Should I replace my lead acid service battery with lead acid or lithium?

[Trefusis]

I read an article saying lithium is:

"3x lighter"
"1.8x more power"
"3x longer life"
"Lower cost"

Is the logic in this article based on facts or marketing hype?

Here is the article:
Lithium battery LiFePO4 100Ah

 

[TSailors]

purchasing price is much higher for lithium but they last 10 years so they are cheaper in the long run .

 

[ctva]

I’ve just installed a lithium system, 2x100ah and what a game changer. With all the extra bits needed, it worked out at £1200 instead of £450 for a replacement lead acid battery bank but gives nearly twice the capacity. And charging is so much quicker.

In my opinion, well worth it.

 

[Tranona]

I read an article saying lithium is:

"3x lighter"
"1.8x more power"
"3x longer life"
"Lower cost"

Is the logic in this article based on facts or marketing hype?

Here is the article:
Lithium battery LiFePO4 100Ah

Depends mainly on your pattern of usage, your existing systems, your time horizon and budget. The properties of lithium are well known and provable and you have to work out whether you can take advantage of these properties. Then what you have to do to your boat's existing systems to make it work for you.


The people who see most benefit are long term liveaboards in substantial boats with high energy consumption that can fit a means of generating and storing energy. This usually means lots of solar and therefore more attractive if you sail/live in areas with lots of sun.

 

[Lucy52]

Be aware that they are not drop in replacements, you will need to protect your alternator, and the charging profile is different. Batteris may be a different size to your LA batteries and may need different leads, and fuses.

 

[Trident]

As you're posting the live aboard section I assume you'll be on the boat a lot - in which case almost certainly lithium will be a big plus. Just be careful what you buy as quality and safety in the BMS' vary .

Good LiFePo4 batteries if treated right will last decades - I'm selling some Renogy Smart 100Ah in perfect condition and still showing 99% capacity after 4 years use on the For Sale forum - thats 1% loss of capacity in 4 years with daily use running my workshop through a 5kw inverter. So if 80% is considered past it then this would last 80 years! They do reportedly die of old age before then but so far the longest continuous use test I have seen with high loads has the battery like new at 15 years old.

 

[Gustywinds]

I knew I wanted to upgrade my inverter and battery capacity to allow overnight use when having no shore power and the combination of lithium batteries with a new inverter/charger made sense for me. The smaller size allowed 3x 100AH in the space previously occupied by 2x 80AH lead acids. The ones for the engine start and the thrusters are still lead acid although I much change the latter at some point.

 

[Sea Change]

purchasing price is much higher for lithium but they last 10 years so they are cheaper in the long run .

Lithium batteries are no longer more expensive, if you are measuring useable capacity.
However there are a number of changes to the rest of the system and that might add up. The exact changes will depend on what you already have installed and how you want to use your boat.

 

[Graham376]

Going back to the title - should I replace my lead acid battery with lead acid or lithium? - I would say that depends on whether your lead acids are providing what you want.

In my case, the 450ah of Trojans I have are doing the job so, when they pack up (5 years old now) I will replace with the same, seeing no point in spending far more to update all the charging system.

 

[geem]

I read an article saying lithium is:

"3x lighter"
"1.8x more power"
"3x longer life"
"Lower cost"

Is the logic in this article based on facts or marketing hype?

Here is the article:
Lithium battery LiFePO4 100Ah

Just read it. Obviously it's a sales document but the essence of it is correct.
Installed correctly, it should last many years.
The biggest advantage i see for the average cruising boat is not having to get the battery to 100% on a regular basis. It's happy to be at a partial state of charge with no ill effects.

 

[mattonthesea]

As above re thinking it through.
We have 200Ah, 30A DC2DC charger with 2x50W panels (Geem, they are Renogy - say no more, they are going!) and a 1kW inverter.We run a small fridge, a travelling kettle and an IKEA portable induction hob.

Suits us fine, although more solar is planned. We anchor for a few days and visit marinas occasionally to fill up on food, water and electricity. That's our journeying lifestyle. Getting gas is difficult so we ration it. Hence the move to leccy.

I think that the key is to work out what your lifestyle needs are and then plan your power to suit.

 

[geem]

As above re thinking it through.
We have 200Ah, 30A DC2DC charger with 2x50W panels (Geem, they are Renogy - say no more, they are going!) and a 1kW inverter.We run a small fridge, a travelling kettle and an IKEA portable induction hob.

Suits us fine, although more solar is planned. We anchor for a few days and visit marinas occasionally to fill up on food, water and electricity. That's our journeying lifestyle. Getting gas is difficult so we ration it. Hence the move to leccy.

I think that the key is to work out what your lifestyle needs are and then plan your power to suit.

We are removing gas from the boat completely when we get home. We will install an electric oven. It's a Panasonic, 3 way with microwave, steamer and grill. On top will go a single ring induction hob with a second one when needed. More solar going on and framed panels to replace the terrible flexi panels. Duogen coming off and going on Ebay. I will fit a bigger alternator. We can already charge at 115A @24v from the diesel generator if we need to.
An additional lithium battery will get built giving us 14kw of domestic battery capacity.

 

[Graham376]

I bet this guy wished (for a few seconds) he'd never had lithium -

 

[Sea Change]

I bet this guy wished (for a few seconds) he'd never had lithium -

Tragic, and utterly irrelevant to this discussion.

The kind of battery in the video is more closely related to your phone, laptop, or power tools, than it is to a LiFePO4 marine battery.

 

[Graham376]

Tragic, and utterly irrelevant to this discussion.

The kind of battery in the video is more closely related to your phone, laptop, or power tools, than it is to a LiFePO4 marine battery.

As well as phones, laptops etc, increasing numbers are keeping electric scooters on board which certainly pose a risk, particularly if left unattended on charge.

 

[Gustywinds]

As well as phones, laptops etc, increasing numbers are keeping electric scooters on board which certainly pose a risk, particularly if left unattended on charge.

This was something that concerned me a little with the E-bike we have onboard so I always charge it on the open rear during the day. Having said that, it doesn’t seem to get very hot. With hindsight I probably should have got one where the battery is removable and I could put a simple thermal alarm on it but hey-ho…

 

[AndersG]

I bet this guy wished (for a few seconds) he'd never had lithium -

Boats use LiFePO4 batteries and they are safer than lead acid and will not catch fire. You can even throw them in a fire! Don't try that with a lead acid battery.

 

[luckybeanz]

Figured I'd chime in here as have some experience... I converted my boat to fully electric in 2020 and built the lithium batteries myself. Lithium is far safer and holds up much better than the old tech. Honestly I don't see any downsides to converting, their price has also come down markedly, for instance you could get 330ah cells to make a 12v system from ALiexpress for GBP250, shipped, add in a daly bms for under 50 and you have over 300 usable amp hours for less than 1 pound an amp hour.

What many also don't know is they charge a lot faster than GEL or AGM due to their lower internal resistance, meaning that having 200w solar could mean that you don't even need to charge them from your alternator. Again, I have seen this with mine as I have two 110watt flexible panels charging 550ah for my house battery and if they are in a non shaded position they easily keep up. Though this is clearly dependent on your usage, I use my bigger 48v bank for the heavy lifting, and where you are located.

The reason people need to change the alternator is because they can absorb a much higher current than GEL/AGM and thus burn out the alternator. There are workarounds here, for instance using the old battery between the lithium and alternator as a buffer, though there are efficiency losses here. You can also use a DC/DC charger or add in a regulator to your alternator instead of replacing the whole thing.

 

[pmagowan]

What is your system Lucky? I was thinking of going to one liquid fuel only (diesel) all else electric on board. Looking at the 48V Integrel system but might need a 24V and 12V bank also for winches and electronics as not much options with 48. I suspect lithium is cheaper over lifespan than other options per usable KWh. Sorry to thread drift/hijack but all part of the consideration

 

[dune16]

I just removed 4 x 140ah agm's (160kg weight. 280ah actual usable capacity) and installed 2 x 300ah Vatrer lifepo4 batteries (53kg weight. 570ah<> usable capacity). Standard alternators are temperature protected and boats chargers have lithium profile. Total cost was £1200 and I have a whole load more capacity. Game changer for us! In my case it was cheaper to go lfp than replace my 4 agm's.