Twin Electric! Salona Yachts

lustyd

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PS. Interesting “a but“ about Lithium in a recent RIN paper - apparently Lithium battery management systems can sometimes shut off the batteries entirely to protect the batteries. Fine by the roadside, but perhaps inconvenient mid ocean. Not sure this has happened much, but AGM simpler technology and will degrade but not go off with a bang.
To be fair, most of those circumstances would be either extremely dangerous or destroy your battery bank even with lead acid, so it's not a bad thing to shut things down. A yacht will probably survive without power while the systems are fixed. It's more than likely some kind of short or temperature event which would cause this, both of which can be corrected to restore power.
 

geem

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At least we are agreed that this is going nowhere. You choose to ignore the facts presented to you by me and others and cherry pick where it suits you. I give in
 

lustyd

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- Flooded Lead Acid - £2.68 / Ah u
- AGM - £3.13 - £7.50 / Ah u
- Lithium Ion - £9.00 - £16.49 / Ah u
How do those figures look if the units are £/year/AH. You cannot ignore the shorter service life of lead acid. My calcs came out at 55p/AH/year for Lithium and £1.40/AH/Year for AGM. That's quite a difference. Both were Victron batteries to make it more fair, and both were packaged batteries - not the best way to buy LifePO4. I assumed a safe 80% discharge on the Lithium and kept the lead at the recommended 30% max discharge for service life, which was 7 years while the Lithium was 25 years. If you deep discharge to 50% on the lead it goes to 82p/AH/Year but then you're praying to get 7 useful years of life.

All of which ignores that the lead is only able to supply that power if it's delivered slowly over a longer period of time. The Lithium can deliver all of the AH pretty quickly, and recharge quickly too so is also a much more useful battery. It also ignores that you can't physically get the same capacity installed with lead on your boat without losing locker space and adding excessive weight.

I didn't put much effort into shopping, but these are the products I used.
Victron Energy AGM Super Cycle Battery 12V 125Ah (M8) - BAT412112081 – Battery Megastore
Victron Energy LiFePO4 Battery 12.8V 100Ah Smart - BAT512110610 – Battery Megastore
 

geem

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How do those figures look if the units are £/year/AH. You cannot ignore the shorter service life of lead acid. My calcs came out at 55p/AH/year for Lithium and £1.40/AH/Year for AGM. That's quite a difference. Both were Victron batteries to make it more fair, and both were packaged batteries - not the best way to buy LifePO4. I assumed a safe 80% discharge on the Lithium and kept the lead at the recommended 30% max discharge for service life, which was 7 years while the Lithium was 25 years. If you deep discharge to 50% on the lead it goes to 82p/AH/Year but then you're praying to get 7 useful years of life.

All of which ignores that the lead is only able to supply that power if it's delivered slowly over a longer period of time. The Lithium can deliver all of the AH pretty quickly, and recharge quickly too so is also a much more useful battery. It also ignores that you can't physically get the same capacity installed with lead on your boat without losing locker space and adding excessive weight.

I didn't put much effort into shopping, but these are the products I used.
Victron Energy AGM Super Cycle Battery 12V 125Ah (M8) - BAT412112081 – Battery Megastore
Victron Energy LiFePO4 Battery 12.8V 100Ah Smart - BAT512110610 – Battery Megastore
You picked the most expensive lead acid AGM battery money can buy! An AGM battery designed to take at least 300 100% DOD discharges! Hardly a run of the mill lead acid battery. Its also designed for high loads that contradicts your statement that lead can only supply power over a long period of time. Its specifically capable of dealing with bow thrusters and windlasses. So taking a more normal quality lead acid battery such as a Trojan your figures look a lot less attractive. You have also not allowed for the alternator safety features needed when using lithium. At least you have posted some figures?
I think the figures posted by Dunedin from a published article seem more realistic and reliable
 

Rappey

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Thats not really accurate.
Can you back that up with any evidence or is it your opinion ? I would guess (but could be wrong) you didnt watch the video i posted as you champion agm whereas the video demonstrates what a waste of money they are .
Im no expert but the way the batterys were tested seemed pretty fair to me ..
If nothing else some of you have produced great info from both points of view and a great thread on li v lead acid :)
As for the boat, its a great concept that for some would certainly work.. (but i think the interior is appaling) ...
 

lustyd

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Shocker. Geem picked holes in what I said. I thought you'd gone :rolleyes:

Go on then, post your own workings including lifespan.
 

lustyd

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As for the boat, its a great concept that for some would certainly work.. (but i think the interior is appaling) ...
The interior certainly is appalling, especially when put in the context of the Uma interior which I think is one of the nicest I've seen for a couple. I'd certainly like their work area and galley with the hefty susan :D I think this boat gets us to a point that it's extremely practical for weekend sailors and very practical for coastal trips. When they sell a few hundred in West coast USA they'll no doubt improve various aspects of the design. With a bit of luck Dan and Kika will give them some interior tips too!
 

Robih

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The Victron lithium battery post above drew my attention as I need 1300CCA to drive a bow thruster, it requires two large AGMs to deliver that power so I looked for the SAE CCA spec of the lithium batteries - but it seems it’s not specified. There is a max current draw shown but not sure whether that equals CCA - does anyone know?
 

geem

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Can you back that up with any evidence or is it your opinion ? I would guess (but could be wrong) you didnt watch the video i posted as you champion agm whereas the video demonstrates what a waste of money they are .
Im no expert but the way the batterys were tested seemed pretty fair to me ..
If nothing else some of you have produced great info from both points of view and a great thread on li v lead acid :)
As for the boat, its a great concept that for some would certainly work.. (but i think the interior is appaling) ...
I watched the video twice. I don’t champion AGM. They are a waste of money. I run open lead acid Trojan deep cycle batteries at the moment. Evidence has already been presented on lithium cost by Dunedin. I am not arguing with that
 

lustyd

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The Victron lithium battery post above drew my attention as I need 1300CCA to drive a bow thruster, it requires two large AGMs to deliver that power so I looked for the SAE CCA spec of the lithium batteries - but it seems it’s not specified. There is a max current draw shown but not sure whether that equals CCA - does anyone know?

Not really the same. Lead batteries can't manage to sustain power like that so CCA describes what they can do for a few moments. Lithium can sustain power so quoted in Amps and will at least in theory deliver that until depleted. I wouldn't push them that hard necessarily so don't cut to close to specs.

I watched the video twice. I don’t champion AGM. They are a waste of money. I run open lead acid Trojan deep cycle batteries at the moment. Evidence has already been presented on lithium cost by Dunedin. I am not arguing with that
No they didn't. There was no link and no information about the workings, and the numbers didn't include service life.
 

geem

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Not really the same. Lead batteries can't manage to sustain power like that so CCA describes what they can do for a few moments. Lithium can sustain power so quoted in Amps and will at least in theory deliver that until depleted. I wouldn't push them that hard necessarily so don't cut to close to specs.


No they didn't. There was no link and no information about the workings, and the numbers didn't include service life.
Try this
 

lustyd

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A few minutes in and it's clear he's not showing his workings, just telling us "facts". A quick look at his website and it appears he's a one man band doing electric installs. Is it you Geem?
 

NormanB

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I would love a system like this boat has and it's great that some are brave enough to build a boat utilising electric motors.
There are up to 80 ft motor cats with a huge amount of solar panels that can motor under solar !
70k more though is way to much . Could buy a nice diesel equiped yacht for that money.
Solar will not get you very far in propulsion terms.
 

NormanB

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Thats not really accurate. You can find loads of articles saying lithium can be taken down to zero with no damage. Its not correct. If you take lithium down below 20% SOC on a regular basis you reduce the life. Its not as bad as doing this to lead but it isn't accurate to say you only need half the capacity.
I had a look at the prices of lithium and lead. Assuming Trojans compared to good quality lithium from a reputable manufacturer lithium is still 3.5 times the cost not including the additional electronics you need as part of the conversion to lithium. Lithium batteries will be destroyed if you over charge them. One mistake with lithium and you need a new bank. Lead are more durable to mistakes. Over charge them a bit and they will survive. Under charge them a bit and they will survive. Once only bad charging event on lithium and game over. Don't believe the hype.
Having said that I will be adding a small amount of lithium to my Trojan bank in a hybrid scheme
If you like the maths you may enjoy this video and he has made all his research available for anyone who wishes to download it. Usual caveats apply. Link to You Tube video on battery research
 

dunedin

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No they didn't. There was no link and no information about the workings, and the numbers didn't include service life.

As I said, I was quoting our hosts publication Yachting Monthly. I commend you to buy a copy.

I am not going to breach their copyright by including copies of their article, but you can try and find online if you wish to. Good article.

I also added in the line immediately below the Ah u costs a service lifecycle point which you clearly missed - But if doing new build or major upgrade to whole system, and prepared to put money in up front for hopefully longer lifespan, then can start to make long term sense over 10 years or so.
 

geem

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A few minutes in and it's clear he's not showing his workings, just telling us "facts". A quick look at his website and it appears he's a one man band doing electric installs. Is it you Geem?
The guy in the video is a renewable energy engineer. He specialises in this field as a consultant and systems designer. He doesn't sell batteries so is independent with no axe to grind. He is not trying to sell batteries. He has three degrees in relevant fields. Renewable energy, energy technology and mechanical engineering.
 

lustyd

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As I said, I was quoting our hosts publication Yachting Monthly. I commend you to buy a copy.

I am not going to breach their copyright by including copies of their article, but you can try and find online if you wish to. Good article.

I also added in the line immediately below the Ah u costs a service lifecycle point which you clearly missed - But if doing new build or major upgrade to whole system, and prepared to put money in up front for hopefully longer lifespan, then can start to make long term sense over 10 years or so.
I wasn't questioning your post, just saying the figures don't inlude lifespan so don't give a good picture. Unfortunately I can't get the magazine locally and these days it's not really worth hunting for as all of the news is out of date and all of the boats in the ads have sold so that leaves the few repetetive articles. I do buy a copy on the way to the boat usually for idle reading.
 

lustyd

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The guy in the video is a renewable energy engineer. He specialises in this field as a consultant and systems designer. He doesn't sell batteries so is independent with no axe to grind. He is not trying to sell batteries. He has three degrees in relevant fields. Renewable energy, energy technology and mechanical engineering.
Yet he (and you) didn't show any kind of workings or sources, and somehow quoted a bunch of figures completely at odds with most peoples experience and most other sources.
 
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