T-Pain Is On A Boat: Re: [Electric Boats] Re: Powerwall from Tesla, residential battery pack at $0.35/wh

I agree completely about going slower. But I also think it's important to burst any overly optimistic bubbles early on.
When I sized my pack, I based my calculations on Eric's data from his Serenity conversion.

My hull speed is 6.7kts.

My preferred cruise speed is about 4kts.

But getting out to the races on time is also important. My system *can* push the boat to close to hull speed. But 4.5 or better yet 4kts is just great for an afternoon "messing about in boats". Slow down to 3kts and I can go for 9 hours on a charge. I prefer to go slower when I can, but I am happy knowing I have that operational headroom should a short-term need arise -- like pushing off a sandbar, or powering around that nav-mark that "came out of nowhere" with back winded sails and a poorly executed emergency tack.

An optimal system will have most of its components maxing out around the same time and hopefully, reaching their efficiency peaks together as well. In my case, my hull, motor, gearbox, controller and batteries all reach within 90% of their peak "continuous" capabilities at full throttle. I am sure I could move my boat in a calm marina with a 12V trolling motor but I also think a heavy weed pack could stop it dead. As could a light headwind, small chop or our slow river current. A 24V direct drive 2kw propulsion package could probably be a very capable fair-weather setup for my boat. But it would have trouble getting me home in 15kt winds an 1-1/2' chop. A 2kw system would never let me go further than my local Lac St. Louis. To go up the Saint Lawrence seaway to the Great Lakes requires a few hours of fighting 4-5kt currents. Even my current setup with a 5kw motor and 5kwh battery pack, I still can't do it without having a portable generator to provide a boost. It all comes down to knowing your environment and your boat.

/Jason

On May 5, 2015, at 15:13, Carter Quillen twowheelinguy@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:

Jason writes:

"Continuous operation at 2000W won't move my 30' boat much over 4.5kts." You say that like it's a BAD thing.

I realize some people have a "need for speed" but when I had a Columbia 34 with a 28 hp diesel, 5 mph was the sweet spot that I cruised at all the time. Same thing on the Arc when I run it's 50 yo, 38 hp diesel. Getting an extra mph or two kills the milage and works the antique motor much harder. Going a little slower has a signicant effect on fuel economy and is a lot easier on the old motor so why not chill out a little and enjoy the scenery. People are in too big a hurry these days. IMO

I realize not everyone is content to poke along at 5 mph but it's really not that bad when you're actually cruising for the sake of cruising. I've learned to enjoy going slower. You really do notice a lot more things that are happening around you. Although I do draw the line at about 3 mph, then it's time to pull over or switch from solar to diesel. I would say if you are in a hurry, a sailboat is probably not the best choice of vessels anyway.

I know it's a cliche but life is a journey, not a destination. Having cruised hundreds of miles at 3 knots I'm thrilled on the days when the wind and currents align and I get to go 5 mph on nothing but sunshine. We may not pass anything but gas stations but it works for me.

Capt. Carter
www.shipofimagintion.com

On Tuesday, May 5, 2015 2:01 PM, "Jason Taylor jt.yahoo@jtaylor.ca [electricboats]" <electricboats@yahoogroups.com> wrote:

Here is a good analysi s of the battery and its price/performance
characteristics.
http://rameznaam.com/2015/04/30/tesla-powerwall-battery-economics-almost-there/

Basically, for anyone living where there is time-of-day pricing for grid
electricity, it makes sense *today* to get this battery for your house.

As for worries about it being a high-voltage energy source on a boat, I
would say that at their price point, it would be cheaper to buy the
10kwh pack, strip it down and repackage it as a 48V pack than it would
be to purchase 16x200ah cells from Balqon. However, if we can make use
of the 350-450VDC output of the pack, it could be interesting. I do
agree that working at higher voltages like this is not the same as 48V.
It requires a different level of packaging, electronic leak detection,
and safety interlock devices.& nbsp; Tesla clains their pack can be installed
on the exterior wall of a house or garage, much like a mini-split
airconditioner unit. So it is waterproofed to a certain extent. This
is certainly not aimed at the hobby, DIY installer, and neither are
144VDC propulsion systems. This will certainly find a place onboard
larger power boats that are already equipped with a mechanical room for
power, data, water and aircon plumbing. The ouptut power from these
packs is still too low for serious consideration as electrical
propulsion. Continuous operation at 2000W won't move my 30' boat much
over 4.5kts. My portable gas generator ouputs 2000W peak, 1600W
continuous which is enough to drive a single 15A household circuit. At
any rate, people considering a large house-bank plus a large inverter
for AC loads will definitely do well to look at this. You know that
Tesla (or Solar City) is also going to be offering an excellent sinewave
inverter to be paired with this pack. Add to it a DCDC converter and
you have a complete boat power system using compact, high-performance,
(soon to be) off-the-shelf components. These battery packs will be as
easily sourced as Trojan T-105s in a few years. I could easily see West
Marine or Defender becoming a distributor.

And just like Hannu says, once one factors in cycle life, lithium
batteries are cheaper than lead today, and only getting cheaper. In 5
years time, they are projecting an additional 20-25% drop in price.

Also, I completely disagree with weight not being a factor on a
sailboat. Carrying weight for the sake of weight is counter productive.
My 5kwh lithium pack (16x 100ah cells for 48VDC nominal) weighs only
125 lbs (compared to about 450lbs for equivalent usable WHr of lead
acid) and takes up just a bit more room than 2 Group31 battery boxes.
125lbs vs 450lbs is a big difference. That is a whole crew-member,
including their ration of beer ;-) I would take 200lbs of movable
ballast on the rail over 325lbs extra ballast under the cockpit any day.

I see this battery announcement for what it is: a shot across the bow of
the status quo. I expect the next few years to become very interesting
in the power-delivery space. And for those of us with battery operated
vehicles, it can only be a good thing. The scale at which Tesla will be
outputting these things will bring down the cost of a sizable boat
propulsion pack significantly.

Cheers,

/Jason

On 2015-05-04 22:28, Hannu Venermo gcode.fi@gmail.com [electricboats]
wrote:
> Those batteries can deliver about 30% of the max load over 5000
> cycles (vs 7000 cycl es for Tesla).
> So, your equivalent energy vs lion is == 30% x 2.5 kWh = 0.750 kWh.
> Cost:
>
> This is actually about 10 / 0.750 = 13.13
> 13.3 x 350 = 4666$ for a usable 10 kWh.
> So, about a bit more (==20%) than the lion from Tesla (guaranteed to
> work 7 years *in daily use*).
> In *daily use* no std traction battery will last more than 3-6 years
> at best.
>
> Or, you can get about 50% DOD out of them for about 2-3000 cycles.
> == 1.25 kWh.
>
> Lion is actually about the same cost as other battery tech, when
> actual power delivered is compared.
> At about 1/4 the mass and space.
>
> On 03/05/2015 02:01, billhopen@yahoo.com [electricboats] wrote:
>
>> they are heavier, 4 batteries weigh 100lbs, that's roughly 2-3 x
>> heavier per Kwh as tesla....but who cares in a boat?,,you are not
>> going up hills, don't need a suspension and boats need balast
>> anyway.
>>
>> the big difference is price, my 4 batteries cost $350. total
>> (delivered cost) while my batteries are 1/4 the power...its 1/10 the
>> cost, that is 2.5x cheaper, and fifty volts is just perfect (and
>> safer in a salt water environment) I don't want no 450 volts when
>> a salt water wave comes in my cockpit, and I'm standing knee deep in
>> short circuit. I don't need an expert electrician to install them,
>> and I just need a $15 Chinese 3000watt PWM controller to run 50v
>> direct to my motor
>
> --
> -hanermo (cnc designs)
>
>
>
> Links:
> ------
> [1]
> https://groups.yahoo.com/neo/groups/electricboats/conversations/messages/26405;_ylc=X3oDMTJxc3NhNTY1BF9TAzk3MzU5NzE0BGdycElkAzUyMTQzODIEZ3Jwc3BJZAMxNzA1ODg0MDkwBG1zZ0lkAzI2NDA1BHNlYwNmdHIEc2xrA3JwbHkEc3RpbWUDMTQzMDc5MjkxNg--?act=reply&messageNum=26405
> [2]
> https://groups.yahoo.com/neo/groups/electricboats/conversations/newtopic;_ylc=X3oDMTJlcmJuaW83BF9TAzk3MzU5NzE0BGdycElkAzUyMTQzODIEZ3Jwc3BJZAMxNzA1ODg0MDkwBHNlYwNmdHIEc2xrA250cGMEc3RpbWUDMTQzMDc5MjkxNg--
> [3]
> ; https://groups.yahoo.com/neo/groups/electricboats/conversations/topics/26393;_ylc=X3oDMTM2cnFmZXVyBF9TAzk3MzU5NzE0BGdycElkAzUyMTQzODIEZ3Jwc3BJZAMxNzA1ODg0MDkwBG1zZ0lkAzI2NDA1BHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTQzMDc5MjkxNgR0cGNJZAMyNjM5Mw--
> [4]
> https://groups.yahoo.com/neo/groups/electricboats/info;_ylc=X3oDMTJlYzl0Y25tBF9TAzk3MzU5NzE0BGdycElkAzUyMTQzODIEZ3Jwc3BJZAMxNzA1ODg0MDkwBHNlYwN2dGwEc2xrA3ZnaHAEc3RpbWUDMTQzMDc5MjkxNg--
> [5]
> https://groups.yahoo.com/neo/groups/electricboats/members/all;_ylc=X3oDMTJmc21ocGpwBF9TAzk3MzU5NzE0BGdycElkAzUyMTQzODIEZ3Jwc3BJZAMxNzA1ODg0MDkwBHNlYwN2dGwEc2xrA3ZtYnJzBHN0aW1lAzE0MzA3OTI5MTY-
> [6]
> https://groups.yahoo.com/neo;_ylc=X3oDMTJkdGY1NGdhBF9TAzk3NDc2NTkwBGdycElkAzUyMTQzODIEZ3Jwc3BJZAMxNzA1ODg0MDkwBHNlYwNmdHIEc2xrA2dmcARzdGltZQMxNDMwNzkyOTE2
> [7] https://info.yahoo.com/privacy/us/yahoo/groups/details.html
> [8] https://info.yahoo.com/legal/us/yahoo/utos/terms/

--
Jason Taylor
--
S/V Fugu
1978 Beneteau First 30
Electroprop PM-20

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Posted by: Jason Taylor <jt.yahoo@jtaylor.ca>
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