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post #81 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

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Originally Posted by mbianka View Post
If one were designing a boat from the ground up that would make sense..

Yes, of course, that is what I mean.

EDIT: Sorry for double posting, I thought the first one did not go through

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post #82 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

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I don't know about craving weight, but keel boats certainly have tons of weight intentionally added for ballast. I get the desire to swap it for something with dual purpose. I think there are two limitations for adding batteries to the keel. Nothing on a boat is actually waterproof, including the hull. We all get some sort of leak eventually. Further, no two keels are alike. This would make manufacturing efficiency very difficult and very expensive.

It would be nice to see an effective long range electric solution, but it's not in the cards with current technology. Actually, most of the advancements in both batteries and charging (solar/wind) have been in manufacturing efficiency, not storage capability. The energy density, therefore storage of potential energy, of carbon based fuels can't be beat so far.
Is it really more complicated to make something waterproof than developing a completely new battery technology (and pay for it)? Including all the safeguards to prevent them from blowing up?

As for 'no two keels are alike,' you could make the same argument for everything. No two cars are alike. Still, there are modular designs (not only batteries but everything, motors that lift your windows, air bags, everything) that work in many different cars. Why not design a boat with a hollow keel and fill it to capacity with something like 8Ds?
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post #83 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

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Originally Posted by hpeer View Post
Bored, canít sleep. Just looked up prices of Lithium batteries, GC2. The cheapest I saw was over $2,000 per batterie. So I would be looking at about $10,000 for my house bank of 4 GC2 batteries? Really? What am I doing wrong?
Deserves a new thread.

IMO forget drop-ins, forget 12V units, forget automotive BCI form factors.

And yes, in the NA market, starting point for quality LFP is at least 7x the cost per Ah compared to lead.

Not an economic proposition really.
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post #84 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

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Originally Posted by MastUndSchotbruch View Post
Is it really more complicated to make something waterproof than developing a completely new battery technology (and pay for it)? Including all the safeguards to prevent them from blowing up?



As for 'no two keels are alike,' you could make the same argument for everything. No two cars are alike. Still, there are modular designs (not only batteries but everything, motors that lift your windows, air bags, everything) that work in many different cars. Why not design a boat with a hollow keel and fill it to capacity with something like 8Ds?
Yes but that's a boat design / mfg issue.

It would take an innovative maker to do it.

99% of boat buyers do not consider living off grid for long periods of time.

Most get back to shore power quite frequently.

And the "waterproof battery bank" that continues to operate under a flooded bilge, well that is not trivial, not in the boatbuilder's wheelhouse, at all.

I think it's possible to create that, aftermarket to suit any boat, have some ideas along those lines if you start a new thread.

But no, just adding more weight is not a universal improvement. The naval architect designed the optimum, and 99% of off-grid cruisers are already loaded way heavier than they intended.
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post #85 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

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Originally Posted by MastUndSchotbruch View Post
Really? Wouldn't a heavier keel improve pretty much every monohull's performance? Am I the only one who likes better sailing quality?
Not everyone has a monohull, and most monohulls are designed to have their keel weight and depth work with all other design elements of the boat. So I doubt a heavier keel would improve performance, and would likely decrease it.

For a given design keel weight, it makes performance sense to put the weight as low as possible, on as high an aspect foil as possible. However, I don't think it would be practical to have batteries in a bulb on the end of a high-aspect foil.

I don't even thing it is practical to use lead batteries as primary ballast on a full-keel boat. What do you do when you need to replace them - tip over? And they would be experiencing a lot of tipping and forces when heeled - more so then if they were in the center of gravity.

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post #86 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

That's all true, but for heavy stuff like tankage and batteries, as a general rule lower the better.

A keel **could** be designed with a space for banks and tanks to get "slotted in" just above its ballast lead.

With modules of compensating blocks attached in those spaces while the weight design is kept "as stock", to be removed as the aftermarket weight is installed there in its place.

Routing channels for a "lowest points" collection plumbing for bilge pumps, combined with third-party designs for low-profile "waterproof" battery modules, intra-bank connection terminations at busses just under removable plates at or above the sole level. . .
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Re: Realistic expectations for my house batteries

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......
And yes, in the NA market, starting point for quality LFP is at least 7x the cost per Ah compared to lead.

Not an economic proposition really.
I dont know where youre getting this from.

My lfp batts were and still are about 2x equvilant trojan t105s
Usable energy

I could market fla batts are much more sensitive, higher maint...and quite dangerous
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post #88 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

I did say in that market.

My base point of comparison is $1-2 per Ah at 12V for lead, including transport to install location.

And usable capacity is not doubled, for good longevity compare 50% to 80%.

Please provide links to pricing, to build say a 400+Ah bank, for

Winston, CALB, GBS, A123 or Sinopoly, in large prismatic cells,

available from known-reputable domestic sellers.

Also adjustable BMS, if over $200 also use a domestic supplier.

I'm a huge fan of LFP, but there are many factors involved to get strictly economic ROI compared to lead, over a decade payback makes it very risky.

But lower weight, less space, no need to get to Full, super high CAR, no need for solar, the cool factor. . .

The reasons to "go for it" go beyond pure financial reasons.
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post #89 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

Electrical equipment needs to be made more efficient ... such as LEDs instead of heated filament lamps... and with the efficiency your boat will need less storage capacity. In addition alternate sources for generating amps should be advancing in design to produce more output... ie more efficient. Both of these will mean smaller storage batteries.

And you can always find a way to use less electricity. I haven't stayed on docks or in slips for 34 years and do fine w/ respect the electric power.
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post #90 of 138 Old 04-15-2019
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Re: Realistic expectations for my house batteries

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Originally Posted by john61ct View Post
Yes but that's a boat design / mfg issue.

It would take an innovative maker to do it.

99% of boat buyers do not consider living off grid for long periods of time.

Most get back to shore power quite frequently.

And the "waterproof battery bank" that continues to operate under a flooded bilge, well that is not trivial, not in the boatbuilder's wheelhouse, at all.

I think it's possible to create that, aftermarket to suit any boat, have some ideas along those lines if you start a new thread.

But no, just adding more weight is not a universal improvement. The naval architect designed the optimum, and 99% of off-grid cruisers are already loaded way heavier than they intended.
OK, I admit I was a bit flippant when I say we crave weight. And obviously there are limits (certainly reached when the outside water level reaches the gunnels

I just wanted to make the point that we put literally TONS of lead into the keel (of monohulls) that does nothing but being heavy. Since one standard complaint about batteries (in particular if they are lead-based) is their weight, why not make it an asset rather than a liabillity.
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