Just completed upgrade from AGM to Lithium

[bhensey]

Originally Posted by SV__Grace

We just completed an upgrade from a 1200ah Mastervolt AGM house battery bank to 1200ah Mastervolt Lithium.

While still at the service dock I shut off shore power and allowed the new house battery bank to discharge to 50% SOC over 3 days, then turned on shore power and it took 3 hours to charge to 100%. I was ecstatic.

We have 200 amps of charging capacity and charging amperage was 196 for the first hour to 70%, then 168 for the second hour to 90%, and in the final hour dropped from 145 to float.

After cruising for 3 years living on the hook full time with AGMs that took forever to charge and required running the generator 2-3 times longer than I think is necessary, this was astounding and worth the investment for me.

It took 7-8 hours to charge my AGMs to 100% and routinely it took 2-3 hours in float to go from 97% to 100%. Charging amperage in bulk mode always started at 190 then quickly dropped to 145 and rarely stayed there for more then 30 minutes before dropping to 90 and below. Awful and frustrating.

In normal use I would run the generator for 3 hours or so to get the AGMs to 95% or so then shut off, but they need to be topped off to 100% at least once a week or their performance will degrade. We lost 2 of the original 6 batteries because I was reluctant to do so.

We are excited about our new lithium batteries which will serve our cruising lifestyle far more effectively than our previous AGMs

Our house battery bank of six 6v Mastervolt AGMs provided 1200ah at 12v, which is 600 usable ah (50%). Current cost of this battery bank is @$4,300.00

Our new lithium battery bank of three Mastervolt 12v 400ah batteries also provide 1200ah, of which 960 is usable (80%). Current cost of this battery bank is $18,000.00. We could have used just two of these batteries instead of three, but I wanted the higher capacity to go longer between charges.

We originally wanted lithium when refitting Grace for cruising 3 years ago but the cost was prohibitive. Since then the cost has come down, the tech is better, and our frustrating experiences cruising with AGMs has motivated us to upgrade. The actual cost over time for lithium is lower for cruisers like us who live on the hook.

Factors include:

- Usable ah- can go longer between charges.

- DoD cycles- Mastervolt AGMs are rated for minimum 2000 charging cycles, lithiums for minimum 3000 charging cycles, 33% longer life.

- Charging time- As described above, it took 3 hours to charge the new lithiums from 50% to 100%, which would be 6-8 hours for the AGMs.

- Charging SOC- Lithiums are fine, even prefer, not being charged to 100% so I can use the peak charge curve for 1-2 hours and stop wherever that is as often as I like. AGMs MUST be charged to 100% at least once a week or so to keep them functional. Not doing so for the first year of cruising lost me 2 of the six batteries I started with.

- Solar/Wind generation- AGMs HATE the variable charge levels of solar and wind generation and require charging to 100% once a week or their ability to accept a charge greatly degrades/diminishes. Lithiums are able to maximize the energy generated from our solar and wind generation.


This past winter I had to change generator oil once per month or so (every 100 hours), a ridiculous amount of generator use. With the lithiums I should be able to get by with wind and solar most of the time and use the generator once or twice a week during the winter for a couple of hours- 12 hours per month vs. 100 hours per month is a BIG difference that figures into the cost and quality of life on the hook.

As a side benefit, lithiums are significantly lighter, so Grace's weight distribution problem from replacing a 110 gallon fuel tank with a 90 gallon fuel tank is fixed, no more 2 degree list when the tanks are full!

In case you worry about safety and fires with lithium batteries, that is an issue with going cheap and not having the proper setup, which can be expensive. Most of what I needed was already in place from Grace's electrical refit of an integrated Mastervolt system, and the battery monitoring and management systems have double and triple redundancies. Lithium is a waste for dock queens, but we are on our boat 100% of the time and pay close attention to all of Grace's systems, so if there's a problem we will know it almost immediately.

Fun fact- we like to use an AC popcorn air popper every evening while watching TV and with the AGMs we would run the generator for 5 minutes to do so (if not charging). With our new lithiums we can do so from battery power without the generator. That one little change is a great metaphor for the difference these batteries will make for us.

We are happy and excited about our new lithium batteries! Our first week was nirvana and we have high hopes that their initial performance will continue.

Sounds great, did you work with a Vendor in the PNW. We are based in Seattle and looking at upgrading to Li this year?

[Maine Sail]

Originally Posted by newhaul

Hey Rod
When we get out there the charts all go out the window.
At least the chart gives a base idea to make a semi informed decision .

The data is certainly more accurate for LFP than it is for lead acid. We are one of the few marine electrical businesses that capacity test lead acid batteries (LiFePO4 too) and I can assure you that most lead acid batteries are flat a$$ dead before they even hit 250 cycles, let alone the 500 or 1000 as the data suggests.

My own LiFePO4 cells have now broken 2000 cycles, vast majority of the cycles to to 80% DoD but many of the cycles were to 0% SoC. The cells were manufactured on May 10th of 2009 (happy belated 12th birthday to my LFP bank) and still, today, 12 years later, exceed the manufacturers rated capacity of 400Ah.

I would challenge anyone to bring me even a single lead acid battery, used or never used/cycled that can still produce 100% of its rating 12 years after the date of manufacturing. Firefly is a clear stand out in lead acid but nearly as expensive as LiFePo4.

[Nkdave]

Thanks for your detailed post! ! We are very interested in upgrading our AGM to Lithium in 5 years. I want to learn as much as I can between now and then.

[Nicholson58]

Sounds great. In your OP you mentioned float. Be very cautious on this. My research a couple years ago revealed that float can destroy Li batteries. I would have had to download Li software to all four of my charging devices to disable float. We did Firefly instead.

https://marinehowto.com/lifepo4-batteries-on-boats/

[SV__Grace]

Originally Posted by bhensey

Sounds great, did you work with a Vendor in the PNW. We are based in Seattle and looking at upgrading to Li this year?

The guy who did our refit in SF Bay has family in WA and we really wanted him to do the job. Waited a year for him to be available and come up here!

[donradcliffe]

Originally Posted by sailjumanji

Not aware of any failures, so can't answer that. Our original AGM setup was two 225 Ah batteries as a house bank, and a 130 Ah as a start battery. Each had an isolation switch, plus there was a emergency parallel switch that would commingle everything. I left these switches in place, and if for some reason the MLI goes offline, I can open the relay to isolate it, and then parallel the house and start systems. I also put a "DO NOT USE" sticker next to the parallel switch. If it gets to this point, the two Yamaha outboards have alternators that put out about 7 amps each, directly to the start AGM. System could survive on that. Plus the solar during the daylight.

I did ask the boat crew, and there are three separate batteries/BMS in parallel, which makes me feel better. I keep a very close eye on the system voltage, so the chances of the bank going offline are slim unless there is a cell or BMS failure. In that event, I'll plan on going with two batteries the rest of the 2 week passage.

[StephenOrmond]

Check out all the data for Lithium Iron batteries and how they work under solar panel charging: Custom Marine Products’ web site. A quick search will get you there.

[newhaul]

Originally Posted by Maine Sail

The data is certainly more accurate for LFP than it is for lead acid. We are one of the few marine electrical businesses that capacity test lead acid batteries (LiFePO4 too) and I can assure you that most lead acid batteries are flat a$$ dead before they even hit 250 cycles, let alone the 500 or 1000 as the data suggests.

My own LiFePO4 cells have now broken 2000 cycles, vast majority of the cycles to to 80% DoD but many of the cycles were to 0% SoC. The cells were manufactured on May 10th of 2009 (happy belated 12th birthday to my LFP bank) and still, today, 12 years later, exceed the manufacturers rated capacity of 400Ah.

I would challenge anyone to bring me even a single lead acid battery, used or never used/cycled that can still produce 100% of its rating 12 years after the date of manufacturing. Firefly is a clear stand out in lead acid but nearly as expensive as LiFePo4.

I have to thank Adelie for the work done to put that battery chart together .
Glad to hear you have surpassed the 2k cycles with no losses. Makes me feel happy with my 250ah bank I'm just over 250 cycles now . Most times never went below 70% ( 30% DOD ) so real light use . Still testing at 264ah .

[StephenOrmond]

Also, your charger will need to be reprogrammed to shut off the float stage. Up to date chargers can accommodate that reprogramming, I’m told.

[SV__Grace]

Originally Posted by Nicholson58

Sounds great. In your OP you mentioned float. Be very cautious on this. My research a couple years ago revealed that float can destroy Li batteries. I would have had to download Li software to all four of my charging devices to disable float. We did Firefly instead.
https://marinehowto.com/lifepo4-batteries-on-boats/

Amazingly informative and thorough article, thanks for the link!

[SV__Grace]

Originally Posted by Maine Sail

The data is certainly more accurate for LFP than it is for lead acid. We are one of the few marine electrical businesses that capacity test lead acid batteries (LiFePO4 too) and I can assure you that most lead acid batteries are flat a$$ dead before they even hit 250 cycles, let alone the 500 or 1000 as the data suggests. My own LiFePO4 cells have now broken 2000 cycles, vast majority of the cycles to to 80% DoD but many of the cycles were to 0% SoC. The cells were manufactured on May 10th of 2009 (happy belated 12th birthday to my LFP bank) and still, today, 12 years later, exceed the manufacturers rated capacity of 400Ah. I would challenge anyone to bring me even a single lead acid battery, used or never used/cycled that can still produce 100% of its rating 12 years after the date of manufacturing. Firefly is a clear stand out in lead acid but nearly as expensive as LiFePo4.

Maine Sail, I have a burning question for you as a real-life experienced user-

In transitioning from the AGM to Lithium owner/user mindset I'd love your recommendation for a practical, routine, every day/week/month charging protocol. Three questions-

1. How low should I routinely allow SoC to go before cranking up the generator?
(assume 0% SoC is 20% battery capacity)

2. When I crank up the generator, how high should I routinely allow SoC to go before turning it off?

3. Assuming the Mastervolt owner's manual is correct in their recommendation to bring their batteries to 100% SoC once per month or so, exactly when should I turn off the generator? As soon as it reaches 100%? When charging amps drop to float levels?

Thanks in advance for any real life guidance you can provide this LiFePo4 newbie!

[bluepearl54]

Very nice. Thanks for sharing. I had lithium’s installed last year and am equally pleased. One complication. As you probably know Pantaenius discontinued underwriting in the US last year. We do a lot of passage making (including a circumnavigation, 2018/2019) so we need a global, or at least international, navigation endorsement. The Jackline program underwritten by Markel seemed the best option. Since my boat is over 10 years old Markel required an insurance survey. The surveyor obviously reported on the lithium batteries at which point Markel told me they would not insure my boat!!!! My boat is a 2006 Hylas 54 in excellent condition. Just thought I would share this experience.

[newhaul]

Originally Posted by bluepearl54

Very nice. Thanks for sharing. I had lithium’s installed last year and am equally pleased. One complication. As you probably know Pantaenius discontinued underwriting in the US last year. We do a lot of passage making (including a circumnavigation, 2018/2019) so we need a global, or at least international, navigation endorsement. The Jackline program underwritten by Markel seemed the best option. Since my boat is over 10 years old Markel required an insurance survey. The surveyor obviously reported on the lithium batteries at which point Markel told me they would not insure my boat!!!! My boat is a 2006 Hylas 54 in excellent condition. Just thought I would share this experience.

No clue as to why but they had no issue with our 1966 spencer 42 it had lfp onboard . It also had two gc2 fla as the starting bank.

[Pelagic]

Originally Posted by GoneDiving

I'm a lithium fanboy but agree that the premium charged by 'drop in' or top tier suppliers is outrageous. Especially so when you compare prices for component parts.

My cost has been:

$8500 for 840ah @ 48v. Call it 3400ah equiv @ 12v
$2500 for 2x5000w inverters
$2000 for 5000w of solar panels
$1000 for cables and controls.

Yes, a big system but the intent is to replace all generators on a converted ex commercial trawler, power a keen diver and a electric domestic galley

All prices are Aussie pesos so I'd expect to halve that if buying in the US with USD

Cheers

Thanks for sharing as my pending switch to lithium mirrors yours...BUT AT 24 VDC

I have a new 5kw Multi, with older 3kw backup

1800w Solar

Could you tell me a bit more about your Lithium purchase as my budget would be half yours
Thanks

[tml]

We switched to AGMs when they first became available ( 1995? ) for our 2 8D house bank @ 475 amps. The primary reason for switching to AGM's was no maintenance. Our batteries were difficult to check and and top up with water. No surprise it became a do tomorrow task and the flooded batteries had a short life.
AGM seemed the answer but looking back I became an AGM serial killer as our boat was regularly at anchor or on a mooring and even with a small solar charger never got to 100%. The AGMs were regularly replaced as capacity reduced.
We began to cruise 6 months a year and battery capacity became the obvious weak link
even with an upgraded smart regulated alternator and more solar. Thanks to these forums and Maine Sail I sorted out that AGM's were always going to be a problem to regularly charge to 100%.
Lithium is an obvious choice and as SV Grace reports is no longer limited to hobbyists happy with tweaking a developing technology. If you have the budget it is a robust high performance system. Certainly as the price comes down I plan to be an enthusiastic buyer.
Until then my suggestion is a step back in time to flooded lead acid. Three years ago we doubled our capacity from two 8D AGM's to eight Trojan T 105 just under 1,000 amps by solving the maintenance challenge that led me to AGMs 25 years ago. Trojan offers a Hydrolink system that links the batteries fill caps. It takes no time to fill the bank and the difficult to access cells are no longer difficult and the bank is regularly maintained.
Lithium is I expect in my future but with T 105's at $125 times 8 = $ 1000 versus a multiple for Lithium patience is required.
Tom