Replace Generator or switch to 100% solar/wind?

[mvweebles]

I didn't catch the "possibly sell in Panama" part. Good catch. For many, AC is not an option in these climates.

Fix the generator. Do what you want with solar and lithium - you won't be sorry with any upgrades, But fix the NL generator you have unless it's been trashed somehow. Using a Honda or one of the lightweight diesel generators will not cut it in the tropics if AC is even mildly important to you.

Peter .

[cat-keys]

Thanks for all the feedback. I will follow the majority of the feedback leaning to replacing the power head. Its true that the Leopard 40 has the genny in a terrible location and there is no guarantee that the moisture in the forward lazarette won't cause the same issue again - but it did last for 11+ years. Expecting the engine to last to 10k hrs - well that would be 20 years down the road by current usage - probably the solar and battery tech will have evolved by then making diesel gennys as obsolete as coal fired steam engines


I will have to replace the house batteries in a year or two, so I am interested in the comparison of Relion vs Firefly - but that's another string...


Thanks very much to the CF for helping me to reach a realistic decision - and not go down the road of a "science project" as one member put is so well. KISS is always the best option I agree

[skipmac]

If you need air conditioning, and occasionally in the tropics you will, then it is theoretically possible without a generator but would only work with a very small unit and a lot more batteries.

Bottom line, fix the gennie and I agree with others that it shouldn't cost that much.

Also, with or without a gennie if you plan on cruising a lot, anchored and off the grid including autopilot and fridge I would add more house battery capacity. At least 600-650 amp hours to get a day or two on a passage with AP running to avoid having to run the gennie or engine to charge.

[OmarNM]

Hi Cat- Keys

I hope my answers helps you to take the best decision in your investment, based on my experience as engineer working not only at multinational generators company, but also at green energy systems and now in the marine hobbies, so I can give you my best advice on different options:

Below my point of view for each question:

Regarding your energy use about 285Ah per day on the hook and 325 underway with radar autopilot etc.

Let’s talk about an average range around 300Ah per day.
First, we are going to determine the energy consumption adding an air conditioner with an inverter and the better option choosing the new technology on 12volts DC air conditioners Low consumption amps on the market:

• For your current 2 x 16,000Btu Cruise air AC-powered system draws Arround 13 Amps each, But starting current says it is about 5 times normal running current for a typical motor. Applying that formula to this brand, gives results (5x13=65 Amps) in the same scenario. Now lets convert this situation to an 12V DC supply with an inverter + adding the energy losses associated with the inverter About 8%:
o We have running current around 13 amps @115volts ac
o We now will have same 13 Amps x 9.58 times aprox. (converting to AC to DC 13 Amp x 9.58 times = 125Amps aprox.) + 8% losses = 134.5 amps (using inverter) and adding the information on the starting amps situation will be double: around 270Amps.


Now, lets analyze another brand on the market:

Regarding the Brand you mention: using a new 24v zero breeze 2300BTU rechargeable unit in our master berth only.

• This seems to be a good brand, good quality, but not for your needs. It is more to refresh an space like a cooling fan than to recirculate and climatize a room. (low Capacity BTU).

Giving you my opinion and suggestions:

There is a brand recognized World wide on marine air conditioners, Mabru Power Systems. They have the most efficient air conditioner running directly from 12Volts DC with the lowest Amps draw.

For example: if you are going to replace your units 16K BTU you can easly choose the 12KBTU DC from Mabru Marine, and you will have the following energy consumption and almost same capacity and less noise and they have an offer that the pump comes included in the price for those new DC units:

The SC12DC from Mabru, Draw amps between 33 to 44 Amps, and you can run the unit direct from the battery. That means you will have around 44 Amps by Hour. So if you have for example just a battery bank of 500Amps, (500 ÷ 44 Ah = 11.3 hours for each Mabru air conditoner) you will have a running time around 11 hours at full speed, during the day with the Sunny day, and also during the night you can reach more running time depending of the external temperature (lower temp = more running time on this DC air conditioner). This unit is an Inverter operation, that runs gradually increasing or decreasing the compressor speed, so you will not have starting amp draw, that is amazing on this brand. The were working on their patent because by the moment are the only one in the world with this capacity with the lowest consumption working on 12V.

Regarding your most important question is that if you have to replace the Generator and associated operation costs by batteries and go green energy, definitely Yes.

The Contras of the Genset is that you will have:

• Noise and smoke.
• Fuel cost and reservoirs weight.
• Every 200 hours maintenance and oil changes (dirty work).
• 115 Volts to then convert to 12V for final usage.
• Other…

In summary….

Cruise air: 16K BTU @ directly working on 115Vols:

• Draw amps 65 starting and then 13Amps.
o @12Volts DC increases to: 134.5 Amps (with starting amps around 270 Amps)


Mabru Marine: 12K BTU @ 12Volts DC:

• @12 Volts DC Draw amps 33-44 Amps
• Starting Amps N/A (starting amps Not applicable)

Instead Spend $19,100 on the Generator + maintenance cost associated you mentioned ($15,600). Just for have fresh air confort for just only use 3 or 4 months a year and then only at night ☹. Not a good deal.

What U will be consuming is around 325Amps a day + your air DC air conditioner, you just have to make the most of your excellent and impressive renewable energy system.

You can reach Lithium batteries + The Mabru Air conditions SC12DC x 2 units with less that have cost than buy a new generator + inverter to move those big and low efficiency Cruise air conditioners.

250 amps Lithium batteries with 2 years warranty around $2300 each
SC12DC 12volts air conditioners around $5500 each. (1.5 amps -12volts low noise pump included)
And you will have almost all your system working directly 12Volts dc.

You can see a youtube videos regarding the difference between the two brands. Also the Mabru air conditioners capacity of condense the humidity of the air is better, which translates into dry air = comfort)

Mabru vs Cruise air Dometic on this youtube video:

https://www.youtube.com/watch?v=SrOQwVQG8jc

I hope my explanation on this scenario helps you to have better idea on what you need.

Regards

Omar Ghassan

[mvweebles]

Originally Posted by OmarNM

Mabru Marine: 12K BTU @ 12Volts DC:

• @12 Volts DC Draw amps 33-44 Amps
• Starting Amps N/A (starting amps Not applicable)

Instead Spend $19,100 on the Generator + maintenance cost associated you mentioned ($15,600). Just for have fresh air confort for just only use 3 or 4 months a year and then only at night ☹. Not a good deal.

Omar - why are these units so dang expensive ($5k)?

BTW - I think the target market for these is not so much solar folks who want to run via battery, but owners of small/mid-sized powerboats who want to run while underway and can afford 40-amps.

Peter

[OmarNM]

Originally Posted by mvweebles

Omar - why are these units so dang expensive ($5k)?

BTW - I think the target market for these is not so much solar folks who want to run via battery, but owners of small/mid-sized powerboats who want to run while underway and can afford 40-amps.

Peter

Hi Peter. I assume the reason for this price, maybe is because by the moment is the only technology that can reach this hi efficiencies @ 12V and should have investment expensive technology to solve the current needs. For every needs there is a solution. I have several friends with Mabru air conditioners, so as an engineer I like to be up to date studying the most resent technology.

I also found a lot of good reviews about this brand.

I found their main website you can reed more about the new DC airs

They have been in the marine business for about 30 years.

If there is another technical question I can help, I will be glad to help the community.

[Pete7]

Originally Posted by OmarNM

I have several friends with Mabru air conditioners, so as an engineer I like to be up to date studying the most resent technology.

In what size boats and can you post some pictures.

In your first posts you mentioned a battery bank of 500Amps, I presume you mean AH? so in the morning after 11 hours of use, how are you going to charge this up along with the other 325AH needed as you say for the rest of the boat?

Pete

[mvweebles]

Originally Posted by OmarNM

Hi Peter. I assume the reason for this price, maybe is because by the moment is the only technology that can reach this hi efficiencies @ 12V and should have investment expensive technology to solve the current needs.

Looks like there are others

https://www.dometic.com/en-us/us/pro...-dc-ii-_-21015 $3900 for 3500btu @ 30A

MES 12s - 12 Volt DC Marine Air Conditioner - 12 Volt DC Air Conditioners $4000 12k Btu @ 40A

[a64pilot]

Originally Posted by Pete7

In what size boats and can you post some pictures.

In your first posts you mentioned a battery bank of 500Amps, I presume you mean AH? so in the morning after 11 hours of use, how are you going to charge this up along with the other 325AH needed as you say for the rest of the boat?

Pete

Your going to have to have a generator. Unfortunately the energy costs of airconditioning exceed any realistic supply from Solar and or wind, that leaves a generator.

Massive battery banks, of any chemistry can of course run AC overnight, but then as you suggest they have to be recharged, and that means a generator run, of usually at least 6 hours.

All DC airconditioning gets you is the ability of running an usually to small of an airconditioner for some time off of a usually massive, meaning real expensive and often heavy battery banks for some hours before they have to be recharged by a generator. You can do that with an inverter, because what makes those DC airconditioners DC is that they have an internal inverter, because the best ones use brushless DC motors, which are actually AC motors. That’s why they are called inverter airconditioners

DC operation is not magic, it’s not more efficient, it is however a marketing ploy for people who don’t understand, they think being DC means they can run it off of their battery bank and they don’t need a generator.

Inverter units can be very efficient, the reason they can be so efficient is that they can slow down the compressor speed which gets into a much higher COP or coefficient of performance, it also greatly reduces the output.

Look up inverter home heat pumps and split units, do some reading and then you will understand. So you can spend $10,000 or so and reduce your AC power use by I’d guess 1/3, and you can spend a small fortune on a large battery bank, most likely Lithium, but your still going to have to run a generator to recharge that bank.
Unfortunately at this time running airconditioners on a boat exceeds the power generation available from Solar and or wind.

[mvweebles]

Originally Posted by a64pilot

Your going to have to have a generator. Unfortunately the energy costs of airconditioning exceed any realistic supply from Solar and or wind, that leaves a generator.

Agreed - which is why I think the target market for these small AC units are small/mid powerboats to run underway without running a genny. Many twins carry a pair of 75A alternators that could easily run one of these 40A units.

I do have a technical question: I quickly found two manufacturers of 12vdc AC units in addition to the Mabru posted by Omar. All state there is no start-up surge. Why not? If true, this would certainly be a benefit compared to 120VAC units.

Peter

[a64pilot]

Originally Posted by mvweebles

Agreed - which is why I think the target market for these small AC units are small/mid powerboats to run underway without running a genny. Many twins carry a pair of 75A alternators that could easily run one of these 40A units.

I do have a technical question: I quickly found two manufacturers of 12vdc AC units in addition to the Mabru posted by Omar. All state there is no start-up surge. Why not? If true, this would certainly be a benefit compared to 120VAC units.

Peter

Most probably they are inverter units, those use as I said BLDC motors that are electronically commentated, they can be brought up to speed slowly, so no surge.
Most regular compressors are on / off, and if the compressor stops right at a compression stroke which is most likely, then that surge to go from zero RPM to full operating, plus to go through a compression stroke is rate the large.
But a soft start virtually eliminates start up surge too. A soft start took my 16k from the Honda not even coming close to starting it even ECO off, to easily starting it even with ECO on, amps slowly ramp out to 12 or so, any surge if present is way below running current.
Let’s take my Webasto 6,000 BTU as an example. First it’s actual as installed in a boat sitting in 90F water and the draw from the water pump, restriction if any ducting etc all in existence, draws 4.5 amps.
It’s also on sale at Defender for $1,300 ish. Add in a $300 soft start and the start up surge is gone, but on a small unit like it is, it’s not a big deal anyway.

I bet when you compare it’s output of 6,000 BTU and power draw with one of those $5,000 DC units, it’s very close to the same, especially when you realize their numbers are “lab” numbers and mine are actual installed in a boat numbers. For instance if I fed 70F water to my AC as opposed to 90F water, then it’s performance increases and it’s power draw will decrease, do the lab numbers include the amp or so draw from the water pump?

Plus a Webasto is not a high end unit, it’s a cheap unit.

AC efficiency has been pretty much flat for decades, it can be increased by way over sizing evaporators and condensers, that’s why home units have gotten so large, huge condensers, but you can’t do that on a boat, space restricts it.

That leaves the newer inverter units, which as I said are BLDC motors, which means they are easily variable speed, the slower a compressor runs within reason the more efficient it gets, of course it output also goes down too. Inverter units usually never cycle off, they run pretty much 100% of the time, but slow way down way at night where the cooling demand is much lower, they can get amazingly quiet when running a low speed too.

So an inverter unit can when cooling demand is low, can use as much as 1/3 less power, plus they get nearly silent as all three fans on a hose unit slow way down a swell as the compressor.
They are a break through, but at max cooling, which is what you see most often in boats especially if used sporadically, there isn’t a whole lot of power use reduction.

They become efficient when used in a well insulated house especially if it has a lot of thermal mass, once everything is cooled down to 75f if that’s the set point and after the sun goes down, then they can slow way down as all they are having to do is remove any heat that gets into the house.

A boat use if most often different, first most are very poorly insulated if at all, secondly they are rarely used 24/7 so that the entire interior is at thermostat set point.
So you want to go to bed and air temp is 90F, but if you can drop it to 80f and use a fan inside you can sleep, so you close up the boat and turn the AC on. For hours a lot of the power the AC is using is going to drop every interior surface by 10F.
Run the AC for an hour to cool the interior and then shut it off, means very quickly the interior goes back to 90F, because all interior mass is at 90F

[OmarNM]

Originally Posted by Pete7

In what size boats and can you post some pictures.

In your first posts you mentioned a battery bank of 500Amps, I presume you mean AH? so in the morning after 11 hours of use, how are you going to charge this up along with the other 325AH needed as you say for the rest of the boat?

Pete

It seemed to me that I had read that the query said that they had a wind generator, so very surely, with the sea breeze at night it maintains the load and could have more energy reserve. Those are estimate calculations (theorical) but I hope this info can be helpfull.

I have almost all pictures in my whatsapp, but I am comping some to my PC to share with you.

Regarding the Amps, yes, Is AH the same. sorry about my english is not my first language. I am from Middle East.

Attached I am sharing some pictures of the Amperage on my friend Boat that we were testing. The draw amps starts on 42.

[mvweebles]

Originally Posted by a64pilot

Let’s take my Webasto 6,000 BTU as an example. First it’s actual as installed in a boat sitting in 90F water and the draw from the water pump, restriction if any ducting etc all in existence, draws 4.5 amps.
It’s also on sale at Defender for $1,300 ish. Add in a $300 soft start and the start up surge is gone, but on a small unit like it is, it’s not a big deal anyway.

a64pilot - interesting you should mention this 6k Btu unit. How big of an area do you cool with it? I seem to recall you're in Florida (JAX?). I was thinking of installing in my V-Berth/Head area. My Willard 36 Trawler carries the beam forward more than a sailboat so the V-Berth is wider, but thinking this might be a good choice for me. Wondering how it works for you? Agree the start-up surge on these small units is not difficult

Also, how did you chose Webasto? I was also looking at MarineAire
https://www.marinaire.com/Marine-air...-p/msba6k2.htm

Thanks in advance -

Peter

[Lurker19]

Originally Posted by cat-keys

4. ... firefly carbon foam 4V 450Ah x 3 = 80% dod 1080 max....

I think your math is a little off here. If you have 3 x 4V, you need to wire them in series which would give you an overall bank of 450Ah @ 12V. At 80% dod that would be 360Ah.

[At Peace]

Hi Cat-Keys,
Why stop at 200w solar panels? There are 330w mono’s on the market and while more expensive, they will pay for themselves in time in fuel savings. Also, with the advances in electrical production and storage, high output alternators and lithium batteries are already replacing the need for a generator, here’s one example of many,

https://www.youtube.com/watch?v=6AsQEg-7oks

.
You will have redundancy covered with maximum solar, wind, and dual high output alternators. I would also consider upgrading the battery bank to 24v to increase capacity and reduce weight. Also, get more familiar with lithium. There are definite benefits and over the life span less expensive not to mention the benefit of resale value.
I would recommend getting with Mastervolt, Whisper Power, or the like and have them design a system to suit your situation, everyone else’s is different.