Only one design of battery onboard and it’s Lifepo4

[Fuss]

The time has come and it’s now.
Lifepo4 is your house bank and your starter battery. They are cheap enough and they do all tasks much better than any other type.

You have 2 choices now with Lifepo4, you are space limited, then build your own.
You have space then get some drop ins.
You like fiddling and pushing the envelope, then build your own.

[smac999]

lol no way.

LIPO is your experimental house bank.

And your agm start battery is your back up house bank when the bms fails or shuts off. Which it will one day.

[Fuss]

At which point would you stop buying agm…. Never based on your answer. However agm is a solution that does no longer make sense.
I have only one type of lifepo4 cell on board and this cell type does everything, it makes the house banks and also starts the motor. The backup is that I could disable one of the house bank batteries and use it for engine starting in emergencies. More redundancy that a lifepo4 and agm battery system.
Plus the agm does not contribute to the house bank
With a single cell type solution, the cells provide redundancy and also when not providing redundancy, they are contributing to the house bank size.
A perfect solution.

[Kettlewell]

They are cheap enough and they do all tasks much better than any other type.

Not as cheap as regular LA wet cells, especially when you include the cost of the charging and monitoring equipment needed. Many of us don't need vast gobs of additional power and prefer tried-and-true systems that are reliable, able to be fixed anywhere in the world, and don't require precise babying that inevitably fails onboard any boat that travels. Just look at all the endless threads about how to setup, maintain, and fix LFP systems.

[Pete7]

Originally Posted by Kettlewell

Just look at all the endless threads about how to setup, maintain, and fix LFP systems.

Hmm, I am not seeing lots of threads which say "help, my LFP has melted and I am 1000 miles offshore running Starlink of my AGM".

I am with Smac on this. Lead acid for the start and possibly bow thruster / windlass if you have such items, then LFP for the domestics.

Agreed the start up price is high, hopefully the life of LFP will show a favourable return on that investment.

Pete

[sailorboy1]

[QUOTE=Kettlewell;3862399. Just look at all the endless threads about how to setup, maintain, and fix LFP systems.[/QUOTE]

Meanwhile look at the newer threads NOT written by people doing a battery science project and note some of us didn't add or change anything other that setpoints.

[JBP]

Almost. While LFP starter capable BMS's are available, they are not yet ubiquitous.

I never understood the passion for AGM. FLA are a fraction of the price and offer nearly the same performance characteristics. OK, you might have to top up the water every month, big deal. I use to use AGM only where severe vibration and tipping might be an issue.

[Fuss]

Ok, so let’s take the lifepo4 that’s I have, that Eve lf280k. 280 ah for 69 euros… that’s the price in Europe today…69 dollars each, so 4 x 69 = 276 dollars for 280 ah….can you imagine that…I know you can’t but if you could this would be a great price for 280ah.
I start my big diesel with these for a year and there is no damage or cell imbalances.
Your small diesel would create no problems in comparison, mine is 6l 135 hp so if yours is less than that, you are on the safe side.
So what’s the setup then to make a 12v system…
So you need 4 for the starting battery
So you need 8 minimum for the 2 x 12v house bank so we are up to 12 x 69 dollars/euros = 828 …828 for a complete lifepo4 280ah setup… unbelievable unbelievable!!! Oh wait a minute I hear you say, what about the BMS , ok ok, then get yourself 3 x cheapo 100a Daly BMS from eBay, they are 72 x 3 = 216 dollars.. so you got nearly all of it for a thousand.
Unbelievable… you’ve got to find something wrong right.. I’ve given you the ultimate lifepo4 system complete with redundancy, but not just for the house bank but also for the starter bank, just use one of the house bank as a backup to the starter…I bet that’s much more redundancy than the agm starter brigade have!!…
Hey while you’re at it buy another 4 cells for the ultimate redundancy and a much better house capacity.
I know what your thinking.. he’s left out the fat cables, he’s left out the T fuse…
You see the push back above in the previous posts and you can be sure there is more coming below.... AGM STARTER BATTERIES ARE NOT DEAD YET… they’re going to comment below and say why AGM is so much better for starting.. here they come, show us the redundancy… it starts with the next post…..

[bgallinger]

I've been running 1 - 100 Ah AGM for engine start and 3 - 100 Ah Lithium for house for 3 years now and it performs perfectly!

[Fuss]

Oh come on you pro AGM starter battery people… your not going to leave poor Mr Gallinger hanging out to dry are you, with his brand new AGM starter battery with no redundancy for when it stops working in the next few years. Of course it performs perfectly..it’s brand new!!
Give him some support.

[sailorboy1]

His 3x100ah LFP house bank will start his engine just fine!

In fact just 1 of them most likely would do it no problem long as it starts right up and not crank for 5+ seconds first.

[wholybee]

LFP is far more reliable, and far harder to damage from user error than any Lead-Acid battery. The BMS protects against over charging or over discharging, and there are no PSOC issues.

Now that the price is basically equal to AGM, AGM only has a place for those too stubborn to change.

[flightlead404]

Originally Posted by Fuss

With a single cell type solution, the cells provide redundancy and also when not providing redundancy, they are contributing to the house bank size.

I have to take issue with this theory.

The only reason to have a house bank larger than x is if you think you are going to need more than x+reserves to run the house.

Once you get into x+reserves you've eaten up the reduncancy.

That's a rather opaque way of saying the battery can serve one and only one purpose: contributing to a house bank of suitable size, or providing redundancy. It can't do both.

[GreenWave]

Originally Posted by Fuss

At which point would you stop buying agm…. Never based on your answer. However agm is a solution that does no longer make sense.
I have only one type of lifepo4 cell on board and this cell type does everything, it makes the house banks and also starts the motor. The backup is that I could disable one of the house bank batteries and use it for engine starting in emergencies. More redundancy that a lifepo4 and agm battery system.
Plus the agm does not contribute to the house bank
With a single cell type solution, the cells provide redundancy and also when not providing redundancy, they are contributing to the house bank size.
A perfect solution.

We went to LiPO4 last fall for house and start. Only have AGMs for bow thruster which are charged with DCDC Orion.

[senormechanico]

Originally Posted by smac999

lol no way.

LIPO is your experimental house bank.

And your agm start battery is your back up house bank when the bms fails or shuts off. Which it will one day.

My single 200 aH LiFeP04 bank (starting included) is eleven years old and working just like new. So there's that data point.
I also installed a NEEY active balancer which keeps the cells within 0.003v every day.