Pulled the trigger on the cheapest LiFePO4 batteries anywhere. And I have a question.

[boatpoker]

Originally Posted by Rohan

OK, I'm really confused now. Serious question, but why wouldn't it be to the battery charger? How else would the boat stop power from the alternator from charging the batteries after they are full? It's not like the alternator has switches or settings on it.

Unfortunately I don't see the alternator listed anywhere on the wiring diagrams.

Here's what I do know. I have removed and reinstalled all the batteries twice on this boat and the only wires to the batteries, other than the solar wires I added myself, are the Pos+ cables from the battery selector switch, and then Neg- cables going to the engine ground. That's it. Maybe the alternator power is instead going directly to the battery selector switch? But then how would it regulate the power? If the regulator is hard wired into the alternator itself, then how would anyone ever adjust it?

Your alternator puts out DC power but your charger requires AC input.
You are seriously over your head. You really need to hire someone who knows what they are doing before you lose your boat.

[sailorboy1]

Originally Posted by Rohan

Is this a typical problem with LiFePO4s or did I get a bad one?

My 4x100ah drop in 12v LFP can start my engine. Sounds your BMS are disconnecting, what are their rated discharge

[Rohan]

Originally Posted by Flod

Rohan, no offence but I don’t think you have enough knowledge to mess around with lithium batteries. There is really so much that can go very wrong and you don’t seem to have done your homework. My advice is to either switch back to AGM or hire someone to help you.

Yeah... if this thread is to be believed, simply using lithium batteries is so dangerous that I'm going to end up in a big fireball. If that's the case, then why would anyone dare use them?

And getting any boat professional out here is very difficult. If I always waited for a pro I never would have left the dock. For years I have had to do almost everything myself. So I'll figure this one out too. I'm not in a hurry.

[Rohan]

Originally Posted by boatpoker

Your alternator puts out DC power but your charger requires AC input.

I never said it was going into the AC input.

You are seriously over your head. You really need to hire someone who knows what they are doing before you lose your boat.

Yet you asked me what adjustments I have made to the alternator. Exactly what did you think my response was going to be? That I opened the alternator myself and tampered with it? I'm just using the standard alternator for this boat. No adjustments. BTW, it's only a 60 amp alternator that most people think is a little small for this boat, but the engine space is limited and won't allow any larger.

What adjustments did you make to your alternator?

[Rohan]

Originally Posted by sailorboy1

My 4x100ah drop in 12v LFP can start my engine. Sounds your BMS are disconnecting, what are their rated discharge

These are the specs:

Battery Capacity: 100Ah
Battery Power: 1280Wh
Battery Voltage: 12.8V
Maximum Charge/ Discharge Current: 50A/100A
Charge Temperature Range: 0-45℃
Discharge Temperature Range:﹣20－55℃
Maximum Charge Voltage: 14.6V
Discharge Cut-Off Voltage: 10V

After some experimentation, two or more batteries can start the engine, or one can do it if it's a little bumped up from a recent charge.

[Rohan]

Originally Posted by Stu Jackson

OEM 1-2-B Switch Wiring History http://c34.org/bbs/index.php/topic,4....html#msg30101

1-2-B Considerations (New 2020 - Rod finally got around to diagramming what I had done in the above link in 2009 )
https://marinehowto.com/1-2-both-bat...onsiderations/


There's also my Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html


Maine Sail did this on lith systems: https://marinehowto.com/drop-in-life...ated-consumer/

I appreciate the links but your articles are really going off topic, advocating serious rewiring and hardware installing (whether using lithium batteries or not) and I'm not looking to rewire the entire boat at this time.

[ixnax]

Originally Posted by sailingharry

Interesting concept. I do nearly 100% of the work on my boat (as mentioned in another thread, even when I want to hire tradesmen, I can't get them to respond).


I'll be building my own LFP this winter, from bare cells. I'll be mostly or completely ABYC compliant (ie, maybe my battery cable will be 10" before the first fuse, not 7" -- not a current intention, but an example of what I mean by "mostly"). I do keep a current set of ABYC standards, read them, and understand them.


It might be nice to get a "Certified Marine Electrician" (I assume you mean an ABYC electrician, since I don't think there is any legal certification) to review and provide a statement on compliance.


So, the question. Have you (or others on the thread) been able to find ABYC electricians willing to provide this service? I'm skeptical that technicians are willing to do this. But to be honest, I've never tried. I do know that riggers do provide a similar service (rigging inspection) so perhaps it is a viable way forward.


On the lines of "mostly compliant," virtually all boats are partially non compliant. My boat came to me with a battery bank that looks very professionally installed. Knowing the boat's history, they poured money into it using top tier vendors. The 4 batteries have a moderate cable (maybe 1/0 or 2/0?) going to a terminal post, each about 2' long. From the battery post is a 4' long 4/0, terminating at 400A fuse. This is horribly not to standard -- more than 7" (and not in sheath), 5 lugs on one post, 2/0 cables protected (downstream, no less!) by a 400A fuse. But the non-compliant work is very professionally installed -- solid mountings, neat wire runs, battery hold-downs are exceptionally robust, etc.

Friend of mine in the Caribbean, an electrical engineer, swapped in Lithiums and found an ABYC Marine Electrician to confirm and sign off the installation. That's just being smart protecting your investment and the integrity of your insurance coverage.

I personally think no one should do it without a real sign off simply because every Lithium install that goes bad brings us one closer to a Lithium exclusion on the next policy. Everyone who has a boat not worth insuring won't care but that's not everyone.

[GILow]

I’m going to pile in on the other advice.

You are a little out of your depth here. Personally, no, I’m not predicting giant fireballs or similar. Instead I’m predicting increasing levels of frustration, very poor battery life, and eventually, the need to be towed in somewhere because you cannot start the engine.

Seriously, people are trying to help and the advice is good. See if you can find someone experienced to go over your electrical system with you and get it to a dependable state. What you have now feels destined to fail soon.

[sailingharry]

Originally Posted by ixnax

I personally think no one should do it without a real sign off simply because every Lithium install that goes bad brings us one closer to a Lithium exclusion on the next policy. Everyone who has a boat not worth insuring won't care but that's not everyone.

I sort of don't agree with this. If it were accurate, I would.


I suspect that there have been vanishingly few insurance claims resulting from LFP going bad. My suspicion is that there are a LOT of LFP installs that "go bad," but "bad" means alternators are fried, batteries are murdered, and customers are frustrated by BMS disconnects. But, from what we hear over and over and over again, is LFP is "safe."


I wonder here on this forum (and maybe we should go look at the off-grid-solar folks too) how many people know first hand of an LFP installation that somehow was so poorly installed that the result ended with an insurance claim?


Seriously, I know of no claims resulting from AGM erupting in flame, and I would hope that LFP is equally safe. If LFP isn't safe, I'm much more worried about what happens 300 miles out at sea when it "goes unsafe" than I am about how my insurance will handle it!

[AKA-None]

Originally Posted by Rohan

I appreciate the links but your articles are really going off topic, advocating serious rewiring and hardware installing (whether using lithium batteries or not) and I'm not looking to rewire the entire boat at this time.

Personally I would read those links to improve my understanding of the technology
But that’s just me

[boatpoker]

Originally Posted by Rohan

I never said it was going into the AC input.

Well where does your alternator connect to your charger if not the input ?

[Rohan]

Originally Posted by GILow

I’m going to pile in on the other advice.

You are a little out of your depth here.

If I gave up whenever I heard that, I never would have even owned a boat or sailed in the first place. Respectfully, no, I'm not giving up.

Seriously, people are trying to help and the advice is good.

Some is. But I've also gotten contradictory advice, which is frustrating. And insulting advice, like that I should get rid of the LiFePo4s and go back to AGMs. F**k that s**t.

See if you can find someone experienced to go over your electrical system with you and get it to a dependable state. What you have now feels destined to fail soon.

Well that's why I'm here. To learn and get better and improve my system. I'll get one someone more experienced to help me when I can. But I'm starting here for now.

[ixnax]

Originally Posted by sailingharry

I sort of don't agree with this. If it were accurate, I would.


I suspect that there have been vanishingly few insurance claims resulting from LFP going bad. My suspicion is that there are a LOT of LFP installs that "go bad," but "bad" means alternators are fried, batteries are murdered, and customers are frustrated by BMS disconnects. But, from what we hear over and over and over again, is LFP is "safe."


I wonder here on this forum (and maybe we should go look at the off-grid-solar folks too) how many people know first hand of an LFP installation that somehow was so poorly installed that the result ended with an insurance claim?


Seriously, I know of no claims resulting from AGM erupting in flame, and I would hope that LFP is equally safe. If LFP isn't safe, I'm much more worried about what happens 300 miles out at sea when it "goes unsafe" than I am about how my insurance will handle it!

It ain't about what is or was it's about the Lithium Battery installation question in the insurance application. To wit: Were they professionally installed and by whom? So apparently, right or wrong, good or bad, the underwriters have concerns. Later when there is a problem it will be what the applicant claimed on the application that will cause a claim denial.

[Stu Jackson]

Originally Posted by Rohan

I appreciate the links but your articles are really going off topic, advocating serious rewiring and hardware installing (whether using lithium batteries or not) and I'm not looking to rewire the entire boat at this time.

The concept was to teach you how your alternator is wired to the 1-2-B switch, and the other options. No one suggested you rewire anything.

Did you miss that part? It was the very first link I provided.


And insulting people who are honestly trying to help you is not a wise move. Cursing in public? (in #42) Even worse.


Good luck, buddy, you'll need it.

[GILow]

Originally Posted by Rohan

If I gave up whenever I heard that, I never would have even owned a boat or sailed in the first place. Respectfully, no, I'm not giving up.



Some is. But I've also gotten contradictory advice, which is frustrating. And insulting advice, like that I should get rid of the LiFePo4s and go back to AGMs. F**k that s**t.




Well that's why I'm here. To learn and get better and improve my system. I'll get one someone more experienced to help me when I can. But I'm starting here for now.

I didn't tell you to give up. I suggested inviting someone who knows more to help you. Time to take a deep breath, reset, and see what is there, not what you think is there.

But ok, I've said my bit. Good luck, and I mean that genuinely, not ironically.