Most sustainable electrical setup

[Pizzazz]

It seems that in the US, LifePO4 costs 3.8x more per useable AHr. The calculation is attached, hopefully with reasonable assumptions. It looks as if the breakeven for LifePO4 exceeds 10 years. May be in a couple of years the prices will come down a bit more to make the business case more solid.

SV Pizzazz

[Dockhead]

Originally Posted by Pizzazz

It seems that in the US, LifePO4 costs 3.8x more per useable AHr. The calculation is attached, hopefully with reasonable assumptions. It looks as if the breakeven for LifePO4 exceeds 10 years. May be in a couple of years the prices will come down a bit more to make the business case more solid.

SV Pizzazz

There's an error in my table. I was couting T105's as 105 AH batteries, when they are actually 225 AH. I thought I had found an error in your table, and then see what I found! But where are you getting them for $130, and without shipping? I've never seen them for less than $200 -- although admittedly I haven't done much shopping in the U.S. since we sold our boat there. From Trojan via Amazon they are $239 plus shipping.



In any case, you should not count BMS or other installation costs in the first level of analysis, because these are not consumables. You compare the cost of consumables first and then analyze whether in your particular case the installation costs are worthwhile. The typical lithium installation in a boat which needs to be converted will actually cost a lot more than $200, but every case will be different, and most of that expenditure is not just to facilitate having lithium but will add concretely valuable functionality, like upgraded charging sources, protection systems, etc. so everyone will have to judge that separately and for his own case.



Also, how can those Winston cells be so expensive? Is there a tariff on them in the U.S.? Is that what people are paying in the U.S.? You could just order them from here: www.ev-power.eu

[GoneDiving]

Originally Posted by Dockhead

To charge a lead bank to 100% takes hours and hours of generator use, which is why you don't do it, consciously killing the batteries with PSOC cycling -- because killing the batteries is cheaper (and more pleasant) than all those generator hours.

A good point. However, to reach 100% SOC Lithium also requires a Constant Voltage stage at decreasing Current levels. Cut off at the end of CC typically only gives ~80% SOC so the 80% usable capacity may be closer to 60% if the owner is also protecting expensive generator hours.

I'd agree that the CV stage for Lead can be a loooong time where as for Lithium its typically only an hour or two.

Cheers.

[Dockhead]

Originally Posted by GoneDiving

A good point. However, to reach 100% SOC Lithium also requires a Constant Voltage stage at decreasing Current levels. Cut off at the end of CC typically only gives ~80% SOC so the 80% usable capacity may be closer to 60% if the owner is also protecting expensive generator hours.

I'd agree that the CV stage for Lead can be a loooong time where as for Lithium its typically only an hour or two.

Cheers.

Yes, but with lithium you would not generally bother with that stage. Most people stop at 90%. In fact you might even stop at 50% if other needs for the generator cease. It's hard to get your head around this after a lifetime of using lead power, but it's just different. All you care about with lithium is that over a certain period of time as many AH of power go in as come out. Lithium batteries are just like a fuel tank, which doesn't care whether it's 1/4 full or 3/4 full and doesn't care if it's left like that. That totally changes the possibilities of opportunistic charging. I guess on my boat I will rarely run the generator just to charge the batteries -- I will charge the batteries incidentally to some other need for the generator. With a large alternator you can also harvest vast amounts of power whenever you run the main engine. If when you get the anchor down, the batts are only 70% full, you don't care whatsover, unlike the case with lead where you start the usual wondering whether you need to grind grind grind with the generator to get a finishing charge on, or whether you'll let it go today and do that
tomorrow.


Also don't forget the huge difference in charge efficiency. After you get to the aborption stage with lead, this falls to 80% or even 70% or less, and less and less as you near a full charge. You don't have this with lithium, which normally has charge efficiency of over 95% throughout the SOC range, so you will just rock through the upper part of the SOC range.


The result will be a radical reduction of expensive generator hours and much less worrying about the batteries. From a 19th century Dr. Frankenstein gothic science experiment, complete with acids and gasses and weird smells and complex operating regime, your batteries become something radically simple, like a fuel tank -- LIKE THEY SHOULD BE.

[Pete7]

Originally Posted by Dockhead

Also, how can those Winston cells be so expensive? Is there a tariff on them in the U.S.? Is that what people are paying in the U.S.? You could just order them from here: www.ev-power.eu

That's a good price, looks like £925 ($1200) for a nominal 100AH battery pack with a BMS including EU VAT, that fits a Group 31 profile.

https://www.ev-power.eu/Winston-12V-...onitoring.html

Just pondering if I could make use of LFP on a small yacht. The way I see it:

LFP Advantages

1. Fast charge rate
2. Fast discharge rate (enable toaster, kettle and induction hot plate)
3. Light weight, 30 kgs saved on 2 x 100A installation.
4. Likely to keep the yacht for many years so long payback benefits.

Disadvantages

1. High upfront cost, plus perhaps DC > DC charger.
2. No existing way of fast charging much above 40A without extra expense (BC and Alt).
3. Lot of work to re-wire existing systems.
4. Probably limited to 1c discharge due to 1000w pure sine wave inverter
5. Price will drop further.
6. Safe option, do nothing now.

An interesting sales blurb:
https://www.ev-power.eu/out/media/LI...R_BOATS_EN.PDF

Pete

[GoneDiving]

Originally Posted by Dockhead

It's hard to get your head around this after a lifetime of using lead power, but it's just different. .

Also don't forget the huge difference in charge efficiency.

The result will be a radical reduction of expensive generator hours and much less worrying about the batteries.

You're preaching to the converted. 😁 I just included my post to indicate that Lithium charge profiles are not square and need to be allowed for.

Your last point cant be over emphasised: Lithium's capacity per unit weight/volume etc and efficiency make it very simple to engineer out any previous concerns. Its very easy to allow for multiples of expected loads so that any start up spikes/cloudy days/extra guest are of no concern.

[Dockhead]

Originally Posted by GoneDiving

You're preaching to the converted. 😁 I just included my post to indicate that Lithium charge profiles are not square and need to be allowed for.

Your last point cant be over emphasised: Lithium's capacity per unit weight/volume etc and efficiency make it very simple to engineer out any previous concerns. Its very easy to allow for multiples of expected loads so that any start up spikes/cloudy days/extra guest are of no concern.

I think the best way to think about it is like a fuel tank. And with a generator on board -- paired with your own private on demand petroleum refinery. You capture what power you can incidentally whether from solar, main engine, generator used for other purposes, and you just don't worry about it. If you see yourself starting to run short, you just crank the gennie and run it however long or short you want to. It's a totally different operating paradigm from lead.

[Dockhead]

Originally Posted by Pete7

That's a good price, looks like £925 ($1200) for a nominal 100AH battery pack with a BMS including EU VAT, that fits a Group 31 profile.

https://www.ev-power.eu/Winston-12V-...onitoring.html

Just pondering if I could make use of LFP on a small yacht. The way I see it:

LFP Advantages

1. Fast charge rate
2. Fast discharge rate (enable toaster, kettle and induction hot plate)
3. Light weight, 30 kgs saved on 2 x 100A installation.
4. Likely to keep the yacht for many years so long payback benefits.

Disadvantages

1. High upfront cost, plus perhaps DC > DC charger.
2. No existing way of fast charging much above 40A without extra expense (BC and Alt).
3. Lot of work to re-wire existing systems.
4. Probably limited to 1c discharge due to 1000w pure sine wave inverter
5. Price will drop further.
6. Safe option, do nothing now.

An interesting sales blurb:
https://www.ev-power.eu/out/media/LI...R_BOATS_EN.PDF

Pete

Of course you could, and I'll help you install it.


Just keep in mind that there is a ripple effect through your system -- you will want to upgrade the alternator for sure. As I recall, you don't have a generator, correct? Besides the BMS you will need some contactors and you will need to make new cables. You will need some kind of monitor. You might want to upgrade your battery charger, or maybe not without a generator.



It's a somewhat involved conversion, but if you're planning to keep the yacht for a long time I would definitely do it in your case. I'll be glad to help with it.

[Pete7]

Originally Posted by Dockhead

Of course you could, and I'll help you install it.

Thanks

Originally Posted by Dockhead

Just keep in mind that there is a ripple effect through your system -- you will want to upgrade the alternator for sure. As I recall, you don't have a generator, correct? Besides the BMS you will need some contactors and you will need to make new cables. You will need some kind of monitor. You might want to upgrade your battery charger, or maybe not without a generator.

Yes, sold the Honda 20i because we didn't use it but wanted the space for the liferaft. Actually might just keep the existing 60A alternator and 40A battery charger. Why? well prior to installing the portable freezer our average DoD was 45AH and max was 74AH measured at dawn before the solar kicked in. Freezer is 45w with equal on/off run time. So tiny really, therefore likely to need 2 x 100A or 2 x 90A LFP sets. 300w Solar upgrade happening now which is likely to be main charging source.

Just occurred to me that if the LFP bank moved away from the rear engine space somewhere else, it removes the temperature problem discussed recently in the other thread and opens up the option of using fewer larger cells.

This needs some thought.

Pete

[GoneDiving]

Originally Posted by Dockhead

I think the best way to think about it is like a fuel tank. And with a generator on board -- paired with your own private on demand petroleum refinery. You capture what power you can incidentally whether from solar, main engine, generator used for other purposes, and you just don't worry about it. If you see yourself starting to run short, you just crank the gennie and run it however long or short you want to. It's a totally different operating paradigm from lead.

This is becoming much easier now as "Hybrid" inverters become much smarter in taking multiple input sources and redirecting them to multiple outputs according to the user's customized settings. "Spare" power can often be directed where ever we want and input sources fully utilized.

Much better than separate chargers, inverters and isolators.

[Dockhead]

Originally Posted by Pete7

Thanks



Yes, sold the Honda 20i because we didn't use it but wanted the space for the liferaft. Actually might just keep the existing 60A alternator and 40A battery charger. Why? well prior to installing the portable freezer our average DoD was 45AH and max was 74AH measured at dawn before the solar kicked in. Freezer is 45w with equal on/off run time. So tiny really, therefore likely to need 2 x 100A or 2 x 90A LFP sets. 300w Solar upgrade happening now which is likely to be main charging source.

Just occurred to me that if the LFP bank moved away from the rear engine space somewhere else, it removes the temperature problem discussed recently in the other thread and opens up the option of using fewer larger cells.

This needs some thought.

Pete

There are two reasons to upgrade the alternator, actually three.

1. You will want to be able to take advantage of the much higher acceptance rate to get more power faster.

2. A normal alternator will get melted down being connected to a bank which can drive it 100% all the time.

3. Your main engine will be happier with more load on it, in case you charge without using it for propulsion.

[john61ct]

Originally Posted by GoneDiving

Lithium's capacity per unit weight/volume etc and efficiency make it very simple to engineer out any previous concerns

Absolutely.

These and all the other **technical** advantages are the real reasons LFP should be chosen.

The purely financial / economic reasons just do not hold up on their own, for non-wealthy prospects in the NA market.

The Deka from Sam's are in no way sub-par, just as good as T-105 at $1 per 12V Ah available locally. Often last 7 years or more, EoL at 70-75% SoH.

T-105s themselves, if you prefer them, are often available for not much more, maybe $1.20 per 12V Ah.

Delivered cost of quality LFP in the US anyway cost at least 4-5x that and that's before BMS or other infrastructure to properly care for the bank. Which can cost as much or more than a small bank (under 4-600Ah).

So minimum 30yr ROI period, and that's just breaking even.

Personally I am very pro LFP, but it is deceptive to claim it is cheaper, in the NA market.

Elsewhere the numbers are indeed very different.

[Dockhead]

Originally Posted by john61ct

Absolutely.

These and all the other **technical** advantages are the real reasons LFP should be chosen.

The purely financial / economic reasons just do not hold up on their own, for non-wealthy prospects in the NA market.

The Deka from Sam's are in no way sub-par, just as good as T-105 at $1 per 12V Ah available locally. Often last 7 years or more, EoL at 70-75% SoH.

T-105s themselves, if you prefer them, are often available for not much more, maybe $1.20 per 12V Ah.

Delivered cost of quality LFP in the US anyway cost at least 4-5x that and that's before BMS or other infrastructure to properly care for the bank. Which can cost as much or more than a small bank (under 4-600Ah).

So minimum 30yr ROI period, and that's just breaking even.

Personally I am very pro LFP, but it is deceptive to claim it is cheaper, in the NA market.

Elsewhere the numbers are indeed very different.

This is starting to get boring so this will be my last post on the subject in this thread, but EVEN IF those North American numbers are correct (and sorry, Sam's Club batts, while a good value, and very attractive for light use, are not the equal of Trojans), lithium STILL stacks up economically if you consider cycle life, for anyone who uses their batteries intensively. I know plenty of people, living entirely off grid, who cycle their batteries hundreds of times a year. And if you figure in the cost of generator hours, then it becomes a no brainer. I'm not all that heavy a user, only 4 months or so on board a year, but even I will save about €600 euros a year just on the generator. Lead really doesn't make sense anymore except for light users, and people with vast solar installations, or people who just can't get their heads around this new tech, and don't want to (and that's perfectly fine too ; everyone's personal choice).

[Pete7]

Originally Posted by Dockhead

There are two reasons to upgrade the alternator, actually three.
1. You will want to be able to take advantage of the much higher acceptance rate to get more power faster.
2. A normal alternator will get melted down being connected to a bank which can drive it 100% all the time.
3. Your main engine will be happier with more load on it, in case you charge without using it for propulsion.

Actually I can't remember when we last needed to run the engine just to charge the batteries, solar normally meet all of our needs. The point of not overloading an alternator is one of the reasons I don't have an external regulator fitted. The solution is to limit the demands on the alternator for large current with one of the those DC > DC battery chargers which also neatly limits the voltage.

I think we will end up with an engine start battery which then supplies the LFP. Not sure were to add the solar and mains BC at the moment, more studying needed.

Pete

[Dockhead]

Originally Posted by Pete7

Actually I can't remember when we last needed to run the engine just to charge the batteries, solar normally meet all of our needs. The point of not overloading an alternator is one of the reasons I don't have an external regulator fitted. The solution is to limit the demands on the alternator for large current with one of the those DC > DC battery chargers which also neatly limits the voltage.

I think we will end up with an engine start battery which then supplies the LFP. Not sure were to add the solar and mains BC at the moment, more studying needed.

Pete

If you'll send me a chart of your existing system (or start a thread so others can chime in) I can start working on it.

HOWEVER, if you rarely need to use the alternator for charging, then you may fall into the category of those with "vast solar installations" (compared to your consumption) who can't really use the benefits of lithium. Why don't you start a thread - will be a great case study.