Charging Lithium and AGM banks

[Scout 30]

Originally Posted by goboatingnow

Why ? ( more dangerous then say the propane or the diesel in a tank or even all that sulphuric acid etc


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Although rare LI batteries can overheat & catch on fire. Charging has to be very carefully controlled. When it comes to boats I like to keep it simple. However, when dual carbon batteries become available I'm getting in line.

[warrior 90]

Originally Posted by Kim Klaka

Why are you mixing Lithiums and AGM? Why not use all lithium, or am i missing something? I have used lithium for starting and house for a year, no problems. A friend of mine has been using them for 4 years, again no problems. You just need belt-and-braces voltage regulation
Re safety of lithiums, there is a lot of confusing info out there. I resolved some of the confusion when I realised there are different types of lithiums, some safer than others. You need to know what type of battery is being described when reading reports. Incidentally, there are some interesting comments on Lithium Ferrophosphate batteries (LiFePO₄) in the report on the stranding of the Volvo yacht Team Vestas Wind, released 3 days ago. http://www.volvooceanrace.com/static/assets/content_v2/media/files/m36616_team-vestas-wind-inquiry-report-released-on-9-march-2015.pdf

Celebrate You writing about Your positive experiences with LifePO4 since the comunity here seems to have a general opinion that I do not share.
There are risks that have to be properly adressed but nothing different than with other hazardous substances on board like fuel, propane, kerosine etc. and also lead acid batteries.
The discharge rates are fantastic and for the house bank I see a clear advantage with the low DOT and long live cycles. Right now prices run around 1 $ / amp for big units...so prices are coming down but most of all it´s tech available now and not some pipe dream who knows when if ever.
EV-Power | WB-LYP700AHA LiFeYPO4 (3.2V/700Ah) Special product
Also with bigger units balancing gets simpler,safer and also more cost effective.
Charging is faster, less gen set time
Read the report of the Vestas Team.
Well, can,t that be handled with a water tight battery compartment and a heatsink for cooling.
So what else is there.
I beleave it´s save to say the issues with charging and discharging with todays tech is not an issue any more just different than lead acid.
Checking on my Victron Combi inverter/charger...no problem just needs an upgrade of software. They also sell Lithium batteries since some time with success even so they cost an arm and a leg.
To me it looks like lead acid batteries will be an obsolete tech sooner or later.
It seems more likely to me the main draw back is the higher initial cost.

[goboatingnow]

Originally Posted by Scout 30

Although rare LI batteries can overheat & catch on fire. Charging has to be very carefully controlled. When it comes to boats I like to keep it simple. However, when dual carbon batteries become available I'm getting in line.

Also although rare lead acid batteries subjected to incorrect charging can explode and release extremely toxic substances.

In fact the charging regime for LA is more complex then Li. There is no requirements for IUI style charging for example.

[Scout 30]

All too often people offer anecdotal evidence as evidence. Saying that because there is a remote risk with diesel fuel, propane gas or lead acid batteries so they are equivalent to the risk Lithium Ion batteries pose is not accurate. Large banks of LI batteries can catch fire just sitting there. For me this is an unacceptable risk in a very combustible fiberglass boat that could house your family a long way from help. Especially when there are safer options available.


While I agree & hope that lead acid batteries will be obsolete soon I hope & expect the same can be said for lithium ion batteries. Not so much because of safety but because of the rare &/or toxic materials involved.


Aircraft makers urge ban on lithium battery shipments | News OK

[witzgall]

Scout,

To which LI chemistry are you referring?

Originally Posted by Scout 30

Although rare LI batteries can overheat & catch on fire. Charging has to be very carefully controlled. When it comes to boats I like to keep it simple. However, when dual carbon batteries become available I'm getting in line.

[goboatingnow]

Originally Posted by Scout 30

All too often people offer anecdotal evidence as evidence. Saying that because there is a remote risk with diesel fuel, propane gas or lead acid batteries so they are equivalent to the risk Lithium Ion batteries pose is not accurate. Large banks of LI batteries can catch fire just sitting there. For me this is an unacceptable risk in a very combustible fiberglass boat that could house your family a long way from help. Especially when there are safer options available.


While I agree & hope that lead acid batteries will be obsolete soon I hope & expect the same can be said for lithium ion batteries. Not so much because of safety but because of the rare &/or toxic materials involved.


Aircraft makers urge ban on lithium battery shipments | News OK

One must be very careful in interpreting situations involving Lithium accidents and how to transpose those experiences to Lithium Ferrous operation in a boat.

Simply doing a " bogeyman" interpretation does no-one any good.

There are failure and risk modes in all batteries, you need to evaluate the situation as it pertains to your installation, use and implementation

dave

[warrior 90]

Aircraft makers urge ban on lithium battery shipments | News OK

I do agree and specially to this article. One has to be carefull with interpretation. All to easy for airlines and builders to offload responsabilities.
One thing is Lithium batteries causing a fire and the other what happens if Lithium batteries are exposed to fire.

*When it comes to boats I like to keep it simple
If You go in to detail lead acid battery charging is nothing simple. It just seems because Battery chargers are sofistgated today.

Lithium charging is simple and with bigger units even more. Like mentioned by others...lot´s of confusion around the subject.
Since the charging tech for Li is totally different than for LA I don´t think it´s a good idear to mix in the same circuit.

To come up with a practical example
I consider a 1000 Ah LA house bank a fairly big unit.
To give a very generous margin in any wich way I would say the equivalent for Li would be 500 AH
While we are talking about a big space and weight in case of LAB with Li I could find lot´s of places eaven on deck to make them 500 AH dissapear.
To be on an absolutly safe side...why not integrating them in the today comun sides of the solar arches for example. They are light weight and would perfectly make sense there in regards to posible safety issues.
Yes OK. now starts the whole dialog with the wire size but choosing the right size and the problem is solved. This problem also exists with all big LA banks because they can not fit in conveniant spaces most of the time....
There are many other realistic spaces for installation and I find it hard to understand all them safety arguments because this can be managed

So what else is there in regards to safety ?

What other issues are there ? .....understanding a Battery Managment System ?
In regards to all the positive sides of Li I think a constructive approach to the subject would be more desirable.

[Moustache]

I am currently planning similar setup for a monohull configuration and therefore it might not be comparable.
Anyhow the thing I learned is that it seems always a challenge to charge 2 different battery technologies from the same source especially if one is a LFP.
After considering many option I concluded that I will use the LFP as service battery and primary starter battery and keep an emergency back-up starter battery fully separated behind a 2 pole switch with an own AC-charger.
Since the LFP is behind a dual bus configuration, the relay on the discharge bus needs to be of a bigger kind since it needs to carry the load of the starter when cranking the engine- like this one:

https://www.bluesea.com/products/770..._-_12V_DC_500A

The other option would have been to use a separate LFP as starter battery.

[goboatingnow]

There are many other realistic spaces for installation and I find it hard to understand all them safety arguments because this can be managed

So what else is there in regards to safety ?

To try and summarise the issues to be considered around LIFerrous use

Assuming you have done basic battery sizing calculations

1. Decide on the appropriate charge limits, i.e. set upper and lower voltage limits and deduce operational charge % , You should get about 70-80% SOC efficiency from Li, without pushing the charge limits

2. Assuming you have sized your battery bank, you need to consider where it should be located. Avoid heat extremes. The battery bank itself should be mechanically strapped or bonded together to prevent cells from " pumping " or suffering case distortion

3. Given the extreme power available in short circuits, battery cables should all be fused at the closet point to the battery terminals. There is a good argument for fusing each individual battery.

4. For safety I would recommend, that a High Voltage cutout system is implemented to protect the battery from overcharging. Optionally a Low voltage cutout is also very useful as LI requires very careful preconditioning charging if allowed to drop below about 20% SOC

5. Individual Battery level monitoring ( its not actually cell level per se) is in my view useful, cheap and good insurance. This allows you to monitor out of balance conditions or any battery abnormality. Battery temp monitoring is a useful safety addition and often very cheap to add.

6. All charge sources should be set up to charge LI . essentially this is simple constant current, constant voltage charging , but with good voltage cutout characteristics. with LVC and HVC protection, you are at least protected if you inadvertently ( or deliberately) use non Li optimised charging profiles. ( say emergency charging etc )

All of these things actually make sense for high value lead acid too by the way


dave

[warrior 90]

Originally Posted by goboatingnow

To try and summarise the issues to be considered around LIFerrous use

Assuming you have done basic battery sizing calculations

1. Decide on the appropriate charge limits, i.e. set upper and lower voltage limits and deduce operational charge % , You should get about 70-80% SOC efficiency from Li, without pushing the charge limits

2. Assuming you have sized your battery bank, you need to consider where it should be located. Avoid heat extremes. The battery bank itself should be mechanically strapped or bonded together to prevent cells from " pumping " or suffering case distortion

3. Given the extreme power available in short circuits, battery cables should all be fused at the closet point to the battery terminals. There is a good argument for fusing each individual battery.

4. For safety I would recommend, that a High Voltage cutout system is implemented to protect the battery from overcharging. Optionally a Low voltage cutout is also very useful as LI requires very careful preconditioning charging if allowed to drop below about 20% SOC

5. Individual Battery level monitoring ( its not actually cell level per se) is in my view useful, cheap and good insurance. This allows you to monitor out of balance conditions or any battery abnormality. Battery temp monitoring is a useful safety addition and often very cheap to add.

6. All charge sources should be set up to charge LI . essentially this is simple constant current, constant voltage charging , but with good voltage cutout characteristics. with LVC and HVC protection, you are at least protected if you inadvertently ( or deliberately) use non Li optimised charging profiles. ( say emergency charging etc )

All of these things actually make sense for high value lead acid too by the way


dave

1.
freeing up space from the Lead Acid batteries gives plenty space FOR MORE CAPACITY.
To SIZING...to get good life expectancy out of Lead Acid Batteries they should not be discharged less than 20-50% of there capacity depending on Battery type. Marine grade batteries usually can be DISCHARGED to 50% OF there DEPTH (DOD)

Example LEAD ACID:
House bank has 1000 AH You can only use 500 AH if You care about Your batteries

LifePO4 batteries usually can be discharged to 20% of there capacity (DOD)
Example LITHIUM:
House bank has 1000AH. You can use 800 AH or what ever the manufacturer recomends on the spec sheet

So this is the moment where You can raise Your capacity using the same space of the lead acid batteries.....THE MORE THE BETTER
The ones to look for are LifePO4 PRISMATIC CELLS
Right now the Winston batteries from China are rebranded to Voltronics and are very cheap. Watch for same lot and warranty
Here are the limits
700Ah, 2-5C, 3V LiFePo4 Lithium Prismatic EV Battery

2.
The proper charge and discharge limits are given by the manufacturers and come with spec sheet of battery.
THERE IS NO PRECENTAGE AS TO GOOD OR BAD
Let´s keep that simple... JUST STAY WITH IN RECOMANDED SPEC

3.
Proper fusing is a must..... like with Acid Batteries
Individual fusing of each battery is not requiered

4.
High Voltage (HV) and Low Voltage (LV) rates recomanded by manufacturer must be controlled and limits and are a MUST for safe operation of Lithium batteries

5.
Monitoring the state of charge and limiting to the Max voltage recomanded by manufaturer on each individual cell is the correct way to balance Lithium batteries.
Cheaper ways of doing this by temperature control or not at all as done many times is the cause of many failures and accidents and is NOT RECOMANDED.
IMPORTANT:
To keep it simple use batteries with high amperage. EACH BATTERY NEEDS A MONITOR....that´s extra cost, wireing and posibility of failure and ease of instalation. The bigger the battery the cheaper the price per AMP HOUR.

6.
CHARGING of lithium batteries does not requiere a top of charge after bulk charging like acid batteries.
THEY ALSO DON,T NEED A CONSTANT TOP OFF TO MAINTAIN THE STATE OF CHARGE.....ONCE THE ARE CHARGED YOU ARE DONE.
THERE FOR BOTH RATES HAVE TO BE ADJUSTED TO THE RECOMANDED RATE OF THE BATTERY MANUFACTURER IN THE BATTERY CHARGER AND AFTER THE BATTERIES ARE CHARGED THE PROCESS HAS TO BE CUT TO PREVENT OVER CHARGE > HVC (High Voltage Cut)

Here is a good manufacturer for controlling Your Lithium Batteries
GLi-CP-1 | GenasunGenasun

or if You want to save money here is some inspiration for battery monitoring and controlling. There are also examples of wireing scematics https://electriccarpartscompany.3dca...ower%20BMS.pdf
HousePower BMS - CleanPowerAuto LLC

[goboatingnow]

Warrior

One has to be very careful in simply saying " use manufacturers specifications ". As has been laid out in the big Li thread on CF, it pays to be more conservative then the manufacturers specifications , especially since manufacturers often use specifications to extract the most from their batteries

Note that " prismatic " really just means " cuboid" to distinguish them from spherical construction. Pouch cells are also " prismatic " for example . In my view there is little differences between cylindric and prismatic in terms of performance.

Cylindric cells by their nature are not made in large capacities as it's not possible to easily parallel cell pouches like they do in larger prismatics

I would still reccomend that individual battery fusing be undertaken , it adds inter battery protection and reduces the need for a single, very high interrupt capacity fuse.

In my experience it's difficult to actually extract 80% of capacity. 100% charging is best avoided in Li used on boats. So useable capacity is more like 70 or even 60% ( ie 20 to 80 charging )

Individual battery monitoring is in my view REQUIRED. This is not the same as balancing BMS etc which are NOT REQUIRED in fractional C environments. This is because you do not want individual batteries to be overcharged in a series string, especially when trying to get close to 100 % charging.

Correct , no float charge , if possible recharge at the 20% point. In practice however this is practically impossible, so recharge activation is often set to about 20% down in commercial systems. In reality , with large capacity, lightly loaded Li, determining a recharge point by voltage is tricky. Either amp counting or tine could be used.

Dave


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[warrior 90]

Originally Posted by goboatingnow

Warrior

One has to be very careful in simply saying " use manufacturers specifications ". As has been laid out in the big Li thread on CF, it pays to be more conservative then the manufacturers specifications , especially since manufacturers often use specifications to extract the most from their batteries

Note that " prismatic " really just means " cuboid" to distinguish them from spherical construction. Pouch cells are also " prismatic " for example . In my view there is little differences between cylindric and prismatic in terms of performance.

Cylindric cells by their nature are not made in large capacities as it's not possible to easily parallel cell pouches like they do in larger prismatics

I would still reccomend that individual battery fusing be undertaken , it adds inter battery protection and reduces the need for a single, very high interrupt capacity fuse.

In my experience it's difficult to actually extract 80% of capacity. 100% charging is best avoided in Li used on boats. So useable capacity is more like 70 or even 60% ( ie 20 to 80 charging )

Individual battery monitoring is in my view REQUIRED. This is not the same as balancing BMS etc which are NOT REQUIRED in fractional C environments. This is because you do not want individual batteries to be overcharged in a series string, especially when trying to get close to 100 % charging.

Correct , no float charge , if possible recharge at the 20% point. In practice however this is practically impossible, so recharge activation is often set to about 20% down in commercial systems. In reality , with large capacity, lightly loaded Li, determining a recharge point by voltage is tricky. Either amp counting or tine could be used.

Dave


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They use the specs to comply with industrie standards and limit their liability

There is a big difference to prismatic cells.
1.Much bigger capacity allows You to build big battery banks with very few cells wich results in simple and easier control.
2.Today up to 500 AH is very easy to get. So You get away with just 4 cell to monitor in the batt. bank.
3.The connections on prismatic cells are way stronger compared
4.The prismatic cells are a lot easier to install

As to fusing individual.With monitors on each cell they don´t get out of line. So I don´t see any need for that.
I rather prefer one large and solid built fuse for the battery bank

As to energy available it´s a fact that many times capacity exceeds the manufacturer specs. So if properly charged I don´t see any reason why not getting the promised energy. What is important to me You also have more power at the end of the discharge cycle compared to lead acid.

What also seems important to me : Lithium charge faster and that keeps the generator hours lower.

Battery monitoring is requiered for save handling. It protects the individual cells from over charging. This is done automatic with the set point. You can visiualize the state as some manufacture offer but it is not essensual.
This small monitors have an LED to indicate state of charge. If something goes wrong there is no charge going to the battery for protection. Checking from time to time is recomanded.

A battery monitor is mounted in every boat. This will tell when the state of charge but I think some thing a little more sofisticated makes the whole story a lot easier. You have Your set points and forget about it. With the set points and solenoids You controll charging and discharging
The Victron is very good at that.
This one is an alternative from Xantrex
Xantrex LinkPro Battery Monitor, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits

For the rest let´s keep it simple..there is nothing tricky...NO rocket science

[goboatingnow]

Originally Posted by warrior 90

They use the specs to comply with industrie standards and limit their liability



There is a big difference to prismatic cells.

1.Much bigger capacity allows You to build big battery banks with very few cells wich results in simple and easier control.

2.Today up to 500 AH is very easy to get. So You get away with just 4 cell to monitor in the batt. bank.

3.The connections on prismatic cells are way stronger compared

4.The prismatic cells are a lot easier to install



As to fusing individual.With monitors on each cell they don´t get out of line. So I don´t see any need for that.

I rather prefer one large and solid built fuse for the battery bank



As to energy available it´s a fact that many times capacity exceeds the manufacturer specs. So if properly charged I don´t see any reason why not getting the promised energy. What is important to me You also have more power at the end of the discharge cycle compared to lead acid.



What also seems important to me : Lithium charge faster and that keeps the generator hours lower.



Battery monitoring is requiered for save handling. It protects the individual cells from over charging. This is done automatic with the set point. You can visiualize the state as some manufacture offer but it is not essensual.

This small monitors have an LED to indicate state of charge. If something goes wrong there is no charge going to the battery for protection. Checking from time to time is recomanded.



A battery monitor is mounted in every boat. This will tell when the state of charge but I think some thing a little more sofisticated makes the whole story a lot easier. You have Your set points and forget about it. With the set points and solenoids You controll charging and discharging

The Victron is very good at that.

This one is an alternative from Xantrex

Xantrex LinkPro Battery Monitor, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits



For the rest let´s keep it simple..there is nothing tricky...NO rocket science

In reality large prismatics are just a series of " pouch " type cells paralleled together. Ultimately it's just a series of smaller cells. You could equally do a tesla on it and use cylindric types in parallel too.

Fusing and monitoring are protecting very different things.

Fusing is to prevent massive short circuit currents flowing in a short of battery failure. A monitor is going to do nothing in that regard.

Actually stopping some charge devices isn't so simple , like alternators.

As I said LVC and HVC should be only used as protection systems not as a way of getting around bad charging regimes

Dave


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[warrior 90]

I don´t want to waiste Your time nore mine with argueing about batteries

I just want to charge them.....
Standard Size Batt Bank 4 units Calp 3,2 Volt 400 Amp

Here is the link again
CA400FI 400Ah, CALB Lithium Battery EV LiFePO4 Prismatic Cell