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@yahoogroups.com] On Behalf Of Greg Martin
Sent: Monday, May 02, 2011 1:38 AM
To: electricboats@yahoogroups.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, "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, "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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