Lithium batteries worth buying?

Depends entirely on your pattern of usage. The big selling points are longer life in terms of discharge cycles and greater capacity for the size/weight. Downside is that you need to revamp your charging arrangements which adds cost and complexity. So really only of interest if you re a full time liveaboard with a long time horizon or weight/space is an issue.

For "weekend" type cruisers who might spend 50 or so days a year on board (therefore 50 cycles) good FLAs are adequate and will give a life of 5+ years, although now that the price of AGMs has fallen they offer up to twice the number of cycles for a premium of 30-50% for a given capacity giving a potential life of 10+ years. AGMs also have a higher charge acceptance rate and lower self discharge so more suited to the typical regime of intense periods of usage followed by long periods of rest. Bit like my Morgan which still has its original 19 year old Red Flash AGM battery. Key to long life is keeping the batteries close to fully charged when not in use and particularly just before a heavy usage cycle.

So the choice of FLA or AGM depends on your time horizon and willingness to pay up front for the extra life, and for Lithium having the usage requirements that justifies the substantial extra investment - although to be fair that cost can be reduced if you are knowledgeable and can build your own system.
 
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If a car's lithium batteries catches fire you can quickly stop and get out. Not so easy on a boat .... Apart from the cost that would be my major concern.
 
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Thank you for replies-our neighbour advised he had just fitted some lithium and prices seemed high but used someone at Hamble so was just curious as whether I needed to investigate more for when our AGM expired which were pricy enough. By the sounds of it for uk cruising AGM seem fine and money might be better spent on a solar panel of some sort.
 
For the average boater who is a weekender or marina hound .... I really cannot see the reason other than space saving to go for Li batterys.

I have posted many times about my preference to buy 2nd hand out of breaker yards ......... guys there usually have the load tester to see which battery is good ... price is nice on pocket. Just because its a breaker yard - does not mean battery is old. Think about it - that battery was most likely starting that junk car right up to its last final journey.

The average life I have had out of such is 5yrs, with one that lasted a lot longer than that. In fact the only reason I replaced was because of lack of charge over winter causing battery to fail. I cruise my boat for quite long trips 2x a year average, one usually of 10 days or more ... with most other 1 - 2 day jaunts.

When shore power available - I have battery maintainers that keep batterys topped up ... about a tenner each, one for each battery.

Given the price and that most of us have 2 or more batterys - should one fail - its not end of world stuff .. and replacement still makes total a lot less than even a new LA job ... let alone expensive Li ...

Li - I use a lot of LiPo and LiFe batterys as an RC addict ...... and TBH - have no wish to have Li on board as battery power - even though they will have management boards and hard cases .........

But that's my take on it ....

Edit : But there is one area that I do use Li .... and that is as emergency power for items such as radio etc. I took the idea of the typical Phone Power Bank you can buy in supermarket and use LiPo's that I no longer use for flights. Example : My old ICOM HH VHF .... no way I was going to buy an original replacement battery ... I metered my retired LiPo's and wired one to that ICOM ... stays powered longer than original ! I have a couple of LiPo / LiFe packs I can use for plotters etc. if main battery bank goes down.

I know this is not boaty ... but I also use those old retired LiPo's for powering hand drills etc. Because RC world has many 12v powered chargers to cater for various Li packs .... I can easily recharge on board if needed. In fact most RC chargers can deliver charge to main boat batterys from mains power ... they have user set modes for most battery types.
 
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jwilson said:
If a car's lithium batteries catches fire you can quickly stop and get out. Not so easy on a boat .... Apart from the cost that would be my major concern.
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Yes but lithium ion used in cars and lithium iron phosphate used in boats are completely different batteries so your point is moot since the LiFePo4 are quite safe.
 
lustyd said:
Yes but lithium ion used in cars and lithium iron phosphate used in boats are completely different batteries so your point is moot since the LiFePo4 are quite safe.
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Tesla have used lifePO4 in their entry level cars where range is not such a factor because it is inherently safer that some of the lithium technologies offering higher energy density but the added risk of fire. The risks of LifePO4 are pretty low. It seems to me that the risks on a boat come from poor installation not the batteries themselves. The biggest single risk seems to be BMS failure that allows serious over charging but even then they don't seem to burst into flames but they get exstremly hot and smoulder
 
LiFePO4 do not catch fire.

EWe converted our boat a year ago and it is one oif the best things we have done. But we have done it properly, we have replaced our alternator to a Balmar lithium compatible unit and we have fitted separate BMS units.

The thing about Lithium batteries is not so much that capacity increases which it does, it is the speed and ease of charging. So as soon as you start your engine, we are putting in 90A at 24v that's about 180A at 12V. Our solar puts every bit of energy into the batteries no matter the state of charge and if we do plug in our start the generator we charge at up to 220A at 24V.

The result is that we can go from 50% to float in 90 minutes with our genny in the past it would take 14 hours to get from 60% to float with lead acit batteries. The energy, noise and fuel saved is amazing.

To do it properly requires a lot of upgrades as your existing cables will not be man enough to carry the charging current. If you are in the Hamble I would contact Paul Knight of Knight Marine. The work he did on my boat is fantastic.
 
Seven Spades said:
LiFePO4 do not catch fire.

EWe converted our boat a year ago and it is one oif the best things we have done. But we have done it properly, we have replaced our alternator to a Balmar lithium compatible unit and we have fitted separate BMS units.

The thing about Lithium batteries is not so much that capacity increases which it does, it is the speed and ease of charging. So as soon as you start your engine, we are putting in 90A at 24v that's about 180A at 12V. Our solar puts every bit of energy into the batteries no matter the state of charge and if we do plug in our start the generator we charge at up to 220A at 24V.

The result is that we can go from 50% to float in 90 minutes with our genny in the past it would take 14 hours to get from 60% to float with lead acit batteries. The energy, noise and fuel saved is amazing.

To do it properly requires a lot of upgrades as your existing cables will not be man enough to carry the charging current. If you are in the Hamble I would contact Paul Knight of Knight Marine. The work he did on my boat is fantastic.
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It sounds like for you and your boat it was a great choice. For us the benefits are marginal and for weekend sailors the cost of doing it properly would not be worth it.
We are properly set up for lead batteries. We never need the generator or engine to charge the batteries. Solar, wind and towed generator can do it all. Conversion to lifePO4 would provide minimal benefit to us but entail vast expense
 
Seven Spades said:
LiFePO4 do not catch fire.

EWe converted our boat a year ago and it is one oif the best things we have done. But we have done it properly, we have replaced our alternator to a Balmar lithium compatible unit and we have fitted separate BMS units.

The thing about Lithium batteries is not so much that capacity increases which it does, it is the speed and ease of charging. So as soon as you start your engine, we are putting in 90A at 24v that's about 180A at 12V. Our solar puts every bit of energy into the batteries no matter the state of charge and if we do plug in our start the generator we charge at up to 220A at 24V.

The result is that we can go from 50% to float in 90 minutes with our genny in the past it would take 14 hours to get from 60% to float with lead acit batteries. The energy, noise and fuel saved is amazing.

To do it properly requires a lot of upgrades as your existing cables will not be man enough to carry the charging current. If you are in the Hamble I would contact Paul Knight of Knight Marine. The work he did on my boat is fantastic.
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Your opening gambit is false so I won’t bother reading the rest.
For everyone else , they can and do suffer thermal runaway if mismanaged.
 
Buck Turgidson said:
Your opening gambit is false so I won’t bother reading the rest.
For everyone else , they can and do suffer thermal runaway if mismanaged.
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Thermal runaway isn't the same as a blazing fire. I cannot find a single confirmed image of a LifePO4 battery with flames billowing out. They seem to smoulder and smoke but no flames
 
jwilson said:
If a car's lithium batteries catches fire you can quickly stop and get out. Not so easy on a boat .... Apart from the cost that would be my major concern.
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The lithium-ion used in car batteries is not the same as the lithium-iron-phosphate used in marine lithium batteries. It's like saying: "I wouldn't eat sodium chloride because sodium burns on contact with water!"
 
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