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Hello you all so I have a Tartan 37 that I am prepping for a Bahamas trip for about 2 months starting in November. Hopefully if things open up I plan on mostly being at anchor on this trip. I have been researching batteries and was looking at the Battleborn 100ah Lithium batteries 950 a pop and the Firefly Oasis 100ah carbon foam batteries around 525 a pop. My budget is around 2k for batteries. That said I could either get 2 Battle Borns or 4 firefly oasis batteries. I have about 350w of solar on the boat. I am not sure which way to go. In the one hand I am getting 200ah and the other 400ah but I believe I can really only use around 50 percent of the Firefly batteries as oppose to most of the lithium. That said it sounds like I have 200ah of use regardless of which battery I go with. With the 2 BB or 4 Oasis usable should be around 200ah. If any of you has had experience with either or are battery and electrical inclined I would appreciate all advice and feedback.

Below is the links to both batteries.

https://battlebornbatteries.com/?gclid=Cj0KCQjwwr32BRD4ARIsAAJNf_3BpEkZbHTI87G6s08dQvC1qZ7u7ADvUydc1MNMiDxuaTxtW1JOf0UaAiSyEALw_wcB

Firefly International Energy

Thank You
:grin:ship-captain::crying:captain:
 

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Buy 6-6V Lifeline AGM. 720 ah/ 360 usable..no maintainence. Less than $1800
You got the right solar setup to keep them maintained
Small footprints
Will give you more than enough power.
Mine last over 10 yers

Check the number of deep cycle the two batteries you talked about and compare to the Lifelines.
 

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According to manufacturer spec sheets:

Lifeline - 500 cycles to 80% depth of discharge
Firefly - 1,300 cycles to 80% depth of discharge
Battleborn - 5,000 cycles to 80% depth of discharge

Lifeline - 1,000 cycles to 50% DOD
Firefly - 4,000 cycles to 50% DOD
Battleborn - 5,000 cycles to 80% DOD (pretty much all lithium batteries quote 80% DOD)

Lifeline - 2,000 cycles to 30% DOD
Firefly - 13,000 cycles to 30% DOD
Battleborn - same 5,000 @ 80% DOD

Mark
 

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On the hook for extended time and often on shore power are 2 very different animals in batt needs
Yes, I should have mentioned that for Lifeline, the lifespan numbers assume immediate recharge to full after each discharge. Otherwise, the cycle counts are lower. Firefly does not assume this, but does require periodic full charge/condition charge (weeks? months?), and partial state of charge does not significantly effect the cycle counts.. Lithium can operate partial state of charge almost indefinitely with no hit on cycle count.

Mark
 

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Don't need to run the numbers - we've lived it. Got rid of 750lbs of L16H lead batteries and replaced with equivalent usable capacity of lithium weighing 150lbs. Took up 1/4 of the space of the lead - we gained an entire locker of space and 1/2" of waterline.

Mark
 

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Im into year 3 of not/never being plugged in

The real shocker...
Run comparison numbers on space requirements and...weight
Our LFP cells were manufactured on May 10th of 2009 (yes they just turned 11 years old). We are never, ever plugged into shore power, only ever charged to 100% SoC every 20 or so cycles to keep the Ah counter from drifting too much, and rarely even have solar turned on.

We charge via alternator only and can pack more than a days worth of energy into the battery in 30 minutes of run time. We don't typically even begin to charge until we near 80% DoD. The bank has been to 0% SoC at least every 50 cycles, up to 1000 cycles, and now to 0% SoC every 100 cycles (too much work to run a capacity test every 50 cycles to see no changes).. The bank now has over 1450 cycles and is still delivering more than the 400Ah rated capacity or better put at 11 years old and 1450 cycles the SoH is more than 100%...

No comparison to lead.

Firefly batteries are a tremendous leap forward for lead acid, but a bit too late to the party for many boat owners who are now moving to LiFePO4 at blistering numbers. The last 5 customers we've had, that were interested in Firefly have chosen LFP instead.

One thing folks fail to consider when buying Firefly batteries is that these batteries are purposely designed for 80% DoD. If you're not cycling them to 80% DoD you are simply not getting your money's worth..

If you run the numbers at 80% DoD vs. 50% DoD the Firefly batteries are actually pretty inexpensive, compared to other premium AGM's, because you need less batteries to achieve the same usable Ah capacity.
 

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Our LFP cells were manufactured on May 10th of 2009 (yes they just turned 11 years old). We are never, ever plugged into shore power, only ever charged to 100% SoC every 20 or so cycles to keep the Ah counter from drifting too much, and rarely even have solar turned on.

We charge via alternator only and can pack more than a days worth of energy into the battery in 30 minutes of run time. We don't typically even begin to charge until we near 80% DoD. The bank has been to 0% SoC at least every 50 cycles, up to 1000 cycles, and now to 0% SoC every 100 cycles (too much work to run a capacity test every 50 cycles to see no changes).. The bank now has over 1450 cycles and is still delivering more than the 400Ah rated capacity or better put at 11 years old and 1450 cycles the SoH is more than 100%...

No comparison to lead.

Firefly batteries are a tremendous leap forward for lead acid, but a bit too late to the party for many boat owners who are now moving to LiFePO4 at blistering numbers. The last 5 customers we've had, that were interested in Firefly have chosen LFP instead.

One thing folks fail to consider when buying Firefly batteries is that these batteries are purposely designed for 80% DoD. If you're not cycling them to 80% DoD you are simply not getting your money's worth..

If you run the numbers at 80% DoD vs. 50% DoD the Firefly batteries are actually pretty inexpensive, compared to other premium AGM's, because you need less batteries to achieve the same usable Ah capacity.
Even though I won’t be in the market for new batteries for 8 more years hopefully I see the LFP seems the way to go.

What brands do you see the most success with ? I see some cheaper made outside the US should we avoid?

The charging. Your recommendation is to drain them to 80% so to get the most out of them. How would you do that with the alternators which recharge when the engine runs?

I have a 720 ah bank which seems appropriate for my use. That means I probably could get away with 300/400 ah of these batteries. That’s a huge amount of money as they seem to be $1200 + per battery
 

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The charging. Your recommendation is to drain them to 80% so to get the most out of them. How would you do that with the alternators which recharge when the engine runs?
I don't think he meant that they need to be drained to 80% for health or lifespan reasons, only that they can be sized to drain to 80% daily. In other words, one doesn't have to drag around unusable capacity just for health or lifespan reasons.

Of course, if they are regularly recharged in the course of normal boating use, no harm in that. If one can count on that regular recharge, then the size of the bank can be lowered accordingly.

Or, like us, go in the opposite direction and connect the A/C, water heater, and 120V watermaker to the inverter to use the capacity/charging.

I've been running the boat off the inverter while on a dock trying to run the batteries down low enough that the solar runs free all day so I can see maximum amount of possible solar production of our rearranged and additional panels. I forgot I was doing this, and proceeded to run an industrial shop vac and grinder off the inverter for 4.5hrs non-stop. 😳 That did it - solar ran full-tilt (luckily a sunny day), and it turns out we can expect a maximum of 480Ah from the solar. Which coincidentally is 80% of our bank capacity.

Mark
 

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I have a 720 ah bank which seems appropriate for my use. That means I probably could get away with 300/400 ah of these batteries. That’s a huge amount of money as they seem to be $1200 + per battery
It's a moving target and ill-defined. Our 600Ah bank with busbars and hardware cost $3,030 shipped to us. I added a couple hundred dollars more management/protective equipment around it, so generously call the entire bank $3,500 at most.

Many others are going a more generic route and getting similar for ~$1,500. Others are also paying a lot more money for fully-integrated electrical systems that also include the batteries - or at least paying a lot more for batteries that can be added to a fully-integrated electrical system.

The 120Ah Lifelines seem to run ~$430 (fast search), so 720Ah bank is ~$2,580 with no connectors or hardware. Seems to be in the same expense range for LFP on overall capacity basis. More expensive if you consider the cost of usable capacity.

Mark
 

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Wow, 750AH of batteries on a mostly weekend boat. I have been cruising full time 4 years and rarely plug in when in active cruise mode and have gone 1 year between SP connecting and only have 440AH, which rarely are below 80% charge in the morning when on anchor.

What are people doing with all this power?

that's thread drift so disregard needing to answer
 

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It's a moving target and ill-defined. Our 600Ah bank with busbars and hardware cost $3,030 shipped to us. I added a couple hundred dollars more management/protective equipment around it, so generously call the entire bank $3,500 at most.

Many others are going a more generic route and getting similar for ~$1,500. Others are also paying a lot more money for fully-integrated electrical systems that also include the batteries - or at least paying a lot more for batteries that can be added to a fully-integrated electrical system.

The 120Ah Lifelines seem to run ~$430 (fast search), so 720Ah bank is ~$2,580 with no connectors or hardware. Seems to be in the same expense range for LFP on overall capacity basis. More expensive if you consider the cost of usable capacity.

Mark
Life line 6 volt $324. 220 ah. 6x $324 = $1944. .. 720 ah bank. No tax free ship. When they go on sale even less $ .
$195 a year for the bank. Not to shabby .

However after read Maine I may rethink. I will find out in 8 yers whether FLA are where I should go

https://invertersrus.com/product/lifeline-gpl4ct/
 

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Wow, 750AH of batteries on a mostly weekend boat. I have been cruising full time 4 years and rarely plug in when in active cruise mode and have gone 1 year between SP connecting and only have 440AH, which rarely are below 80% charge in the morning when on anchor.

What are people doing with all this power?

that's thread drift so disregard needing to answer
:ship-captain:

360 usable ah. Usually three full days for us. Don’t have to be. Right now we are on a 17 day excursion. Another 17 in October. And we’re not minimalists.

Don. Usage is then 270 ah as we average 90ah per day. CPap machines, Refrigeration, Ninja Blender , pumps it all adds upadds up. No solar. And we usually sail not motor to keep 5 knots like most coastal cruisers.
 

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Wow, 750AH of batteries on a mostly weekend boat. I have been cruising full time 4 years and rarely plug in when in active cruise mode and have gone 1 year between SP connecting and only have 440AH, which rarely are below 80% charge in the morning when on anchor.

What are people doing with all this power?

that's thread drift so disregard needing to answer
This discussion got me interested in the next upgrade. I have UPS 2 - 12v UBS AGMs 8D going strong since 2012. The two are rated at 490ah The pair cost something in the $800-$900 range. I do have a few small solar panels and do when aboard motor for a couple hrs a day.

The next version below is 6 - 12v UPS AGMs 4D rated at 100ah e/o total 600ah. I can use 5 and move the start battery into the main battery box. These 4D sell for about $175 e/o giving a total cost of just over $1,000 and they are a lot less at 64# e/o compared with the 8D at 154#.
 

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man i feel like a minimalist reading this. Wife and I use about 30Ah a day. We have a 160ah bank and make it about 3 days before it gets to 50% SOC. Thats running a fridge, lights, and charging devices (including a laptop) Not sure what else I’d use more power for.
 

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man i feel like a minimalist reading this. Wife and I use about 30Ah a day. We have a 160ah bank and make it about 3 days before it gets to 50% SOC. Thats running a fridge, lights, and charging devices (including a laptop) Not sure what else I’d use more power for.
What kind of fridge do you have that uses so little amps?
 

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This discussion got me interested in the next upgrade. I have UB 2 - 12v UBS AGMs 8D going strong since 2012. The two are rated at 490ah The pair cost something in the $800-$900 range. I do have a few small solar panels and do when aboard motor for a couple hrs a day.

The next version below is 6 - 12v UB UGMs 4D rated at 100ah e/o total 600ah. I can use 5 and move the start battery into the main battery box. These 4D sell for about $175 e/o giving a total cost of just over $1,000 and they are a lot less at 64# e/o compared with the 8D at 154#.
I’m confused the ugm 100 amp batteries at 65 lbs are group 31 not 4d correct?

You could get 6- 6v usb and get 600 ah for same weight , same footprint and more cycles
 

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I’m confused the ugm 100 amp batteries at 65 lbs are group 31 not 4d correct?

You could get 6- 6v usb and get 600 ah for same weight , same footprint and more cycles
Yeah there are many ways to skin the cat.... With 12vs I can have stat with 3 batts... add them up to 6 and they fit in the same box. I am not understanding why 6v cucle more than 12... I have drawn a 6v scheme as well. I don't deeply discharge because I use the motor for the fridge and not the batteries... so my loads are occasional instruments, pumps, lighting, AP inverter, heating, windlass and entertainment equipment.

12v refer and electric kitchen wuild be on a lot and draw a lot I assume. A couple of solar panels keeps batts topped up and we are not on shore power all summer.
 
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