Thanks Myles. Those numbers really put things in perspective. I think I also read somewhere that the ZEBRA batteries were mostly recommended for continuous and regular users. You're right it would not make any sense at all if you only used them a few times per month. Modec produces commercial EVs, like delivery trucks and for commercial fleets of taxis, delivery and utility trucks that work everyday and go back to the recharge station at night so it makes more sense for them, probably. For boats, maybe if you had a water taxi or a charter service or just really knew you were going to go sailing everyday- and- your grid power source was eco, then it would make sense. Where I'm at, I don't feel as bad using grid power since we get a lot of our power from wind turbines.
I'm also very curious- and I admit, I'm no expert, I really do need to get smart on how to calculate this- how feasible would it be to supply that much power regularly to the ZEBRA batteries with a big enough solar array that you could have on a boat? Is that even a practical option, if you had say, a couple of 100 watt panels over a bimini? Presumably one of those big panels would have to be dedicated just to keeping the sodium hot. When they say a solar panel is rated at 100 watts, is that over 24 hrs or are you screwed at night?
-Greg
--- In electricboats@yahoogroups.com, "Myles Twete" <matwete@...> wrote:
>
> Ah, thanks.I missed the 14%/day number.
>
> So, in my case, averaging perhaps 2.5 outings per month at 50ah*36v (or
> 1.8kwh), I currently use 4.5kwh/mo on average from the grid.
>
> If instead of 6-yr old PbA, I used a Zebra pack, those 2.5 outings per month
> (assuming a 5.4kwh pack) would cost me an additional 30*0.14*5.4kwh or
> 23.8kwh/mo extra. That would be an increase in my boat's grid power
> consumption of 428% over what I now use. 100% recyclable or not, these
> sodium batteries would completely defeat the purpose of being low impact for
> me. Another way to look at it is this: Even if I justified 100% increase in
> grid power consumption, I'd have to be using my boat enough to use
> 23.8kwh/mo. At 36v, that's 660ah/mo. With an average cruising current of
> 30-40amp for my boat outings these days, that's about 16-20 hours per month,
> with a max of 2-3hrs at that average each trip. There's no way I'm going to
> be going out 5-10 times per month to justify even this significant 100% grid
> power increase scenario.
>
>
>
> Flooded lead acid batteries self discharge about 8-20%/month. That loss is
> 20-50x less than the loss required in extra power just to heat an equivalent
> pack of sodium batteries. You really need a daily driver to justify this
> kind of effective added cost from the grid and impact on the environment. I
> mean, if you're going electric partially for ecological reasons, how do you
> justify any more than 200% more in added power from the grid monthly? That
> marina power may not come from solar, hydro or wind.
>
>
>
> Lithium is rare, but alternatives are being found and there's still no
> shortage of lithium for making batteries or we'd see a spike in prices for
> EV-scale cells and we haven't. Meanwhile, the Zebra batteries are noted as
> "expensive" at the link you provided.
>
>
>
> It's good you pointed out the recyclability of batteries. Assuming these
> sodium batteries are indeed 100% recyclable, that puts them on par with lead
> acid. Unfortunately, as I read it, LiFePo4 batteries are considered
> unrecyclable. I'd like to know otherwise if that's the case, but as I read
> it, there are instructions online all over for how to "dispose" of them in
> the garbage and that's it..very sad.
>
>
>
> -Myles
>
>
>
>
>
>
>
> From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
> On Behalf Of Greg Martin
> Sent: Tuesday, May 03, 2011 4:17 AM
> To: electricboats@yahoogroups.com
> Subject: [Electric Boats] Re: Future Proof... Reason #149 Why I Love
> Electric Propulsion
>
>
>
>
>
> Myles,
>
> I'm definitely not an expert, I just got the info online. The company that
> supposedly makes them, FZ Sonic / CEBI, a European company had all those
> stats on a page on their website when I last posted and when I just went to
> check again just now it's blank for some reason. Interesting, maybe they
> just suddenly stopped making them? Another source,
> http://www.mpoweruk.com/zebra.htm is where I got the 14% from.
> Of course, there's also:
> http://en.wikipedia.org/wiki/Molten_salt_battery#ZEBRA_battery
>
> I'll keep checking the CEBI website, they had a really good list of pdf
> files with all the stats, I don't know what happened to it. In the meantime,
> it looks like GE is developing a similar battery- the Durathon, have you
> heard of it?
>
> http://geenergystorage.com/index.html
>
> As for the benefits of this type of battery over LiFePo, I think one of the
> big benefits is that Sodium batteries are more the environmental choice,
> since Sodium is more abundant and the batteries would be 100% recyclable.
> Sodium batteries would be potentially cheaper if everyone adopted them,
> since Lithium is rare and would become a fought-for commodity if everyone
> had to have it.
>
> -Greg
>
> --- In electricboats@yahoogroups.com
> <mailto:electricboats%40yahoogroups.com> , "Myles Twete" <matwete@>
> wrote:
> >
> > Greg-
> >
> >
> >
> > Have you found detail numbers anywhere as to how much power is required to
> > keep the Zebra pack at 520degF when not in use?
> >
> > Without numbers, I would guess that a 10kwh pack would require at least
> > 100watts continuous power to maintain this temperature even if it's well
> > insulated.
> >
> > Overnight, 100watts amounts to 2.4kwh, or 24% of a 10kwh pack's capacity
> > daily.as I said, it may make sense for daily drivers, navies and for those
> > who don't have an environmental conscience as regards burning electrons to
> > get no benefit, but.
> >
> >
> >
> > Anyway, I couldn't find numbers online for this and so the above is all
> > pulled out of thin air. Please provide whatever info you know about this.
> >
> > But honestly, with the price of the Chinese LiFePo batteries being in the
> > 1.05-1.20/ah range and with similar cycle life and energy density as the
> > molten sodium battery, I can't see why anyone with a boat would want to
> > consider the sodium alternative. I haven't seen any good argument for them
> > here that includes at least the downside costs of high heating
> requirements
> > and potential high initial costs---never mind the meltdown risks. I'm all
> > for seeing new batteries and options, but I want to be able to
> realistically
> > compare them---for that we need data.
> >
> >
> >
> > Thanks in advance.
> >
> >
> >
> > -Myles
> >
> >
> >
> > From: electricboats@yahoogroups.com
> <mailto:electricboats%40yahoogroups.com>
> [mailto:electricboats@yahoogroups.com
> <mailto:electricboats%40yahoogroups.com> ]
> > On Behalf Of Greg Martin
> > Sent: Monday, May 02, 2011 1:38 AM
> > To: electricboats@yahoogroups.com <mailto:electricboats%40yahoogroups.com>
>
> > Subject: [Electric Boats] Re: Future Proof... Reason #149 Why I Love
> > Electric Propulsion
> >
> >
> >
> >
> >
> > Thanks Jim. Modularity- that's a great word to describe electric
> propulsion
> > systems. I figured when I installed my lead-acid batteries in my boat,
> that
> > they would last only long enough until the next better batteries came
> along.
> > Maybe I'm just an optimist, or I need to count on maintaining my batteries
> > for a long time, but I am really hoping that my next batteries will be
> much
> > lighter, have more capacity and will be easy to maintain and won't harm
> the
> > environment.
> >
> > As for Molten salt/ ZEBRA batteries, they do seem interesting. I don't
> know
> > if I'm completely sold on them yet either but it is definitely interesting
> > that they are already being used by well established EV companies and the
> > Royal Navy and Innovanautic are using them at sea. They do seem to have
> > their purpose, and might be ideal for certain use. For day cruising when
> you
> > always go back to the dock at the end of the day and re-charge, they might
> > work great. I'm wondering if you wanted to go completely off-grid, if the
> > batteries could be maintained with a big enough solar array and wind
> > generator.
> >
> > Another reason I looked into this and I bring it up is because I was
> > approached by someone from Spain who is involved with Innovanautic. They
> are
> > looking for partners and want to expand into the US. Personally, I'm not
> in
> > position, but if you're interested in a potential business opportunity
> > please introduce yourself to Borja on Electric Seas.
> >
> > -Greg
> >
> > --- In electricboats@yahoogroups.com
> <mailto:electricboats%40yahoogroups.com>
> > <mailto:electricboats%40yahoogroups.com> , "luv2bsailin" <luv2bsailin@>
> > wrote:
> > >
> > > Right-on Greg.
> > > I had the same kind of thoughts about the "modularity" of our systems.
> > I've got a new set of flooded golf car batteries in my Albin 25 which I
> > expect to last 5 years or more. Who knows what will be available then?
> > Meanwhile I can continue to enjoy and refine my drive system and be
> > confident that things will only get better on the battery front. If
> nothing
> > else, the rise in popularity of newer technologies will keep downward
> price
> > pressure on the older tech, thus lowering the entry cost for folks just
> > getting started.
> > > I'm not sold on those molten salt batteries, not for my kind of use
> > anyway. There are some suitable applications I'm sure, but the fact that
> > they need to be kept hot means they need constant energy input in order to
> > be ready for use. Not a good recipe for efficient "off grid" operation,
> but
> > might work for commuter cars, ski boats, aircraft, or some other
> > intermittent-use applications where you need high power-to-weight ratio
> > while in motion but can stay plugged in to a reliable energy source most
> of
> > the time.
> > > Jim
> > >
> > > --- In electricboats@yahoogroups.com
> <mailto:electricboats%40yahoogroups.com>
> > <mailto:electricboats%40yahoogroups.com> , "Greg Martin" <ffmagellan@>
> > wrote:
> > > >
> > > > Everyone has probably thought of this already but one thing that I
> think
> > is really cool about electric propulsion is that as energy storage
> > technology (our Achilles Heel) improves, our boats will be ready to swap
> out
> > the old batteries for the next better thing. I know we're all on the edge
> of
> > our seats, waiting for the next better battery, right? Our electric motors
> > work with lead- acid and lithium ion batteries of course, but they would
> > also work with any future wonder that may develop- be that fuel cells,
> > hydrogen, ultracapacitors, cold fusion, or...?
> > > >
> > > > What does everyone think of ZEBRA batteries? For those that haven't
> > heard of them, they are thermal sodium batteries that use molten salt as
> an
> > electrolyte, and proponents claim that they have 4x as much capacity and
> are
> > lighter/ smaller than the alternatives. They use salt and so are better
> for
> > the environment and potentially cheaper. They are also currently being
> used
> > in EVs (Think City and Modec), by the British Royal Navy on submarines and
> > are now even being used on a sailing yacht in Europe, apparantly with
> great
> > success.
> > > >
> > > > Here's a short summary, with links and references about ZEBRA
> batteries
> > and Innovanautic's use of them on their boat in Europe:
> > > >
> > > >
> http://www.electricseas.org/profiles/blogs/innovanautic-inspires-europe
> > > >
> > > > What do you think?
> > > >
> > > > -Greg
> > > >
> > >
> >
>
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