Lithium Batteries

[geem]

LiFePo4 batteries are much better than that at accepting charge. They have minimal internal resistance so will take whatever your charger can give them in bulk charging (BMS allowing), and they don't really require an absorption phase unlike a lead acid battery, so charging is much more efficient. Most manufacturers recommend charging at 0.5C or thereabouts for best life, so for a 100Ah battery normal bulk charging should be 50A, and it will be full in 2 hours. A 100Ah lead acid battery will not normally pull anywhere close to that unless very discharged, and they will not be fully charged until the absorption phase is complete which can take a couple of hours.

We almost never charge with the generator and never with the engine. Solar is our main charging system. We also have wind and towed generator charging. We will never have those massive charge inputs. We cook in gas by choice

 

[Minerva]

Also make sure they can't get down to zero degrees if you have the charging sources active over winter

Is that so? I’m hoping for my next boat to be in service, in Scotland year round and with the hopeful potential to sail a chunk further north.

does this mean that lithium are not suitable?

 

[Trident]

Is that so? I’m hoping for my next boat to be in service, in Scotland year round and with the hopeful potential to sail a chunk further north.

does this mean that lithium are not suitable?

Lithium gets damaged if it has an active charge at 0 or below - there are options of course - Renogy do LifePo4 100AH batteries with a self heating pad built in - obviously it uses some of its own power to warm it and keep it around 5 degrees . Or you can heat the battery compartment or insulate it well. I have the batteries on my boat sitting on a foam pad about 2 inches thick on the bridge deck floor and maybe an inch of foam on all 4 sides and in a battery cupboard inside the saloon - this has stayed above 2 degrees C when its been -5 outside but thats as cold as its been here since I've had them.

 

[Minerva]

Lithium gets damaged if it has an active charge at 0 or below - there are options of course - Renogy do LifePo4 100AH batteries with a self heating pad built in - obviously it uses some of its own power to warm it and keep it around 5 degrees . Or you can heat the battery compartment or insulate it well. I have the batteries on my boat sitting on a foam pad about 2 inches thick on the bridge deck floor and maybe an inch of foam on all 4 sides and in a battery cupboard inside the saloon - this has stayed above 2 degrees C when its been -5 outside but thats as cold as its been here since I've had them.

Thanks. That’s been some useful information to digest

 

[kwb78]

We almost never charge with the generator and never with the engine. Solar is our main charging system. We also have wind and towed generator charging. We will never have those massive charge inputs. We cook in gas by choice

If you have 720W of solar, that’s over 50A into a ~12V battery at maximum output and potentially more if you use wind and towed hydro at the same time, so you could get quite a decent charge rate under optimal conditions. A lead acid battery won’t see that charge rate very often if at all, but a lithium battery will.

 

[Daverw]

I have a Mutiplus and the bluetooth dongle - are the advanced settings available with this please., @Trident

With the app and the bluetooth dongle I can set inverter/charger/both mode, and restrict draw on the AC input ("PowerControl" / "PowerAssist", which doesn't seem to work very well) but I can't find settings for the charging voltages, Dynamic current limiter, WeakAC or Search mode.

It looks like the advanced settings are only available using the USB programming cable, but maybe I'm missing something?

You can also access all settings via VRM and victron configure and download/upload. Mine is connected via cerbro GX and dont need the dongle just RJ 45 cable. Do have to use pc though as Victron configure does not run on iPad

 

[geem]

If you have 720W of solar, that’s over 50A into a ~12V battery at maximum output and potentially more if you use wind and towed hydro at the same time, so you could get quite a decent charge rate under optimal conditions. A lead acid battery won’t see that charge rate very often if at all, but a lithium battery will.

What does that mean? We have 4x Trojan T105s. We see that charge rate as often as it is available from the sun. Our Victron MPPT records the peak solar.

 

[geem]

There is a very good article on Rod Collins web page about charging AGM batteries. He explains that the combined bulk and absorption phase is about 7 hrs. You can fast bulk charge then you get a long absorption. You can slow bulk charge then you get a fast absorption. Either way it's about 7 hrs.
Also, he built his own lithium bank 15 years ago using Winston cells. Still go strong with full capacity. From the research we have done Winston cells are the best on the market. It's why we chose them for the liquid cooling project I am working on

 

[DuncanHall]

Looking at other options I found Fogstar. It seems to have good customer feedback https://uk.trustpilot.com/review/fogstar.co.uk and has been trading dor arround 5 years. I may take a punt onto one of their 280 units coats £900 . They dont have the benefit of an external BMS but if the company went the construction seems simple enough to replace components.

 

[Poey50]

My two-pennyworth.

When people change their lead acid batteries they tend to ignore the fact that the battery is one part of an integrated electrical system. Lead acid has few demands, is tolerant of moderate abuse, and is relatively cheap enough to suck it up and buy replacements if the life expectancy is disappointing. In summary, with lead acid you can get away with reducing the problem just to the battery and mostly ignoring the system. You simply can't afford (literally and metaphorically) to do that with lithium systems.

It may be my reading of things but I see an overly-casual approach creeping in to installing lithium, one that does not pay sufficient regard to the whole system and how functional this will be on a boat. Lithium battery manufacturers absolutely encourage this.

A systems approach would need to include:

An energy audit including not just the storage capacity needed but how to replenish the capacity without turning the boat into a power station.
Attention to all charging sources being compatible with lithium chemistry.
Particular attention needs to be given to ensuring that a BMS shut-down does not destroy the alternator diodes and other marine electronics.
Cell-level monitoring by BMS.
Automatic and effective balancing of cells.
An audible warning system as BMS triggered shut down approaches.
A construction method that allows charge and load circuits to be separated or at least a robust system for compensating for complete pack shut-down. (Imagine this happening at night under engine crossing a busy shipping lane to focus the mind.)
Class-T (or equivalent) fusing to give high amperage interrupt capacity.
Means of compensating for low-temperature cut-off.
Means of compensating for high ambient temperatures that can shorten lithium life.
Consideration of high-amperage requirements -e.g. engine start, windlass. (For engine start at least, lead acid is still the standard.)
Compatibility of the system with emerging technical requirement standards and insurance issues.

The system should operate with minimal operator input - i.e. as automatically and safely as possible. Lithium doesn't care that you were careful to personally monitor your charging and discharging every day for the last thousand. You will eventually forget and a single serious thermal runaway or over-discharge - while not likely to destroy your boat - will certainly kill your investment.

This is the paper to read and digest before doing anything.

LiFePO4 Batteries On Boats - Marine How To

 

[geem]

My two-pennyworth.

When people change their lead acid batteries they tend to ignore the fact that the battery is one part of an integrated electrical system. Lead acid has few demands, is tolerant of moderate abuse, and is relatively cheap enough to suck it up and buy replacements if the life expectancy is disappointing. In summary, with lead acid you can get away with reducing the problem just to the battery and mostly ignoring the system. You simply can't afford (literally and metaphorically) to do that with lithium systems.

It may be my reading of things but I see an overly-casual approach creeping in to installing lithium, one that does not pay sufficient regard to the whole system and how functional this will be on a boat. Lithium battery manufacturers absolutely encourage this.

A systems approach would need to include:

An energy audit including not just the storage capacity needed but how to replenish the capacity without turning the boat into a power station.
Attention to all charging sources being compatible with lithium chemistry.
Particular attention needs to be given to ensuring that a BMS shut-down does not destroy the alternator diodes and other marine electronics.
Cell-level monitoring by BMS.
Automatic and effective balancing of cells.
An audible warning system as BMS triggered shut down approaches.
A construction method that allows charge and load circuits to be separated or at least a robust system for compensating for complete pack shut-down. (Imagine this happening at night under engine crossing a busy shipping lane to focus the mind.)
T-class (or equivalent) fusing to give high amperage interrupt capacity.
Means of compensating for low-temperature cut-off.
Means of compensating for high ambient temperatures that can shorten lithium life.
Consideration of high-amperage requirements -e.g. engine start, windlass. (For engine start at least, lead acid is still the standard.)
Compatibility of the system with emerging technical requirement standards and insurance issues.

The system should operate with minimal operator input - i.e. as automatically and safely as possible. Lithium doesn't care that you were careful to personally monitor your charging and discharging every day for the last thousand. You will eventually forget and a single serious thermal runaway or over-discharge - while not likely to destroy your boat - will certainly kill your investment.

This is the paper to read and digest before doing anything.

LiFePO4 Batteries On Boats - Marine How To

Very well summarised. Hit the nail on the head

 

[PaulRainbow]

It may be my reading of things but I see an overly-casual approach creeping in to installing lithium, one that does not pay sufficient regard to the whole system and how functional this will be on a boat. Lithium battery manufacturers absolutely encourage this.

Great post in general, i particularly agree with this.

The recent thread about Geems engine batteries provides a good example or three.

 

[Alex_Blackwood]

Great post in general, i particularly agree with this.

The recent thread about Geems engine batteries provides a good example or three.

Where is "Zing" when you need him?

 

[DuncanHall]

Thanks all for the advice. I recognise that its some days since posting but I read the long self build thread!

My professional background was in nuclear safety so I thought I would add some of the requirements of diversity and redundancy into my decision making.

Several of the requirements that I picked up were.

1. We should be able to ensure that the system is resiliant from a single component failure.
2. There should be a warning before the batteries shoudown on low voltage.
3. We should be able to charge the batteries when its sub zero. For example when the boat is on the hard in winter and systems may still be required.
4. There should be sufficient capacity to run the inverter at peak power without shuting the system down. For examplesomeone plugs in a kettle by mistake!
5. If the Batteries shutdown there should be en easy way to swith to a diverse supply.
6. There needs to be protection for the alternator.

Requirement 1 is not met by using a single battery or by utilising several batteries operating on 1 BMS.
Requirement 2 can be met using the alarm function on my Victron BMV 700
Requirement 3 can be met using batteries with integral heating elements or a separate heating pad
Requirement 4 means I need to be able to draw about 250A peak 300 would be a safe bet.
Requirement 5 could be met by having something that take power from the lead acid batteries on my vessel that run the bow thrusters and engine start.

My proposed solution is to use 3 drop in fogstar drift 105AH batteries as I will effectivly have redundancy of BMS's. The batteries have heaters. I will upgrade my 60A alternator to 100A and fit a Stirling 1260 Battery to battery charger. This has the option of using the stirling as a DC power supply to my DC loads thus givng diversity of supply.

 

[Poey50]

Thanks all for the advice. I recognise that its some days since posting but I read the long self build thread!

My professional background was in nuclear safety so I thought I would add some of the requirements of diversity and redundancy into my decision making.

Several of the requirements that I picked up were.

1. We should be able to ensure that the system is resiliant from a single component failure.
2. There should be a warning before the batteries shoudown on low voltage.
3. We should be able to charge the batteries when its sub zero. For example when the boat is on the hard in winter and systems may still be required.
4. There should be sufficient capacity to run the inverter at peak power without shuting the system down. For examplesomeone plugs in a kettle by mistake!
5. If the Batteries shutdown there should be en easy way to swith to a diverse supply.
6. There needs to be protection for the alternator.

Requirement 1 is not met by using a single battery or by utilising several batteries operating on 1 BMS.
Requirement 2 can be met using the alarm function on my Victron BMV 700
Requirement 3 can be met using batteries with integral heating elements or a separate heating pad
Requirement 4 means I need to be able to draw about 250A peak 300 would be a safe bet.
Requirement 5 could be met by having something that take power from the lead acid batteries on my vessel that run the bow thrusters and engine start.

My proposed solution is to use 3 drop in fogstar drift 105AH batteries as I will effectivly have redundancy of BMS's. The batteries have heaters. I will upgrade my 60A alternator to 100A and fit a Stirling 1260 Battery to battery charger. This has the option of using the stirling as a DC power supply to my DC loads thus givng diversity of supply.

Your Requirement 1. Many people (me included) prefer a single pack with a reliable BMS external to the pack. If you are designing a system then it is not too much additional trouble to start with bare cells (Winston preferably) and buy something like a REC BMS which has a very good reputation. People have built successful systems using up to 1000 ah cells since previous concerns about the vulnerability of the internal structure of large cells seems to have been unfounded. You do get redundancy with several drop-ins in parallel but you need cell-level monitoring and ability to change parameters which not all drop-ins have. BMS control on drop-ins is by way of MOSFETs internal to the BMS rather than external relays which are better for carrying high current. With an external BMS and relays you can avoid many issues by having charging and load circuits on separate buses. That way if you have a high voltage shutdown you can still draw current and, vice versa, with a low voltage shutdown you can still take a charge. See the Nordkyn Design articles that I link to in the first page of the build thread (below). If you start with bare cells you will discover just how much you would otherwise pay for the drop-in plastic cases and stickers. Cases can also used cynically to hide cheaper components and poor connections.
Your other requirements look sensible. Do add a 7th which is fusing of sufficient amperage interrupt capacity to manage the mass of power than can run into a dead short. Class-T fusing is the usual recommendation here.

 

[PCUK]

This is all very useful info'. Can I drop in a slight thread drift with an additional question! If I fit two LifePo batteries for house use, what would be the best battery type for engine starting? Also, will my standard 140 amp alternator need any additional regulator to properly charge all three batteries at the same time through VSR's or diodes. Many thanks.

 

[DuncanHall]

Your Requirement 1. Many people (me included) prefer a single pack with a reliable BMS external to the pack. If you are designing a system then it is not too much additional trouble to start with bare cells (Winston preferably) and buy something like a REC BMS which has a very good reputation. People have built successful systems using up to 1000 ah cells since previous concerns about the vulnerability of the internal structure of large cells seems to have been unfounded. You do get redundancy with several drop-ins in parallel but you need cell-level monitoring and ability to change parameters which not all drop-ins have. BMS control on drop-ins is by way of MOSFETs internal to the BMS rather than external relays which are better for carrying high current. With an external BMS and relays you can avoid many issues by having charging and load circuits on separate buses. That way if you have a high voltage shutdown you can still draw current and, vice versa, with a low voltage shutdown you can still take a charge. See the Nordkyn Design articles that I link to in the first page of the build thread (below). If you start with bare cells you will discover just how much you would otherwise pay for the drop-in plastic cases and stickers. Cases can also used cynically to hide cheaper components and poor connections.
Your other requirements look sensible. Do add a 7th which is fusing of sufficient amperage interrupt capacity to manage the mass of power than can run into a dead short. Class-T fusing is the usual recommendation here.

The Class T fuse requirement is a useful addition. Having read a bit more it seems sensible to change the existing 250A Megafuse in my system for a T Type.

I did look at using Winston cells end an external BMS but the cost was comparable to buying the victron 200AH unit which appears to be similar. This was by buying from GWL and adding a 5 year guarentee.

Having a single BMS still leaves the system to be vulnerableto a single point of failure.

 

[Poey50]

The Class T fuse requirement is a useful addition. Having read a bit more it seems sensible to change the existing 250A Megafuse in my system for a T Type.

I did look at using Winston cells end an external BMS but the cost was comparable to buying the victron 200AH unit which appears to be similar. This was by buying from GWL and adding a 5 year guarentee.

Having a single BMS still leaves the system to be vulnerableto a single point of failure.

Victron make excellent kit but last time I looked the BMS was not included in the battery pack. It isn't a true drop-in (and all the better for that, IMO.) I wouldn't buy Winstons from GML. Julia Yu is the person to contact for sale direct from the factory. These are Grade A cells and are very well matched for capacity and internal resistance. I have read of numerous sales through her - although have had no direct contact myself. Everyone seems to have had a good experience and she will talk people through the rather nerve-wracking business of purchasing from the Far East. She is Hong Kong based and ships to all parts of the world. She can be directly messaged on Facebook but there is a more general email address. If using it, I would nevertheless endeavour to deal direct with her ... sales@skypowerintl.com

 

[roaringgirl]

We live aboard and installed lithium when our AGMs gave up a year ago. My thoughts based on my experience:

- the victron bluetooth interface for BMS, BMV, smart batteries, battery protection switches and MPPTs makes life easier to check what's going on quickly. Having almost everything using the same UI is worth a lot.
- you will need to separate charge and load connections to you bank
- you will need to design and implement solutions for each charge source to be stoppable by the BMS
- the BMS is the emergency shutoff which you hope never gets used. Each charge source (including the alternator) should monitor battery voltage and be set to stop charging before the BMS has to get involved.
- Balmar external alternator regulator is great although fiddly to configure!
- We have 2×200Ah smart with external BMS. Yes, BMS is a single point of failure, but is cheap and we have a spare in the workshop onboard.
- Each battery's max output is rated at 200A. Obviously, this is more than enough!
- The low internal resistance allows us to take advantage of all the solar that's available, with no absorption phase. It has been going so well that I'm about to replace our hob with induction and still expect to never have to run the engine to charge.

 

[geem]

We live aboard and installed lithium when our AGMs gave up a year ago. My thoughts based on my experience:

- the victron bluetooth interface for BMS, BMV, smart batteries, battery protection switches and MPPTs makes life easier to check what's going on quickly. Having almost everything using the same UI is worth a lot.
- you will need to separate charge and load connections to you bank
- you will need to design and implement solutions for each charge source to be stoppable by the BMS
- the BMS is the emergency shutoff which you hope never gets used. Each charge source (including the alternator) should monitor battery voltage and be set to stop charging before the BMS has to get involved.
- Balmar external alternator regulator is great although fiddly to configure!
- We have 2×200Ah smart with external BMS. Yes, BMS is a single point of failure, but is cheap and we have a spare in the workshop onboard.
- Each battery's max output is rated at 200A. Obviously, this is more than enough!
- The low internal resistance allows us to take advantage of all the solar that's available, with no absorption phase. It has been going so well that I'm about to replace our hob with induction and still expect to never have to run the engine to charge.

Who batteries did you buy or did you build your own? If you built your own, which cells?