to it one will find a 100% US made and assembled product, save for the China cells having absolutely no provenance or guarantee on quality. My apologies to the vendor if I'm wrong.

4. Conclusion

It is quite clear this is a "Drop-In" solution as I have defined being an internal BMS with no external communication and having a BMS speced to suggest it is a LA replacement with no modification to existing infrastructure solution.

However having regard for maybe some WIP by Delos not yet revealed, not mentioned or even without it, I suspect the Delos crowd will dodge most of the bullets attached to their discounted/free LFP instalation for these reasons, bearing in mind they are not typical users.

a) They are onboard all the time and at least half the crew are energy savy and the Skip is no idiot.

b) They consume a lot of energy and despite all the charge sources, the prospects of them having a HVE where they are most at risk is more remote compared to other users. At sea their principal charge source is AC Chargers via an AC Generator courtesy of fuel tankage and not withstanding that tankage are very cognisant of what they consume so prospects of an HVE are low.

c) That said you would think they are least at risk when at sea even with multiple energy sources driving LFP and even inexperienced people switching things on and off, However with the introduction of large Inverter/Charger with a "pass through" facility not contemplated by their boats 2 decade old electrical distribution and switching suddenly high load AC devices come into play like Hot Water, Air Conditioning and now an Induction Stove. The prospect of a LVC has just increased, but without a LFP BMS that can't do anything other than shut down all power long after it should be.

d) Their next greatest risk is being on "Shore Power" in ydtms of an HVE. They need to get a handle on that prospect quick smart.

e) The most annoying thing is Delos being a major social media influencer will tip people into "Drop-In" LFP nonsense. ABYC need to get cracking to stop this happening.

End of sermon and I hope some can expand upon my agricultural analysis of this Delos instal as a "Drop-In Case Study".

Thank you for the clarification about what you are considering "drop-in" versus what I guess I was considering "built-in BMS". I was confusing the two because I am not as concerned about the built-in BMS that doesn't communicate with the rest of the system if the rest of the system is indeed set up to handle exactly what you are using.

You also assume poor quality is synonymous with "drop-in" and I can't argue that that is the current state of play as I don't know, but it doesn't necessarily have to be does it? Can't BMS devices be built-in to the battery that are good quality? and if so wouldn't it meet the needs of battery protection that you are concerned about.

I think you under estimate the number of users that have similar use patterns as Delos. I think most cruisers would like to be in that use pattern but have developed "coping mechanisms" to get to 100% charge every day and therefore have overdeveloped charging systems that are not really needed. They would need more protection from overcharging then others who rarely get to 100%. Many would be happy keeping their batteries in the middle of the safe range with the variety of charging sources they have but I certainly understand that others do have other needs. I am just coming from someone with a similar profile and can see some benefit in a good quality built-in BMS battery.

I appreciate where you guys are coming from as suppliers that have to make all your clients happy these solutions are more difficult to explain and manage. I have yet to be convinced though that for people who live on the hook and understand their charging sources and can control them that the concept of a good quality lithium battery with an accurate and effective built-in BMS wouldn't be helpful.

Jim

[Hoopla]

Originally Posted by OceanPlanet

Note that the Lithionics "internal BMS" modules that we sell ALWAYS come with an external charge control circuit that we call the "FCC".

Bruce

I pride myself knowing what who makes what and as far as Lithionics concerned always went to the external BMS as the best out there and as their system sales suggest.

The fact Lithionics internal packaged BMS/Contactors (while not my cup of tea) but fully featured, also comes with external communication I have totally missed. Lithionics should make that feature more visible to differentiate their offering to the Drop-In rubbish.