Advice on buying Lithium Batteries

[Sea_Sense]

Hi - I have just discovered my 460 amp hours domestic batteries are knackered but I guess they are 5+ years old. I was thinking of checking out lithium batteries - I have heard there are now some that you can charge through your engine battery saving the issue of purchasing a new charging system. Is this case? Any advice or threads I should read gratefully accepted.

 

[B27]

Several threads on here.
Best to start by being clear about your 'needs' 'wants' and budget.

Four new LA batteries and invest a bit in looking after them better may well be a good way forwards.

 

[Sea_Sense]

Several threads on here.
Best to start by being clear about your 'needs' 'wants' and budget.

Four new LA batteries and invest a bit in looking after them better may well be a good way forwards.

Thanks for the feedback

 

[Sandy]

Hi - I have just discovered my 460 amp hours domestic batteries are knackered but I guess they are 5+ years old. I was thinking of checking out lithium batteries - I have heard there are now some that you can charge through your engine battery saving the issue of purchasing a new charging system. Is this case? Any advice or threads I should read gratefully accepted.

Gosh, what have you done to 'knacker' them after just five plus years? Are they all knackered or just the one?

What charging do you currently have? Alternator/wind/solar/generator/shore power.

How often do you use the boat? Daily/weekly/monthly/now and then.

 

[Sea_Sense]

thinking about it - it probably 7 + years - I can’t actually remember exactly when. Charging has been by shore power and alternator - Boat has not been used much over the last 4 years but before that weekly for long weekends and long sailing holidays around northern France. Have always tried not to run the batteries below 65%. Which gives me about 150 amps before recharging. I run a fridge (20 amps every 24 hours) and the normal gps and ray marine instruments. I have 2 children who like to charge their phones, tablets etc so I was thinking about adding more batteries or lithium. So I was interested in how much adjustment I would have to make if I add lithium

 

[geem]

thinking about it - it probably 7 + years - I can’t actually remember exactly when. Charging has been by shore power and alternator - Boat has not been used much over the last 4 years but before that weekly for long weekends and long sailing holidays around northern France. Have always tried not to run the batteries below 65%. Which gives me about 150 amps before recharging. I run a fridge (20 amps every 24 hours) and the normal gps and ray marine instruments. I have 2 children who like to charge their phones, tablets etc so I was thinking about adding more batteries or lithium. So I was interested in how much adjustment I would have to make if I add lithium

Bowvthruster, electric windlass, solar? These would makes a difference on how you wire lithium. If you have a bowthruster and windlass, wiring these from the engine battery would make sense. Solar would wire to the lithium. The alternator can't charge the lithium directly so you would need a DC/DC charger. In addition, you would want a smart shunt to monitor SOC of the lithium. Hope this helps

 

[Sandy]

thinking about it - it probably 7 + years - I can’t actually remember exactly when. Charging has been by shore power and alternator - Boat has not been used much over the last 4 years but before that weekly for long weekends and long sailing holidays around northern France. Have always tried not to run the batteries below 65%. Which gives me about 150 amps before recharging. I run a fridge (20 amps every 24 hours) and the normal gps and ray marine instruments. I have 2 children who like to charge their phones, tablets etc so I was thinking about adding more batteries or lithium. So I was interested in how much adjustment I would have to make if I add lithium

I wonder if my bolding is the root of your problem; lack of use.

@geem knows I am not a fan of lithium on 'lightly used boats' in the UK as I don't see any advantage in using the technology.

I changed all of my batteries to AGMs as they can take a faster charge and there is no risk of leaks should one ever crack, added a Victron power management system; shunt, shore power, battery sensor (voltage and temp) and a MTTP, plus 200 watts of solar. I now really understand my power usage.

Adding solar means that the batteries are constantly at float when I'm not using the boat rather than being charged when down at the marina. The major driver to solar was moving from a marina to a river mooring.

It might be worth costing a new lithium set up against replacing what you have and adding a good power management system (I like Victron) and a bit of solar.

Note: I have 390Ah of house batteries and struggle to use an average of 10 amps per hour while underway. The solar usually keeps up with my usage. The squeaky has left home, but from time to time I have crew who are surgically attached to their phones, and prefer my beer warm.

 

[geem]

I wonder if my bolding is the root of your problem; lack of use.

@geem knows I am not a fan of lithium on 'lightly used boats' in the UK as I don't see any advantage in using the technology.

I changed all of my batteries to AGMs as they can take a faster charge and there is no risk of leaks should one ever crack, added a Victron power management system; shunt, shore power, battery sensor (voltage and temp) and a MTTP, plus 200 watts of solar. I now really understand my power usage.

Adding solar means that the batteries are constantly at float when I'm not using the boat rather than being charged when down at the marina. The major driver to solar was moving from a marina to a river mooring.

It might be worth costing a new lithium set up against replacing what you have and adding a good power management system (I like Victron) and a bit of solar.

Note: I have 390Ah of house batteries and struggle to use an average of 10 amps per hour while underway. The solar usually keeps up with my usage. The squeaky has left home, but from time to time I have crew who are surgically attached to their phones, and prefer my beer warm.

If I had a small cruisers for use in the UK in would definitely have lithium. Lithium batteries are smaller lighter and will last many, many years. Far longer than lead. When space is at a premium on small boats, lithium allows you to have lots of Ah in a small space and you can use way more of the battery capacity than you can with lead. You would need the same good quality power management system for lithium. In many ways lithium is a better fit on small simple boats as you are unlikely to have large loads such as powerful inverter or electric cooking so you get a far simpler installation.
You can charge them up more quickly than lead with a DC/DC charger running at 50% of the alternator rating and you don't need to worry about sulfation or getting them to 100% SOC on a regular basis.

 

[B27]

For a small cruiser, it's actually quite a lot of spending to upgrade to Lithium.
LifePO4 drop-ins don't seem to be intended for engine starting.
Mate of mine has a typical two-battery cruiser, his engine battery has just 'called time'.
No drama as the house battery is a leisure Lead acid, so easily capable of starting the diesel.

A lot of people don't really need any more than a good leisure battery and a solar panel or two.
Other people seem to get value out of big battery banks and hundreds of pounds worth of charging and monitoring kit.

It's something to be aware of, engine battery, with solar float charging, gave no warning, it went from apparently happy to dead in an afternoon. It's not like a car when slow cranking will give you a week's warning to order a new battery.
So I think back up for the starter battery is an absolute must, unless you're always going to be able to sail on to every mooring etc.

 

[geem]

For a small cruiser, it's actually quite a lot of spending to upgrade to Lithium.
LifePO4 drop-ins don't seem to be intended for engine starting.
Mate of mine has a typical two-battery cruiser, his engine battery has just 'called time'.
No drama as the house battery is a leisure Lead acid, so easily capable of starting the diesel.

A lot of people don't really need any more than a good leisure battery and a solar panel or two.
Other people seem to get value out of big battery banks and hundreds of pounds worth of charging and monitoring kit.

It's something to be aware of, engine battery, with solar float charging, gave no warning, it went from apparently happy to dead in an afternoon. It's not like a car when slow cranking will give you a week's warning to order a new battery.
So I think back up for the starter battery is an absolute must, unless you're always going to be able to sail on to every mooring etc.

You can have a link from lithium to charge an engine battery but if its duff, that might not help. If you had lithium battery you built yourself, you can start from the lithium by bypassing the bms. This would only be for emergency use but lithium is capable of huge amps

 

[Tranona]

If I had a small cruisers for use in the UK in would definitely have lithium. Lithium batteries are smaller lighter and will last many, many years. Far longer than lead. When space is at a premium on small boats, lithium allows you to have lots of Ah in a small space and you can use way more of the battery capacity than you can with lead. You would need the same good quality power management system for lithium. In many ways lithium is a better fit on small simple boats as you are unlikely to have large loads such as powerful inverter or electric cooking so you get a far simpler installation.
You can charge them up more quickly than lead with a DC/DC charger running at 50% of the alternator rating and you don't need to worry about sulfation or getting them to 100% SOC on a regular basis.

The OP already has (probably) sufficient capacity for his needs so the smaller and lighter is a bit of a red herring - although valid if one wants greater capacity but are limited in space. The vast majority of UK cruisers with a usage pattern like the OP manage very well with LA, particularly with a bit of solar. Note he says he uses shorepower and does not seem to spend long periods at anchor.

As ever before diving in and telling him he needs lithium the best thing is to suggest a power audit - consumption and power generation then number of cycles a year. Remember, unlike you weekend/holiday cruisers are lucky if they get more than 60 days a year on board reliant on the boat's power- and even then many of these with a young family will likely be on shorepower. The 800+ cycles of AGMs give a life of 10-15 years.

BTW there is no suggestion from the OP that he wants to exploit the potential of lithium by spending the extra on inverters, electric cooking etc. Just replacing his aging bank

 

[xyachtdave]

Gosh, what have you done to 'knacker' them after just five plus years?

Leaves his fridge on 24/7.

 

[Sea_Sense]

Bowvthruster, electric windlass, solar? These would makes a difference on how you wire lithium. If you have a bowthruster and windlass, wiring these from the engine battery would make sense. Solar would wire to the lithium. The alternator can't charge the lithium directly so you would need a DC/DC charger. In addition, you would want a smart shunt to monitor SOC of the lithium. Hope this helps

Yep I have bowthruster and anchor windlass, and clipper shunt battery monitor, no solar yet. I have 40 ft van de stadt, and the batteries are placed near the areas they are needed. So anchor windlass and bow thrusters have the domestic batteries at the front of the boat and engine battery is at the back of the boat. So lots of battery wiring to consider if I went lithium. I am assuming I need to change my victron battery charger as well?

 

[geem]

The OP already has (probably) sufficient capacity for his needs so the smaller and lighter is a bit of a red herring - although valid if one wants greater capacity but are limited in space. The vast majority of UK cruisers with a usage pattern like the OP manage very well with LA, particularly with a bit of solar. Note he says he uses shorepower and does not seem to spend long periods at anchor.

As ever before diving in and telling him he needs lithium the best thing is to suggest a power audit - consumption and power generation then number of cycles a year. Remember, unlike you weekend/holiday cruisers are lucky if they get more than 60 days a year on board reliant on the boat's power- and even then many of these with a young family will likely be on shorepower. The 800+ cycles of AGMs give a life of 10-15 years.

BTW there is no suggestion from the OP that he wants to exploit the potential of lithium by spending the extra on inverters, electric cooking etc. Just replacing his aging bank

I didn't dive in and tell him he needed lithium. He said he was interested in lithium. Trying reading whatt I said. I actually answered Sandys post not the OP. I also said that if I had a small cruiser in the UK I would have lithium for all the benefits I pointed out. I actually asked the OP what other systems he had before answering his post

 

[Sea_Sense]

Leaves his fridge on 24/7.

 

[geem]

Yep I have bowthruster and anchor windlass, and clipper shunt battery monitor, no solar yet. I have 40 ft van de stadt, and the batteries are placed near the areas they are needed. So anchor windlass and bow thrusters have the domestic batteries at the front of the boat and engine battery is at the back of the boat. So lots of battery wiring to consider if I went lithium. I am assuming I need to change my victory battery charger as well?

Converting your boat to lithium would not be straightforward. It would also be expensive. Due to the inrush current attributed to large DC motors such as bowthrusters and windlasses, you cannot simply install lithium batteries and power these devices from the lithium as the high inrush current load can/may damage the BMS. You would have to use a lithium battery that has an external BMS like an REC where the load doesn't pass through the BMS. These BMS cost circa £750, not including the battery.
I have fitted lithium to Jeanneau and Beneteau 45 footers where all bowthruster and windlass loads were wired from the engine battery by the factory. In this case, installation of lithium for the domestic load is straight forward. All that was needed was the lithium batteries, a Victron smart shunt and a DC/DC converter to charge the lithium from the engine battery when the engine was running. Both boats already had good solar installations with Victron mppts.
With regard to using lithium for engine starting, I don't believe this is a good idea. Lead is super cheap for starter use. Alternators are designed to charge lead batteries so it's already set up for this type of battery and there is little benefit of lithium here.
If you were keen on going down the lithium route I would consider whether it is possible to run you bow thruster and windlass from the engine battery then running your domestic loads from dedicated lithium batteries. This way you can take advantage of relatively cheap lithium batteries with simple lithium BMS.

 

[xyachtdave]

I knew it, the fridge!

 

[Tranona]

Yep I have bowthruster and anchor windlass, and clipper shunt battery monitor, no solar yet. I have 40 ft van de stadt, and the batteries are placed near the areas they are needed. So anchor windlass and bow thrusters have the domestic batteries at the front of the boat and engine battery is at the back of the boat. So lots of battery wiring to consider if I went lithium. I am assuming I need to change my victron battery charger as well?

The key thing about many decisions like this is to first determine what your current needs are and what constraints you have. Then look at how you might remove or minimise those constraints. So, for example reducing consumption (LED lights an obvious one) or increasing power generation - the obvious being solar. These 2 can have a significant impact on your net daily use and therefore on your buffer capacity. Your existing buffer is not out of line for your size of boat and pattern of usage so the first choice is moving from FLA to AGM which typically increases potential life by 50%+ for a 30% premium with minimal changes, maybe just adjusting the settings on your charger. Additionally AGMs have a higher charge acceptance rate and lower self discharge which is useful if you keep your boat in a marina and use shorepower or have solar to keep the bank fully charged when you are not using the boat (that is most of the time!).

Lithium starts to become attractive if you want to do more things with electricity or spend longer away from shorepower while still using all your goodies. Hence the popularity with long term cruisers and liveaboards, particularly if they are in sunnier climes where solar can meet most of their needs.. This type of user can also benefit from the greater potential life 300+ cycles a year rather than 60 or 70. Unlike even 2 years ago there is little difference in cost in relation to usable capacity between AGMs and lithium.

If you think you can benefit from the different properties of lithium the big question is how best to introduce them into your boat. That is back to your original question and there is no simple answer. Not only a choice of ways of doing it in general and in relation to your existing equipment.

 

[Sandy]

Leaves his fridge on 24/7.

Errrrr. Batteries like to be used.

 

[lustyd]

Errrrr. Batteries like to be used.

Lithium doesn’t care either way, and for someone who doesn’t use the boat a lot would be the better option as you can turn everything off and leave for a couple of years and the battery will be fine. Do that with lead and results will vary but often the battery would be dead.