LFP batteries now proven to be 100% safe

[goboatingnow]

Originally Posted by PaulCrawhorn

200W solar will often get to 60-70 Ah (12V) input - in excellent insolation conditions only - over the course of a full day.

Even FLA can absorb a 10-12A actual charge rate if the bank is well discharged and over 100Ah capacity.

So you are right, 11am is unlikely unless the sun is high in the sky very early and the panels are pointing 90° right at her.

And of course, no lead bank gets to actual Full in less than 6-7 hours regardless of how many amps the charge source is "offering".

My batteries are full at 11am based on my extensive metrics. That’s includes precision voltage and current logging with instruments well beyond the reach of most yachties

No further debate is useful unless you are standing on my boat.

[goboatingnow]

Originally Posted by PaulCrawhorn

Not THAT significantly unless you accept PSOC abuse, shortening bank lifespan a LOT. Check out Maine Sail's article on just how important getting to endAmps is.

And of course, if you are regularly "deep cycling" only 10% of capacity, you are carrying way too much "dead lead".

I get 5-6 years from the banks on average this is from €105 batteries.

Much better to have big LA banks drawn down slightly then less Ah heavily drawn down

Sealed LA being recharged every day to 100% doesn’t suffer PSOC

seemingly few people here have properly instrumented boats or really understand conventional sealed lead acid.

Mainsail endamps piece is over simplistic.

My end amps metrics clearly indicate absorption is over. Both my mppt controller and my bmv 712 independently agree and they are using tail current measurements

Absorption is very short for draw downs <15 percent of battery.


My bank is sized correctly for spring and early winter sailing were numbers are different. No dead lead at all. This capacity has been in this boat since new.

Further debate on this topic is closed unless people have contrary precision instrumented data to publish.

If you have contrary data by all means argue it otherwise it’s just your opinion

Given the contrary claimed expertise I’m sure opponents have extensive high precision metrics to back up their “ opinions “

[goboatingnow]

Next year I go to LFP so I’ll be drawing 25Ah out of 300 plus AH then. You guys will probably tell me I can’t do that either !!

I have 400Ah in the lab but I’ll not bother installing that.

In fact I may just put in 200Ah and use the rest for other projects. But they are cheap Chinese LFP so a bit of AH headroom is useful I think.

I have some extra precision wifi shunts for this project in build so the metrics will be even better as I’m interested in tracking detailed consumption and recharge figures. I have a new electronic DC breaker project in build and it reports on each consumer independently so that alone adds considerable density of metrics.

As I have all re Nmea2000 units including power switching , tankage , engine instruments etc it will be interesting to see where the discharge current is going in detail.

I can double the Solar too but don’t really see the advantage currently.

[newhaul]

Originally Posted by goboatingnow

Next year I go to LFP so I’ll be drawing 25Ah out of 300 plus AH then. You guys will probably tell me I can’t do that either !!

I have 400Ah in the lab but I’ll not bother installing that.

In fact I may just put in 200Ah and use the rest for other projects. But they are cheap Chinese LFP so a bit of AH headroom is useful I think.

I have some extra precision wifi shunts for this project in build so the metrics will be even better as I’m interested in tracking detailed consumption and recharge figures. I have a new electronic DC breaker project in build and it reports on each consumer independently so that alone adds considerable density of metrics.

As I have all re Nmea2000 units including power switching , tankage , engine instruments etc it will be interesting to see where the discharge current is going in detail.

I can double the Solar too but don’t really see the advantage currently.

When you make the switch to LIFEPO4 with the 240 watts solar you will be happy . So will your LifePo4 house bank for the next 30+ years . But for good longevity if you have the room go with the 400ah. Never heard a sailor say they have to much power . You will find a use for it .

[wholybee]

Originally Posted by goboatingnow

Next year I go to LFP so I’ll be drawing 25Ah out of 300 plus AH then. You guys will probably tell me I can’t do that either !!

I have 400Ah in the lab but I’ll not bother installing that.

What happened with me after installing Lithium, is that I very quickly realized everything else I could do because of it, and my usage went up. Notably, my daily solar production went up by about 50% compared to FLA. So, while I was using every bit of energy produced by my solar prior to the upgrade, all of the sudden I had extra. That was enough to add electric cooking. To watch a movie every day on the "big screen" etc.

I went from 200Ah of FLA and 100Ah of daily usage, to 300Ah of LFP and 170Ah of daily usage. I really abused my FLA, and they didn't last long. I'm using the LFP the same way, and they don't care.

[wholybee]

Originally Posted by newhaul

When you make the switch to LIFEPO4 with the 240 watts solar you will be happy . So will your LifePo4 house bank for the next 30+ years . But for good longevity if you have the room go with the 400ah. Never heard a sailor say they have to much power . You will find a use for it .

I don't think going from using ~8% of capacity to ~6% will make a damn bit of difference in longevity. Depth of discharge doesn't make a very large difference with LFP anyway, even if he was using 95%. Temperature has the largest effect, and that effect is larger at higher SOC. At the latitude gbw is, high temperature isn't a worry.

I have read one study that showed that repeated short cycles (using a very small % of capacity and keeping the battery in that range) produced a memory effect in LFP batteries. The effect was small, and it was reversable. I wouldn't worry about it, but if anything over many years that is most likely the effect he will see. But I seriously doubt he will even see that.

I would definitely build 2 packs, maybe 3, and find other uses for them. I would also increase my usage to about 60-80Ah(what I expect the solar could produce daily), and be very happy, but that is just me

[goboatingnow]

Originally Posted by newhaul

When you make the switch to LIFEPO4 with the 240 watts solar you will be happy . So will your LifePo4 house bank for the next 30+ years . But for good longevity if you have the room go with the 400ah. Never heard a sailor say they have to much power . You will find a use for it .

I’ve no interest in > 7 years in reality. So it may be that 200-250 Ah is better , ie less then current SLA. I’d like the battery box room back.

[goboatingnow]

Originally Posted by wholybee

What happened with me after installing Lithium, is that I very quickly realized everything else I could do because of it, and my usage went up. Notably, my daily solar production went up by about 50% compared to FLA. So, while I was using every bit of energy produced by my solar prior to the upgrade, all of the sudden I had extra. That was enough to add electric cooking. To watch a movie every day on the "big screen" etc.



I went from 200Ah of FLA and 100Ah of daily usage, to 300Ah of LFP and 170Ah of daily usage. I really abused my FLA, and they didn't last long. I'm using the LFP the same way, and they don't care.

You see I’ve no desires to add any consumers. At most I might add electric water heating via an invertor but my SLA handles that now.

So it’s not a factor for me.

My main aim is a much smaller battery box and less weight

[donradcliffe]

Originally Posted by Baronkrak

How do you prevent the parallel batteries from circulating internal current?

I use Ohms Law.

[goboatingnow]

Originally Posted by wholybee

I don't think going from using ~8% of capacity to ~6% will make a damn bit of difference in longevity. Depth of discharge doesn't make a very large difference with LFP anyway, even if he was using 95%. Temperature has the largest effect, and that effect is larger at higher SOC. At the latitude gbw is, high temperature isn't a worry.



I have read one study that showed that repeated short cycles (using a very small % of capacity and keeping the battery in that range) produced a memory effect in LFP batteries. The effect was small, and it was reversable. I wouldn't worry about it, but if anything over many years that is most likely the effect he will see. But I seriously doubt he will even see that.



I would definitely build 2 packs, maybe 3, and find other uses for them. I would also increase my usage to about 60-80Ah(what I expect the solar could produce daily), and be very happy, but that is just me

All research shows depth of discharge is the major contributing factor to lithium degradation , temperature is another but as you say this is not an issue for me where ambients tend to be 40 degrees C or less.

The memory effect on LFP is small and not consistently demonstrated at all.

As I said my feeling is 3x80-100ah lfp batteries , remove the SLA starter battery completely

I have no extra electrical consumers planned and non are on the horizon. I like cooking by gas , have no room for a microwave or washing machine , tv is only used at winter. Hence I don’t foresee any primary change in consumption

Given the cells configurations I have 4x50 AH batteries would equally be practical

[donradcliffe]

Originally Posted by goboatingnow

Next year I go to LFP so I’ll be drawing 25Ah out of 300 plus AH then. You guys will probably tell me I can’t do that either !!

I have 400Ah in the lab but I’ll not bother installing that.

In fact I may just put in 200Ah and use the rest for other projects. But they are cheap Chinese LFP so a bit of AH headroom is useful I think.

I have some extra precision wifi shunts for this project in build so the metrics will be even better as I’m interested in tracking detailed consumption and recharge figures. I have a new electronic DC breaker project in build and it reports on each consumer independently so that alone adds considerable density of metrics.

As I have all re Nmea2000 units including power switching , tankage , engine instruments etc it will be interesting to see where the discharge current is going in detail.

I can double the Solar too but don’t really see the advantage currently.

Certainly not KISS, but you will be happy with your installation from Day 1.

I have delivered two boats with LFP, one with a top end Mastervolt system with remote relays, and one with a drop in 200 ahr battery and a VSR which combined the LFP with the LA start battery whenever the voltage goes above 13.3 volts. Both were huge improvements, and the only trouble I had was with the Mastervolt system where the AI took the boat dark and wouldn't talk to me without the override PIN.

I also have a 200 ahr LFP in the RV which is connected to the AGM chassis battery with a VSR. The RV uses a propane refrigerator so consumption is low, but it is really nice to be able to run laptops and watch the TV's without worrying about the battery.

[wholybee]

Originally Posted by goboatingnow

My batteries are full at 11am based on my extensive metrics. That’s includes precision voltage and current logging with instruments well beyond the reach of most yachties

No further debate is useful unless you are standing on my boat.

It's weird that I am the only person that thinks the math supports you.
The 6-7 hours rule is for batteries discharged much further than you. You are starting at 85-90%. Mainesail has demonstrated charging an AGM from 50% to 100% in 5:30.

https://marinehowto.com/how-fast-can...ry-be-charged/

In his tests, he exited bulk at ~70% SOC, in 19 minutes. It took 5:10 minutes to fully charge from there. So surely it will take you less time to fully charge from 85-90%. 4 hours seems completely reasonable.

Yes, the charge rate drops considerably as a Lead-Acid battery becomes full. You can probably charge at 100A or so in bulk at 50% SOC. At 85% SOC, that probably drops to 15A, and your solar can charge at that rate. I am at a lower latitude than you (less daylight in summer) and I make good power at 7am, you probably sooner. I would thus expect full charge by 11am.

I don't even need fancy instruments to conclude that.

[goboatingnow]

Originally Posted by wholybee

It's weird that I am the only person that thinks the math supports you.

The 6-7 hours rule is for batteries discharged much further than you. You are starting at 85-90%. Mainesail has demonstrated charging an AGM from 50% to 100% in 5:30.



https://marinehowto.com/how-fast-can...ry-be-charged/



In his tests, he exited bulk at ~70% SOC, in 19 minutes. It took 5:10 minutes to fully charge from there. So surely it will take you less time to fully charge from 85-90%. 4 hours seems completely reasonable.



Yes, the charge rate drops considerably as a Lead-Acid battery becomes full. You can probably charge at 100A or so in bulk at 50% SOC. At 85% SOC, that probably drops to 15A, and your solar can charge at that rate. I am at a lower latitude than you (less daylight in summer) and I make good power at 7am, you probably sooner. I would thus expect full charge by 11am.



I don't even need fancy instruments to conclude that.

The objections here unlike you are being advanced As unsupported opinions. There’s is no supporting contrary data.

My bank is discharged to about 10% or 15%. The solar has way more power over the time to recharge that capacity.

Absorption mode exit is determined by tail current. End of story. I measure that. My batteries exit absorption after approx 40 minutes. ( my setpoiht voltage is on the higher side )

I’ve even verified it on the last bank with specific gravity test.

Hence you’re convinced

I’ve posted the data. The battery is at 100% by 11am in high summer ( the data is there to see )

[s/v Jedi]

Originally Posted by goboatingnow

That’s a myth the instrumentation shows no such currents exist in practice

I’m not even sure what he means… normally this is between parallel cells when they aren’t matched, but I don’t see how parallel batteries can circulate an internal current… by definition, the internal current doesn’t exist outside the battery

[s/v Jedi]

Originally Posted by goboatingnow

Next year I go to LFP so I’ll be drawing 25Ah out of 300 plus AH then. You guys will probably tell me I can’t do that either !!

I have 400Ah in the lab but I’ll not bother installing that.

In fact I may just put in 200Ah and use the rest for other projects. But they are cheap Chinese LFP so a bit of AH headroom is useful I think.

I have some extra precision wifi shunts for this project in build so the metrics will be even better as I’m interested in tracking detailed consumption and recharge figures. I have a new electronic DC breaker project in build and it reports on each consumer independently so that alone adds considerable density of metrics.

As I have all re Nmea2000 units including power switching , tankage , engine instruments etc it will be interesting to see where the discharge current is going in detail.

I can double the Solar too but don’t really see the advantage currently.

Don’t forget to install some extra capacity to feed the solenoids

Have you seen the new cylindrical 100Ah cells? They have studs at the ends like LTO cells.