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Old 28-07-2020, 02:39   #76
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Re: New Generator or Lithium?

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Originally Posted by Fortytwo View Post
How does your power consumption double under way I should have said...
Autopilot, radar, chart plotter.
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Old 28-07-2020, 02:45   #77
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Re: New Generator or Lithium?

So what is the power usage for each?
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Old 28-07-2020, 03:01   #78
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Re: New Generator or Lithium?

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So what is the power usage for each?
I built my own Excel model and did some research on energy consumption of the various components. Unfortunately CF does not permit XLS attachments, so I can only attach a screenshot - you can see the usage in Watts/Amps in one of the columns. The top and bottom are identical except I toggle % Duty Cycle (example: A/P only runs when underway). I have 800W of solar which should generate around 300AH/day on average (higher in summer, lower in winter). My energy demand is around 250AH (a fridge and a freezer). I carry 700AH of LFP battery storage. With rare exceptions, I can sit off-grid indefinitely even without a generator which I have for A/C.

A bit dated as it's pre-LED, this link to the 2012 Pacific Cup Energy Mgmt page has a very good discussion on this, including a very robust spreadsheet attachment at the bottom. Intended audience is precisely my original observation: I suspect many sailors simply do not account for the energy usage underway.

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Old 28-07-2020, 03:24   #79
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Re: New Generator or Lithium?

I agree with Weebles' above post. Most of us do not calculate the electrons we use. At best we estimate, hmmm, I am one of these lately. Even tough I made also a extended spreadsheet, first iteration about 25 years ago, done in Lotus, then in Quattro and now in Excel.
My underway usage does not as dramatically differ from being at anchor as your usage does.... at least that is my estimation
I further differentiate (in my spreadsheet) between night and daytime. During nighttime I use more, both at anchor and underway: ie running lights, cabin lights, also radar is switched on more at night.
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Old 28-07-2020, 03:42   #80
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Re: New Generator or Lithium?

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I agree with Weebles' above post. Most of us do not calculate the electrons we use. At best we estimate, hmmm, I am one of these lately. Even tough I made also a extended spreadsheet, first iteration about 25 years ago, done in Lotus, then in Quattro and now in Excel.
My underway usage does not as dramatically differ from being at anchor as your usage does.... at least that is my estimation
I further differentiate (in my spreadsheet) between night and daytime. During nighttime I use more, both at anchor and underway: ie running lights, cabin lights, also radar is switched on more at night.
My underway vs at-anchor usage is dramatically different for two reasons: First, I have an engine with alternator running so can afford the energy. Second, my Willard 36 trawler has a flybridge and lower helm, both with MFDs and VHF running. My guess is not a single line-item is correct, but in aggregate, the overall usage is roughly-right due to compensating errors.

I do not have an estimate for sailing instruments but would guess in aggregate, similar to one MFD. No matter how you slice it, energy consumption underway is going to be higher than at-anchor, perhaps considerably so (A/P alone). A non-issue for a powerboat with engine running underway. But I am curious how sailors manage - the Pac Cup article I linked is one of the few realistic discussions I've come across.

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Old 28-07-2020, 03:47   #81
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Re: New Generator or Lithium?

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How does your power consumption double under way I should have said...
Every boat is different, but I think it is more correct to think of the minimum power required as rising significantly while sailing.

The minimum power consumed while still keeping comfortable and the boat functioning normally is a very important figure if you are planning to manage well without a generator. One of the difficulties faced by the OP is that generator equipped boats often have a high minimum power requirement due to the inherent system design and equipment choices. Fixing this issue is not always simple or inexpensive and with only a small solar array this may cause problems.

The other factor is when sailing many boats have decreased solar production as the panels are more frequently in shade.
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Old 28-07-2020, 04:00   #82
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Re: New Generator or Lithium?

I don't think this is very complicated. You can take one of two approaches. You can start by saying "Here's all the energy I might possibly want/need" and design a system accordingly. The venerable Honda will figure prominently into solutions that start from that premise. And yes, going from this view can get expensive and complicated.

Or you can say "Here's how much energy I can reasonably generate." And then back-in to that to figure out whether that's an acceptable lifestyle. For the OP, 125AH is a pretty decent amount of energy with a ton of cruisers out there happily having a cold beer each evening. Provisioning this route is fairly economical and simple - pair of solar panels, MPPT, and opportunistically upgrading batteries when they die.

If AC is a need/want, then you have no choice but go with Option 1. If not, and you're willing to be careful with energy usage (which again comes naturally to most sailors), then Option 2 becomes realistic.

I really don't think this is that difficult, and I don't think there are as many "It depends...." as many folks say. Doing an energy budget is easier than provisioning a boat. And only has to be done once.

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Old 28-07-2020, 04:30   #83
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Re: New Generator or Lithium?

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Or you can say "Here's how much energy I can reasonably generate." And then back-in to that to figure out whether that's an acceptable lifestyle. For the OP, 125AH is a pretty decent amount of energy with a ton of cruisers out there happily having a cold beer each evening. Provisioning this route is fairly economical and simple - pair of solar panels, MPPT, and opportunistically upgrading batteries when they die.
Absolutely. The solar option is fantastic. Solar panels are quiet, reliable and fuss free. Personally, I hate generators.

Our previous yacht that we cruised on full time for over 10 years had 360w of solar and this generated 95%+ of our power. Our first yacht only had a 75w solar panel and no other power generation equipment and while not cruising full time in this vessel, many trips were over a month long. Small solar systems can work well.

However, the equipment and expectations need to meet the available power. Talk of electric cooking and hot water heating and a boat designed originally for generator power with 300w of solar suggests the expectations will not match the reality. I hope I am wrong. We do not have many details or a power audit. On the plus side, the solar insolation in Australia and the South Pacific (the OP’s location) is reasonably good, which will help significantly. While we do not know the intentended cruising ground hopefully Scotland in winter is not on the agenda .

More details are needed for a definitive answer, but hopefully the discussion and various opinions have helped the OP and others considering a similar system.
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Old 30-07-2020, 09:25   #84
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Re: New Generator or Lithium?

UPDATE - I also monitor TrawlerForum, sister site to this CF site. A person on a 34-foot trawler posted his install of 2x110w panels, essentially the same as the OP is considering. See attached screenshot - 1.3kwh/day (PNW - long days right now), which equates to around 100AH/day. Still won't get OP hot water from his electric water heater, but that's a fair amount of energy without the hassle of a generator - Honda or otherwise. Should easily cover rest of energy consumers.

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Old 30-07-2020, 16:21   #85
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Re: New Generator or Lithium?

This has turned into a fascinating thread surpassing my expectations so a big thanks to everyone. Just to clarify a few things:

- I can heat my small hot water tank directly from the main engine. I just don't like the idea of having to start the main engine solely to do so which is why occasionally using an inverter to get it luke warm enough for a shower sounds appealing.
- I don't think I'll need AC. I plan to cruise Queensland and the south-west Pacific in the winter when it's warm but not hot. South-east Australia during the summer can be hot but generally humidity is low. However, if I decide to head up to South-East Asia that will be a different story.
- I just became a grandfather and want to retire early so, YES, I'm on a budget!
- My biggest power needs will be while sailing overnight with instruments and auto-pilot.

I'm thinking of getting a fold-up solar blanket which I would set up at anchor. It wouldn't be permanently installed so I could hang it off the boom or in front of the mast depending on where the sun is best. They seem very inexpensive (200 watt for $250 AUD), compact and light so I'm surprised not see more of them on boats. These guys have a nice setup:

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Old 30-07-2020, 16:43   #86
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Re: New Generator or Lithium?

You can't beat cheap rigid solar panels. Cheap per Watt, super reliable and zero maintenance.

Those flexi, walk on, fold up panels either don't last or rarely perform as advertised. There are gazillions of posts and youtube vids that highlight the problems with these options.

We lived on and off grid on the US West Coast for seven years. We started with old wind, solar, generator and flooded lead acid. Ended up with 1kW of solar, carbon foam house bank and Victron MPPT controllers. Generator was hardly used except in the PNW. Wind was useless, towed generator was useless. Solar accounted for 96% of our power generation needs except in PNW.

I logged all data for seven years. We recently sold our beloved Liberty 458 in San Diego during first wave of COVID. You find all our ships logs and images of our install at www.sailingtheplanet.com

We avoided Lithium because we had a lot of good Balmar old school regulators, large alternators and inverters

For a new build I would put as much solar as possible and Lithium batts. No genny, no wind, no towed generation and just cheap automotive alternators. I would use one of the new alternator regulators that can avoid going to float too early. All those old school multi stage regulators are all focussed on FLA not lithium.

Lithium batts have very low internal resistance so can accept massive charge and discharge rates. We also heated hot water off our batts. Interestingly we found our MPPT controllers would often go to float too early. Heating hot water midday was needed to ensure we fully recovered our previous days consumption. This was due to the limitation of lead based batteries to accept high charge rates. Our 1kW solar bank would generate over 80A in full sun.

We probably wont buy another boat for at least two years. It will have lots of solar, lithium batts and no genny, wind, towed solar or complex engine or gennie charging.

Solutions like Nigel Calder's 9kW engine charging and high rate alternators and complex power controllers are overkill unless you want to run AC of batts or have little sun and clear skies. We'll only be cruising in sunny ares from now on
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Old 30-07-2020, 17:00   #87
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Re: New Generator or Lithium?

leftbrain,

My Victron solar charge controllers sense the battery voltage when the sun comes up and sets the absorption time based on that reading. The lower the voltage the longer the absorption time. Lithium is always going to have a higher voltage than LA so the absorption time would be set to the minimum. I don't know how your charge controllers work but that might be the issue. I'm going to update the charge controller as I've been told the new firmware and software will make it fully adjustable.
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Old 30-07-2020, 17:05   #88
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Re: New Generator or Lithium?

Quote:
Originally Posted by Budawang View Post
This has turned into a fascinating thread surpassing my expectations so a big thanks to everyone. Just to clarify a few things:

- I can heat my small hot water tank directly from the main engine. I just don't like the idea of having to start the main engine solely to do so which is why occasionally using an inverter to get it luke warm enough for a shower sounds appealing.
- I don't think I'll need AC. I plan to cruise Queensland and the south-west Pacific in the winter when it's warm but not hot. South-east Australia during the summer can be hot but generally humidity is low. However, if I decide to head up to South-East Asia that will be a different story.
- I just became a grandfather and want to retire early so, YES, I'm on a budget!
- My biggest power needs will be while sailing overnight with instruments and auto-pilot.

I'm thinking of getting a fold-up solar blanket which I would set up at anchor. It wouldn't be permanently installed so I could hang it off the boom or in front of the mast depending on where the sun is best. They seem very inexpensive (200 watt for $250 AUD), compact and light so I'm surprised not see more of them on boats. .....
I did an analysis of what it would take to heat water for a shower from FLA batteries. https://www.cruisersforum.com/forums...ml#post2856119

Total energy used for a shower is pretty reasonable. The key thing is that it is a heavy demand item, that is, when it is running it needs a lot of current, since it runs for a relatively short time total energy is modest. In order to handle the high loads you will want a fairly large FLA battery bank, 600-800Ahr, so that Peukert doesn't take such a big bite.

You are on a Westerly 43. You should be able to put that much aboard. I have a 20' boat and I have 300Ahr at the 20hr rate.

If you want to go electric cooking a large bank will serve that well too. For cooking total energy will probably be higher so you will need more solar to stay charged.

If you want to save on autopilot energy, get a windvane, no electric draw and generally more reliable than autopilots which is a long term cost savings. A used Aries would probably do the trick, but there are plenty of other used vanes out there too.
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Old 30-07-2020, 17:06   #89
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Re: New Generator or Lithium?

As a workaround you can set the float voltage to the same as absorption voltage or slightly less. That is if your controllers offer that functionality. I looked at Victrons site and there was a lot of new stuff there since I visited the site years ago.
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Old 31-07-2020, 07:26   #90
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Re: New Generator or Lithium?

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I have a choice to make. Our 18 year old Farymann 18 W single cylinder 4 kva diesel generator has a compression problem and I can't find parts to fix it. Instead of buying an expensive new generator I'm considering biting the bullet and upgrading our batteries to 400 amp hour LiPo4s with a 2,000 watt inverter. For charging we will have a Rutland wind generator, 300 watts solar and a 100 amp alternator with its own regulator. Our existing lead acid batteries (330 amp hour house bank) are nearing the end of their life but we probably would have replaced them with AGMs if the generator was still working.

Our AC usage has included powering a microwave, electric kettle, small hot water tank, small space heater and laptops. We are part time cruisers and like living on the hook.

I understand it wouldn't be sensible to run a space heater off a lithium bank, but does the above set-up sound like a rational alternative to buying a new generator?



If the resale value of your boat is an issue, here is my story. I replaced the generator on my 41 foot trawler with 10 golf cart batteries, high output alternators, and a 2,000 watt inverter. A couple years later when I went to sell the boat, I had to add a generator. No one wanted to buy my trawler without a generator. So, in effect, the whole deal cost me double what it would have cost to simply replace the generator in the first place.


May or may not apply to your situation!
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