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bell ringer
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Discussion Starter #1 (Edited)
never mind, it was an expensive question and I withdraw it as a annoyance




go about your business, there are no battery questions here
 

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A better quality LFP bank than that one properly cared for will last much longer than the FF bank ever could

With that one, no one can predict.

The FF will not require (as much) new learning and infrastructure, and buying from one of Bruce's dealers a much more reliable support / service / warranty.

That LFP unit from that seller, is much much more a roll of the dice IMO, and getting to the point where you really know what is going on and how to (try to) get maximum longevity

much more like taking on a whole new hobby.

I admit I am an overthinker, more meticulous about the longevity issue than most, like to be more "certain" of success than many,

so maybe you just toss that LFP unit in, treat it like a drop in, and end up getting 10+ years before it dies and you're happy?

Or maybe it dies in a couple years and you're not. . .
 

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3,709 Posts
thoughts?
I think you should get FLA golf cart batteries.

1. They worked for you so far with no complaints. At least not more than your normal ones.
2. You don't seem to be heading toward larger power loads like 120V watermaker or water heater, etc.
3. Your implied cruising plans are such that you will probably be someplace where it is somewhat easy to replace them in 4-5yrs.

4. RegisteredUser, SeniorMechanico, Jephotog, and I are not sure we want you to know the secret lithium club handshake and chick-magnet phrases.

Mark
 

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Master Mariner
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8,207 Posts
I was surprised when I went on the Firefly site that they do not sell a 4D footprint battery. I thought 4D was a common size battery box on mid-sized yachts.
 

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I dont really need these batteries
I dont have big loads
Ive been thru more of my share of batts in my life and i latched onto these because i was tired of fkg around with batts
So far its been true bliss
 

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I dont really need these batteries
I dont have big loads
Ive been thru more of my share of batts in my life and i latched onto these because i was tired of fkg around with batts
So far its been true bliss
The first rule of lithium club is that we don't speak of lithium club.

Shhhh.

Mark
 

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I was surprised when I went on the Firefly site that they do not sell a 4D footprint battery. I thought 4D was a common size battery box on mid-sized yachts.
There are only two or three makers, of quality true deep cycling batteries in 4D or 8D

Of course many boaters just go down to auto parts or Wally's, but they won't stay above 80% SoH for long in daily depleted usage.
 

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FF are chronically backordered. When I looked at this last year before covid they were chronically back ordered. However I know the secret handshake. Be nice and I may show you it.
 

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bell ringer
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4,758 Posts
Discussion Starter #11
In the end Firefly is the answer for me.

- 4 x 12V batteries (464AH) = more redundant and reliability than 1 x 12V LFP "box" (400AH) with all it's BMS wires and other "stuff" any of which if fails takes all the house battery power down
- can be installed as 2 separate banks
- less concern about charge source etc
- more "local" support and supply (probably still 0 far as a real world timely item)
- more AH (even though I don't need it)

Really neither battery makes sense for me as the only thing I am gaining is not having to worry about getting to 100% state of charge anymore. It makes no money sense as to a cost/use as there is nothing that touches FLA in that regard. From 3 days of research the only real LFP advantage I see is if you really need a lot of battery capacity and don't have the space for the Firefly batteries
 

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In the end Firefly is the answer for me.

- 4 x 12V batteries (464AH) = more redundant and reliability than 1 x 12V LFP "box" (400AH) with all it's BMS wires and other "stuff" any of which if fails takes all the house battery power down
- can be installed as 2 separate banks
- less concern about charge source etc
- more "local" support and supply (probably still 0 far as a real world timely item)
- more AH (even though I don't need it)

Really neither battery makes sense for me as the only thing I am gaining is not having to worry about getting to 100% state of charge anymore. It makes no money sense as to a cost/use as there is nothing that touches FLA in that regard. From 3 days of research the only real LFP advantage I see is if you really need a lot of battery capacity and don't have the space for the Firefly batteries
Very logical... you can add or remove 12v "units" for any reason. If you use sealed batteries such as AGM they can be mounted sideways as well.. and don't "need" a battery box.. but batteries need to be secured mechanically. With lighter 6v batts... one failure means you remove another (working) battery.

Don't deeply discharge your batts - cycle them... that's what shortens their service life.
 

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bell ringer
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4,758 Posts
Discussion Starter #13
FF are chronically backordered. When I looked at this last year before covid they were chronically back ordered. However I know the secret handshake. Be nice and I may show you it.
I just checked and the FF are in stock and I can get 4 G31s from Marine Warehouse for $1935 uncluding shipping.
 

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bell ringer
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4,758 Posts
Discussion Starter #14 (Edited)
Well ................................ 2 end to end G31 Firefly batteries will not fit into my 4D boxes and even if I take the boxes out the space is not long enough as the boat was designed for 2 4D batteries. So would have to install in a werid way with twisting/turny cabling.

Turns out the LFP 400ah "box" is really 2 x 200ah series batteries in parallel. It fits easy into the space of 1 of my current batteries.

I would have saved a lot of time by taking a basic measurement at the start :-(
 

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Senior Member
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11,766 Posts
Very logical... you can add or remove 12v "units" for any reason. If you use sealed batteries such as AGM they can be mounted sideways as well.. and don't "need" a battery box.. but batteries need to be secured mechanically. With lighter 6v batts... one failure means you remove another (working) battery.

Don't deeply discharge your batts - cycle them... that's what shortens their service life.
? I don’t understand . 2working 6v In my case 240 ah. It takes 2 group 31 for that in a much larger footprint. In fact two of my 6 volt is almost the ah of a single 4d at much less size.

Plates on 6v are generally thicker so the also have more cycles in them than the 12 volt group 31.
 

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bell ringer
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4,758 Posts
Discussion Starter #17
Well ................................ 2 end to end G31 Firefly batteries will not fit into my 4D boxes and even if I take the boxes out the space is not long enough as the boat was designed for 2 4D batteries. So would have to install in a werid way with twisting/turny cabling.

Turns out the LFP 400ah "box" is really 2 x 200ah series batteries in parallel. It fits easy into the space of1 of my current batteries.

I would have saved a lot of time by taking a basic measurement at the start :-(
Talked myself out of the LFP and cancelled my order. I just don’t see them being easy to maintain if you want the long life to justify the cost. So back to the Firefly and i am going to make some mock ups and see about fitting them. Maybe will have to only use 3, or maybe I will just stay with FLA for $500.
 

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We’ve gone in a stream of consciousness circle and it’s now complete.

Good education though.
 
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