LifePO4 chemistry not as important as we thought

[FlyingScot]

At least according to Nigel Calder, who is obviously well respected in regards to marine electrical installations.

It caught me by surprise to hear him say that chemistry is less important than quality (brand, construction, features). I'm paraphrasing him, but listen to the first few minutes of this video and let me know your thoughts. I think he is using large Torqeedo packs.

https://www.youtube.com/watch?v=XH_Nf0wAVLQ

I personally have Victron LiFePO4 and consider them to be high quality and well respected. No regrets. There is no reason you can't have both high quality and LiFePO4, except maybe price.

[SailingHarmonie]

If you buy a set crappy of LiFePO4 batteries and they die in a year or two you are clearly worse off than if you have a great set of AGMs that last 7 or 8 years.

I see nothing surprising about that. Have we already forgotten that cruising boats have used FLA, GEL and AGM batteries successfully for generations? You do not NEED LiFePO4 batteries to have a successful cruising boat. You do NEED batteries that are reliable, work when needed, and are predictable.

If I have FLA batteris in rough service, and I expect them to last 3 years, I can plan and work with that, just as I can plan and work with LiFePO4 batteries that last 15 years. What IS a problem is if I have a LiFePO4 battery I expect 15 years from and it dies after 3. From a maintenance, reliability and cost standpoint that is a killer.

[gonesail]

i'm thinking AGM (or GEL) before i go with LiFePO4

[FlyingScot]

Originally Posted by SailingHarmonie

If you buy a set crappy of LiFePO4 batteries and they die in a year or two you are clearly worse off than if you have a great set of AGMs that last 7 or 8 years.

I see nothing surprising about that. Have we already forgotten that cruising boats have used FLA, GEL and AGM batteries successfully for generations? You do not NEED LiFePO4 batteries to have a successful cruising boat. You do NEED batteries that are reliable, work when needed, and are predictable.

If I have FLA batteris in rough service, and I expect them to last 3 years, I can plan and work with that, just as I can plan and work with LiFePO4 batteries that last 15 years. What IS a problem is if I have a LiFePO4 battery I expect 15 years from and it dies after 3. From a maintenance, reliability and cost standpoint that is a killer.

I'm guessing you didn't watch the video.

He is talking about various lithium ion chemistries.

I could have also been more clear.

No one is saying you need Lithium batteries to be happy.

[Pete7]

Originally Posted by gonesail

i'm thinking AGM (or GEL) before i go with LiFePO4

I think Jeff hit the nail on the head at the end, when he said not everyone needs Lithium.

However, I would also question AGM for a house bank. AGMs do have some advantages, but which ones do you think you need for a house bank?

Pete

[rslifkin]

Originally Posted by Pete7

I think Jeff hit the nail on the head at the end, when he said not everyone needs Lithium.

However, I would also question AGM for a house bank. AGMs do have some advantages, but which ones do you think you need for a house bank?

Pete

On some boats, the increased mounting flexibility over FLA and not needing easy watering access is worth it.

[sailorboy1]

I currently have the newer "cheap" drop in LFP. If they last 5 years I am OK with that as batteries to me are still a consumable.

At current prices I can replace my $300/100Ah batteries every 5 years 5 times before getting to the cost of the "quality" ones. So that is 25 years and I doubt I still have the boat by then.

So a lot depends on how you look at it.

[SV Confianza]

Originally Posted by sailorboy1

I currently have the newer "cheap" drop in LFP. If they last 5 years I am OK with that as batteries to me are still a consumable.

At current prices I can replace my $300/100Ah batteries every 5 years 5 times before getting to the cost of the "quality" ones. So that is 25 years and I doubt I still have the boat by then.

So a lot depends on how you look at it.

I have also been testing the cheaper ones. At least ones that have reasonable build quality.

I am just daisy chaining them together, and I'm about to add a 400ah Li-Time battery to test as well. Class T fuses on the positives between different brand batteries, and a few shunts to see how current is moving around between the batteries.

This is definitely NOT the most efficient set up. I'm trying to do a long term test to see if it's reasonable for the average cruiser to save a lot of $$$ and still get a reliable lithium setup. I want to see how much capacity doesn't really get used in this configuration, how much cycling the batteries do to each other, and if I have any faults.

[wholybee]

I watched a bit of the video but not the whole thing.

It should be braindead obvious that a higher quality battery is going to be safer than a poorly bult battery. But does that change anything? Maybe. Maybe not.

Consider this. A boat that is carefully built such that there is zero chance of a short circuit. As a result, no fuses are used. Safe? Of course not.

So, would you compare that to Lithium chemistries? A battery built to exacting specifications such that there is no chance of the types of events that cause thermal runaway. But you then use NMC or something else instead of LFP. Safe? (Hint: auto manufactures do this; have there been cases of cars catching fire?)

If there is a thermal runaway problem on a boat mid ocean, your f'ed. No amount of high-quality battery construction will save the boat once thermal runaway occurs, no matter how rare that event is.

The idea of "safe" is subjective. On a car, or a boat that is inland or coastal, you can take a lot more liberty and still have a "safe" boat. But even if they are high quality and built to exacting standards, if the "less safe" chemistries are used, there will be a few cases of failure, and if on an ocean boat the result would likely be lost lives. So, I reject the idea that non LFP chemistries are safe. They will be safe-enough on some boats, and not safe-enough on other boats. That decision needs to be made case-by-case.

[SailingHarmonie]

Originally Posted by Pete7

I think Jeff hit the nail on the head at the end, when he said not everyone needs Lithium.

However, I would also question AGM for a house bank. AGMs do have some advantages, but which ones do you think you need for a house bank?

Pete

AGMs can work very well as house batteries, but it depends on your usage and charging capability.

On a traditional cruising boat with little or no solar power and chargine from the drive engine alternator the battery bank is only rarely brought to a full charge. This is a sure road to destroy AGM batteries before their expected lifespan.

On our boat, solar supplies about half our energy needs. I'd like more, but space is limited. The balance of our energy needs are made up by a very efficient permanent magnet DC generator.

Early in the morning the generator comes on and automatically brings the battery up to 93% SOC. On a good solar day, the batteries have dropped to absorbing less then 0.1C by the end of the day. That 100% charge lasts all through the next day, and then the following day the batteries are brought to full again with the combination of generator and solar.

The system supplies all the power we need, easily and simply. Switching to Li would not change the amount of power we need to generate, although with improved charge acceptance we would cut about 30% off our generator run time.

We will revisit Li technology and its costs and benefits again when this set of batteries dies. But for now, they are 4 years old, and still do a full discharge at the original specification capacity.

[Chotu]

Originally Posted by SV Confianza

I have also been testing the cheaper ones. At least ones that have reasonable build quality.

I am just daisy chaining them together, and I'm about to add a 400ah Li-Time battery to test as well. Class T fuses on the positives between different brand batteries, and a few shunts to see how current is moving around between the batteries.

This is definitely NOT the most efficient set up. I'm trying to do a long term test to see if it's reasonable for the average cruiser to save a lot of $$$ and still get a reliable lithium setup. I want to see how much capacity doesn't really get used in this configuration, how much cycling the batteries do to each other, and if I have any faults.

I have 400AH Li-Time batts.

Absolutely fantastic! They work perfectly and have been for coming up on a year

[sailingharry]

Originally Posted by SailingHarmonie

Early in the morning the generator comes on and automatically brings the battery up to 93% SOC. On a good solar day, the batteries have dropped to absorbing less then 0.1C by the end of the day.

I surely hope you mean 0.01C? I am pretty sure you did.

So many people say they are at 100% charge by noon with their AGM on solar, and that is all but impossible (regardless of how much generation and solar capacity you have). But you said by end of day, which is much more realistic.

[Chotu]

Originally Posted by sailingharry

I surely hope you mean 0.01C? I am pretty sure you did.

So many people say they are at 100% charge by noon with their AGM on solar, and that is all but impossible (regardless of how much generation and solar capacity you have). But you said by end of day, which is much more realistic.

I am one of these people so I am very curious what you mean.

by noon, my charge controller drops out of charging and goes into float/charged.

I use 90-100AH overnight and do about 30 amps charging rate most days (and I only have half my solar hooked up! Lol). So by noon it's done.

Whoops. AGM. I think I’m getting tired and should go to bed lol. I thought that was about lithium

[SailingHarmonie]

Originally Posted by sailingharry

I surely hope you mean 0.01C? I am pretty sure you did.

So many people say they are at 100% charge by noon with their AGM on solar, and that is all but impossible (regardless of how much generation and solar capacity you have). But you said by end of day, which is much more realistic.

Thanks for catching that! And for giving me the benefit of the doubt. I DID mean 0.01.... and our full batteries include the generator pumping them from 65% to 93%, not JUST solar alone.

And you are so right... people think that 100% on their SOC meter means, well, 100%. It is so much more complicated than that...

[CarlF]

Now coming up on my 2nd year with a LifePO4 house bank (also called LFP) , I would never go back to AGM -- because I anchor out a lot and/or sail a lot without an engine or genset running. I had two sets of AGM batteries fail in less than 3 years from PSOC sulfation because I didn't plug in at a slip most nights to charge the bank all the way to 100%.

If you are like me, the cost of Lithium is much less than AGM over a 10 year - or even a 6 year period. My 300AH Killovault batteries each cost $1800 and have a 7.5 year 100% replacement warranty. My last Lifeline 100AH group 31 batteries cost $465 ($1395 for 300AH) and came with a 3 year pro-rata warranty.

With that - some comments to the video:

Yes - the quality of the battery and the repuation of the manufacturer counts. It amazes me that people would buy the cheapest lithium battery on Amazon when they would only buy quality lead acid batteries with brand names like Trojan, Lifeline, Deka - or even West Marine. My lithium drop in batteries are Kilovault brand - from a large Massachusetts company that's been around for decades. I bought the through a marine dealer who handles the Victron, Balmar and other marine electronics gear you need for a quality battery installation. Just like lead acid, there are four or five brands commonly installed in boats - pick one of those. Ask for recommendations from other boaters.

Second - all lithium house banks on boats are LFP. Don't call them "lithium" or "lithium-ion" any more than you would conflate the explosion risk of a boat with a gasoline or diesel engine.

As Nigel says - any battery - either lithium or lead acid - should be certified to UL 1973. Low quality lead acid batteries catch fire too. There are several brands of lithium batteries so certified.

Nigel is right that lithium batteries without a heater should not be used in temperatures below freezing. But few boats mount their batteries in unheated spaces. If you do, get a battery with a built in heater. Again, my Kilovault has one.The same for high temperature - my Kilovaults can charge in a temperture up to 113 degrees. Unlike a car or RV, boats usually pick a cooler space to mount batteries. If you put an AGM in a 113 degree space its life will be shortened by about 50%.

BMS shutdown - much is made of this but it should never happen in a proper LFP installation. It's certainly never happened to me in the last two years. The BMS is basically a computerized fuse. If the battery has too much current drawn, is charged at too high a voltage, or is charged too fast the BMS will cut off the power. The BMS is a smarter fuse than you have with your AGMs. While your AGM can be ruined by a too low or too high charge voltage -- that can't happen with an LFP because the BMS will protect it. You can also blow a fuse on your AGM bank that will cut off your power. Unlike the LFP BMS which resets itself, you'll need to install a new fuse on your AGM bank. Neither should ever happen if you design your system properly.

A great deal of handwaving is made about "communication". The worry is that a BMS shutdown can blow the diodes on your alternator. This is exactly the same as what happens if you turn off your master battery switch while underway. Again, this should never happen. However there are now several good ways to protectd the alternator without having communications in your BMS - and most modern alternators have "avalanche" diodes which aren't susceptible to this in the first place. "Communication" is just one of the ways you can protect your alternator. There are several others that are equally good.

So if you normally plug in each night at a slip, there's little reason to go to LFP. But if you anchor out without running a genset all night, LFP are more economical over the long run and just as safe.

And finally, these batteries pack a lot of power. If you are not very experienced around marine electrical systems hire a pro to install it. Your insurance company is likely to ask.