New Lithium setup for off grid cruising - and air conditioning

[noelex 77]

Overall, your plans are a little ambitious in my opinion. Even a small amount of air conditioning combined with all electric cooking and the other house loads is a tough ask via alternative energy on a 40 foot monohull.

In the right climate it is not impossible, but your cruising area/season will be constrained. A more relaxed and stress free solution would be to scale back your energy consumption.

At least have some back ups such as windscoops/fans in place or air conditioning, and propane/butane options to substitute for electric cooking when cruising areas of reduced solar insolation.

Originally Posted by Networker

Perhaps I do but the other 2 300AH batteries and go with 1800AH off the bat.

It is energy production rather than energy storage that is the limitation in your planned system. Increasing battery storage will be of limited benifit.

Originally Posted by Networker

And see how far I can get with a larger alternator or look at wind and hydro, or all 3. That would get me where I need to be it seems.

A larger alternator would be the first step and something I would recommend even if I feel it would not totally solve your energy balance in all situations.

Wind can be productive, but with such a large amount of solar for the boat size, it is hard to situate this where the resultant shading will not impact the solar output.
Hydro can be great on the right boat, but there are reliability problems that do not seem to have been solved, and it works better on fast boats.

[Networker]

Originally Posted by mvweebles

Because of your hi-current loads, I do not recall a more ambitious solar project on a boat. Usually, people either couple solar with a dose of conservation; or the punt the hi-current items to a generator due to the energy density of diesel fuel which is on board.

I sincerely wish you the best success. Please report back on how it goes - we could all learn a lot from you.

Peter

Will do for sure, both to share what works and doesn’t. Once I have it running I can share the actual details. I called Integrel as they have a massive alternator that can put in 8-9kW of power, but they don’t make a frame for my engine. I could either have one machined or see if an electric motor could spin it and provide the RPM’s.

[Simi 60]

Originally Posted by Hermia II

I've installed a 800Ah/24v bank of Victron LiFePo4 batteries. .

Jeebus, that's a fair bit
Here was me thinking we had big batteries with that much in AGM
Contemplating LFP replacement of 480ah if I can get a viable deal.

[T1 Terry]

Originally Posted by Networker

Dometic ECD 6k BTU (I have the 16k version of this now). https://www.dometic.com/en-us/outdoo...5?v=9108732762

It says it's only 4.6A consumption, so I assume it's a 4.6AH draw? Seems a bit low, I have to be calculating it wrong.

4.6 amps run current, but at what voltage?

To determine the battery load, multiply the current draws x the voltage to give you watts. Multiple this by the number of hrs you expect to run the appliance, this will give you watt hrs. Add them all together to give a total 24 hrs Whr consumption, multiply that by 10% to allow for inverter losses, then divide by the battery voltage.

As an example, a 2400w heating element would draw 10 amps @ 240vac, 20 amps @ 120vac and 220 amps if you include the 10% inverter losses @ 12v.
Run that heating element for 1/2 hr would be 1320Whr used out of the battery, @ 12v the load would be still 220 amps but it would only use 110Ah of capacity out of a quality lithium battery.

If you want to run air conditioning, you will need an inverter type unit because it has a soft start and the current load varies depending on just how much work it needs to do at any given time. But be aware, when it is running at full load while trying to pull the temperature down, it will draw the maximum current, just the same as a non inverter type unit. The gain is removing the harsh start up current requirements because it doesn't actually turn off, it just slows the motor speed to the point it can maintain the set temperature .....

We fit up quite a few 40ft motorhomes for full off grid all electric operation, but they have a big roof area with no shade issues and they also have a DC to DC charger that assists when the motor is running if needed. In winter down south (this side of the globe) the peak sun hrs are only around 2.5 at best, so the maximum output from the solar x 2.5 hrs ..... so they don't use reverse cycle air conditioning for heating but rather diesel heaters and switch to propane for water heating. In summer or up nth closer to the tropic of Capricorn, no problems, so the season and position on the globe will make a huge difference to how much solar you can harvest.

Hope that helped and didn't totally confuse the issues

T1 Terry

[T1 Terry]

Just to give you an idea of the amount of shade free solar required by these big motorhomes, they have between 2,000w and 3,000w of solar on the roof and they still have to be thrifty with energy use during winter .....

T1 Terry

[Networker]

Originally Posted by T1 Terry

4.6 amps run current, but at what voltage?

To determine the battery load, multiply the current draws x the voltage to give you watts. Multiple this by the number of hrs you expect to run the appliance, this will give you watt hrs. Add them all together to give a total 24 hrs Whr consumption, multiply that by 10% to allow for inverter losses, then divide by the battery voltage.

As an example, a 2400w heating element would draw 10 amps @ 240vac, 20 amps @ 120vac and 220 amps if you include the 10% inverter losses @ 12v.
Run that heating element for 1/2 hr would be 1320Whr used out of the battery, @ 12v the load would be still 220 amps but it would only use 110Ah of capacity out of a quality lithium battery.

If you want to run air conditioning, you will need an inverter type unit because it has a soft start and the current load varies depending on just how much work it needs to do at any given time. But be aware, when it is running at full load while trying to pull the temperature down, it will draw the maximum current, just the same as a non inverter type unit. The gain is removing the harsh start up current requirements because it doesn't actually turn off, it just slows the motor speed to the point it can maintain the set temperature .....

We fit up quite a few 40ft motorhomes for full off grid all electric operation, but they have a big roof area with no shade issues and they also have a DC to DC charger that assists when the motor is running if needed. In winter down south (this side of the globe) the peak sun hrs are only around 2.5 at best, so the maximum output from the solar x 2.5 hrs ..... so they don't use reverse cycle air conditioning for heating but rather diesel heaters and switch to propane for water heating. In summer or up nth closer to the tropic of Capricorn, no problems, so the season and position on the globe will make a huge difference to how much solar you can harvest.

Hope that helped and didn't totally confuse the issues

T1 Terry

Very helpful.

[Networker]

Originally Posted by Adelie

America’s Test Kitchen did a video test counter top ovens. The Breville won by a huge margin on a bunch of cooking factors. I have the model number in my Amazon wish list if you want it. Big enough for a chicken, that’s big enough for me.

It’s surprisingly large and versatile, can even air fry in it.

[Adelie]

My understanding is that “air frying” is just the original marketing term for convection ovens that have the “pot” form factor.

[wingssail]

Originally Posted by Networker

Hi all, recently got a new boat, a 2000 Beneteau 40 CC and one of the first things we’re doing is upgrading the electrical systems. We have plans of circumnavigating and living off the hook for a few years, and want as many of the creature comforts of home as possible.

One of the benefits of the boat is a massive engine compartment, so I’ve been monitoring the temperatures of it while running in July in Miami and it’s cool enough to keep LiFePO batteries in there. I will also build a shielded battery box in any event, but the space has room for about a dozen 300AH batteries should I go that far. The boat currently has 2 brand new 200AH AgM batteries for the house bank and 2 starter batteries. I am replacing the AGM’s with 4 300 AH Lithium batteries. After a lot of research, and looking at DIY approach vs full blown Battleborn system, decided to go somewhere in the middle and get good quality, but cheap batteries off Amazon. I ended up getting these: Ampere Time 12V 300AH https://www.amazon.com/dp/B08K7HZ6KZ...FAFH707BWT5QDG

What gave me confidence was a review on Will Prosse’s YouTube channel, and after a tear down, he confirmed these are excellent batteries with good build quality, they just don’t have low temp cutoff protection. https://youtu.be/FQUhjDkQY5Q

Which is ok, as he then recommended a simple workaround: https://youtu.be/XpO4s6Lrrmc

Costs plus shipping was $1300 each +$200 shipping, or $1500 total. So $6000 for 1200 AH. Not the best price compared to DIY, but cheaper than Dakota or BattleBorn. It’s so cheap I might get two more, but will wait and see how this works first.

To power the lead starter batteries, I am keeping the 60AH stock alternator on my Volvo Penta MD22L connected to the lead starter batteries for now. To bridge the 2 battery banks, I got a Victron 12v DC to DC battery charger. This will allow current from the lead bank to flow to the Lithium without harming the alternator. I will upgrade the alternator in the fall, at least 160-180AH, and connect it directly to the Lithium bank via a good external regulator. I’m looking at a Mark Grasser DC alternator given how it handles temperature, as well as a serpentine belt upgrade. External regulator is TBD, looking for suggestions.

The lithium bank is being powered by 4 SunPower 170W flex solar panels and 2 370W hard panels, for 1420W of power. At 5 hours of charge time on a good day in the tropics, I should see it put about 350-450AH back into the system. I’d love more panels, but am real estate constrained. The flex panels will go on the bimini while the 2 hard panels will go on the existing solar arch. Each panel has a dedicated Victron MPPT to compensate should one panel be shaded without pulling the rest down.

I connect it all to a Victron MultiPlus 3000W charger/inverter. Shore power is selectable via 110 or 220 via a Victron Centaur charger/selector.

To monitor everything, I got a Victron Cerbo GX and touch panel, a 500AH Victron SmartShunt and a Victron Smart Battery Monitor.

Major loads on my system. I’m pulling out the propane stove and going with a Force10 electric, which should draw 60-100AH depending on how long I cook. I have a newer 16k BTU domestic AC unit for the whole boat that I will rip out and replace with a 6K BTU version just to cool just the owners cabin at night and run it off battery. Should draw about 60AH, running at night should be about 200-300ah (I’m hoping) if it’s half duty cycle. Let’s see. The rest is water heater and refrigeration, 110v electronics and all the regular 12v draws on the system. Daily draw should be about 300-600ah depending on AC, which isn’t quite enough for my solar alone.

I’m looking at a wind generator to help out, perhaps a hydro generator, and a larger alternator. Trying to stay away from a generator. Without AC, this is more than capable of powering the boat and factoring in a few sunny days, with AC I need to watch and see how it works. Will update this thread with photos as we start the installs over next few weeks, and update with consumption reports as the summer goes by. Getting this boat ready to cruise Bahamas all winter, so this summer and fall is to shake out all the electrical kinks.

Don't know how far down this road you've already traveled but I see some major difficulties, both in the installation/operation and maintenance of this system.

But anyhow I am going to recommend you don't do it.

In the first place just installing all of this is a major project. You have a variety of technical stuff to fit and connect and in some cases I am not sure you won't have some headaches getting it all to work together.

In the best case it might just work but only if everything is optimal. How will you know how everything is functioning? I wonder how much monitoring granularity you will get from the Victron equipment. The whole boat may become a big black box.

Where I really would be concerned is the batteries. In order to make 300AH they have put 12 3.4v cells connected in a combination of series and parallel, and for this they have one BMS board. So if any cell goes out of spec the whole battery shuts down? What then? And what information is passed to the monitoring system to tell you what the problem is?

And how to you go about fixing something when one of these technical marvels goes bad in the Bahamas (and assuredly, something will, it's a boat).

You know, if you want all the comforts of home, stay home. Or you can fly to the Bahamas and stay in Airbnb, WITH all the comforts of home, for less money and certainly less headache.

[Networker]

Originally Posted by wingssail

Don't know how far down this road you've already traveled but I see some major difficulties, both in the installation/operation and maintenance of this system.

But anyhow I am going to recommend you don't do it.

In the first place just installing all of this is a major project. You have a variety of technical stuff to fit and connect and in some cases I am not sure you won't have some headaches getting it all to work together.

In the best case it might just work but only if everything is optimal. How will you know how everything is functioning? I wonder how much monitoring granularity you will get from the Victron equipment. The whole boat may become a big black box.

Where I really would be concerned is the batteries. In order to make 300AH they have put 12 3.4v cells connected in a combination of series and parallel, and for this they have one BMS board. So if any cell goes out of spec the whole battery shuts down? What then? And what information is passed to the monitoring system to tell you what the problem is?

And how to you go about fixing something when one of these technical marvels goes bad in the Bahamas (and assuredly, something will, it's a boat).

You know, if you want all the comforts of home, stay home. Or you can fly to the Bahamas and stay in Airbnb, WITH all the comforts of home, for less money and certainly less headache.

*if* a battery goes bad, they’re under warranty by the manufacturer and I also bought more extended warranties from Amazon. Worse case if a battery goes bad I get a new one. This isn’t an unheard of setup, many have done it before on boats and RV’s and are working fine, including a few in other threads. This is just the first half of the upgrade, and not too complex.

I’ll have a whole other thread on upgrading all the electronics. Everything is original to the boat, from instruments to auto pilot. Some of it works, others don’t. I’m upgrading every single one, just got new Raymarine Axiom chart plotter, instruments, new radar, Vesper Cortex AIS/VHF (which will also be my alarm and monitoring system), new Raymarine autopilot with remote control, even got an Apple car play stereo system, will add Apple TV or fire sticks to each TV as well. All lights are going LED, looking at Philips Hue, and the wireless and internet network will be upgraded. I’m now exploring how to add Amazon Alexa to the systems like I have at home to operate my boat (I.e turn on lights, turn on AC at a certain time, or tell it to make water at noon, etc).

[fxykty]

Originally Posted by Networker

Great suggestions. I haven’t made the purchase yet and have also looked at a induction stove top that I can add fiddles and gimballs to. And a breville smart convection oven.

We’re on a cat so a bit different motion but we just use a silicone baking sheet to keep pots from moving on the induction stove top surface. No pot holders or fiddle rails needed.

I would suggest that you reuse your existing gimbal system, or build a replacement one, then mount the induction stovetop (whether built in or portable) on top of that. Then the heeling is taken care of and the silicone baking sheet takes care of pot movement. KISS

For an idea of current draws we have a 2 burner induction hob rated for 3.5KW. We’ve seen a maximum of 3KW through our inverter, though it is intermittent after the initial preheat - 3KW then 100W then 1.5KW then 80W then 2.2KW then 120W, etc. The induction hob is incredibly fast and efficient at cooking stuff. Another tip is to use good quality induction-specific pots, not just ones that can be used with induction. Less buzzing and crackling and more efficient heat generation.

We also have the Breville Smart Oven Pro. That is rated at 2-2.4KW and we’ve seen over 2.2KW through the inverter while it preheats. Once at temperature it cycles as well, but generally higher averages around 1-1.5KW. It fits nicely in the cavity left by the removal of the propane oven we had previously, with enough space that we use it in there. Because of its relatively small size and powerful fan it is very effective, especially grilling.

Cooking and using an electric kettle a few times a day for two people is between 70-120Ah @12V, and up to double that if baking.

We have a 5KW inverter and we’ve overloaded it a few times if we run too many things at a time. Don’t forget all the other AC and DC loads - they all affect how much power you can draw. At least with LFP the batteries can handle the current draws and almost no voltage drop is nice.

[Pete7]

Originally Posted by Networker

To power the lead starter batteries, I am keeping the 60AH stock alternator on my Volvo Penta MD22L connected to the lead starter batteries for now. To bridge the 2 battery banks, I got a Victron 12v DC to DC battery charger. This will allow current from the lead bank to flow to the Lithium without harming the alternator.

Just keep an eye on the temperature of that DC>DC charger. This is my Victron temperature after an hour. Its mounted on the outside of the vertical nav seat with a 4" hole behind it to help air flow and cooling and it still gets too hot to touch. Power comes from a 60Ah Valeo alternator similar to yours. A computer fan install behind it is next.

Pete

[Networker]

Originally Posted by Pete7

Just keep an eye on the temperature of that DC>DC charger. This is my Victron temperature after an hour. Its mounted on the outside of the vertical nav seat with a 4" hole behind it to help air flow and cooling and it still gets too hot to touch. Power comes from a 60Ah Valeo alternator similar to yours. A computer fan install behind it is next.

Pete

Yikes.

I just got a few Be Quiet 120mm computer fans as most of the Victron equipment seems to run really hot.

Steve

[Pete7]

Originally Posted by Networker

Yikes.
Steve

Oh and it was raining outside so the cabin certainly wasn't anything like the temperatures you have to deal with during the summer, perhaps 15c tops at the time.

Pete

[mjgill1]

Originally Posted by Networker

*if* a battery goes bad, they’re under warranty by the manufacturer and I also bought more extended warranties from Amazon. Worse case if a battery goes bad I get a new one. This isn’t an unheard of setup, many have done it before on boats and RV’s and are working fine, including a few in other threads. This is just the first half of the upgrade, and not too complex.

I’ll have a whole other thread on upgrading all the electronics. Everything is original to the boat, from instruments to auto pilot. Some of it works, others don’t. I’m upgrading every single one, just got new Raymarine Axiom chart plotter, instruments, new radar, Vesper Cortex AIS/VHF (which will also be my alarm and monitoring system), new Raymarine autopilot with remote control, even got an Apple car play stereo system, will add Apple TV or fire sticks to each TV as well. All lights are going LED, looking at Philips Hue, and the wireless and internet network will be upgraded. I’m now exploring how to add Amazon Alexa to the systems like I have at home to operate my boat (I.e turn on lights, turn on AC at a certain time, or tell it to make water at noon, etc).

Seems like an ambitious project. Good for you. If your daily Ah usage will be handled by what you propose, then you should be good. I recently upgraded our Alternator and external regulator to the ElectroMaax system. I quickly found out that high output alternators create a lot of heat. The best thing I have done since is to install a 4" fan to exhaust the heat to the outside through a cowl installed on the transom. The heat rated exhaust hose terminates just behind the alternator and I drilled holes to allow what amounts to bilge air to enter the engine compartment. I installed a switch for the fan next to the engine start in the cockpit. This has made all the difference in that our alternator never is down regulated due to excess heat anymore. Also, we leave the fan running for a bit after motoring and we don't have the excess heat we used to down below from the engine cooling down. It's a real win win! I haven't met a single person that is happy with a wind generator, but know of folks that are ok with hydro. As for your water maker, when you are not using it, you can pickle it and it will be good until you use them it. It's my understanding that LiFePO4 really like to run and can be run between 20% and 80-90% SOC so you don't have to worry about getting to 100% SOC like we with AGM's do. We have new electronics. You're going to really like those Axiom plotters. We sure do. Good luck!