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Old 21-12-2020, 02:29   #391
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by mglonnro View Post
As I understood it from talking to OV, it went the other way around. Their design and recommendation called for more power, but he wanted to go without a generator anyway.
Fair enough, if that is what happened.

But I did say that Jimmy swallowed too much hype. However it happened, he overestimated the practical power generation from the system in real life conditions. Some combination of wishful thinking on Jimmy's part, and unrealistic promises from OV. Obviously the two things reinforce each other.
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Old 21-12-2020, 03:22   #392
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by mglonnro View Post
As I understood it from talking to OV, it went the other way around. Their design and recommendation called for more power, but he wanted to go without a generator anyway.
How do you get more power? More battery? Generator was out of the question.
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Old 21-12-2020, 04:04   #393
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Yihang View Post
How do you get more power? More battery? Generator was out of the question.
Well, a generator See, it didn't work out in the end

Here's a fictive reconstruction of what might have happened:

Quote:
Cornell: Please design the electrical system for 12 kWh average daily use.

OV: Ok, Sir! Your wish is our command!
[a few months later]

Quote:
Cornell: We're not going to use any stinkin' gas stoves. We're going zero emission all the way. In with the induction!

OV: But.. but.. you won't have enough electricity to run that if you want to cook food and get hot beverages for two persons!

Cornell: We'll be four.

OV: Ok, but that seriously won't work. You'll run out of juice! Please, please, please, consider installing a generator or a sufficient amount of sun power!

OV: Hello?

OV: Hellloooo? Anyone there??
[one month later]

Quote:
EXTRA! EXTRA! NEWS! NEWS! ZERO EMISSION CIRCUMNAVIGATION ABANDONED! READ ALL ABOUT IT!
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Old 21-12-2020, 10:30   #394
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Re: Jimmy Cornell goes Electric, with a Cat

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OK, I see. Well, it may be ( speculation alert ) more complex and have more variables than can be accommodated by software. The specific RPM that works, for that install, would depend on prop type ( brand), size and pitch, and water flow variables, and maybe other factors I'm not aware of.



As it is, it's pretty easy. In manual when you're sailing along, with the throttle at OFF, there won't be much, if any, regen happening. Then you nudge the throttle in forward up until you see the regen value jump up. That will be about max. for the current boatspeed. If the boat speeds up in a gust, or downhill on a wave for example, the prop spins faster and there is corresponding more regen.

If all that manual mode does is allow you to set the minimum prop speed, that seems very dumb and surely something that the auto mode already does (turn on auto mode, it figures out the speed, sets the prop for that speed).

My extrapolating from the information in this thread of the manual mode (as there is none on the OV site, so I guess they don’t think it’s important, or they realise that it’s a deal breaker for open ocean cruising and hide it) is that manual mode is needed when the boat speed is variable, to enable you to continuously adjust the prop for the current speed. If that’s the case, stupid.

Watt & Sea figured out a variable prop that auto adjusts for speeds up to 25 knots. That’s a system that works! OV in auto mode doesn’t, and in manual mode who knows?
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Old 22-12-2020, 13:01   #395
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Re: Jimmy Cornell goes Electric, with a Cat

Perhaps he should have had more solar.. or waited a little longer..
https://inews.co.uk/news/environment...plained-803609
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Old 22-12-2020, 18:38   #396
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by Yihang View Post
How do you get more power? More battery? Generator was out of the question.

Batteries don't provide more power. They store a limited amount, for a limited time, to even out the power generation curve. But, at the end of the day, putting in 10 times as much battery does little for the problem.


If (a BIG if) you routinely find that you have surplus power (the battery is at 100%, the "generators" are spinning at no load), and you also find that there are routine times when the battery is very low, then more battery helps. But if you never (or rarely) get to 100%, the battery is big enough.


And if you do find you are topped up (battery at 100%), there are other ways to "store" the power. You can do laundry that day, run the watermaker till the tanks are topped up, manually drive the freezer to sub-zero temps, pick that day to roast the turkey. All of these use that surplus power when it is available, so that you don't pull it from the battery a few hours later. Many of us, still on diesel, do this as a routine matter -- when you have that 8 hour motor ride on a glassy sea, make lots of water and sub-cool the freezer.
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Old 22-12-2020, 19:53   #397
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by sailingharry View Post
Batteries don't provide more power. They store a limited amount, for a limited time, to even out the power generation curve. But, at the end of the day, putting in 10 times as much battery does little for the problem.


If (a BIG if) you routinely find that you have surplus power (the battery is at 100%, the "generators" are spinning at no load), and you also find that there are routine times when the battery is very low, then more battery helps. But if you never (or rarely) get to 100%, the battery is big enough.


And if you do find you are topped up (battery at 100%), there are other ways to "store" the power. You can do laundry that day, run the watermaker till the tanks are topped up, manually drive the freezer to sub-zero temps, pick that day to roast the turkey. All of these use that surplus power when it is available, so that you don't pull it from the battery a few hours later. Many of us, still on diesel, do this as a routine matter -- when you have that 8 hour motor ride on a glassy sea, make lots of water and sub-cool the freezer.

Hi,

Take a shower etc. I understand the batterie's don't generate power. But they do indeed 'provide more power', in the form of stored power like you said. Especially if jimmy decided plugging in between ports was less of a sin than having a generator. If you were going to be off grid for 2 months it would not be useful but for jimmy it seemed he planned to stop at ports on a regular basis anyway.

The reason I asked the question was because short of installing a generator or a bigger motor-both seemed unlikely given the mission, the only other possible explanation is he could have meant more storage to get him by between ports.

But to be honest any of the above would not be a satisfactory solution for what jimmy wants to do. Installing a generator or plugging in frequently at ports would negate the whole point of the expedition.
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Old 23-12-2020, 04:02   #398
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Re: Jimmy Cornell goes Electric, with a Cat

Many of us "hybrid" folks -- big diesels, propane cooking, solar, Watt&Sea (a great product that is MASSIVELY overpriced -- glad it came with the boat), wind, etc, can get much of our electric from alternative energy. I'm not near 100% yet, but my solar pretty much sucks -- when I finally get around to doubling it, I may be there.


The problem is, when you step away from fuels, is the high energy stuff. The usual debate is propulsion -- there are not enough photons from the sun to create enough power to meet most cruisers needs (yes, niche people with a mission do it all the time). But an equal issue, and perhaps Jimmy's downfall, is heat. Boat heat, water heat, cook heat -- all are insane energy hogs. My inverter was wired at the factory so that the water heater can't even run on the inverter! It draws a KW, which will wipe my 800Ah battery slick (defined as 50%, of course) in 4 hours. Yes, it won't run 4 hours straight, but the point is, it draws a LOT of power. The microwave does run on the inverter, but it's 1KW+. An induction burner may be more efficient than a resistive burner, but it still draws 1000 times what an LED cabin bulb draws.


Propane for the galley, all by itself, might have changed the equation.
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Old 23-12-2020, 06:18   #399
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Re: Jimmy Cornell goes Electric, with a Cat

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Propane for the galley, all by itself, might have changed the equation.
Yes, I think so too! And it would have been at least theoretically possible to run the cooking on some sort of renewable gas.
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Old 23-12-2020, 06:34   #400
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by sailingharry View Post
But an equal issue, and perhaps Jimmy's downfall, is heat. Boat heat, water heat, cook heat -- all are insane energy hogs.
Boat and water heating could have been cut way back. Not fun but put on more layers and be a little stinky but very doable.

Cooking heat really shouldn't have been that hard unless they were using it in a foolish way (6hr to slow cook a brisket in the crock pot for example). Using induction, pressure cooker or other fast methods, it's really not that much power being used.
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Old 23-12-2020, 06:40   #401
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Re: Jimmy Cornell goes Electric, with a Cat

https://cornellsailing.com/2020/12/s...ero-journal-9/

Still undecided on whether to go again but he is going to London for his Vaccine. I guess he posted that before knowing about the lockdowns.
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Old 23-12-2020, 07:58   #402
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Re: Jimmy Cornell goes Electric, with a Cat

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Installing a generator or plugging in frequently at ports would negate the whole point of the expedition.
Well, plugging in would half-work as well, as long as the charging electricity is renewable. Same for the generator, if that runs on renewable fuel.

It would, however, seem easier to use more solar and get the regeneration working properly
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Old 23-12-2020, 10:26   #403
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Re: Jimmy Cornell goes Electric, with a Cat

Plugging in isn't as easy as it sounds. I just did some math. Assume you want to motor with 10HP for 5 hours, and then recharge at a dock. That's 35KWh (10HPx700W/HPx5h). A typical 30A shore power cable is good for around 3KW. That's 10 hours at 100% circuit capacity to recharge! Frankly, I wouldn't want to see that load put on a typical marina circuit for that long.


Let's not even think about cost! 10HP for 5 hours is probably around 3 gallons of fuel, or $10 here in the US. Shore power connection is $15/night, but I've seen more.



I only did this math for a moderate motor for single day. I suspect Jimmy's bank can support at least this much, and hopefully much more (so even longer to recharge). I didn't consider 50A cables (are they 220V? That would be a big improvement!). I didn't consider house loads, etc. Just a single discharge and recharge cycle. You often hear "just plug in" but I've never considered (or run the math) on the impact of that.
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Old 23-12-2020, 11:32   #404
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Re: Jimmy Cornell goes Electric, with a Cat

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Originally Posted by BigBeakie View Post
FWIW, I investigated this a couple of years ago and got uncomfortable with the level of support just getting answers to questions, so we dropped it. There were no issues on the Betamarine side of things, but the supplier of the EP side seemed incapable of supporting the solution if it was not located in the UK.
Yes I talked to them too and they were not so confidence inspiring or even enthusiastic.

The price too was also monumental.

I have decided to do my own version. Its not quite done yet. All the difficult bits done, but this last year has slowed progress down. Chasing the bits was a treasure hunt. But using- a Thunderstruck belt reduction, with a RV tow car cable operated Shaft disconnect, behind my new 4JH4-TE.

My thinking is it is mostly a diesel generator.

I also like the of some redundancy too. Ie if my Yanmar get a bad .
... ( insert your fault) bad fuel, starter motor, etc Im not completely hooped.
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Old 23-12-2020, 13:07   #405
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Re: Jimmy Cornell goes Electric, with a Cat

Quote:
Originally Posted by sailingharry View Post
Many of us "hybrid" folks -- big diesels, propane cooking, solar, Watt&Sea (a great product that is MASSIVELY overpriced -- glad it came with the boat), wind, etc, can get much of our electric from alternative energy. I'm not near 100% yet, but my solar pretty much sucks -- when I finally get around to doubling it, I may be there.


The problem is, when you step away from fuels, is the high energy stuff. The usual debate is propulsion -- there are not enough photons from the sun to create enough power to meet most cruisers needs (yes, niche people with a mission do it all the time). But an equal issue, and perhaps Jimmy's downfall, is heat. Boat heat, water heat, cook heat -- all are insane energy hogs. My inverter was wired at the factory so that the water heater can't even run on the inverter! It draws a KW, which will wipe my 800Ah battery slick (defined as 50%, of course) in 4 hours. Yes, it won't run 4 hours straight, but the point is, it draws a LOT of power. The microwave does run on the inverter, but it's 1KW+. An induction burner may be more efficient than a resistive burner, but it still draws 1000 times what an LED cabin bulb draws.


Propane for the galley, all by itself, might have changed the equation.


SH:
You are overstating the problem.
Yes, your inverter would drain your bank in 4hr running continuously. But there’s nothing that you should be running that draws that much power continuously. When you start your engine the starter draws 400ish amps but you don’t run it continuously for an hour, it runs for seconds and the total draw is probably under 1Ahr.


What are the big energy users on a very comfortably outfitted yacht:
Propulsion
Interior heating
Stove top cooking
Oven cooking
Domestic hot water
Refrigeration
More or less in order of greatest to least demand.

Let’s clarify demand, by that I mean total energy (amp-hr) not the instantaneous load (amps).

Let’s ignore propulsion as that’s a whole special world all it’s own and interior heating because that’s highly variable depending on cruising locale and season.

Most people have got refrigeration worked out as a normal part of house loads so we’ll ignore that too.

So cooking and water heating.


To deal with these you need to consider:
Instantaneous load
Total draw
Power storage
Power production
Total bank size


Cooking has high instantaneous loads, and if you use on demand water heating that does too. A 2 burner 120v induction stovetop will use up to 1800W. Likewise a convection oven will draw up to 1800W. In Europe voltage and peak wattage will be higher.
Chronomite on demand water heaters drawing 1800 or 2400W will raise the water temp 35F and 47F respectively at just over 1/3gal/min flow rate.

You’ll need a bigger inverter, 4,000W if you want to run stove and oven at full at the same time. Even then you’ll need to be careful not to run hot water at the same time. And it should be a true sine wave inverter so a bit more expensive but not terribly so.


Total draw for cooking:
I’ve done testing on the relative efficiency of butane vs induction stovetop cooking. Butane was about 50%, induction about 75%. Directly the only thing this is relevant to is determining that gas puts twice the heat into the boat while cooking, which is a consideration if cruising in the tropics. Indirectly it allows me to estimate how much electrical energy use to expect cooking without having to spend the money to set up the galley and test it.
In another thread I asked people how long a tank generally lasted them, how big the tanks were, how many people on board and did the feel they cooked a lot. Based on this I figured out that for a couple that cooks a lot and eats out rarely total cooking electrical demand would be about 150Ahr/day with no effort towards conservation.
The weakness of this estimate is the ratio of baking in an oven vs cooking on a stovetop was not estimated and I have not determined the relative efficiency of a propane oven vs an electrical convection oven. Given that a propane oven needs significant ventilation thru the oven for combustion air and and electrical oven can be a lot tighter I assume the convection oven will have at least as good of an efficiency advantage as induction. I am still gathering the equipment to actually test the relative efficiencies but it will probably be a year before the testing is done.
When I did the analysis I create a spreadsheet to estimate average daily cooking draw if you converted based on how much propane you are using now. I’ll post that later after I get done with work today.

Conservation measures that could reduce the demand would be heating up pots with food then turning off the power and covering with a pot cozy. Wonder-Bag. Things in that vein. If you are willing and have the space you could carry a tubular solar oven could deal with some of the baking.

I tested a bread maker baking a 2lb loaf: 330W-hr or about 27Ahr at 12.5v. Whenever I get the convection oven I want, I’ll test how much power is required to bake the same sized loaf. Stay tuned.

Hot water:
In another thread I figured out that using an electric on demand water heater you could take a 4 or 5 gal shower at 1/2gal/min at 105-110F with a water intake of 75-80F which would require 10-15Ahr. I don’t have the exact numbers at hand I’ll link to that post when I can find it. if you want longer showers it’s more demand. If you want more water flow I think you max out at about 3/4gal/min using 120v. You can get more flow if the feed water starts warmer. You can also decrease electrical demand if the fees water is warmer. That can be achieved by preheating the water with solar or by having a tank that heats from the load dump from a wind turbine or when there is more solar than the batteries can absorb.

Let’s say 10Ahr/d showering every other day for a couple.

So cooking and showering is 160Ahr/d with no significant conservation measures.


To support that you will need an additional 320Ahr of battery capacity. I use Trojan T-1275 batteries so that would be 2 extra batteries. I couldn’t find room for 2 extra batteries on my 20’ boat, but then again I’m not cooking much on a boat that small either. On the Cal 34 or 36 that I aspire to, 2 more batteries should be doable.


160Ahr/d demand means you will need an additional 480W (call it (500W) of solar panels, or another wind turbine of some size. 500W of panels is a significant chunk of real estate on a moderate sized boat. This is where an electrical galley becomes difficult.

On a Cal 34 I’ve figured out that I can permanently mount about 800W or so by mounting panels on a stern arch, both sides of a Bimini and both sides of the dodger. I could hang more off the quarters of the boat or slide outs from the arch or Bimini but I would be hesitant to go that far. 800W is going to net me about 267Ahr/d.

If I’m using 160Ahr to cook and shower that leaves 107Ahr for all other house loads. I suspect that would be tough on a lot of cruising boats.

That means if you cook a lot and want to go electric you may need to add solar panels in less convenient places, use conservation measures when cooking and find some conservation measures for the normal house loads.

When a I asked people about their propane use I didn’t think to ask if they were heating water on the stove for bathing purposes so there may be a small but significant overestimate of demand.

If you are willing to use conservation measures and maximize installed solar panels then going to a solar galley should be reasonably feasible.


All of the above is based on a 12v DC & 120v AC systems using lead batteries (FLA, Gel, AGM, CF).
Using a different voltage system or Lithium will change the above some but mostly in details.

With LA batteries the particular chemistry chemistry you use will affect how big a bank you need at a minimum. My understanding is that Gels do not like putting out high amps, so a bigger bank is better. High amps being relative to bank size so the load any single battery is limited.

If the stove and oven are both operating near full so let’s call it 3100W which is 250A.

With a Gel bank let’s say we want to limit draw to 0.25 of total capacity (C) so 0.25C. For a 250a load that means you want about 250 / 0.25 = 1000Ahr bank.

For FLAs I would be happy at 0.33C which would mean a 760Ahr bank.

For AGM & CF 0.4C so 625Ahr bank.

How big a bank you install will depend on the size of you normal daily draw, how much reserve you want and how much room you can devote as well at the need to size for highest instantaneous load as just discussed.

Additionally there’s Peukert, specifically the effect where the faster you draw power from a Lead battery the less you get out of it. So a bigger bank helps mitigate that effect.


It seems to me that the biggest hurdle to an electric galley is generating the energy. If you have a bigger boat (40’+) then you probably have enough real estate to go all solar. If not then a wind turbine and/or some hydro generation may do the trick but that will depend on normal wind patterns wherever you are and your normal sailing speed.

If you have an existing propane range that works then there are no monetary reasons to change the system, though you may want to do so for functional reasons (difficulty sourcing propane in remote locations) or reasons of personal value (desire to decrease fossil fuel usage.).

That said you can take steps towards an eventual transition:
A. Add the on demand hot water heater and start enjoying hot showers. Unless you electrical system is already marginal the extra 10-20Ahr/d probably won’t result in a need to upgrade the existing battery bank or solar panels. You will need a 2000-2500W inverter for this but I would go straight to a 4,000w model so future expansion doesn’t require a new inverter at the same time.
B. If you regularly bake bread get a bread maker. This will decrease propane use at moderate increase in electrical demand. How moderate depends on how often you normally bake.
C. Get a small induction hob and induction pan. $70 or so and it can be used in hot weather when you want to limit heating up the boat more while cooking or when you need one more burner.
D. Get a Wonder-bag and use it while cooking. It’ll save on propane use.
E. Next time your battery bank needs replacing rearrange everything to maximize the number of batteries and the biggest capacity you can install. Even if it’s years until you convert, the larger bank will last longer than a smaller one since you won’t be cycling it as deeply.
F. When you install more panels, aim for the largest you can fit. Size the support framing for the biggest panels that will fit a space. Install big panels rather than moderate sized ones that meet your current needs. So maybe 2 big panels on the Bimini rather than 2 moderate sized one on the Bimini and another on the arch. Extra solar means decreased need to run the engine or generator when normal production is impeded by weather or during off season trips in higher latitudes.


Finally an inductive burner doesn’t consume 1000 times the power of a LED cabin light. My hob uses 900W on high and a good LED cabin light uses 1.5W so that’s like 600 times. It seems like you don’t know what they each draw or you’re overstating the disparity to bolster your argument.

And the burner only runs for minutes at time vs the light which will burn for hours so the disparity is even smaller.
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