LITHIUM BATTERIES FOR DUMMIES!

[peter57]

Originally Posted by BenFranklyn

Pelagic, Some hard won experience worth considering. Lithium batteries do give great energy density. I installed a complete Victron system with 2 of the 24VDC, 180 AH power packs and they gave me something comparable to what 8 of the 8D Lead Acids gave me. Saying that I would never do it again as the system has been too unreliable. Worse then the unreliability is the lack of any support from the factory or knowledge of the product from people in the yards, including those listed as Factory authorized technicians. If you are going to actually travel as I do then you can expect to sit at distant ports for weeks on end trying to get these systems to work or find parts that pretty much do not exist in the distribution chain. Its really nuts. What we eventually did was to run an alternative feed harness that allows me to disconnect the lithium system completely and wire my panels directly to the engine battery bank. I needed to increase the size of the engine bank which reduced my weight savings from the Lithiums but it was absolutely necessary. Some of the new self contained Lithiums may be worth looking at once they have some history. The idea that I can swap back to an AGM in some distant port is priceless. Another technology that looks interesting is the Firefly carbon foam lead acids.

If you decide you must go Lithium, do a little experiment once you obtain a parts list from the company you have chosen. Get on the phone and see just how much support you can get on the products from there list of service centers and see how many of the parts are available to purchase immediately.

Best of luck in your endeavor.

You could have installed a "Victron colour control GX remote panel" which can be connected to the internet and your provider can connect and diagnose the problem from his work place to where ever you are, no need for the trained lithium expert in the area your at.

[Pelagic]

I have been studying the recommended reading for the last 24 hrs, so happy to share my base line cliff notes, borrowed mostly from Eric’s terrific blog.

My goal is to bring me from an Ion Dummy to an informed buyer, so sorry if the first posts are really basic.

• The only desirable Li-ion chemistry on board a yacht is Lithium Iron Phosphate
• Lithium Iron Phosphate (LiFePO4, sometimes also referred to as LFP) is by far the most robust type of lithium battery developed so far. The other types of lithium-ion batteries are mostly completely unsuitable and unadvisable for use on board a yacht.
• There is a lot of misinformation and lack of understanding of this battery technology, including and especially amongst people marketing marine electrical equipment. The technology is not where their core interests lie.
• Engineering issues are often poorly resolved in marine installations and some lithium batteries installed on yachts as DIY systems have been associated with much anger and bitter cringing, for no reason of their own.
• Many of these installations have ended in a very expensive fiasco. Poor engineering and inept advice from battery resellers and marine electrical equipment manufacturers are the #1 problem with lithium today.
• Badly engineered lithium battery systems are still causing enormous amounts of electrical damage on board vessels, which typically doesn’t get reported back.
• Moving from lead-acid batteries to lithium cells represents a paradigm shift. Lithium cells must not be operated or treated the same way as lead-acid batteries

Lithium Batteries
• Deteriorate if left fully charged and must generally be kept in a partial state of charge
• Can be stored for years in a partial state of charge with little or no adverse effects
• Are quickly and irreversibly damaged by trickle-charging
• Are destroyed by overcharging
• Are destroyed by excessive discharge
• Are quickly damaged by charge temperature compensation schemes
• Can be damaged if charged at very low temperatures
• Must use charge termination once full
• Age and degrade much more rapidly at higher temperatures
• Protecting lithium cells from heat is essential in terms of achieving a long life. The objective should be trying to keep them around some 15-25°C (59-77°F) as much as possible.

More Technical explanations are within these Links which need to be read

Electrical Design For a Marine Lithium Battery Bank | | Nordkyn Design

• Before even considering sourcing any battery cells, the on-board electrical system must be reviewed and all connections pertaining to loads must be physically separated from charging sources. On a standard, tidy installation, it all leads to positive and negative busbars. At a minimum, the positive bus must be split into distinct charge and load buses and the corresponding cabling moved.
• High-current DC disconnectors must be installed in the paths between the battery and the new busbars, so the battery can be isolated from loads and/or charging sources if needed.
• The cells that will make up the battery need to be charged and carefully balanced before they can be interconnected to form a bank.

Protection and Management of Marine Lithium Battery Banks | | Nordkyn Design
• Electronic protection circuitry must be installed to ensure that none of the cells can ever exceed their operating voltage limits and the battery never starts heating up.
• All charging sources and regulators that will ever feed the new battery need to be re-assessed for suitability: either they can be reconfigured to operate acceptably, or they will need replaced.

As others have said , you really need to study this stuff before deciding

My next Post will be about what I want to explore in detail, for my application, once I understand a bit more of the fundamentals:
http://nordkyndesign.com/lithium-bat...-fundamentals/

[john61ct]

There is a "calendar aging" effect while stored, but much slower wear than when cycled.

Much reduced at lower temperatures, SoC as low as possible but never allowing self-discharge to below IMO 2.9Vpc, keeping around 3.0 safer.

Full discharge, and charging while too cold, can mean instantly converting to a pile of Hazmat waste.

[john61ct]

The biggest reason LFP is the only suitable Li chemistry for boats' House usage, is that all the others have a high risk of thermal runaway.

Boom bad.

[Pelagic]

This post did not attribute the author or where the content was taken from. This is a violation of copyright.

We received a formal complaint and complied with the request to remove the photos and visuals.

TAKEN FROM http://nordkyndesign.com/electrical-...-battery-bank/ and duly noted.

Please do not post without attribution as we are obliged to comply with requests to remove.



After reading Alctel’s study recommendations my Summary and Thoughts:

• The yacht LFP history is only 10 years old and still going thru a learning curve at Buyer’s expense.
• Drop in LFP units on the market are the worst example of this and should be avoided.
• DIY units really takes a professional knowledge to design as shared here https://www.entropypool.de/2015/05/1...system-design/
• I am more on the level of IIY (Install It Yourself), once I have an acceptable design and sourced the components…. Begs the question…. who reliably does this consulting?
• When in doubt go with Mastervolt, Victron or the OPE-Li3 / Lithionics system. These companies have well thought out marine specific systems.

Basic Design Options are:
Dual DC Bus Systems
Dual DC bus systems represent the optimal solution in reliability, resilience and functionality with lithium batteries:
• Power on board is not lost if an issue is detected with a cell reading excessive voltage. This can happen if a charger regulates poorly, cell imbalance is developing, or there is a system setup issue.
• A low-voltage disconnect doesn’t compromise recharging and the system has a chance to recover by itself.
This makes the dual DC bus topology very desirable on board marine vessels, but it also comes with higher engineering requirements.
The split DC bus configuration is the gold standard in terms of reliability and functionality for lithium battery installations. It is the preferred pathway for engineering elaborate lithium-only systems and for critical applications as it allows for specific and optimal responses to both excessive charge and discharge situations. It requires capable equipment and good system design to achieve this result.

Controlling a dual DC bus system requires a BMS offering suitable outputs: this is not commonly found on systems intended for electric vehicle (EV) conversions, which tend to rely on a single “disconnect all” contactor.
Attempting to build a dual bus system with an inadequate BMS all too often results in installations where both buses can (and therefore will, sooner or later) end up connected with no battery to charge; at this point, an unregulated charging voltage usually gets fed straight through into the boat’s electrical system, leading to a memorably expensive wholesale fry up. The ultimate in terms of the depth of thoughts afforded by the incident is when it happens at sea.

Key Challenge with Dual Bus Lithium Systems

• It is fair to say that, today, a majority of DIY dual DC bus lithium systems contain critical design flaws their owners are often unaware of, or have decided to ignore because they could not solve them properly.
• This is often related to the use of a junk-grade BMS solution, carefully selected for no other reason that others have used it, coupled with a lack of design analysis.

See first Drawing:
The conversion of an existing installation to use a lithium battery bank with a dual bus system first entails segregating charging sources from electrical loads.
See sample dual Busbar:
Skipping this step is not really possible unless another (lead-acid) battery remains in circuit after the lithium bank is disconnected.


Alternative 1 – Lead-Lithium Hybrid Bank

• The simplest safe lithium installation: leaving a sealed lead-acid battery in parallel with the lithium bank at all times allows disconnecting the lithium capacity in case of problem without any issues. The additional SLA doesn’t contribute to any meaningful capacity; its function is ensuring charging sources always see a battery in circuit.
• The practical result of such an arrangement is that the lithium battery ends up doing virtually all the work, because it is first to discharge due to its higher operating voltage. The charging voltages are no longer high enough to provide effective charging for the lead-acid cells, but as those are being trickle-charged above 13V all the time, they can be expected to remain essentially full and it hardly matters.
• The lead-acid battery needs to be able to absorb whatever “unwanted” current may come its way if the lithium bank gets disconnected due to a high voltage event for example. In some instances, a single sealed lead-acid (SLA) battery can be sufficient. SLAs are the best choice for this application as they don’t consume water and are very inexpensive; gel cells should be avoided as they are costly and a lot more intolerant to overcharging and AGMs would be a complete waste of money in this role.

The drawbacks are:
• Some charge gets lost trickling continuously into the SLA, more so in a lead-acid battery in poor condition.
• It doesn’t fully eliminate the lead and associated weight.
• Removal of the SLA from the system, at some point in the future, would create an unexpected liability.

Some advantages are to be found as well:
• Disconnection of the lithium bank can be managed with a single contactor; there is no need to implement a split bus. This can allow using some small BMS solutions incapable of managing a dual DC bus.
• The lithium bank is literally added to the installation in place, normally without cabling alterations required, but not without voltage and regulation adjustments.

With this in mind, it certainly is the simplest fully functional design one can build, as long as protection and automatic disconnection are still very properly implemented for the lithium bank.

Should the lithium bank ever become heavily discharged, the additional lead-acid capacity can start contributing, but this would also leave it at a reduced state of charge for a time afterwards and cause it to start sulphating. This is not automatically much of a concern, because it may not happen (this depends on the BMS low-voltage disconnect threshold) and it doesn’t actually result in much harm if it does. The SLA needs to remain in a reasonable condition however, in order to be able to absorb any transients if the lithium bank gets dropped off due to excessive voltage and not continuously discharge the lithium cells at an excessive rate.

My thoughts given the infancy and marketing hype of LFP is to hedge your bet and investment with a smaller LFP House bank and retain 50% of my LA house bank as a safety valve. This would be easy to achieve on Stargazer as a retrofit and a way to grow into LFP technology…..
Am I missing something basic…so far??

[alctel]

Keeping a SLA battery as a way to handle the loads after a disconnection/as a backup makes a lot of sense and I think this is how at least one of the blogs (Nord) did it I think.

I didn't have room/displacement to have any lead-acid on, so I went LifePO4 only and
separated the charge/discharge buses, and put the alternator on a separate relay which trips before the main charge disconnect relay and cuts power to the regulator, safely disconnecting the alt. All the rest of my charge sources (solar, AC battery charger) can handle a sudden disconnect without issue.

[Pelagic]

Originally Posted by john61ct

Here's my "boilerplate" LFP summary, mostly collected from past threads here, with special thanks to Maine Sail.

Any and all feedback is welcome, especially if more "canonical" information from the master thread conflict with my summary.

______
Systems: OceanPlanet (Lithionics), Victron, MasterVolt, Redarc (Oz specific?)

Bare cells: ​Winston/Voltronix, CALB, GBS, A123 & Sinopoly

Best to size your cells for two parallel strings for redundancy, unless you have a separate reserve/backup bank. Don't go past three, or you may see balancing issues that affect long-term longevity, maybe four in a pinch.

Note nearly **every** vendor, also those of ancillary hardware touted as "LFP ready", gives charging voltages **way too high** for longevity.

My (conspiracy) theory is that manufacturers would prefer their cells get burned out in under 10 years.

EV usage is very different from much gentler House bank cycling. Most EV people talking "lithium-ion" mean other chemistries not as safe as LFP, much shorter lifetimes, and with completely different setpoints and behaviors.

My charge settings for LFP: 3.45Vpc, which = 13.8V max for 4S "12V".

The point is to look at the SoC vs Voltage chart, and avoid the "shoulders" at both ends, stay in the smooth parts of the curve.

Either "just stop" charging when voltage is hit, or if you want another couple % SoC capacity, stop when trailing amps **at your spec'd voltage** hits endAmps of .02C, or 2A per 100AH.*

Note even at the "low" max charge voltage, letting the charge source continue to "push" even low currents long past the endAmps point is **over-charging, and will** greatly reduce lifecycles.

So if you can't then "just stop", set Float well below resting Full voltage, at say 13.1V, but that is a compromise, and *may* shorten life cycles.

With LFP, you don't need to fill up all the way at all, as far as the cells are concerned. In fact, it is bad for them to sit there more than a few minutes. Therefore only "fill up" if consumer loads are present, ready to start discharging, ideally right away.

Many sources claim there is a "memory effect" from keeping charge voltage and ending point exactly the same every time lower than manufacturer specs, that can apparently over time lead to apparent lower capacity. The recommended fix is to "go higher, into the shoulder" every so often, similar to "conditioning" a FLA bank monthly. To prevent the issue, vary your setpoints a bit, sometimes go a point or two higher or lower, vary Absorb time a bit etc. There is no consensus just how serious the problem is.

Store the bank as cool as possible and at 10-20% SoC, or maybe higher to compensate for self-discharge, if not getting topped up regularly (I would at least monthly).*

Letting the batts go "dead flat" = instant **permanent unrecoverable** damage.

Same with charging in below 32°F / 0°C freezing temps.

Persistent high temps also drastically shortens life.

Charging at 1C or even higher is no problem, as long as your wiring is that robust, vendors may spec lower out of legal caution.

Again, going above 14V won't add much AH capacity, but will shorten life cycles dramatically.

And of course, we're talking about gentle "partial C" House bank discharge rates, size appropriately and be careful feeding heavy loads like a winch or windlass.

Following these tips, letting the BMS do active balancing is unnecessary and potentially harmful, just look for LVD / OVD and temp protection. Multiple layers of protection are advised if it is a very expensive bank, so you don't rely on any one device to keep working.

Check cell-level voltage balance say monthly to start, then quarterly, finally every six months if there are no imbalance issues, but only if that seems safe to you.

Hi John,
Thanks for the boilerplate Notes.

If I research and cost out my present mindset that an LFP Hybrid system is the way to begin, some early decisions to make.

My House batteries are located in the dining Salon, on two levels which perfectly counterbalance the weight of the Generator on ER Starboard Side. The electrical locker is just behind batteries and raises to Port Console in Pilothouse.

Existing 24v House Bank: 8 pieces on 2 shelves (series /parallel) total 920 Ah

Retain 4 of my Trojan AGM’s in seat locker (460 AH) in case I needed to operate on LA for extensive periods in remote places) (Batteries 1,2,3,4,in sketch and what you see in seat locker) (only one year old and I will have no trouble selling the other 4 in Subic)

On sub floor level, install about 300AH of LFP where it is cooler replacing Batteries 4,5,6,7 with LFP. (I could put both types in the same location, but in case of isolating and trouble shooting, separating them might be better)

Battery Choice
All my present Charge/Invertor systems are Victron, so is it worth paying the premium of making a Hybird system with them?

If Yes, then what is the difference between: (See Pricelist)
LiFePO4 battery 24V/180Ah 4,75 kWh BAT524181200 and
Lithium HE battery 24V/100Ah 2,5kWh BAT524110300…. Could not find out what HE means?

On first look the (100Ah HE) would allow me to grow (buy 3), but I am not sure if I am comparing apples with apples or old and new LFP production batteries?

For Hybird, If I were using your Bare Cell suggestions, what would be my comparable cost for 300AH (24V) I am too dumb at the moment to figure that out and may be beyond me.

300AH @ 24v Recommendations only limited in height of SubFloor to 14” including Cable for a Hybird System


Your general notes and cautions are all appreciated.

Got me thinking that I could possibly use the AGM’s for Bow Thruster and Windlass loads, and have a switch on the old Victron 24v 50A Skyla Charger to keep the AGM’s happy

Understand that with Hybrid Voltage Sensing
NEVER, EVER, SENSE THE CHARGING VOLTAGE DIRECTLY AT THE LITHIUM BANK TERMINALS IN THIS CONFIGURATION

The sensing voltage required for charge control must be sourced upstream of the lithium battery disconnector, or in other words from the SLA battery, so it remains valid even after a disconnection of the lithium capacity. This is very important, otherwise uncontrolled, unlimited charging of the lead-acid battery will occur after the lithium capacity gets isolated.

So all of this got me to thinking about 2 separate monitoring and fail safes to maximize life expectancy of both types

[john61ct]

Sourcing good prismatics is a real challenge - worth its own thread for your specific location - and luck has played enough a part with my non-repeatable experiences I don't feel confident making specific recommendations.

I would only deal with the complexity of dual large banks as Reserve vs Main, if I also eliminated dedicated Starters, and in the context of a rip-out start-over from scratch redesign.

In your case just replacing the lead House bank is likely better, have a thorough testing period on shore before going 'into production'.

[tanglewood]

You are a quick study!


I believe the Victron HE batteries are NMC, not LFP.


Re separate charge and discharge busses, you can also individually (or in groups) control the various charging and load sources, thereby accomplishing the same thing as separate charge/discharge busses. I think it is generally a more civilized way to control the charging sources rather than just pulling the plug on everything. Also, if your charge sources are sufficiently programmable and set properly, they should shut off themselves before being commanded from the BMS.

[geoffa]

Good morning.
This is an important thread. The application of a new technology in an eclectic manner might be problematic.
Below is my solution.
Li for a 48v cct. 240 for house. 12v for engine lead.
48v consists of 160 30ahr pouches mechanically series parrallel connected. Mechanically connected because the pouches are intolerant of solder type heat. To protect botj input and output is cct breaker protected at 60A. This means charge discharge can never ever get near rated current of pouches.
The 48v power source is 2.4kw of solar into a controlled MPPT with adjustable settings for charging Li.
Output is thru cct breaker into 2x6kw low frequency inverters. One always in reserve. The inverters are low voltage protected at a point well above rated discharge risk of li.
Temp protection is provided through the MPPT. Additional thermistor to switch 4 x12 fans in series never switched on.
48v to keep currents down.
The 12v engine battery is constantly cjarged through 240v battery charger when engine not running.
Output of inverter protected by 10a RCD cct breaker. Yes if you run toaster and hair dryer the cct will trip.
The theoretical energy density is 16kwh. In fact I have never been able to test this.
An expensive device is the energy monitor as the relative flat voltage discharge of the system required some sophistication in manufacture.
This system has worked well for three years the only problem being the first batch of solar panels which were plastic film which deteriorated to lose 90% of power. Now use conventional glass.
Geoff
FIEAust CPEng NER

[Rimica]

Just a report on my experience with Lithium.


I bought a brand new catamaran last year and I had requested that the electrical system be 12 volt and Lithium. The builder put an all Mastervolt system in the boat (700 Amp batteries, switches, relays, fuses, charger and inverters). All of it is connected to an onboard computer for monitoring. This is the source of the numbers I am giving below.



I have been sailing for 15 months now full time. The system is superb. I have 700 amp of Mastervolt lithium batteries. Over 15 months they have accumulated 54 cycles out of an expected usefull life of 4000 or so. They should last another 90 years at that rate. I run everything off the batteries including my Air Cond but not the stove.



I am at the dock 2 days a week on average where any accumulated deficit gets topped off. I do not have a generator on board. I use solar panels (550 watt) and a Watt and Sea water generator. When the boat goes over 8 knots (easy on a Cat) it is self sufficient over a 24 hour period. This includes watermaking.


The downside of large capacity lithium is the charging if you do not have a DC generator. After several days at anchor I can be at 50% of capacity. I therefore have 350 amp to generate to go back to 100% charged state. The boat use 10amp an hour when anchored and 15 to 17 when sailing on autopilot. While sailing at 8 knots and with the water generator I produce 30 to 35amp, 15 go to the boat and 15 to 20 go to the batteries. I need to sail 15 to 17 hours in good conditions to fill the batteries back to 100%. Here in the Med the sails from point to point are shorter. I seldom succeed in getting back to 100%. Crossing the Atlantic will be no problem, I will run out of food before running out of electricity.



My view after 15 month of experience would be that:
1) Lithium was worth the expense given the weight saving and the capacity

2) Charging is not a problem if the sailing is over long distances.
3) No need to run engines to charge while at anchor for several days particularly if its sunny
4) If no long distance sailing is expected or if no water generator having a meaningfull output at the cruising speed of your boat is installed then one has to think about a DC generator for recharging unless you go back at the dock every few days.


I am thinking about adding a DC generator. Fisher-Panda has a 90kg 3,200 continuous watts. This would shove 200 to 230amp an hour in the batteries. That means that after 4 days at anchor, I run the machine for 1.5 to 2 hrs and I am back to 100%. Then I could have an electric stove and Nirvanna is reached.


Caveat:
I do not run my AC 24/7. When sailing, it is not on. When at anchor I will run only the one in the Master bedroom to cool it off before going to bed (30mins) on very hot days. I do not heat my hotwater tank at anchor. I do not use my wahsing machine unless at the dock.



Background:

I am an energy pig. I have an always on computer on board plus 2 other portable that needs recharging once a day in addition to "always on" WIFI and 4G receiver. I have a fridge and a freezer plus a Nespresso coffee maker.


Notes:
Charging the batteries with the engines is not realistic. My 2 engines at 2,000rpm will put out 145amp continuous in total. That is 2.5 hours at 2,000 rpm to get back the 350amp above. In an anchorage it is not doable. You need to leave and go for a 3 hour boat ride and come back. Not a solution in my view. In the Med, 5 boats will have taken your spot before you come back.


I have tried, for interest sake, to use the small Honda generator (2,000 Watt) to charge the batteries. It was connected to my charger which outputs 100amp. First the Honda is not powerfull enough to permit the charger to output 100amp. I need to set my charger to 80amp max for the generator to work. In fact I have to ramp up the charger starting at 25amp and bring it to 80 by stages otherwise the Honda chokes. At 80 amps, you need to run it for 4 to 5 hours to go back to 100% charge and it is noisy (65 to 70 dBs). Its is better than running the engines though.



Hope I contributed positivly to the discussion


Thx

[Pelagic]

Thanks Rimica, wonderful user's analysis.
To confirm, your solar is only 550 Watts?

[geoffa]

A good story. As an aside part of my design criteria was no generator no shore connection. No use of engine alternator for house.
As my boat is pilot house displacement I did have surface area for solar 2.4kw.
I choose 48v for a number of reasons, closer rail is to solar voltage mppt is more efficient. I squared r means 1:16 in heating within system, cable dimensions influence flexibility of layout, interrupt capacity at 12v much bigger worry input ccts on inverters run at much lower current read longer life. Heat management is critical to reliability and the 16 times extra heat is a lot.
Why not 96v mainly because this becomes a safety issue, best not get hooked up on 96vdc and I struggled to find control and conversion equipment at a reasonable price with this voltage. It would have been good to have a 48v whole of boat rail but this is not viable at the moment. If I have a complete loss of solar and drain the batteries I have a very long recharge as for safety reasons the maximum input to the system is 60 amp. This could be back fed through the inverters as 240v so a small generator would be fine trouble is it would take a long time.
My solution here is got old fashioned demand management. Never got below a level approaching drained.
Cost was a no brainer the pouches cost half the price of realistically equivalent lead.
Price split was about 50% li 30% solar and 20% inverter mppt and cct breakers.
Hope this helps the conversation.
Geoff

[kmacdonald]

Originally Posted by Pelagic

I think Brian on Delos has a good technical base to use as a standard for asking basic questions.

1. With the same space available, is that 8D drop in solution recommended?

2. Sticking with Ah battery ratings (if we can) and an electrical hungry boat...(I have also just switched to induction stove) what is the optimum LiFeP04 capacity you should size to compared to your previous AGMs?
For example, my 8 x 8D 12v AGMs are sized @ 1040Ah @ 24v as it then only consumes about 10-12% SOC in 24hrs at anchor with 5 people

Do you recommend downsizing?

Yes. 400 Ah @ 24V would be more than enough if you are using 100 Ah a day. (does that include induction stove?) Leaves plenty of extra capacity.

[kmacdonald]

Originally Posted by Pelagic

I think Brian on Delos has a good technical base to use as a standard for asking basic questions.

1. With the same space available, is that 8D drop in solution recommended?

2. Sticking with Ah battery ratings (if we can) and an electrical hungry boat...(I have also just switched to induction stove) what is the optimum LiFeP04 capacity you should size to compared to your previous AGMs?
For example, my 8 x 8D 12v AGMs are sized @ 1040Ah @ 24v as it then only consumes about 10-12% SOC in 24hrs at anchor with 5 people

Do you recommend downsizing?

I saw that about Delos and wondered. Brian is quite capable and a good candidate for Lithium but I don't know anything about what he put in. I'm sure he will update his experience with them. I got the impression he may be the guinea pig for a new company but could be wrong.