Lithium batteries worth buying?

[ryanroberts]

> The pros sound great, what of the cons ?!!

Trashing your alternator if their internal BMS disconnects is the main risk with a drop in setup on boats I believe

 

[Tranona]

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.

Rather proves the point, that you have to look at your power requirements and usage patterns and determine the optimum system to meet them. The thing that annoys me about the snake oil salesmen who push lithium only ever talk about the potential benefits and never ask the basic question about whether your requirements can take advantage of those, never mind whether it is the most cost effective approach.

As we see regularly on this forum there are still many people using just a couple of leisure batteries and a 1.2 both switch- and some even advocating buying used batteries from a breakers yard. So the sort of system you have is light years away from most others. For the vast majority of boatowners, lithium is of no value.

 

[roaringgirl]

> The pros sound great, what of the cons ?!!

Trashing your alternator if their internal BMS disconnects is the main risk with a drop in setup on boats I believe

You can use a relatively cheap balmar external regulator to do this safely - this can even be done with an internally regulated alternator if you open it up and bypass the internal regulation.

 

[Zing]

> The pros sound great, what of the cons ?!!

Trashing your alternator if their internal BMS disconnects is the main risk with a drop in setup on boats I believe

That shouldn’t be a risk. A proper BMS will shut down the alternator before it cuts the battery and when it does that the battery won’t need cutting anyway.

 

[Zing]

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

I did see one in flames. An alu cased lifepo4, very thin layer construction, which had a nail bashed through it.

 

[Pete7]

We switched to a hybrid 85A flooded lead acid (FLA) with 120A LifePO4 (LFP) mix a year ago and love it. The FLA is there just in case the LFP shuts down unexpectedly. Also we discharge the LFP down a bit before leaving the yacht and isolate it from the solar, leaving the FLA connected to run the bilge pump just in case.

The speed at which they charge up compared to FLA is astonishing taking everything we can throw at the LFP. It also runs our 1600w inverter so we are switching to a mix of electric and gas cooking. Can't remember when we last used the gas to boil the kettle, we just use the small electric kettle now. Halved our gas usage last year and more to come.

An experiment at Easter cooking on electric only for 2 days showed we are a little short of solar for full electric. We need to increase from 300w to about 500w really, so that may be a job next winter. We can charge via the alternator but in 3 weeks away last summer we only needed to do this twice, solar providing enough for a mix of gas/electric and general consumption on board.

Pete

 

[Refueler]

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.

All batterys have potential for causing or being a fire. All Lithium based have more capability of causing or being that fire. LiFePo4 are just one of the safer Lithium based.

The simple fact is that the charge and discharge rates are the key to that simple fact. To reduce the risk - your LiFePo4 cells are hard cased and with BMS. But they can and do still fail with sometimes awesome effect.

Now onto a matter that I never see posted - but actually is an important fact to know about :

A lot of discussion hinges round the energy density and discharge / charge of Lithium based ...BUT so far - I do not see mention of the two C rates applicable.

Just because a Lithium can discharge at awesome rates - does not mean you can charge at similar rates. To do so in fact can cause accumulative damage and at minimum - the cells do not achieve full charge. C rates are basically the rate energy can be put into or taken out of a cell. Lets take a cell - capable of 100C discharge - theoretically that cell can discharge at 100x the rated capacity in amps. Just for example : a 3AH cell with 100C rating can discharge at 300A. Yes well - in the Lithium user world - we laugh at some of the tripe specs brands put out. But that same cell will usually have a substantially lower charge IN C rate ... usually less than a 1/4 of the charge OUT C rate.
The net effect is that - you can discharge that cells at high rates and enjoy all the Lithium power - but when charging - you need to take into account that the rate needs to be substantially lower to enjoy full and long life of the cells.

Don't believe me ? Easy enough to check online.

 

[Refueler]

Rather proves the point, that you have to look at your power requirements and usage patterns and determine the optimum system to meet them. The thing that annoys me about the snake oil salesmen who push lithium only ever talk about the potential benefits and never ask the basic question about whether your requirements can take advantage of those, never mind whether it is the most cost effective approach.

As we see regularly on this forum there are still many people using just a couple of leisure batteries and a 1.2 both switch- and some even advocating buying used batteries from a breakers yard. So the sort of system you have is light years away from most others. For the vast majority of boatowners, lithium is of no value.

Hi T ...

Like the reference to breakers yard !!

How did I get to using Breaker Yard batterys ?? It was from the mechanics who worked with me on my race car ..... I was like most people - battery would go down - go buy a new one. But then I was told where the 'break down' batterys we had in the Hi-Ace van came from ... In return for use of garages gear on my race car - I did electrical stuff on cars that they really did not like doing. I met my first wife actually by repairing ignition on her Viva ...
The van had a bank of Lead Acids in for running diagnostic gear as well as starting cars when away from residential areas / power etc. Those lead acids were from the local yard .....

It got me thinking later when I got the boat ... so I got one from the yard and put on my Alacrity .... that battery was sold with the boat years later still chugging away. Never regretted it ...

As you rightly say - it all depends on what use you have on board. Is the expense worth it to change ? Can you have enough power from conventional ? I have 2x 90A/h on my boat with a bog standard alternator on the 4-107 ... two battery trickle charge maintainers powered from mains ... I can happily cruise for 10days or more in Swedish Archipelago ... with only 2 stops in marina based ... rest to islands without power. Engine use ? maybe 1 - 2 hrs odd days ...
All on batterys that cost me ~20 euros each.

 

[Pete7]

The net effect is that - you can discharge that cells at high rates and enjoy all the Lithium power - but when charging - you need to take into account that the rate needs to be substantially lower to enjoy full and long life of the cells. Don't believe me ? Easy enough to check online.

Well, I can discharge a 120Ah LFP battery at 150A and charge a 80A. I can't generate 80A on my yacht even with maximum solar and engine together. So it isn't an issue.

A couple points for reference. The kettle will draw 75A at night and the induction stove maxed out about 120A. However, in practise we use the induction stove at half power max, about 800w say 75A although it cycles on and off to maintain the temperature. What it means is we can cook on electric, run power tools and the hoover on board without caning the FLA or suffering huge voltage drops. A washing machine is a future option and we already have a small freezer.

Yes, you can use a pair of car batteries and spend hours charging them with the engine, or look to new ideas. We all have a choice and I certainly would foist Lithium on anyone unless they really wanted to adopt it. For us the deciding factor was the need to replace the 34 yr old cooker as I was getting worried about its condition. That lead to looking at all the options for cooking including fitting air fryer.

Pete

 

[lustyd]

Well, I can discharge a 120Ah LFP battery at 150A and charge a 80A. I can't generate 80A on my yacht even with maximum solar and engine together. So it isn't an issue.

Pete

I suspect that’s true of most yachts. As the generating capacity rises the battery bank tends to rise even more so it would be hard for it to be a problem, especially with modern controllers.

 

[Kukri]

Just replaced my 4 x 110 AHr domestic bank with like-for-like lead acid. For my sailing, occasional weeks and weekends throughout the summer season, mostly marinas, the complications and complexities of lithium far outweigh the advantages.

Same here.

 

[Refueler]

I was just posting after reading someone charging at extreme high rates ...

Not saying his set-up is wrong. Just posting to show that there is a difference charge IN ... Charge OUT rates.

Not all battery packs can handle high charge rates IN ... and this C rate could be a factor ...

 

[geem]

I did see one in flames. An alu cased lifepo4, very thin layer construction, which had a nail bashed through it.
[/QUOTE]
Got a photo? Never ever has from what I can see

 

[coopec]

I did see one in flames. An alu cased lifepo4, very thin layer construction, which had a nail bashed through it.

I know nothing about them but....

"The LiFePO4 batteries are the safest type of Lithium batteries as they will not overheat, and even if punctured they will not catch on fire. The cathode material in LiFePO4 batteries is not hazardous, and so poses no negative health hazards or environmental hazards." 31 Oct 2019

BatteryStuff Articles | Overview of the Different Types of Lithium Batteries on the Market

 

[Zing]

[/QUOTE]
Got a photo? Never ever has from what I can see
[/QUOTE]
I actually posted on this before. My earlier post:
270ah DIY LiFePO4 build

 

[geem]

Got a photo? Never ever has from what I can see
[/QUOTE]
I actually posted on this before. My earlier post:
270ah DIY LiFePO4 build
[/QUOTE]
Wow! Never seen one that actually had flames before. Slightly scary. No wonder some insurance companies are not too happy. Can't do that with lead batteries

 

[Zing]

Got a photo? Never ever has from what I can see

I actually posted on this before. My earlier post:
270ah DIY LiFePO4 build
[/QUOTE]
Wow! Never seen one that actually had flames before. Slightly scary. No wonder some insurance companies are not too happy. Can't do that with lead batteries
[/QUOTE]
When assessing risk, note the older style of LiFePo4 don't appear to have any evidence of susceptibility to catch fire even with ridiculous abuse such as in this test, which is not a real life simulation. Note also that this chemistry can be dealt with by a water hose unlike LiPos, which in my view should not be on a boat.

An essential question is also what is the relative risk and note that the alternative of lead acid batteries can explode. My old installation had a fan and vents to the outside to remove hydrogen gas. I am persuaded that LiFePo4, especially the older style, are extremely safe. Furthermore, in the context of the other fire risks at sea. Cooking gas engine fire and electrical fire for example, they are a negligible and acceptable risk.

How batteries can explode - and how to avoid it - Yachting Monthly

 

[geem]

I actually posted on this before. My earlier post:
270ah DIY LiFePO4 build

Wow! Never seen one that actually had flames before. Slightly scary. No wonder some insurance companies are not too happy. Can't do that with lead batteries
[/QUOTE]
When assessing risk, note the older style of LiFePo4 don't appear to have any evidence of susceptibility to catch fire even with ridiculous abuse such as in this test, which is not a real life simulation. Note also that this chemistry can be dealt with by a water hose unlike LiPos, which in my view should not be on a boat.

An essential question is also what is the relative risk and note that the alternative of lead acid batteries can explode. My old installation had a fan and vents to the outside to remove hydrogen gas. I am persuaded that LiFePo4, especially the older style, are extremely safe. Furthermore, in the context of the other fire risks at sea. Cooking gas engine fire and electrical fire for example, they are a negligible and acceptable risk.

How batteries can explode - and how to avoid it - Yachting Monthly
[/QUOTE]
I had a lead acid battery explode. It had a duff cell but the charger didn't recognise that so kept piling the amps in. It eventually went bang. No fire though. Fire in batteries scares the hell out of me. At least when a solar reg fails on a lead acid battery you don't get fire. You can overcharge but that just kills the batteries. With lifePO4 when a BMS fails you can get thermal runaway. Still not seen a LifePO4 fire as a result of thermal runaway just smouldering.
As it stands at the moment with all things considered, I think lead is a safer chemistry that is not inherently reliant on electronics to keep us safe from fire or smouldering. Fire yet to be proved

 

[Refueler]

What I find worrying - after scrolling through various online Lithium Battery dealers - I'm not talking about eBay / AliExpress or other sites - but those in business of supposedly giving expert advice and then selling their Lithium batts to public. (I wont name and shame - it can lead to all sorts of unpleasantness for YBW as well)

Worrying ? The 'false' sales blurb they dish out in terms of .... no fires .. safer than anything else .... drop in replacement ... fit and forget ....

All I can say is that if someone is looking to change - then please get a proper guy in to do the job - don't just go by what the online cr** says ....

No battery or power tech is to be played with lightly ...

 

[Tranona]

Here youtube.com/watch?v=2bNBYJZde6M is a good example of first the "snake oil salesman" pushing only the benefits without going through the process of needs assessment and second demonstrating that if you do it properly it is neither cheap nor a trivial activity. It is clear that in their situation lithium is one of the choices that could be appropriate, but there are many ways of improving an existing system that is normally fitted to that sort of boat for far less cost and work.