I'll bet that Tesla also uses some really $pecial 12-volt battery. <g> Congratulations on your new ride, John.
On 8/12/2020 2:12 PM, John Weiss wrote:

Used to be.  Went all the way, and now have a Tesla Model 3.

Used to be.  Went all the way, and now have a Tesla Model 3.

On Aug 12, 2020, at 1:15 PM, John Kohnen <@Jkohnen> wrote:

So you're a fellow Prius driver, John! :o)

Toyota's got everybody convinced that the Prius computer is real picky about what sort of 12 volt battery it likes. <sigh> To keep us from putting just _any_ battery in our Prii, batteries in American cars have _Japanese_ standard terminals, and Japanese cars have _American_ standard terminals! But $450 to replace your Prius battery was highway robbery! My Prius's (2006) battery died a while back, and I got a fancy-dan Optima battery, better than the stock Toyota battery, for $237.99 through Amazon. It's a bit of a hassle to get to the Prius battery, but not enough so to justify what your dealer charged you. <sigh>

https://smile.amazon.com/exec/obidos/ASIN/B006VFEJJQ/themotherofal-20


On 8/11/2020 9:17 PM, John Weiss wrote:

The Prius battery may be a bargain. IIRC, I had to pay the Toyota dealer $425 for a replacement AGM!

The replacement battery they sell for Prii may be something to look at. >40 A/H (and the rate at a more aggressive discharge than the usual lead/acid rating) and a built in BMS, for $349 each.

--
John <@Jkohnen>
"Necessity is the mother of invention" is a silly proverb. "Necessity is the mother of futile dodges" is much nearer the truth. (Alfred North Whitehead)


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So you're a fellow Prius driver, John! :o)
Toyota's got everybody convinced that the Prius computer is real picky about what sort of 12 volt battery it likes. <sigh> To keep us from putting just _any_ battery in our Prii, batteries in American cars have _Japanese_ standard terminals, and Japanese cars have _American_ standard terminals! But $450 to replace your Prius battery was highway robbery! My Prius's (2006) battery died a while back, and I got a fancy-dan Optima battery, better than the stock Toyota battery, for $237.99 through Amazon. It's a bit of a hassle to get to the Prius battery, but not enough so to justify what your dealer charged you. <sigh>
https://smile.amazon.com/exec/obidos/ASIN/B006VFEJJQ/themotherofal-20

On 8/11/2020 9:17 PM, John Weiss wrote:

The Prius battery may be a bargain.  IIRC, I had to pay the Toyota dealer $425 for a replacement AGM!

The replacement battery they sell for Prii may be something to look at.  >40 A/H (and the rate at a more aggressive discharge than the usual lead/acid rating) and a built in BMS, for $349 each.

The Prius battery may be a bargain.  IIRC, I had to pay the Toyota dealer $425 for a replacement AGM!

The replacement battery they sell for Prii may be something to look at.  >40 A/H (and the rate at a more aggressive discharge than the usual lead/acid rating) and a built in BMS, for $349 each.

If price isn't an issue... $949 each, and I'd need two. <sigh> And a Battery Management System (BMS) to care for them. 150 A/H! :o) My flooded lead/acid batteries only have about 40 A/H practical capacity.
The replacement battery they sell for Prii may be something to look at.
>40 A/H (and the rate at a more aggressive discharge than the usual
lead/acid rating) and a built in BMS, for $349 each.

On 8/11/2020 3:34 PM, John Weiss wrote:

If price isn't a deterrent, and weight is the issue, look at these LiFePo4 batteries:

https://www.ohmmu.com/group31

John. I just ordered a "cheap" 65 pound short shaft from the back alleys
of Sri Lanka or some such. But, of course, you brought me up short with
discussion of 24 volts...I still have an unused 24 of unknown thrust--about
65, I think,
...
Somewhere in my checkered past there
was mention of lower tron consumption with higher voltage...is that your
implication with the above "higher math?" Dan.

On Aug 11, 2020, at 4:24 PM, elaineginader <elaineginader@...> wrote:



One of the first things I did to Larimar is oar locks but I need a seat and that's almost done. I rowed her the first year I brought her to Elk City but I missed going with the Coots because I was late. It would be nice to see how she handles. But we'll see what happens.

On Tue, Aug 11, 2020, 3:47 PM John Kohnen <jkohnen@...> wrote:

The Yaquina River between Elk City and Toledo isn't a very good place
for a sailboat. Bring your kayak. I hope you can manage to bring Larimar
to Fern Ridge before the water is all gone. Bob L and I poked around
with his boathook yesterday and discovered that the depths given below
are a little pessimistic for the end of the Richardson ramp (but about
4" optimistic for the depth in my slip out on E Dock <sigh>). There's
about a foot more water at the end of the Orchard Point ramp.

http://preview.tinyurl.com/FRidgeSlips

On 8/9/2020 4:25 PM, elaine wrote:
> Being stuck at home has its advantages. I took my Enterprise
> sailing/racing dinghy to the Toledo Boat Show last year and as some of
> you know I had my share of problems. One that has been on my mind was
> that I couldn't figure out how to keep the rubber down. I've been
> researching since to figure this dilemma as I would love to sail her on
> some future Coot messabouts. Today it all came to me and now it'll work
> correctly. I think I'll bring the Enterprise to the Halloween float just
> so I can test it out. Or if things work out I may take her to Fern
> Ridge. We'll see.

--
John <jkohnen@...>
A man of courage never needs weapons, but he may need bail. (Lewis Mumford)


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John,
Displacement can be deceiving when thinking about moving a hull through the water.  It's not so much the "weight" as it is hull shape which determines the size of the bow wake.  The the bow wake is created by pushing the boat through the water and pushing it requires power. Complicating this, it's somewhat exponential so that as you increase speed the power required goes up a lot, especially as you approach hull speed (top end of displacement motion).  The electric boat community has worked this out well, and as I recall the rule of thumb is doubling the power for an increase of a knot approaching hull speed.  So moderate speeds, in the realm of half hull speed, can be fairly efficient, like your "leisurely, rate of progress".
Regarding 12 vs 24 volts.  From your examples, 5 amps x 24 V = 120 watts  &  30 amps x 12 V = 360 watts;  lower watts = less losses to heating in all components.  If you are using lead acid batteries, either flooded or AGM, higher amperage cause losses due to the peukert effect which can be quite significant at the higher amperage.

Being stuck at home has its advantages. I took my Enterprise sailing/racing dinghy to the Toledo Boat Show last year and as some of you know I had my share of problems. One that has been on my mind was that I couldn't figure out how to keep the rubber down. I've been researching since to figure this dilemma as I would love to sail her on some future Coot messabouts. Today it all came to me and now it'll work correctly. I think I'll bring the Enterprise to the Halloween float just so I can test it out. Or if things work out I may take her to Fern Ridge. We'll see.

They have dock carts available at Richardson with big wheels that roll over the cleats on the dock gangways easily. With the water so low it's a slog pulling the cart loaded with to group 24 batteries up the gangway, and I worry about a disaster it the cart got away from me going down! <g>
For my usual use, I think I could keep the batteries up with a solar charger, and two group 24s will give me enough range the rare occasion when the wind dies completely when I'm far from my slip, and they'll be less likely to damage my back than group 27s when I _do_ need to get them home to recharge. I'll have to get in touch with Joe Grez at Electric Paddle for his advice on a solar charging system. During the Salish 100 last year I overheard him discussing the best sort of panels to use, but I forgot most of what he said. <g> Joe did the whole Salish 100 using only solar power, with one of his standard Electric Paddle batteries as a buffer.
https://flic.kr/p/2gGQwZm
Last night I did a short run in Tuffy at full "throttle" while watching the ammeter. After initially rising to a bit over 50 amps while accelerating, from a 4 amp rate, the current draw settled down at 49 amps. I didn't have a GPS along, but I backed off after s short run because I was afraid I'd get a bloody nose from the speed. ;o) It did seem like Tuffy was going along at a good clip.
Alas, Minn Kota doesn't give you any useful information on their Web page anymore, or at least the last time I looked. <sigh> The _rough_ rule of thumb about their trolling motor ratings used to be about one amp maximum current per pound of rated thrust, or a half amp per pound for the 24 volt motors. Though my 50 lb. electronic controlled 12 volt motor is only rated at 42 amps. Go figure... Anyway, by that rule of thumb, the 80 lb. motor bolted to Tuffy's keel should only draw 40 amps max. If it is indeed an 80 lb. motor... Did they make larger 24 volt motors? Tuffy has an odd propeller with its tips folded, making little end plates. She didn't have it in 2017. Perhaps it's more aggressive than the stock Minn Kota prop. If the current prop is indeed overloading the motor, maybe she'd do better with the stock prop... At any rate, I won't ever be running the motor at full speed for more than a few moments, if I get in a "situation" while maneuvering.
I think I'll do some test runs with a fresh charge in the batteries, and a GPS, just before I pull Tuffy out, so I can haul the batteries home in the boat on her trailer rather than hauling them up from the dock again. ;o)
On 8/11/2020 6:46 AM, Electri-Cal wrote:

Hot foot it over to a sporting gooda store, luggage store or, some even used gear places.  A folding suitcase crooling carrier works fine.

> ...

Hot foot it over to a sporting gooda store, luggage store or, some even used gear places.  A folding suitcase crooling carrier works fine.
...

... Just yesterday I finished wiring the 48 volt to 24 V converter.  Now the ev bicycle pack can be the third backup pack.
...
I have another converter to make the bike pack power a MKota directly also, so ready to go there too, after I get a motor to run all this stuff.  I forger how much run time the bike pack has on paper, but nees a good in water testing. It seems that the pack weighs about half a wet battery, while adding more run time, due to the lower the pack can be drained by a good deal.  Time will tell how this works out, keep fingers crossed.
...