Could someone check my math please?

[Na Mara]

Right let’s take this proposition about gensets really seriously

The smallest genset I could find was a Farymann 4.3kw. The super quiet version retails for about 5400 euros. That makes it almost exactly the same price as the EFOY 210. The EFOYs installation cost is maybe 200euros whilst the gensets is maybe 1000.

The genset weighs 91kg. With the necessary counterbalance, glassed pads, and plumbing the whole thing installed will be about 140kg. The EFOY installed on a new shelf will be about 20kg. Let’s say that I carry on average 10 cartridges for the fuel cell, then the whole thing weighs about 100kgs. Like the genset this weight is mostly low in the boat but it’s going to be more spread out so maybe not as good for the boat’s motion.

In order to maximize the time between genset runs I would add another 300Ah of batteries taking me to 900Ah which should allow 48 hrs of sailing between charging. That’s another 120 kg but this is weight right over the keel on the centerline. In total the genset and batteries come to 260kg. The extra cost of the batteries is about 600 euros so the total cost of the genset is 7000 euros. After that it is just maintenance and fuel.

The EFOY would be part of a system with a duo gen hydro generator so add another 30kg on the transom and a further 4000 euros to the price. That puts the EFOY system at 10000 euros installed with a total weight of 130kg distributed around the boat.

Sailing demos got 7000 hrs and probably something like half a million amphours out of their genset before it died.

The EFOY gives maybe 50000Ah before it dies and maybe more like 100000Ah in conjunction with a hydro generator.

To meet my needs the genset would need to provide maybe 1000Ah a week. It could theoretically do that I 3 hrs but let’s say 8 to allow for charging inefficiencies. It uses about 2l/h so that is 16l a week. Call it 15l a week. We carry 350l diesel. Let us say that 200l is reserved for propulsion. That gives us 10weeks of power that we can carry this way. As we only carry two months of water, this is fine.

Here the fuel cell wins as I can carry maybe 200l of fuel around the boat relatively easily and that is about 40 weeks worth if the hydrogenerator is doing its job.

Conclusions: the proponents for gensets on this forum are mostly correct.

1. A genset will produce something like 5- 10 times the charging amps over its lifetime compared to a fuel cell and thus will last 5 -10 times as long.

2. In my case it would weigh twice as much but the weight is centralized over the keel rather than distributed about the boat.

3 The fuel cost is way less, something like a tenth, and the fuel is easily stored and sourced.

4 autonomy on diesel is worse than on methanol in our case, but not by much.

5 the genset is cheaper to install to my spec than the EFOY.

So everything speaks to doing a genset if it’s a choice between that and a fuel cell, with perhaps the sole exception being noise pollution. But I can mount the super quiet version in my well insulated engine bay and set this up so it only needs to be run for maybe a hour and a half every other day. I could probably live with that.

I stand corrected. I never thought of myself as a genset kind of guy but to be honest my boat was obviously deigned with one in mind ( otherwise why the massive open space in the engine bay). It was not designed with hydrovanes, hydrogenerators, or solar panels in mind.

I will give the genset idea more thought I promise.

Thanks for the thought provoking comments

[barryglewis]

1) Not all lithium batteries are equal. Check out the resilience of Winston brand for example, surely no more dangerous than lead acid?
2 ) We've used a SailGen for around 50k miles. Crossing the Atlantic lost a lot of power due to weed (especially W Atlantic and through to Jamaica,) fouling it, needed clearing sometimes every 15 minutes! It certainly encourages sailing faster, as need 6knots plus to get full benifit. Note, going to windward we tend to sail 4 to 5 knots for comfort, and the very downwind Panama to FP in light winds our average speed was seriously impacted by rolling (beam swells) throwing the wind out of the sails. We would really like a hydrogenerator that produced more than 5 A at 3.5 to 4 knot!
And note, our yacht is a former racing yacht,
3) re fuel cell, We cook on meths, (really ethanol plus a dash of methanol) and getting pure meths is just about impossible in many countries. "Good" quality is likely to be 90% with the additives being .. who knows? If you go the fuel cell route, plan on taking all your requirements with you!
All the best

[Na Mara]

There are EFOY dealerships all around the North Atlantic. If I was doing anything other than a North Atlantic circuit or med sailing sourcing the fuel cartridges would be a serious problem but for the circuit we are planning the cartridges are readily available.

[Na Mara]

On the genset, I should also mention that I would probably go the 2-3kw AC generator charging my batteries through my 230V battery charger. That limits the charging amps to the batteries to about 10% of rated bank capacity during the charge phase and winds down from there as you approach float. If I increase my bank to 900Ah then that is 90A. If I am running every 2 days to top up say 300Ah then it will need to run for about 15 hrs a week to meet my needs which actually means more like 20-25l per week in fuel. All of a sudden I'm down at 8 weeks maybe of diesel autonomy if I leave 180-200l for propulsion. That isn't great. I could probably live with it as I would also carry only two months water and have no plans for a water maker (we will be stopping in marinas every couple of months in any case to provision) but its not great, and certainly a lot less autonomy than a fuel cell. I guess I could add an additional fuel tank as well, but Id really rather not.

That said, it is a thought that the only places in the world where you can readily get hold of the fuel for the EFOY is the North Atlantic and Med. If I went this route I would be committing to this geography somewhat and I'm not sure I like that. Sailing is about freedom after all. What if i get to the caribbean and just decide to keep heading west? At that point the EFOY would become a bit of a liability as I can't carry two years of the fuel and that or more is what I would need to do. Also the unit would wear out and need replacing and how would I get hold of a new one in south east asia?

[carstenb]

Na Mara I really think you are making this overly complicated. Some basic things that are different sailing outside the Baltic.

1- speed - we have sailed close to 30,000nm over the past 4 years. our boat is a performance cruiser, so built for speed. once you load your boat up for long term cruising you will have added something 2 tons of weight (don't shake your head - ask anyone - this is a truth and 2 tons is on the low side.) 2 tons of extra weight means your boat slows down. you say your boat makes 5 knots in force 3 (7-10 knot winds) Maybe going uphill where you generate extra apparent wind, but downhill there is no way this will happen - even flying a genakker. Figure 3 knots of speed going downhill (the most prevalent sailing angle when sailing an Atlantic loop) That means wind generators, hydrogenerators are not making any electricity at all - forget them.

2- swells - atlantic swells are larger than in the baltic and in light winds your boat will rock and roll much, much more than you are used to - your genakker will collapse. You will be sailing poled out.

3- the only fuels you can rely on finding with any regularity on an atlantic loop are diesel and gasoline. forget anything else. Even propane can be a challenge - while blue camping gas is available throughout most of the caribbean - there are places where you will struggle to find it.

4- a big solar arrangement (minimum 700w) and a good sized battery bank (min - 700ah) will probably work for you, especially if you turn off many of the non-essentials (2nd chartplotter, radar etc etc) unless really needed. Supplement the solar a good generator on the engine and you will make out fine. You seem to have a major aversion to using your engine (I don't understand this - but ok). If you really don't want to use the engine, buy a generator and be done with it.

All the rest is not really worth considering, solar and an engine/generator are easy to install, easy to maintain and parts etc are available almost anywhere Hydropods, EFOYs etc are going to a great source of frustration for you.

And everything i have said about spare parts, etc is double as true once you pass through the panama canal - in the pacific you can forget getting parts - you must carry them with you and the tools to be able to fix anything yourself. Between panama and NZ/australia the only place to get parts or service is tahiti (very, very expensive).

Out there you have to be able to do it all yourself.

If you plan to go out there - you will need a watermaker - think about installing one

[Na Mara]

Carstenb.

I grew up sailing the west coast of Scotland and Ireland. Believe me, I know what Atlantic rollers are like.

I totally concede the need for a water maker in the pacific. If I head that way I will get one.

My boat really does not suit a gantry for solar. It would have to sit 2 m off the deck, it would interfere with the existing structures, as we store the boat inside over winter and wish to cruise canals it would need to demountable, and in my opinion such structure look awful on most boats (boats with low slung aft cockpits excepted).

I just can’t do 700w of unshaded solar with out ruining my enjoyment of the boat.

My problems with running the engine for power are twofold.

1. It significantly adds to the wear on them. Not only is this bad economically as it shortens their life and increases maintenance cost (filters should be charged every 100hrs), but it also will decrease the reliability of your get out jail free card.

2 Its uneconomical in fuel. A 2kw AC genset charging my batteries through a charger uses maybe 1.5l an hour. My engine at 1500 revs uses 4l/hr. I only carry 350l of diesel so that 3 times boast in economy is worth the extra kilos and price of a genset for me.

I think I have now decided what I am going to do.

This off season I am going to put a PICO BMS on the boat, increase the bank to 600Ah, put a 90w directable solar panel from victron on over the radome and a Rutland 1200 wind generator on the other quarter ( it’s windy where we are and over much of the terrain we will cover). On the BMS I will log how much charge I get from the present 55A alternator (that is after all nearly 10% of the rated capacity of the bank), how much I get from the wind and solar, how much exactly the auto is using and how much exactly the fridge is using and how much in total we use under sail and at anchor.

I will then see how much of a shortfall I have once I have exhausted all the convenient generation and economizing options.

If it is sufficiently large that I am constantly running the engine for electricity, or if I later add AC, want to go propaneless (though as I carry 6-8 months of the stuff and am very well versed in it’s safe usage, I can’t think why I would) or to add a water maker, then I will add a 2-3kw AC genset.

The decision is made. I have asked the yard to quote for the work. I’ll let you know next season how it’s all working out and whether a genset is in our future.

P.s if the shortfall is persistent but small, I am not ruling out a fuel cell. If I’m only a few crucial high quality amp hours away from not having to run the engine then I still think the cell can make sense. But only if my usage is low enough that the unit will last me years and I can carry a years worth of fuel at a time. If not then it’s a small genset.

[Jim Cate]

My engine at 1500 revs uses 4l/hr.

I see t hat your mind is set, so this is perhaps not germane, but I doubt if your engine burns 4 L/hr at 1500 rpm when only driving a small alternator. I suspect you took that figure from the manual's fuel burn vs rpm tables, and those are calculated at full load.

And do realize that the stock 55 amp alternator will not deliver that current for long before it dials back the output due to heat buildup... or burns up if you have a regulator that can drive it that hard.

dunno if this knowledge would have changed your decision, but it's da facts, ma'm

Jim

[ka4wja]

Na Mara, et al,
I think I again have somethings of interest to share...just hope it comes off respectfully?

~~~~~~~~~
EDIT: I 100% agree with carstenb here!!!

Originally Posted by carstenb

Na Mara I really think you are making this overly complicated.

I was going to post all the below yesterday, but took a breath and decided to sleep on it....'cuz I was concerned that my comments / attempts at explanation, would read as "preaching".
Or, even worse....

So, here it is late Sunday afternoon, and I'm going to read this again....and hopefully some of you (especially Na Mara) find it helpful?

~~~~~~~



I see a great deal of discussion of on-board energy here, and surprisingly much of it regarding fairly rare systems / devices, that has little resemblance to the norms / standards...so, while I focused a bit on what works, works for almost everyone, and how to get-it-done, I didn't write much on the "why's" of what are the accepted norms...

{btw, when it comes to fuel-cells, here in the US, well Florida at least.....edited all this, 'cuz it's off topic...}


So, what constitutes "accepted standards"? Who knows, huh?

Well, I'm going to do my best to explain what has happened in the last few decades, in regards to cruising boats / energy, etc...to show why/how solar (and low-current DC refrigeration, and efficient water-makers, etc.) have become the modern accepted standard for most cruising boats in tropical waters and summertime mid-latitudes...


Please bear with me...and please take no offense if you're still doin-it-old-school....



Human nature shows that there are some folks that do something one way....it works for them, at that time, and maybe continues to work well for them....so, no worries!


As things change (changes in technology / efficiencies / reliability, etc.) if they are happy, there is no reason for them to change....and no worries, no worries for them, nor for anyone else...



But, with boat electrics, refrigeration, electronics, etc....we've had significant changes over the years / decades, and while the costs involved in changing/upgrading all of your systems is usually prohibitive, some times we must....but, most times we just live with what we have and wait... LOL



[Cases-in-point here:

a) Maritime Communications....with the 1992 roll-out / implementation (and final requirement for compliance by Jan 30, 1999) of the GMDSS, we had Digital Selective Calling (DSC) being used as a signaling method for ship-to-ship and ship-to-shore radio comms (VHF, MF, and HF), so there were no longer Voice Radio watchkeeping requirements....these being replaced by DSC Radio watchkeeping....
So, while cruisers with old non-DSC radios could still yack at each other on our VHF and SSB "Cruising Nets", if we wanted to contact a merchant vessel or shore station, etc., for a Safety or Distress situation (or even to inquire about the weather forecast), we would need a DSC radio to do so...

(FYI, except for USCG, NZ Maritime, and Aus Maritime Authority, who all still do maintain a Voice Radio Watch.....the remaining ~ 80 HF coast stations worldwide, and ~ 450 MF coast stations world wide, and the 1000's of SOLAS-grade vessels at sea, worldwide....are all only required to monitor DSC only)

So, we all really needed to upgrade our marine radios....
And, most have done so over the past 20 years....so, that's good!




b) But, looking at another "change"....just because solar panel efficiency has risen, and costs of these newer / higher-efficiency panels having dropped significantly....this has not spurred very many to change / upgrade...

(fyi, as example, my 14 year old solar array still works great, so I haven't yet upgraded it....but if I have a panel failure, I will use that as the impetus to upgrade!)


When we look back even just 5 - 10 (or 15) years ago....and we factor in the lack of educational info / facts back then, regarding:
solar panel shading;
importance of proper panel configuration and wiring;
and the positive effects of MPPT controllers....
And, you can start to see why effective use of solar today is substantially better than even those doing so 10 years ago!




c) And, of course, there is the even older recommendations to store energy in large refrigeration holding plates....rather than in batteries....

Although, here again both approaches work, it's just that improvements in refrigeration reliability (some slight improvements in efficiency) and lower costs and complexities of battery systems, makes easy low-current 12vdc refrigeration much more effective....BUT...

But, the largest factor in our refrigeration changes / improvements are the "parallel" changes/improvements in alternative energy!

You see, back when solar was wickedly expensive (wind generators weren't cheap either, and never did produce much charging below 15kts wind speed) and the few who could afford sizable panels weren't well informed of the extreme issues of shading....and, with some sailing smaller boats (especially in the transom), there simply wasn't as much room for panels...
So, back then, many of the few that had solar didn't get enough energy production from it....so, it became the thing that everyone dreamed of using, but few actually found it effective...

So, back then, everyone needed to run an engine or genset to charge their batteries anyway, so engine-driven-refrigeration was typical (or sometimes a big 12vdc powered frig compressor, drawing 40-50 amps), and this was used to freeze the holding plates once (or twice) each day, storing the energy in those plates to keep food fresh or frozen....all-the-while charging the batteries too...


But, what we've seen in the past 15 years or so....we've had the lowering of costs of solar, reliable MPPT controllers, and a much better understanding among cruisers of how important getting your panels away from any shading....
So, we have a new way of doing things...

It's silent, reliable, and works....and, with lowering costs / improvements in batteries too, we can now better store our energy in the batteries, and let a simple DanFoss refrigeration unit cycle on/off as needed to maintain even frig and freezer temps...(no need to run an engine or genset)

Heck, even the revered old-school Nigel Calder started recommending low-current DC refrigeration (DanFoss units), and making sure you used just one large house bank (rather than the old "2 banks, wired thru an A/B switch)....and that was about 15 years or so, ago....


It takes a while for things to trickle-down, and sometimes quite a while before they become the accepted standard...]


Now-a-days, for most cruisers in tropical waters or summertime mid-latitudes, these are what have become the accepted standards/recommendations....

And, I hope I've given you all some background ($$$) on why/how...



In general, I usually try not get too involved in the discussions of exact costs, and/or cost comparisons, of various systems on-board....rather I mostly try to focus on the facts of a particular system/device (with only some minor reference of costs), and its ability to be effective for the desired application...
And, let the individual sailor make their own decisions...


But, here I'd like to highlight some things...



Recently I made casual mention of the cost of solar panels years ago, but maybe some haven't noticed? Now, I don't want to relive the old days, but in case you didn't see what I wrote....
I remember the days in the early to mid-1980's, when a high-quality 55 watt panel cost over $800, and was about the size of today's 80-100 watt panels....and if you could find a 75 watt, for $1000 to $1100, that was a steal!! heck, the second largest item on a bill-of-materials for a remote low-power TV translator site were the solar panels!

Look at that again...$800 for a 55 watt panel, the size of today's 80 - 100 watt panel....that's what we started with, in regards to solar....


Now, depending on whose data you look at, solar module (panel) costs have fallen by 97% since 1980 or so...

If you look at this chart, from a 2012 study (and also look at the current prices of solar panels, today, in 2020) you can see one very big reason why solar panels have become the number one choice by many looking for reliable alternative energy these days....

AND, you'll also see why just 20 years ago many just couldn't afford it, certainly many couldn't afford enough solar on-board their boats (nor did they have room for enough unshaded solar), to make a significant impact on their energy generation...



Remember, just 10 - 15 years ago, as we were starting to see many sailors adding solar, solar panels had an approx cost of $6 to $7 per watt....and efficiencies were 15% to 16%....


FYI, when I installed my current solar array in late 2006...the cost of Kyocera KC130 panels were about $800 - $850 each....that's over $6/watt, and about 15% to 16% efficiency...



Now today, smaller panels (100w to 150 watt) are still in the $2/watt to $3/watt cost, but you can buy a 335w LG panel for $399....or the more efficient (same-sized) 375w LG panel of $595....

And, there are other decent panels that cost in the $1/watt to $2/watt....

{yes, the big X-22 Sunpower panels are about $4/watt, but they're darn good....the best efficiency, best at longevity and best at low sun angles....but probably not worth the $$ for most}


Of course, there are cheap (unknown quality) panels, such as the $199, 375 watt ET Solar panel....but, I'm not a fan of the "cheap" unknown quality panels....




I think you all see my point....just because something used to be "the way it was done" / used to be "the accepted standard", does not mean it will always be that way....


Sure electrons flow thru wire the same way, but we have MPPT controllers that adjust the load on the panel to always have the maximum power (the "M" and first "P" of MPPT) coming out of the panel, and at the same time convert that voltage from the panels, to provide the maximum power and/or best charging profile to your batteries...now, how is that for putting those tiny electrons to better use, huh? LOL


Of course, there are other pluses too....
Like using high-voltage panels that can many times allow for reasonable priced wiring from panels to controller (still need BIG wire from controllers to batteries)....and with the higher-voltage panels we can sometimes (depends on a lot of variables) get better performance from partially shaded panels....

{btw, my old "standard" of using lower-voltage panels, thereby allowing you (in emergency situations, while monitoring the batteries), to directly connect the panels to the batteries in the event of a controller failure, is gone-by-the-wayside now....I've accepted that well-made controllers are damned reliable...so, no worries there...and no reason to be restricted to lower-voltage panels...}


And, of course many sailors are now well-informed on the importance of keeping your panels from being shaded!!!




So, again....while many will give good reasons to do something one particular way, I'm trying to show why the current "accepted standards / recommendations" are what they are...and how/why they have changed in the past 10 - 15 years....

And, allow you all to make your own decisions...



Hope this helps?

Fair winds..


John


P.S. Na Mara, to reiterate my point from a few days ago....you do seem to have room for 350 - 500 watts of unshaded solar....and, with a decent sized battery bank....if your energy budget is accurate, you could get enough energy from about 400 - 450 watts to be 100% energy independent, except for days and days of cloudy skies...

What you decide to do with this info, is your choice....and you've got a few years to figure it out, so no worries!

Have fun!

[CassidyNZ]

Originally Posted by IanTrail

Wow, we all have hugely different experiences:

We sure do.

Originally Posted by IanTrail

Forget a 50 watt solar panel for charging. It's good for keeping the battery topped and the intruder alarm going when the boat is left for weeks unused but the output is negligible. However, I have met guys with catamarans covered in panels who do get useful output - but you need a lot.

Agreed on the 50W panel, use it to charge your cellphone. But we have about 700W of solar (4 panels) and in the middle of a sunny day we routinely see 40A - 45A coming in tapering up and down on the fringes. With a daily consumption of 200Ahrs, our electrical needs are easily taken care of. You don’t need “a lot”.

Originally Posted by IanTrail

I hate to say, as a sailor, that there is no substitute for burning diesel!

See above. We run the diesel to move the boat and use that time to get other stuff done (make water, heat water). We very rarely run the diesel just to get other stuff done.

Another comment elsewhere in this thread (sorry, can’t wade through full-page posts), it has been mentioned more than once that electrical consumption while sailing is double that while anchored. I wonder what causes this because electronics (autopilot, navigation, AIS, etc.) used while sailing are quite small draws on power. I see only subtle changes to electrical drain between sailing and not sailing. What is being used on your boats while sailing that is not being used at anchor that will double the current draw?

[Na Mara]

It’s the autopilot that is the big power hog underway. Depending on weather and sea state mine can use up to 80Ah a day. Often it’s less than that but I budget on 80 Ah a day to be on the safe side.

[waterman46]

The EFOY cell would be a very attractive option to a generator if you can carry enough methanol onboard and if you re-fill cartridges yourself. Some on-line sources say you can refill one yourself, so let's consider only the cost of the methanol.

The M10 EFOY unit produces, with one cartridge filled with 10l of fuel, 11.1kWH or 925AH, according to the specs. 11.1k/925 is 12.0V exactly. So it seems the unit only outputs exactly 12V. ( I don't know if it can be dialed up to charge batteries, but if you want to charge batteries then you may need a DC-DC convertor.)

The cheapest methanol I could find cost $65 for 5gal or 95l. So it will cost $6.80 to refill the 10l cartridge.

The 925AH produced by one cartridge refill will last about a week at 120AH per day. So the cost for this sounds very good.

If you cannot refill cartridges, then your cost is $80 per cartridge. Not a good value at all for one week of power.

You'll have to carry 10l per week at this rate, so if you can actually carry 200l on board, that should last 4 or 5 months. When that runs out, you'll probably have to have it shipped from somewhere. Find out if methanol in bulk is available where you want to cruise.

[Statistical]

Originally Posted by waterman46

The EFOY cell would be a very attractive option to a generator if you can carry enough methanol onboard and if you re-fill cartridges yourself. Some on-line sources say you can refill one yourself, so let's consider only the cost of the methanol.

The M10 EFOY unit produces, with one cartridge filled with 10l of fuel, 11.1kWH or 925AH, according to the specs. 11.1k/925 is 12.0V exactly. So it seems the unit only outputs exactly 12V. ( I don't know if it can be dialed up to charge batteries, but if you want to charge batteries then you may need a DC-DC convertor.)

The cheapest methanol I could find cost $65 for 5gal or 95l. So it will cost $6.80 to refill the 10l cartridge.

The 925AH produced by one cartridge refill will last about a week at 120AH per day. So the cost for this sounds very good.

If you cannot refill cartridges, then your cost is $80 per cartridge. Not a good value at all for one week of power.

You'll have to carry 10l per week at this rate, so if you can actually carry 200l on board, that should last 4 or 5 months. When that runs out, you'll probably have to have it shipped from somewhere. Find out if methanol in bulk is available where you want to cruise.

One thing to keep in mind is fuel cells have very short lifespans. The unit's output will decline by about 20% every 3,000 hours of operation.

At 120 Ah per day (14 hours) that will be about 9 months of operation before you lose 20% of of output. At 18 months capacity would be 64% (0.8^2) of new. At 3 years it would be 40% (0.8^4) of new. Also the warranty doesn't cover using refilled cartridges. This isn't an EFOY limitation fuel cell poisoning is a limitation of all fuel cells.

They are great as an emergency or standby power source but for continual operation it is going to get expensive. A genset has higher upfront cost and certainly a lot more installation work but is going to last 50x as long and diesel is cheap and universally available.

[Na Mara]

It all depends how many Ah I am short on average after charging whilst moving under engine, and from the solar panel and wind generator.

Let’s say I’m only short by 20-40 Ah a day. A genset to meet that need is a sledge hammer to crack a nut whereas an EFOY will give me two-four years of High quality service even using your numbers.

Moreover, what I’m reading on the mobile home sites indicates that your numbers aren’t accurate. Many have had one of these for the best part of a decade with many thousands of hours on them with not much loss in performace. There were initial problems with fuel purity and a misunderstanding about a lifespan listed on a warranty, but real life experience of them suggest that the former has been solved and the latter was truly a misunderstanding.

Basically, it’s not financially sensible to pay for a genset installation if all I need is my batteries topped off occasionally whereas that is precisely what the EFOY was designed to do. If on the other hand I am short by 100+Ah a day, then the case for a genset is strong.

[Statistical]

Originally Posted by Na Mara

It all depends how many Ah I am short on average after charging whilst moving under engine, and from the solar panel and wind generator.

Let’s say I’m only short by 20-40 Ah a day. A genset to meet that need is a sledge hammer to crack a nut whereas an EFOY will give me two-four years of High quality service even using your numbers.

Moreover, what I’m reading on the mobile home sites indicates that your numbers aren’t accurate. Many have had one of these for the best part of a decade with many thousands of hours on them with not much loss in performace. There were initial problems with fuel purity and a misunderstanding about a lifespan listed on a warranty, but real life experience of them suggest that the former has been solved and the latter was truly a misunderstanding.

Basically, it’s not financially sensible to pay for a genset installation if all I need is my batteries topped off occasionally whereas that is precisely what the EFOY was designed to do. If on the other hand I am short by 100+Ah a day, then the case for a genset is strong.

They are not my numbers they are EFOY's numbers. If they didn't degrade 20% in 3,000 hours they wouldn't be reporting they degrade 20% in 3,000 hours. It is not like that stat is good marketing helping to sell more units.

Also lasting many years and thousands of hours of use isn't in contradiction with degrading 20% in 3,000 hours. If you are actually only short 30 Ah a day then I agree a generator is overkill as that can be met with an an upgraded alternator or a mere 90W of solar.

Anyways when you have reached the point that you are saying I can buy a $6,000 fuel cell every couple years to avoid the "high" cost of a generator it is pretty obvious you have already decided and damn the torpedoes. Best of luck.

[Na Mara]

I’m not dismissing the genset. If I am substantially short on Ah it’s what I will do. But I’m also not dismissing the fuel cell. If I am only a little short on such a regular basis that running the engine for power is annoying and I can’t make up The shortfall some other convenient way, Then I may do an Efoy. It all depends how successful the generation system and economization I am doing this year turns out to be.