LiFePO4 and absorption charging

[CaptainRivet]

Originally Posted by HeinSdL

Well that is exactly the way to do it and is what I do. But to be able to "tweak some settings" to get the system functioning as intended I need to learn about it and discussions like this augment my understanding very well. Otherwise there can be no tweaking and you end up with a suboptimal solution.

On the other topic of using lead for critical systems, in particular using the start battery, yes why not but in my case I don't want to go that far with the rewiring. I have a large house bank which does everything since the boat was built and now that is LFP. Charged by Victron's 50A XS directly from the start battery as well as 600W solar. Nothing wrong with that set up, works a dream for me with a boat which doesn't have large energy needs.

But.... I did keep the old AGMs which were still in very good shape and might consider putting them in parallel with the LFP (doing absolutely nothing most of the time) when being particularly reliant on the autopilot on eg a broad reach/run with significant waves and a lot of wind. That is one of the few situations I can imagine when I would not want to entertain an unscheduled shut down. Otherwise a disconnecting LFP I could not care so much about (and is highly unlikely anyway).

Replace that lead starter with an LTO with only an active balancer, last 30000cycles or >30years, doesn't shutdown, doesn't need to be floated and can be even recharged from 0V and works -40 till 85 degrees. Well and in the security department it's the worlds best free available chemistry, you can even drill into it while using it.
As it has an low resistance like LFP the alternator must be temp protected, that's the only requirement otherwise you can charge it with any profil of lead or LFP.
That's real security, the lead with its 300cycles in best case and it's constant floating needs is a joke and an AGM the worst chemistry regarding security (a slightly damaged regulator is enough to cause a fire that will burn you vessel down)...just used because people don't know anything else.
The main failure in a proper system with
A) lead is the lead battery, that's why you always have multiple,
B) an LFP its the main battery fuse failing, not because of an incident but because of a quality issue. That's how low the probability is.
Well and when a LFP shuts down a lead would have been long dead before. An LTO doesn't need to be shut down, it can take the abuse, suffers a bit lifespan (which you have plenty so can sacrifice at bit) but still works.

[Chotu]

Originally Posted by CaptainRivet

Replace that lead starter with an LTO with only an active balancer, last 30000cycles or >30years, doesn't shutdown and can be even recharged from 0V and works -40 till 85 degrees. Well and in the security it's world best free available chemistry, you can even drill into it while using it.

speaking of starting batteries, I can’t wait to get starting batteries with a bms.

I have a lithium starting battery on my motorcycle. I have put it into storage so many times and forgot to disconnect the battery. Invariably when I get back, the battery is completely dead.

now, if this was a traditional Lead battery I would have needed to buy a new one. Probably each time. But no. LIFEPO4 starting battery.

What happens is the BMS cut it off before it dies completely and that allows you to just simply recharge it and start the motorcycle and it’s good as new

[CaptainRivet]

Originally Posted by Chotu

speaking of starting batteries, I can’t wait to get starting batteries with a bms.

I have a lithium starting battery on my motorcycle. I have put it into storage so many times and forgot to disconnect the battery. Invariably when I get back, the battery is completely dead.

now, if this was a traditional Lead battery I would have needed to buy a new one. Probably each time. But no. LIFEPO4 starting battery.

What happens is the BMS cut it off before it dies completely and that allows you to just simply recharge it and start the motorcycle and it’s good as new

Even if you disconnect the battery it will be still dead because BMS internally uses power...often forgot by the LFP dropin users.

That's why you get either
1) an LTO without a BMS and just an active balancer which doesn't consume any energy
Or
2) a winston 12V 40,50 or 90AH sealed without a BMS, that one
https://www.nothnagel-marine.de/prod...-batterie.html, oldest I know is 9 years old and still starts effortlessy daily a big old-school diesel engine. Capacity was still above 100AH of a 90AH battery after 7years...and they only sell them since 9 years...
Just use a battery disconnect switch so no stray current can draw it down if you store for longer.

[newhaul]

Originally Posted by CaptainRivet

?? How do you come to that conclusion?

Perhaps you should read what I posted. And your response to me which was.

Quote:
Originally Posted by newhaul View Post
With a system setup similar to mine or jedis you won't be hot and dark like that as all the essentials are run off of your lead based start battery .
Your reply.
Mine too (its even certified) but that's not was majority out there have...Chinese surprise box dropins without communication is and will be still the majority out there

All together one would say you are running a lead based start.
What's so difficult about reading what people write.
And don't say language barrier we all have seen your detailed dissertations on batteries .

[newhaul]

Originally Posted by Chotu

speaking of starting batteries, I can’t wait to get starting batteries with a bms.

I have a lithium starting battery on my motorcycle. I have put it into storage so many times and forgot to disconnect the battery. Invariably when I get back, the battery is completely dead.

now, if this was a traditional Lead battery I would have needed to buy a new one. Probably each time. But no. LIFEPO4 starting battery.

What happens is the BMS cut it off before it dies completely and that allows you to just simply recharge it and start the motorcycle and it’s good as new

Li Time has one out now .

[Chotu]

Originally Posted by newhaul

Li Time has one out now .

Cool!!! i’ll trust that. I’m ecstatic about the value of the house bank from them

Vevor won me over too. I’ve been buying things from them. Currently at 3500+ hours on 3 diesel heaters from them. after this winter they’ll be around 8000 hours

Then there is Lifan. Motorcycle will. not. DIE! ha ha. I bought it while I was working on the boat in Florida to have some cheap toy to ride around on the trails and the roads as a diversion because I was getting a little claustrophobic being stuck in Florida. I figured it would break that winter and it would be disposable. Well, it’s still going and going. I forget but I’m around 5000 miles mostly off road on that thing. Starts and runs like a Toyota Camry.

I feel like I have navigated my way through the Chinese products to find good quality at good price. value

[sailorboy1]

its funny that we all have been using "cheap" Chinese batteries for years in our electronic devices, Yet boat people feel they need something more "special" even if it is Chinese products put together by "someone else".

The same thing could be discussed about lead acid batteries. For some reason boaters though/think they needed something more special than golf carts

[newhaul]

Originally Posted by sailorboy1

The same thing could be discussed about lead acid batteries. For some reason boaters though/think they needed something more special than golf carts

Well for the gc2 style 6v batteries it was mostly bang for the buck which does include warranties.
Myself I preferred the trojan t105 it was the price for the warranty that I looked at . Now I could have gone for the rolls sterette but cost per warranty was not there.
Now with LIFEPO4 it's more the cost per watt hour. As they all have the same basic warranty.

[00X]

Originally Posted by HeinSdL

Just to reply to some of the posts regarding micro management, hatred even for being obsessed by a ... battery ... Well I like to learn about these things. Here. At the screen. Not when entering a harbour at night in tricky conditions and all of a sudden you have no clue why no more 12V. And there are people here with ideas and know-how which I like to hear out/learn from. That's why this is a ... forum! It does not mean I spend my sailing hours gazing into a Victron app but it does mean I am less likely to join the rather large brigade of people out there on the water who, frankly, have no clue about very much really. In any case not about their own boat/boat's systems.

Spending a few minutes here reading up on a topic ≠ spending hours on the boat doing the same

+1 To add. All our brains are wired different. Some of us enjoy watching, micromanaging, learning. Not sure why thats a bad thing.

[Chotu]

Originally Posted by newhaul

Well for the gc2 style 6v batteries it was mostly bang for the buck which does include warranties.
Myself I preferred the trojan t105 it was the price for the warranty that I looked at . Now I could have gone for the rolls sterette but cost per warranty was not there.
Now with LIFEPO4 it's more the cost per watt hour. As they all have the same basic warranty.

those had been my preferred batteries for decades too. In fact, these LiTimes directly replaced a bank of t105s that was abused to death

[nfbr]

Balancing is overrated. Good cells dont drift much if initially well balanced.

[toddedger]

Originally Posted by nfbr

Balancing is overrated. Good cells dont drift much if initially well balanced.

And not overcharged

[WE9V]

Originally Posted by Chotu

i’m charging at 1.5C. maybe 1C occasionally if cloudy.

i have 1500 watts solar, twin flexmax 80 controllers and a 400AH bank

How does this math work out? Assuming 12V system: 1500 watts / ~13.5 Volts during charging = 111 A. 111 A / 400 Ah bank = 0.277 C

[CaptainRivet]

Originally Posted by nfbr

Balancing is overrated. Good cells dont drift much if initially well balanced.

The big IF and how do you know the cells are good in the no communication dropin?

Balancing is not overrated.
Without a 48V battery LFP is not possible doesn't matter how good the cells are, thats already partly for 24V as well.
You can run LFP with no BMS but an active balancer but not a with a BMS but without balancer. Only exception are 1p4S metricously over the whole SOC curve matched cells like in the sealed winston 12V 40/50/90AH battery without BMS.

An active balancer costs 15$ and when adjusted correctly cannot harm a battery but can improve its lifespan and capacity plus prevent shutdown and desasters.
Meanwhile 99% commercial BMS have active balancer because of that.
And well I can pay 1.2$ per AH for perfect cells which won't need a balancer (till 24V)for a long time, or I can buy 0.18$ per AH and fit an active balancer and get the same stable battery with the same AH for 1/6 of the price.
Best combo for bluewater cruiser is have 1 day consumption in 1.2$ quality you can always count on and rest capacity for 0.18$ per AH.
.

[Sailshabby]

Originally Posted by sailorboy1

maybe it's true, or probably is true, and maybe not true at all

In this case you only need it if you can not just be happy and need something to help you

AND if you really are going to be unhappy not knowing why ask a bunch of people on a forum who don't have the same batteries as you instead of asking the manufacturer of yours??????????

Incredibly helpful, as usual.