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Old 03-19-2015, 08:28 AM   #21
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That seems far more user friendly than the current state of Li tech IMO. Plug and play, no degree in electrical engineering needed to understand the voodoo.

Yep, agree.

Especially since we already have two banks of G31 AGMs.

I'm still pondering on the golf cart solution, though. Our space is such that I have room for only three G31s on the port side, and either three G31s or four GCs on the starboard side (or only one 8D).

The starboard side is the one coming into its 10th season, and it's also the side that takes a pretty big hit running our electronics. The GC solution gets me the most capacity (440 Ah) even if it would end up being more expensive in the long run that these -- apparently magic -- Firefly G31s.

Pondering.

But at least now I'm only pondering which LA AGM, not which chemistry.

-Chris
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Old 03-19-2015, 03:03 PM   #22
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That seems far more user friendly than the current state of Li tech IMO. Plug and play, no degree in electrical engineering needed to understand the voodoo.
Are they really drop in replacements for standard lead-acid? That Firefly powerpoint presentation says that float charging is not recommended, but all lead-acid charging profiles that I'm aware of include float.
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Old 03-19-2015, 03:28 PM   #23
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Changing a charger I can accept as it is sometimes needed converting to AGM. But one of these...

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...at least looks like a dang battery and will fit in an existing box. Have you ever seen what these guys go through to convert a sailboat over to a Lipof4 battery?

When you have to start out by constructing the battery itself wiring together the individual cells before getting it to the boat I'd call this plug and play. Forget all the other crap you need to go with the Lipof4 just to get your money's worth out of it.
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Old 03-19-2015, 04:55 PM   #24
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Are they really drop in replacements for standard lead-acid? That Firefly powerpoint presentation says that float charging is not recommended, but all lead-acid charging profiles that I'm aware of include float.

I suspect that while the presentation (penultimate slide) suggests that a float charge isn't necessary, and there are maybe some cycle life downsides to keeping a Firefly on float for long periods (slide 6)... but not that a float charge will actually kill the batteries.

Perhaps that means that if a user-customizable profile isn't available on the charger du jour... maybe just turning it off once the charger goes to float would be sufficient.

??

That slide 6 seems odd, though. I think it's saying these batteries work best when only between 0-80% state of charge. I'm OK with the 80%, but down around zero % seems a bit adventurous.

Still, they're saying up to 3600 cycles to 50% DoD (which is also 50% SOC). These are lab numbers, of course -- not real world -- but that's still a major leap of 3.6x more cycles than a Lifeline 6V golf cart system.

Hard to say whether it's snake oil or magic...

But yes, aside from some minor details I'd say the Group 31 footprint and something that smells like a duck (AGM profiles) is near enough "drop-in" to warrant further investigation.


And as Craig said, some folks do have to update chargers if changing from FLAs to AGMs. We didn't, but some of the newer chargers also offer more options for pre-set AGM profiles, so eventually changing chargers may be a good thing to do, anyway. And by then, maybe somebody at Firefly/Schwab could have answered a query or two about that float thing. Or maybe some of the charger makers will have added a pre-set option for no-float -- which I guess would essentially be an auto-off option, or some such.)

(Much of that slide presentation was about solar batteries and panels, too, including the title, so maybe some of the info was more focused on that, and some of the Firefly info was perhaps coincidental to their main purpose. Maybe. Might have been nice to hear the spiel that goes with the slides.)

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Old 03-19-2015, 06:05 PM   #25
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According to the specs published by Firefly. The Group 31 battery is only rated at 600CCA. (1150 for an Odyssey/Diehard Platinum Group 31). I can't find any reference to the AH available with this battery.

If this battery has sufficient amp hours, it might make a good deep cycle house battery. With only 600CCA, I'm not sure I would want one to drive my windlass or thrusters.
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Old 03-20-2015, 02:20 AM   #26
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I can't find any reference to the AH available with this battery.
Amp-hour capacity is usually based on a 20 hour load. From this spec sheet they claim the battery can deliver 5.8A for 20 hours, which works out to 116 Ah.
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Old 03-20-2015, 02:35 AM   #27
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Have you ever seen what these guys go through to convert a sailboat over to a Lipof4 battery?
Yes! But least there are a bunch of marine installations of LiFePO4 battery banks now, and some accumulated experience about how to operate them.

Do you know of any Firefly Oasis installations on boats? I haven't seen or heard of any.

This is a company that has gone bankrupt once. They have a technology that looks good in a press release, but is missing some pretty important details, like: what is the proper charging profile to use for these batteries? The spec sheet's data is footnoted "*Proper installation and charging required", but there's no indication anywhere of what proper charging is. It looks to me that if you install these, you'll be experimenting as much as if you had installed LiFePO4's.
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Old 03-20-2015, 03:15 AM   #28
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My study on LI a year or so ago showed it is still very much the domain of the tinkerers whom wish to get a whole lot of cycles. Sail cruisers benefit in two ways. Weight/space savings and time between charging as you can take 80% of charge out between charges.

My end opinion was unless you are seriously after an electric driven boat or long term cruising on the hook your throwing money at a problem that doesn't exist. 10 years on your existing bank testify to that.

If your needing some new reading material that would take days to sift through there's at least two 1,000+ post threads at CruiserForum that have input from some really knowledgeable folks.
That's been my conclusions as well, Craig. The average trawler owner doesn't benefit as much from the reduction in weight and space as some of the other users who are converting.

Another year or three, and the batteries will be significantly cheaper; the charging systems will be less delicate, and everybody will be converting.
I'm biding my time for a little while longer.
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Old 03-20-2015, 07:18 AM   #29
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"Another year or three, and the batteries will be significantly cheaper; the charging systems will be less delicate, and everybody will be converting.
I'm biding my time for a little while longer."

5 -10 years and you will still be a Beta Tester.
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Old 03-20-2015, 08:25 AM   #30
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My study on LI a year or so ago showed it is still very much the domain of the tinkerers whom wish to get a whole lot of cycles. Sail cruisers benefit in two ways. Weight/space savings and time between charging as you can take 80% of charge out between charges.

My end opinion was unless you are seriously after an electric driven boat or long term cruising on the hook your throwing money at a problem that doesn't exist. 10 years on your existing bank testify to that.

If your needing some new reading material that would take days to sift through there's at least two 1,000+ post threads at CruiserForum that have input from some really knowledgeable folks.
Chris,

You have some really good advice above. I have read the CruiserForum thread a few months ago and my take is that unless cost is no object it will NEVER be cost effective in the next 10 years.

Why, because it also entails changing so much of your electrical system.

Which leads me to another issue, as I reread your OP, I did not realize you were wanting to keep two different battery systems on board. That solution would significantly increase your cost and as others have mentioned, brings far more risks than benefits.

Last year, I like you, wanted, needed, to decrease battery charging time to make it nicer to anchor more often and longer. Thus my reading of the CF thread.

My initial solution was to add a second alternator, though at the same time, I changed my fridge/freezer from one that used 18 amps per hour to one that used 5 amps. I also added 440 watts of solar power.

Lo and behold, all of a sudden I didn't need the second alternator. 24 hours on the hook meant -150 amp-hrs; not -450 as needed previously, thus my gen time became two hours, not 8

You seem set in trying to cobble together something, yet want to try something new. I think you would be far better served to rethink your plan entirely.

What is your daily, 24 hr, use in amp-hours?

Why not make one large house bank? and add a starter battery.

One large bank will be much easier to deal then having two banks being charged at different rates.

Two banks as you envision simply can not be as efficient as one bank.

Good Luck
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Old 03-20-2015, 10:34 AM   #31
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Chris,

You have some really good advice above. I have read the CruiserForum thread a few months ago and my take is that unless cost is no object it will NEVER be cost effective in the next 10 years.

Why, because it also entails changing so much of your electrical system.

Yep, have come to agree. Didn't take long, either. That long thread on CF hurt my head!

Which leads me to another issue, as I reread your OP, I did not realize you were wanting to keep two different battery systems on board. That solution would significantly increase your cost and as others have mentioned, brings far more risks than benefits.

Well, it wouldn't have been that I wanted to have two systems; just that only one of the two banks is coming up toward replace time...

Last year, I like you, wanted, needed, to decrease battery charging time to make it nicer to anchor more often and longer. Thus my reading of the CF thread.

My initial solution was to add a second alternator, though at the same time, I changed my fridge/freezer from one that used 18 amps per hour to one that used 5 amps. I also added 440 watts of solar power.

Lo and behold, all of a sudden I didn't need the second alternator. 24 hours on the hook meant -150 amp-hrs; not -450 as needed previously, thus my gen time became two hours, not 8

Sounds like good changes. We already have efficient fridges (came with the boat), but don't really have room for much solar. Not yet ready to think about taking that one yet... although maybe in future it could happen. Depending on usable space on our hardtop...

You seem set in trying to cobble together something, yet want to try something new. I think you would be far better served to rethink your plan entirely.

Well, not exactly More like wanting to remain with the same basic chemistry (LA AGMs), realizing that an easy plus-up is switching that bank from 3x 12V G31s to 4x 6V GCs -- and I have space to do that -- but at the same time wanting to be sure I'm not missing a good opportunity to begin transitioning to a different chemistry (Li). Given that a simple replacement with AGMs maybe sees me 10 years down the pike... as long as now isn't a good time to switch, I'm good with that. Pretty much the consensus, for an easy transition, is to bag the Lithiums for now, for exactly the reason you mention above. I'm good with that.

What is your daily, 24 hr, use in amp-hours?

Can't remember, off-hand, but I posted it for somebody else in another thread a while back. Think that was on TF... It's within our current capacity, although I usually have to turn off our bridge electronics while at anchor to be within a comfortable margin. And run the genset morning and evening to recharge while we're cooking. Or when we're trolling for long periods on the port engine, I've had to use the parallel switch to restart starboard. It happens, this starboard bank I'm planning to replace/upgrade is the same one that runs our electronics.

Why not make one large house bank? and add a starter battery.

One large bank will be much easier to deal then having two banks being charged at different rates.

Falls into the same category of "too much other stuff" to deal with. This particular manufacturer has been cranking systems like ours out for donkey's, largely aimed at a typical powerboat market: marina hoppers. Having the two separate house banks hasn't really been too big an issue, actually; consider that I also have two separate houses.

Good point about the separate rates, though. My research on chargers, and discussions with our current charger manufacturer, leads me to believe that's not too big a deal, though, at least when staying within the same or similar basic chemistry. That came up first when I wanted to start the transition from FLA to AGM... but didn't want to toss out a perfectly good port bank, and I didn't want to buy 7 batteries all at once. In an overall system that also has a third bank with a relatively tiny genset start battery. Charger guys said no problem; the charger will only send what's demanded to any of the 3x banks.

Two banks as you envision simply can not be as efficient as one bank.

I think that's likely to be mathematically (physics-ly?) correct, but I think in this case the difference isn't going to be enough to worry me too much. I do appreciate the critique, though, very much.

Good Luck

Very good post, Richard, thanks, I appreciate it. Thought easier to follow imbedded responses....

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Old 03-20-2015, 10:37 AM   #32
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Cruising world has an article on Lithium batteries. They looked at three sailboats built with them. Here's my takeaways:

Pros
- can absorb a charge much faster, minimizing run times to recharge
- higher current density. More amp hrs for same space usage
- can be more deeply discharged, reducing number of charging cycles needed
- one setup is projected to have working range of 3000-5000 charging cycles


cons
- possibility of thermal runaway. Precise low and high voltage regulation is key to avoidance
- lithium once ignited can not be extinguished by any onboard device. It will burn till it sinks (sounds like meltdown to me)
- need new charging system
- likely need new forced ventilation on charging system
- must design into system a way to avoid low voltages in battery. Either solar panels, auto start on a genset, etc.
- must be installed in an "always dry" location

Two of the three boats they used for the article are owned by electrical engineers. It seems to me that the complexity of these systems coupled with the potential perils of a voltage mismanagement not to mention the system cost factor make these systems lucrative only to those who wish to tinker on the cutting edge.

The payoff of being able to run 18k BTU AC and a microwave from the batteries just doesn't come close to tip the scale in their favor. For me the technology looks very promising and I'll happily wait in the sidelines for it to mature before considering, in the meantime it'll be tried and true systems for us.
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Old 03-21-2015, 07:08 AM   #33
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Besides the cost of the batts , most charging sources will need to be 2x or 3x the size to be able to supply the amps the set can absorb .

Providing 300+amps from the main engine or noisemaker is difficult and expensive.

In this case a short time recharge will really be expensive.

Since most energy is required to use on the fridge freezer , it would seem better tech fridges would be easier than experimental batteries.

Richard dumps 150AH a day in the reefer setup, so he has to create at least 200AH to recharge the house batt set.

As larger truck alts are cheap (135ah) feeding a DC fridge with a modern fast freeze eutetic plate might be a simple no risk solution.

The hassle would be on shore power where the DC load could overwhelm most shore chargers.

And of course creating fridge retrofit kits to fit many size old fridges.
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