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Boat was on the hard for 6 months of the last 6 years. Got it with flooded lead. Immediately changed to agm. They get of to 100% regularly. Very rarely below 80%. If switched to Li would need to glass in pb to keep trim. Carbon foam is still on back order from most places so premium cost with no discounts at present. Hopefully will change by the time I need to re up on batteries. Please understand Li remains a possibility. With review the calculus when the time comes. Have several friends who switched to carbon and are quite pleased. At time of purchase carbon was cheaper then Li Ah to Ah. Expect that will return as production increases to demand.
This year while in the windwards wake up to batteries being at 13.1-13.4. During the day solar is frequently diverted to heat sinks. In this setting don’t get to exploit the numerous advantages of Li. Even wondering if pb may suffice if we continue to stay in this cruising grounds.
 

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Even wondering if pb may suffice if we continue to stay in this cruising grounds.
Your only two choices are lead or lithium. Carbon foam is still a lead acid battery no different in chemistry than all other lead acid batteries.

https://www.morganscloud.com/2018/05/05/battery-options-part-1-lithium/

Nice short review worth reading before blowing the bucks.
That link goes to a paywall, so can't read the article. However, one should take Morgan's Cloud writings with a grain of salt. They have been seriously wrong, or uninformed, on several things in the past, and sometimes confuse their celebrity with expertise.

If you really want to read up, we have a resident here - Mainesail - who has done some very good work and communication about lithium batteries in boats. There are also great threads and blogs written by people similar to Mainesail who have also done a lot of hands-on experimentation. I would go to these places before Morganscloud for gaining knowledge in this area.

Mark
 

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Different strokes for different folks. What impresses me with Morgan cloud is when wrong they fess up and publish a correction. Their readership is quite vocal in letting very little slide and consists of many long term cruisers.
Always look forward to Mainesails input.
 

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After reading Maine Sails treatise on lithium versus AGM batteries until my brain hurts. I'm more convinced than ever but I made the right choice to just stick with AGM batteries for my boats electric propulsion system and Gels for the house battery bank. Adding the complexity and cost of the lithium system just does not make sense for my sailboat.
 

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After reading Maine Sails treatise on lithium versus AGM batteries until my brain hurts. I'm more convinced than ever but I made the right choice to just stick with AGM batteries for my boats electric propulsion system and Gels for the house battery bank. Adding the complexity and cost of the lithium system just does not make sense for my sailboat.
For many boaters use/applications LFP does not make financial sense unless you plan to DIY then the cost is comparable to AGM..... For many who want to DIY they often don't make smart sense because too many folks don't care to do the research and ruin them far too early.

Still my own 400Ah cells are now 10 years old and they still deliver in excess of 400Ah with over 1100 cycles on them. Other than Firefly I can't think of more than a couple of lead acid batteries we've tested, at more than a year old, that could deliver their full Ah rating. Just two weeks ago we had a customers West Marine / East Penn AGM's in the shop for testing. At 16 months old they could only muster 61% of their rated capacity (technically dead in less than 16 months)... Ouch!!!

At this rate I fully expect our bank to last at least 15 years but perhaps even 20 or more.

Considering it cost us less than a bank of Odyssey TPPL AGM's, that would have long ago been dead, the value for us was certainly there even though we only use the boat for 6-months each year. There are also other hidden benefits, since installing LFP I've not once had to dig into the Espar, to clean it, where with LA it was literally an every spring ritual. :wink
 

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For many boaters use/applications LFP does not make financial sense unless you plan to DIY then the cost is comparable to AGM..... For many who want to DIY they often don't make smart sense because too many folks don't care to do the research and ruin them far too early.

Considering it cost us less than a bank of Odyssey TPPL AGM's, that would have long ago been dead, the value for us was certainly there even though we only use the boat for 6-months each year. There are also other hidden benefits, since installing LFP I've not once had to dig into the Espar, to clean it, where with LA it was literally an every spring ritual. :wink
My first set of AGM's for my Electric Propulsion system lasted eight years. Actually only one of the batteries got flaky due to a parasitic load that was on it over the winters. I think I could have gotten 10 years out of the bank otherwise. I replaced them all since they were eight years old just to keep the ages the same.

With the second set I made a big mistake. Of the four batteries shipped two arrived in a visibly damaged condition. They were replaced by the shipper but, I should have rejected all four because the next season one if the other batteries failed after a short amount of time in operation. This season I will be replacing only that one since the others are still fairly new. I expect I'll get close to ten years out of the current bank if the past is any indication. Hopefully by then Lithium prices will have lowered and the batteries become more plug and play than they currently are. But, I said the same thing when I initially converted to Electric Propulsion in 2008. :)

Not sure why a difference between Lead Acid and Lithium batteries would affect you Espar heater?
 

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My first pair of 8D AGMs lasted 8 years... did not have a separate start battery... OEM one two both switch. upgraded system... blue seas 8080 swtich.. optima blue top start... paralleled 2 AGMs for house bank... upgraded regulators added ech charge and link 20 monitor... changed to all LEDs. 7 years... and they seem fine. I expect them to expire within the next couple of years.
 

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Our first set of 6-6volt lifeline AGM lasted 10+ years with very little loss till the end. Even the we probably could have eeked another year but because of our extended vacations on the hook decided to replace. The 720 ah bank is overkill for us, but I really don't want to have to sorry about power. 6 volts are easy for me to handle myself . We can fit 6 into the space . We have a blue top spiral starting battery. We do equaluze the Lifelines monthly to prevent premature suffication.

For our usage they have fit the bill and are very low maintenance.
 

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Handling lead batteries is something you shouldn't have to do much. Last time I had time I had to do it I paid the yard guy to lift them from the cabin sole up to the berth and place them in their compartment. The rest I was able to do with a halyard and a winch. Having said that.. I suppose smaller and lighter makes more sense. But geometry rules and not all batts will work for the designated space/volume. My compartment is 20.25" x 24.5". I could make the 20.25" a few inches larger but I have to move my heater. 2 8Ds fit nicely and the AGM start batt lives close by.
 

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Pricing of quality bare LFP cells likely will not fall, demand in fact is rising faster than supply can expand.

Protective gear with BMS functionality will fall, ideally open hardware designs, open source firmware, compatible with a range of cells brands and sizes, and user-configurable setpoints.

Which will force packaged-system vendors to be more competitive unless they just want to "skim the cream" at the top end.
 

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@Maine Sail write up is amazingly detailed. I'm only about half way through, but have learned a ton already. For starters, I did not realize there were amperage discharge limitations in many pre-packaged LFP batteries, as low as 50 amps. I was thinking about the ReLioN brand, so I looked it up. They have a 100amp discharge. I need to understand this more.

Hopefully, I have many more years before needing to replace my Gels again. Maybe enough time to build my own system. My batts were new last year. However, I doubt I'll wait until the are in desperate need. My bank is simply too small at 400ah.

When folks say their LA banks last 8-10 years, I bet they simply have so much capacity, they can't really tell they've lost a bunch of it. I got 8 years out of a Gel bank, which was still working fine, it just had notably lower capacity.
 
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@Maine Sail write up is amazingly detailed. I'm only about half way through, but have learned a ton already. For starters, I did not realize there were amperage discharge limitations in many pre-packaged LFP batteries, as low as 50 amps. I was thinking about the ReLioN brand, so I looked it up. They have a 100amp discharge. I need to understand this more.

Hopefully, I have many more years before needing to replace my Gels again. Maybe enough time to build my own system. My batts were new last year. However, I doubt I'll wait until the are in desperate need. My bank is simply too small at 400ah.

When folks say their LA banks last 8-10 years, I bet they simply have so much capacity, they can't really tell they've lost a bunch of it. I got 8 years out of a Gel bank, which was still working fine, it just had notably lower capacity.
I suspect cycling the batteries shortens their service life. If true it makes sense to set up a large amp capacity and not draw it down too much keeping it topped up with a high output alternator and alternate charging sources. I also think (guess) that keeping batt temps lower then higher improves their service life. I could be wrong about this and I would like read what others think of this approach.
 

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I suspect cycling the batteries shortens their service life. If true it makes sense to set up a large amp capacity and not draw it down too much keeping it topped up with a high output alternator and alternate charging sources. I also think (guess) that keeping batt temps lower then higher improves their service life. I could be wrong about this and I would like read what others think of this approach.
The deeper you discharge the battery the more you reduce the number of charge cycles available. It's why I tend to switch to Electro-sailing mode when I see my EP bank has dropped to 75% from the initial 100% full charge. I never wait until it has dropped to 50% which is often quoted as acceptable for lead acid. Specs for my 8A4D batteries say that discharging by 25% results in over 1000 cycles while discharging to 50% reduces that to 500 cycles.
 

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Yes informal anecdotes about battery life rarely include the %SoH data when replacement EoL was determined.

Many if not most just keep running until failure.

But there are top-notch FLA banks that safely get 13 even 15 years, but they weren't picked up at big box retail.
 

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[MENTION=6212]... For starters, I did not realize there were amperage discharge limitations in many pre-packaged LFP batteries, as low as 50 amps. I was thinking about the ReLioN brand, so I looked it up. They have a 100amp discharge.
Likewise I'm researching and learning about LFP batteries. Honestly I'm a hard-sell because am a big believer in 2V industrial FLA, but trying to be open.

I'm having discussions with a manufacturer in China. They quote 2000 cycles at 100% discharge, per their factory testing. They will build a bank to your specs and requirements. So this is what they've come back to me asking (which coincides with what Minnewaska says above):

"About the LiFePO4 battery packs you requirements of 12V 1000ah , we would like to know more:
1, Do you have request to dimensions?
1, Could you please tell us the application to use?
3, Do you have request to max. discharge current and charge curret? So we can make right BMS protection system for you.

Only knowing all your specific, so we can make right solution for you and quote the best price for you.

Lithium battery can be customized form your request, we can follow your request to design, including dimension, max. discharge current and charge current,"
 

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High on my list of expectations is that they be maintenance free. This means I don't have to add water and possibly deal with leaking batter acid if I used sealed batteries. Using sealed batteries means you don't need a traditional batter box and the batts can be placed in any orientation where you can fit them. Of course you will want to limit long wire runs.

Batteries of all types seem to be happiest and life longer when the are not deeply discharged before recharging. Therefore you want to limit the amount of amps you draw and add alt charging sources which prevent (hopefully) deep discharging. If you have a deep discharge you'll want a high amp charging device such as a smart regulated high output alternator.

So the approach involves... controlling and limiting your amp draw.... having alt charging sources to be replenishing used amps and a high output source for charging quickly when needed.
 
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